Category Soviet Robots in the Solar System

THE N-l LUNAR MISSION SERIES: 1969-1972

Campaign objectives:

Apollo 8 subjected the Soviets to the same anxiety felt by the Americans after the successes of the USSR in earlier years. A re-evaluation of Soviet plans resulted in a new resolution on January 8. 1969. The human circumlunar program would continue despite the clear recognition that relative to Apollo 8 it would appear both late and inferior to the world. Also, the human landing program would proceed even though it was evident that if they were not delayed by serious problems the Americans were likely to be first. Once the lunar programs were accomplished, the Americans would be upstaged in the late 1970s by using the N-l for Korolev’s originally envisioned destination, Mars. The space station program and robotic flights to the Moon, Mars and Venus were to be accelerated and represented in the press as the main thrust of the Soviet program.

The N-l rocket, the Soviet counterpart of the Saturn V, w;as a key element in this strategy since it w ould launch the spacecraft that w ould see cosmonauts land on the Moon. N-l development began in 1962 and the first launch was initially expected in 1965, but there were major delays due to organizational infighting, budgetary issues, and a total redesign of the vehicle in 1964. In particular, engine development was a key technological and organizational factor. As a result, development of the N-l fell behind relative to the Saturn V.

In early 1969 the N-l w as deemed ready for testing, hurried by the advance of the American manned lunar landing program. These launches carried orbital versions

Подпись: First spacecraft: Mission Type: Country і Builder: Launch Vehicle: Launch Date ': 7 7me: Outcome:Подпись:Подпись:Подпись: Spacecraft launched
7K-L1S No.3S

Lunar Orbit and Return Test Flight USSR TsKBEM ^

N-1-3L

February 21, 1969 at 09:18:07 UT (Baikonur) First stage failed in llight.

7K-L1S No. SL

Lunar Orbit and Return Test Flight USSR, TsKBEM "

N-1-5L

July 3, 1969 at 20:18:32 UT (Baikonur) First stage exploded at liftoff.

7K-LOK No.6A

Lunar Orbit and Return Test Flight

USSR TsKBEM

N-1-7L

November 23, 1972 at 06:11:55 UT (Baikonur) First stage exploded in flight.

of the circumlunar Zond spacecraft. All the launch tests failed, in every case due to problems in the first stage. The first test was in February and the second in July, just as the US was preparing to launch Apollo 11. Although the race to Moon was nowr lost, the Soviets, still hoping one day to land cosmonauts on the surface, persisted in their automated testing of the cireumlunar spacecraft with back to back successes by Zond 7 and 8 in August 1969 and October 1970 respectively. Another N-l test failed in June 1971. as did the fourth in November 1972, a month before the final Apollo lunar landing. At this point the N-l was abandoned, ignominiously ending the Soviet manned lunar program.

Spacecraft:

The 7K-LOK lunar orbital Soyuz differed significantly from the circumlunar Zond. It had a wider skirt on the service module, which now had two engines. One was the standard Soyuz engine, which on an operational mission would perform lunar orbital rendezvous. The new engine was larger, and was to boost the LOK out of lunar orbit and back to Earth. An orbital module was included just like the Earth – orbital Soyuz, but it differed in some ways. It had more ports for lunar observation and an attitude control system and docking system on the front for rendezvous and docking with the returning lunar lander. It also had a large hatch. In contrast to Apollo, the cosmonaut was to transfer between the orbital module and the lunar

image128

Figure 11.15 The Soyuz 7K-LOK lunar orbiler (courtesy Energiya Corp).

lander by spacewalking. As the 7K-LOK was the first Soviet spacecraft to have fuel cells for electrical power, it did not need solar panels.

On an operational mission the lunar orbital Soyuz would be carried above the LK lander, which would be on the Block D propulsion system, here serving as the fifth stage of the N-l. This whole stack would be accelerated out of parking orbit towards the Moon by the fourth stage, which would then be discarded. The Block D was to perform midcourse maneuvers, lunar orbit insertion, and preliminary maneuvers in orbit, before flying the lunar lander down to an altitude of about 1,500 meters, where it would be released and the lander would ignite its own engine for the final phase of the descent. This was quite different from the Apollo system.

The payloads for the first two N-l test launches were the Block D. a dummy LK and instead of the 7K-LOK, which was not ready, a 7K-L1S Zond cireumlunar test spacecraft fitted with an attitude control block for operations in lunar orbit. The plan was for these missions to insert the modified Zond into lunar orbit and then return it to Earth. However, as noted, both launches failed. The third N-l was basically just a test of the launcher itself, and it carried only spacecraft mockups. However, for the fourth test it was decided to launch a complete 7K-LOK lunar Soyuz and a dummy LK lunar lander. The plan called for spending 3.7 days in lunar orbit, during which the spacecraft would image future landing sites before returning to Earth.

N-l test launches:

N-l no. l: 7K-L1S No.3S circumlunar vehicle and dummy LK lunar lander.

N-l no.2: 7K-L1S No.5L circumlunar vehicle and dummy LK lunar lander.

N-l no.3: Mockup LOK and LK spacecraft.

N-l no.4: 7K-LOK No.6A lunar Soyuz and dummy LK lunar lander.

7K-L1S launch mass: 6,900 kg

7IC-LOK launch mass: 9,500 kg

Mission description:

The first test of the N-l failed on February 21. 1969. Two of the thirty engines in the new first stage booster shut down just before liftoff, but the rocket was designed to handle this situation by burning the remaining engines for longer. At 5 seconds a gas pressure line broke and at 23 seconds an oxidizer line broke, resulting in a fire in the array of engine noz/lcs that burned through engine control system cables and caused the booster to shut down at the 70 second mark. The automatic escape system drew the Zond clear and the capsule landed safely 35 km from the launch site. The debris from the exploding vehicle fell 50 km away. The blast shattered windows across a wide area, including those in assembly buildings and a local hotel.

The second N-l test failed spectacularly on July 3, 1969, just thirteen days before the launch of Apollo 11. After ignition, the massive rocket rose to a height of about 200 meters and then fell back onto the pad in a huge explosion that totally destroyed the pad and severely damage buildings across a wide area. A US spy satellite caught an image of the aftermath. At the 0.25 second mark the oxidizer pump in one of the first stage engines had been damaged by ingesting a foreign object through its feed lines and it exploded. The resulting fire quickly engulfed the engine compartment of the booster. At the 10 second mark the control system shut dowm most of the engines and the vehicle fell and exploded. The 7K-L1S escape system worked perfectly and the capsule was recovered 2 km away. This disaster banished the hope of using this rocket to compete with the Americans as they prepared for their first manned lunar landing.

N-l launches did not resume until long after the race to the Moon was settled. The third test failed on June 28, 1971. Booster roll control was lost 48 seconds into the flight and the vehicle broke up. The fourth and final test failed on November 23. 1972, when the first stage exploded at 107 seconds into the flight, just a few seconds before it was to have shut down and handed over to the second stage. Ironically, the cause may have been excessive shock to the engine array arising from the sequenced shutdown of the central engines. Any remaining hopes the Soviets had for sending cosmonauts to the Moon were lost in this final failure.

image129

Figure 11.16 Third N-l launch attempt just before clearing the tower.

Results:

Коле.

Space гасе

FIRST ON THE MOON, FIRST ON VENUS, AND FIRST ON MARS

The latter hall’ of the 20th Century will forever be known as the time when the human race broke its Earth-bound chains and began to explore the boundless reaches of interplanetary space. The Soviet Union initiated this enterprise with its Earth orbiting satellite ‘Sputnik’, meaning ‘fellow traveler’, in 1957, and shortly thereafter Soviet scientists made the first attempts to send spacecraft to the Moon and to the planets. What followed were 38 years of triumph and tragedy in one of the most cxcitmg adventures in recent human history.

The first pioneers of space flight lived in the first half of the 20th Century. Tsiolkovsky, Tsander and Kondratyuk in Russia, Obcrth in Germany, Goddard in the US, and later Korolev and Glushko in the Soviet Union, von Braun in the US, and Esnault-Pcltcrie in France, all believed that humankind could travel to other planets in the Solar System using new developments in rocket propulsion. These early visionaries established the notion that it was in fact possible to fly to the planets, but their dreams became reality only after the intervention of World War II created the technological catalyst for accomplishing deep space propulsion. By the end of the 20th Century, humans had set foot on the Moon and had sent robotic spacecraft to most of the planets, as well as to some comets and asteroids.

Most of the history of space exploration in the 20th Century is characterized by intense competition for dominance between the USSR and USA. At the dawn of the ‘space age’ the two nations were developing TCBMs to drop nuclear warheads on each other’s cities. Europe and Japan were preoccupied with rebuilding after the devastation of World War II. The USSR launched the first artificial satellite, Sputnik on October 4, 1957, using a modified version of their first operational ICBM. The first human space flight was also Soviet; Yuri Gagarin’s orbital flight of April 12, 1961. These events shocked Americans, who had difficulty imagining how they could not have been first into space. The Americans also immediately recognized the implications of these events for their national defense. The USA mobilized a massive space development program of its own in 1958, and on May 25, 1961 President

W. T. Huntress and M. Y. Marov, Soviet Robots in the Solar System: Mission Technologies >

and Discoveries, Springer Praxis Books 1, DOl 10.1007/978-1-4419-7898-1 1,

© Springer Science 4-Business Media, LLC 2011 4 Space race

Kennedy formulated a national goal to land a man on the Moon before the decade was оul implicitly meaning that this man should be American, not Russian.

The Soviet Union was slow to respond to the challenge, but in 1964 initiated a national program to send a cosmonaut to the Moon ahead of the Americans. The Americans won the ‘race’ on July 20, 1969. with Apollo 1 Us touchdown on the Sea of Tranquility. The Soviet program stalled after a series of failures of the N-l heavy rocket, their equivalent to the American Saturn V, but the USSR produced dramatic results with robotic lunar rover and sample return missions through 1976. The Americans shut down their Apollo lunar program in 1972 after six successful flights to the lunar surface.

The space race’ was a Cold War phenomenon, but just like the international air races in the first half of the 20th Century, the space race resulted in an explosion of research and technological development. While competition in space exploration between the USSR and the USA originally focused principally on flying humans to the Moon, there w as also competition to fly robotic spacecraft to the Moon and beyond, and this yielded remarkable feats of engineering and enormous scientific progress in understanding our Solar System and technological progress for Earth applications. If it had not been for the political imperatives of the Cold War, it is highly unlikely that the national investments required for this progress would have been made. After the fall of the Soviet Union in 1991, the Russian robotic space exploration program withered aw’ay.

This book provides the technical details of the Soviet Union’s robotic space exploration missions, beginning with the attempted launch of a lunar impaetor on September 23, 1958. and concluding with the final launch in the Russian national scientific space program in the 20th Century, the Mars-96 mission, on November 16. 1996. Each flight campaign is placed into the political and historical context in which the entire endeavor occurred, chronicling the boldness of the program, the daring spirit of its creators, the genius of its implementation, and the successes and in some cases the tragic failures in its execution. The book is in two parts. Part I describes the pieces that must be combined to make up a space program: the key players who make things happen; the institutions that design, build and operate the hardware; the rockets that offer access to space; and the spacecraft that carry out the enterprise. Part II is a chronological account of how the pieces are put together to undertake space flight and mission campaigns. Each chapter covers a particular period, usually several years, when specific mission campaigns were undertaken during launch windows determined by celestial mechanics. Each chapter in Part 11 gives a short overview of the flight missions that occurred during the time period and the political and historical context for the flight mission campaigns, including what the Americans were doing at the time. The bulk of each chapter is devoted to the scientific and engineering details of each flight campaign, and in each case the spacecraft and payloads are described in as much technical detail as is available at the time of writing this book, the progress of the flight is described, and a synopsis of the scientific results is given.

The Soviet robotic space program was dramatic, and was driven by a thirst for technological achievement and a desire for international recognition and respect. It achieved all these things. Soviet robotic spacecraft were first on the Moon, first on Venus, and first on Mars.

Mission description

Of the six Ye-1 spacecraft launched, only two survived the process. A seventh was returned to the barn after its launcher failed to lift off. Aware from press reports that the Americans were to try for the Moon on August 17, Korolev managed with great effort to prepare a vehicle for the same day. There were a number of malfunctions during pre-launch preparations, but he knew that his flight path to the Moon was shorter than the Americans so he waited before risking a launch to see if the Florida launch succeeded. When the US rocket blew up after only 77 seconds of flight, he stood down in order to perform more careful preparations and additional testing. How ever, the launch on September 23 failed when the strap-on boosters of the first stage developed resonant longitudinal vibrations in the second minute of flight. The various stages separated at 93 seconds, fell back and exploded. Reacting to pressure to beat the US to the Moon, Korolev is said to have lost his temper and replied "Do you think only American rockets explode? ‘ Indeed not, and he could not know that the Soviet lunar program w ould be plagued w ith rocket failures for years to come.

The second American attempt at the Moon was scheduled for October 11, amid a flurry of press coverage. Korolev w’as again ready that same day. The wdiole world w as aware of events in Florida, but only a few in the USSR were aw are of Korolev with his linger on the launch button at Baikonur, ready to beat the Americans to the Moon using a faster trajectory. News of the US launch was relayed to Korolev. But the third stage failed, preventing Pioneer 1 from reaching the Moon. Sitting now in the catbird seat, Korolev proceeded with his launch. Later the same day, the second Luna 8K72 launcher blew up 104 seconds into its flight due to the same vibrations wiiich had destroyed the first vehicle.

The two failures in row w’ere demoralizing. It w’as discovered from analyzing the w reckage that the additional mass of the third stage was creating resonant vibration in the basic R-7 booster wThich had not been present before. The problem was solved with minor design changes, but it would take two months and Korolev had to watch over his shoulders as America made a third attempt on November 8. but this too fell short.

The third launch on December 4 failed yet again, this time caused by a different problem. The rocket sailed through the period wdien vibrations broke up the previous two rockets, but after 4 minutes of flight the thrust of the second stage engine began to diminish and then the engine shut dow n due to a gear box failure in the hydrogen peroxide turbine pump. Frustrated, but relieved by the fourth American failure two days later on December 6, Korolev prepared for another

image54

Figure 6.5 Luna, launch

image55

Figure 6.6 Luna 2 mounted on the Block L fourth stage prior to launch.

attempt. The fourth launch was a success and on January 2, 1959, put Ye-1 No.4 on a trajectory to the Moon. The spent third stage released a 1 kg cloud of sodium gas on January 3, some 113,000 km from Earth, producing a glowing orange trail visible over the Indian Ocean with the brightness of a sixth-magnitude star. The experiment provided data on the behavior of ionized gas in near-Earth space, and was used for tracking. Luna 1 (as the probe was later named) missed its target and passed within 5,965 km of the lunar surface on January 4 after 34 hours of flight. The miss was caused by a late second-stage shutdown command from the ground radio guidance. Nevertheless, Luna 1 holds three cosmic ‘firsts’, being the first spacecraft to achieve escape velocity, the first spacecraft to fly close by the Moon, and the first spacecraft to enter an independent heliocentric orbit. Contact was lost on January 5, after 62 hours of flight, possibly when its battery drained.

Luna 1 was a major success and feather in the cap of Soviet space exploration, but it failed to impact the Moon as planned and the program goal was not yet fulfilled. After further problems with the R-7 in the beginning of 1959, another spacecraft was readied that incorporated modifications to the magnetometer, Geiger counters and micrometeoroid detectors resulting from the successful m-flight measurements of both Luna 1 in January 1959 and the American Pioneer 4 lunar flyby in March. The modifications earned it a new Ye-IA designation. The first attempt to launch a fifth spacecraft, Yc-IA No.5, was aborted on June 16, 1959, when it was discovered that the third stage tank had been filled with the standard kerosene instead of the higher density type required for this mission. The tanks were emptied, refilled with the proper fuel, and a second launch attempt made two days later. All went awry when the launch vehicle deviated from the planned trajectory after 153 seconds. One of the gyroscopes in the inertial guidance system had failed, and the launcher was destroyed by ground command.

An aborted launch of a sixth spacecraft occurred on September 9, 1959, when the core sustainer engine failed to reach full thrust upon ignition. ‘Hie launcher remained on its mount, and all the engines were shut down after 20 seconds. The rocket was replaced by a backup. The spacecraft on the aborted rocket was probably the Ye-1A Ко.6 model. Three days later Luna 2 (Ye-IA Ко.7) was successfully launched on a lunar trajectory. On 13 September, at a distance of 156,000 km, the spent third stage released its sodium cloud. Luna 2 impacted the Moon at 23:02:23 UT September 14. after 33.5 hours of flight, near the Autolycus crater in the Marsh of Decay region at about 29. Г N 0.0 E. Some 30 minutes later, the third stage of the Luna launcher also impacted the Moon.

Luna 2 was the first spacecraft to impact another celestial body. The Soviets had announced their transmission frequencies and Jodrcll Bank in hngland tracked the spacecraft through its the final plunge to silence. There had been some claims in the West that Luna 1 was a fraud, but Sir Bernard Lovell’s tracking and radio recordings provided all the proof needed that Luna 2 had hit the Moon. Nikita Khrushchev celebrated the achievement by presenting President Eisenhower with duplicates of the Soviet emblems that had been carried to the Moon at a United Nations meeting in Kew York on September 15, 1959.

Results:

Luna 1 was the first spacecraft to reach the vicinity of the Moon. The measurements obtained provided new data on the Earth’s radiation belt, and discovered the solar wind – a thin, energetic ioni/cd plasma flowing outward from the Sun past the Earth and Moon. It established that the micrometeoroid flux between Earth and Moon was small, and placed an upper limit on the strength of any magnetic field that the Moon may possess at no more than 1/10.000th that of Earth.

Luna 2 was the first spacecraft to impact on the Moon. It verified at much closer distance that the Moon had no appreciable magnetic field, and found no evidence of radiation belts around the Moon.

Closeouts on a Venus spacecraft, a Moon rocket, and desperation at Mars

TIMELINE: MAR 1972-DEC 1973

The year 1972 opened with the last launch of a 3MV spacecraft, Venera 8, marking the final use of the Molniya launcher for a Soviet lunar or planetary mission. Using Venera 7’s measurement of the temperature at ihe surface, and an inferred pressure, the over-engineered descent capsule was simplified to enable Venera 8 to carry more instruments. It was dispatched on March 27 and the lander operated successfully on the surface of Venus. Two other significant closeouts were in 1972, the launch of the fourth N-l rocket in November whose failure led to that project being canceled, and the final Apollo landing in December.

The second and final robotic lunar rover, Lunokhod 2, was delivered to the Moon by the Luna 21 mission in January 1973. Apart from this, the year 1973 witnessed perhaps the most frustrating campaign in the history of robotic planetary flight. The Soviets were acutely aware of US plans to launch sophisticated orbiter/landers to Mars in 1975. Encouraged by the near-success of the Mars 3 lander, they devised an audacious campaign for 1973. This opportunity was less favorable than that of 1971, which precluded sending orbiter/landers, so instead they launched four spacecraft in July and August: Mars 4 and 5 were orbiters, and Mars 6 and 7 carried landers to be released during flybys. During the development of these spacecraft, the Soviets had incorporated a new transistor into many spacecraft systems. These were discovered before launch to be faulty, with limited lifetimes due to technological “innovations’’ in their manufacture. They could not be trusted to last for the duration of the flight to Mars, yet they could not be replaced in time to achieve the launch window. It was a terrible dilemma. Rather than stand down and wait for the next Mars opportunity in 1975, when the US missions would be launched, the Soviets decided to proceed and hope that at least one of the landers would succeed. But the transistor lifetime tests proved to be accurate, and there were failures in all four spacecraft which ultimately resulted in disaster for this campaign.

W. T. Huntress and M. Y. Marov, Soviet Robots in the Solar System: Mission Technologies and Discoveries, Springer Praxis Hooks 1, DOl 10.1007/978-1-4419-7898-1 13,

© Springer Science+Business Media, LLC 2011

Подпись: 1972 2 Mar Pioneer 10 Jupiter flyby 27 Mar Venera 8 entry probe 31 Mar Venera entry probe 16 Apr Apollo 16 lunar landing 23 Nov N-I Moon Rocket test 7 Dec Apollo 17 lunar landing 1973 8 Jan Luna 21 rover 5 Apr Pioneer 11 Jupiter/Saturn 21 Jul Mars 4 orbiter 25 Jul Mars 5 orbiter 5 Aug Mars 6 flyby/lander 9 Aug Mars 7 flyby/lander 3 Nov Mariner 10 Venus/Mercury
Closeouts on a Venus spacecraft, a Moon rocket, and desperation at Mars
Подпись: Success, Lunokhod 2 Successful Jupiter and Saturn flybys Failed to achieve orbit, flew past Mars Completed 22 orbits, early failure Successful descent, lost at landing Entry system failed, flew past Mars Successful flybys at Venus & Mercury

Launch date

Crippled by ailing systems. Mars 4 was unable to enter Mars orbit and sailed past the planet. Mars 5 achieved orbit, but fell silent after only 22 orbits. After an early failure in its telemetry system, the Mars 6 flyby spacecraft had to be commanded in the blind. It miraculously made automated midcourse maneuvers, optical navigation on approaching Mars, and dispatched its entry system on the correct trajectory. The entry system entered the atmosphere, descended by parachute, and sent back mostly garbled data on its compromised communications system. Contact was lost when the lander was released near the surface. The Mars 7 flyby spacecraft released its entry system as planned, but this failed to function and missed the planet. The lack of any real results from this massive campaign was not explained until after the collapse of the USSR.

Meanwhile the US launched Pioneer 10 on March 2, 1972, for the first mission to the outer Solar System. It went on to make a flyby of Jupiter, the largest of planets. In November 1973 Mariner 10 was launched lo use a flyby of Venus for a gravily – assist to reach Mercury. *And Pioneer 11, launched in April 1973, went on to use this same technique at Jupiter lo reach Saturn.

COMMUNICATION AND TRACKING FACILITIES

Lunar and interplanetary missions required facilities for tracking spacecraft on their journeys through deep space and to communicate with them for navigation, control and data acquisition. Korolev chose Ycvpatoria in 1957 as the site for these facilities because it offered a southerly latitude near the plane of planetary orbits. It was also conveniently close to the Black Sea and Crimean resorts.

Known as the Center for Long Range Space Communications (TsDUC), its first facility was a 22 meter antenna built in 1958 for lunar missions. The first phase of construction for planetary missions was ready in 1960. Korolev built his receiving stations by scavenging old naval parts – using the hull of a scrapped submarine, a revolving turret from an old battleship, and a railway bridge on top of the turret to hold the antenna array. Each array consisted of eight antennas in two rows of four all of which moved in unison. There were two sites, one to the north for the receivers and the other to the south for the transmitters. The receiving station had two such antenna arrays, each using eight 15.8 meter dishes. They operated in the meter band at 183.6 MHz, in the decimeter band at 922.763 and 928.429 MHz (32 cm), and in the centimeter band at 3.7 GHz (8 cm) and 5.8 GHz (5 cm). The transmitter station had one array of eight 8 meter dishes. This ‘Plutori transmitter was rated at 120 kW and operated at 768.6 MHz (39 cm). A ground-link microwave station was set up for transmitting data to a second station at Simferopol and then on to other locations in the USSR. The TsDUC facilities went online September 27, 1960, only a day before

image22

Figure 3.4 Receiving station at north facility (left) and transmitting station at south facility (right), Yevpatoria.

image23

Figure 3.5 Cosmonaut Yuri Gagarin, king of the Soviet tracking ship fleet.

the optimal launch date for Mars, although the first Mars launch did not occur until October 10. Between 1963 and 1968 Yevpaioria and Simferopol each received a 32 meter “Saturn’ dish, and five others were installed at Baikonur in Kazakhstan, Sary Shagan in Balkash, Shclkovo near Moscow, and Ycniscicsk in Siberia. In 1979 a 70 meter ‘Kvanf dish was built at Yevpatoria. TsDUC now also has a 64 meter antenna at Bear Lake near Moscow, and a 70 meter dish in Ussurusk near Vladivostok. All deep space missions were operated from Yevpatoria until a new control facility was opened in Moscow in 1974.

The USSR did not have a worldwide network of tracking stations like NASA’s Deep Space Network, with serious consequences for deep space mission operations. Critical operations such as planetary encounters had to be planned for times when the spacecraft could communicate. And since signals could not be picked up when a spacecraft was below the horizon, spacecraft were designed to transmit only when Yevpatoria had a line of sight. This system required carefully controlled timing of spacecraft operations and reorientation of the spacecraft for high-gain operations. To provide a measure of relief from the limitations on spacecraft operations imposed by a single ground station, the Soviets deployed tracking ships in the world’s oceans. These ships also tracked missile tests, covered manned space missions, and tracked interplanetary missions making the second firing of their upper stage to escape Earth orbit into interplanetary space. The ships were not a wholly satisfactory solution for deep space tracking, as only small dishes could be mounted on the ships and weather conditions could severely hamper operations. The first ships deployed in 1960 were the Illchevsk, Krasnodar and Dolinsk. In 1965/6 the Illchevsk and Krasnodar were replaced by the Ristna and Bezhitsa. A third generation consisting of the Borovichi* Kegostrov, Morzhovets and Neve! were deployed in 1967. These were all converted merchant ships of about 6Л00 tons displacement with crews of 36. In May 1967 the first purpose-built traeking ship was introduced, the Cosmonaut Vladimir Komarov (17.000 tons). The Cosmonaut Yuri Gagarin (45,000 tons) and Academician Sergey Korolev (21,250 tons) joined the fleet in 1970. In addition, a number of smaller traeking vessels were deployed: the Cosmonaut Pavel Belyayev, Cosmonaut G corgi Dobrovolskiy Cosmonaut Viktor Patsayev and Cosmonaut Vladislav Voikow

THE SECOND VENUS SPACECRAFT: 1964

Campaign objectives:

By the end of 1962, the Soviets had made five attempts at Venus. Only one mission. Venera 1, survived its launch vehicle and succeeded in reaching interplanetary space but the spacecraft failed early in transit. All six spacecraft in the second-generation 2MV Mars/Venus series, including the three Venus missions, fell victim to launch failures. Adding to the frustrations, the Americans had a successful flyby of Venus in 1962 with their Mariner 2. Undaunted, the Soviets improved the 2M V as the 3M V for the 1964 opportunities to Venus and Mars.

The initial flight tests of the new spacecraft were lost to launch vehicle failures, the first in November 1963 on a test to Mars distance and the second in February 1964 on a test to Venus distance. Despite of these losses, the Soviets proceeded with their 1964 program for Venus and Mars.

Spacecraft launched

First spacecraft:

3MV-1A No.4A

Mission Type:

Venus Spacecraft Test

Country; Builder:

USSR OKB-1

fjnmch Vehicle:

Molniya-M

Launch Date ‘: I ime:

February 19, 1964 at 05:47:40 UT (Baikonur)

Outcome:

Launch failure, third stage exploded.

Second spacecraft:

3MV-1 No.5 (Cosmos 27)

Mission Type:

Venus Atmosphere .’Surface Probe

Countryi Builder:

USSR OKB-1

Launch Vehicle:

Molniya-M

Launch Date! Time:

March 27, 1964 at 03:24:42 UT (Baikonur)

Outcome:

Failed to leave Harth orbit, fourth stage failure.

Third spacecraft:

Zond 1 (3MV-1 No.4)

Mission Type:

Venus Atmosphere; Surface Probe

Country і Builder:

USSR OKB-1

launch Vehicle:

Molniya-M

Launch Date: Time:

April 2, 1964 at 02:42:40 UT (Baikonur)

Mission End:

May 25, 1964

Encounter Date/Time:

July 19, 1964

Outcome:

Failed in transit, pressurization lost.

Launches to Venus were attempted on March 27 and April 2, straddling the ideal date. The first spacecraft was stranded in parking orbit but the second was deployed on a trajectory for Venus. Just as the launch vehicle was plagued by a troublesome fourth stage, the spacecraft had troublesome avionics systems. Immediately named Zond 1 when it became evident 3MV-1 No.4 would not be able to fulfill its mission at Venus, the spacecraft fell silent after less than 2 months in flight. Even if it had succeeded in deploying its entry probe, the decent capsule would not have survived to the surface, it was designed to survive only to 1TC and withstand pressures up to 5 bar. At the time there were two opposing theories for conditions on the surface of Venus. The high brightness temperatures measured by terrestrial radio telescopes, and confirmed by Mariner 2 during its flyby in 1962, could be interpreted either as a surface as hot as 400°C or as a hot ionosphere and cool surface. The easier design path was for the popular vision of a planet like Earth with a cool surface and maybe even an ocean. When the 1964 Venus launch window opened and Zond 1 set off, the controversy was not yet settled, although the weight of evidence was leaning to a hot surface. Radio observations of the planet from Earth later in 1964 would discredit the cool surface theory, but by then it was too late to redesign the Venus probes for the 1965 launches. The hot surface theory was firmly established after the flight of Venera 4 in 1967, which coincided with the highly successful Manner 5 llyby.

Spacecraft:

Currier spacecraft:

The 3MV Venus spacecraft were almost identical to their 3MV Mars counterparts, although the solar panels were less densely populated with solar cells. On the probe versions of the 2MV and 3MV, the entry vehicle was to be deployed just prior to the spacecraft entering the atmosphere and burning up. Instruments for interplanetary science and measurements in the near vicinity of the planet prior to destruction were carried on the main spacecraft. Communications from the probe would be direct to the Earth.

image82

Figure 9,8 The 3MV-1 Venus probe spacecraft (courtesy Energiya Corp).

Launch mass: 800 kg (3MV-1A No.4A)

Launch mass: 948 kg (Cosmos 27 and Zond 1)

Entry system mass: 290 kg

Entry vehicle:

The 3MV entry probes were intended to obtain data during the descent through the atmosphere, survive impact, and return data from the surface. In the case of Venus the dense atmosphere that meant the probes would impact slowly enough to have a fair chance of surviving and operating for a short period of time on the surface. The 3MV probes were similar to the 2MV ones, being 90 cm in diameter and containing parachutes, batteries, sequencers, and two redundant 32 cm transmit­ters each with an antenna for direct communications to Earth, in addition to science instruments.

image83

Figure 9.9 Zond 1.

Payload:

The payload for the test flight to Venus distance was probably similar to that of the lost test flight to Mars distance. The payloads for the missions to Venus launched on March 27 and April 2. 1964. were identical.

Zond l carrier spacecraft:

1. Radiation detector

2. Charged particle detector

3. Gas discharge and scintillation cosmic ray and gamma-ray detectors

4. Ion traps

5. Magnetometer

6. Micrometeoroid detector

7. Lyman-alpha atomic hydrogen detector

Zond 1 descent I landing capsule:

1. Temperature, pressure and density sensors

2. Atmospheric composition, acidity and electrical conductivity experiments

3. Gamma-ray surface composition detector and cosmic ray detector

4. Visible air glow photometer

5. Mercury level experiment

The atmospheric structure experiment consisted of two platinum wire resistance thermometers with ranges of -60 C to 460 C and 0 to 330 C, an aneroid barometer with a range of 0.13 to 6.9 bar. and a beta ray ionization chamber densitometer that was integrated with the thermometers and had a range of 0.0005 to 0.015 g/cc with a 5% error. The atmospheric composition, acidity and electrical experiments consisted of a set of gas analyzer cartridges wnth chemical and electrical tests for various gases including carbon dioxide, nitrogen, oxygen, and water vapor. The photometer was to search for airglow during the night landing. It was sensitive over the range 0.001 to 10,000 lux, and included the mercury level experiment to measure wave motion in a putative ocean. The anti-coincidence gas discharge and scintillation counter cosmic ray and gamma-ray detector was primarily to measure the surface composition of radioactive elements potassium, thorium and uranium from gamma-ray emissions on the surface, but it was also to be used during the interplanetary cruise to measure primary cosmic rays.

A micro-organism detector w as planned for the 3MV Venus and Mars landing capsules, but was never included in the payloads.

Mission description:

The first lest launch of this series failed when the third stage exploded. LOX leaking through a valve froze a fuel line which later broke. The loss of 3MV-1A No.4A so close to the imminent Venus launch window must have been disheartening, but the Soviets continued with preparations to launch the other two spacecraft.

The first attempt to launch the 3MV-1 No.5 spacecraft on March 1 was postponed owing to problems with the launcher during pre-launch tests. The second attempt on March 27 using the same vehicle failed when an electrical fault caused the fourth stage to lose attitude control and the engine did not restart for the escape burn. It was designated Cosmos 27 by the Soviets. This loss did have a very valuable result. For the first time a flight recorder had been added to the fourth stage telemetry system, and on its second pass the downlinked telemetry indicated a failure that was able to be traced to a generic problem in the I-100 control system circuitry. It required only 20 minutes of re-soldering to fix this for subsequent flights.

The third Venus spacecraft was dispatched successfully on April 2, 1964, but its initial trajectory was inaccurate and a midcourse maneuver was made the next day at a range of 564,000 km from Earth. It was the first midcourse maneuver carried out by a Soviet planetary spacecraft. Venera 1 and Mars 1 had both had this capability, but neither had been able to exercise it. However, Zond 1 w as in serious trouble. Л leak in the pressurized avionics section was detected right after launch due to a erack in the weld seam of the quartz dome for the Sun and star navigational sensors. The location of the leak w as determined from analysis of how’ the escaping gas perturbed the spacecraft. After a week, the transmitters and other electronics failed when they were switched on as the pressure fell to about 5 millibars, which permitted coronal discharges to short out power lines. The ion engines also failed their test, operating erratically. Owing to sensible backup design, communications w^ere able to continue using the entry system, and a second midcourse maneuver w7as made on May 14 at a distance of more than 13 million km from Earth. This resulted in a trajectory that would fly by the target at 100,000 km. In fact, the initial trajectory w’as probably so wide of the mark that even if the spacecraft had been fully functional, it would not have been able to adopt a collision course. Due to the pressure leak the Soviets did not reveal Venus as the target, merely announcing that the mission w7as a deep space engineering test, and named it Zond 1 rather than Venera 2. The leak was fatal, and on May 25 thermal control w? as lost and communications failed. The inert spacecraft passed Venus on July 19.

Results:

Zond 1 did return data on interplanetary plasma, including cosmic ray and Lyman – alpha measurements from the avionics module and proton measurements from the cosmic ray instrument in the lander capsule, but much of the data returned appears to have been lost.

THE VENUS-IIALLEY CAMPAIGN: 1984

Campaign objectives:

For the Soviets this campaign combined a Venus flyby/entry mission with a flyby of Comet Halley, and it was their first (and thus far only) multiple-target mission. After releasing their entry systems at Venus in June 1985 the two flyby spacecraft were to be re-targeted by the gravity-assist of their encounter with the planet onto a course to intercept Comet Halley in March 1986.

In addition to a lander, the entry system carried an atmospheric balloon. The idea to float a balloon in the atmosphere of Venus grcwr from French-Soviet cooperation initiated after the successful Venera 4 mission in 1967. France and the Soviet Union had come to a rapprochement of sorts in the Cold War, opening a breach in the Iron Curtain by establishing cooperation in space science. In 1974 Dr. Jacques Blamont of CNES and Boris PeLrov, Chairman of the Intercosmos Council, began to discuss a joint mission consisting of an entry probe to deliver a large French balloon into the atmosphere of Venus, and a Soviet orbiter to provide the communications relay. By 1977 a date had been tentatively set for a 1984 launch of the ‘Venera-84’ mission to mark the bicentennial of the Montgolfier brothers’ invention of the hot-air balloon, and the division of work had been established. Jacques Blamont and Mikhail Marov were named as science co-chairs for the mission. The French would supply the two 10 meter diameter balloons with their 50 kg gondolas, including transponders for very long baseline interferometry (VLB!) tracking, and the Soviets would supply the spacecraft, entry systems, and the remaining mission support. But events changed these plans.

In the late 1970s the world’s space science community was beginning to plan for the eagerly awaited apparition of Comet Halley in 1986. The IJS offered to carry a French ultraviolet instrument on one of its spacecraft. When the US withdrew from this effort in 1979 the Soviets offered to fly the French instrument on Venera-84 to enable it to observe the comet from Venus orbit – which would be a more favorable vantage point because although the comet would approach that planet no closer than 40 million km. that was much closer than it would approach Harth. In the process of investigating how to improve observations of Halley from Venus the Soviets found that it would be possible to utilize a gravity-assist during a flyby of Venus to set up an encounter with Halley. The science value of a mission to both Venus and Halley as argued by Jacques Blamont intrigued Roald Sagdeev, Director of 1K1, who set out to have it supersede the Venera-84 mission. The new project w as called ‘Vega’ as a Russian contraction of’Venera’ and ’Galley’, with the name of the comet using a G’ because there is no H’ in the Cyrillic alphabet. Valery Barsukov. Director of the Vernadsky Institute, w as far more interested in Venus than he w as in the comet, but Sagdeev sold the mission to him by including a lander, albeit at the cost of reducing the size of the balloon package to enable both to fit inside the standard entry system. Three years of intensive development of the Venera-84 mission, including partially manufactured hardware, was lost. When the furious French declined to participate further, the small balloon became a Russian project. Nevertheless, Sagdeev managed to coax the French into providing several instruments for the lander and balloon, as well as two key remote sensing instruments for the Halley encounter. And by taking advantage of their bridging position between the East and the West, the French were able to gain the participation of the Deep Space Netw ork in the VLB1 network that would measure the dynamics of the balloons as they drifted in the atmosphere of Venus. For the first time, therefore, the arch rival Americans became a participant in a Soviet planetary mission, albeit by providing tracking resources. The University of Chicago supplied an instrument to investigate dust particles during the Halley flyby, but this was arranged through the science community as a private venture rather than at government level and the principal investigator had to assure the US military that he was using only commercial parts from his local Radio Shack store! He dismissed the military’s concerns with. "Let them [the Soviets] copy this, it will set them back years.’

Sagdeev, by enthusiasm, energy, and personal effort, instituted the new project as a broadly international venture by off ering 120 kg on the spacecraft for instruments originating from countries outside the USSR. This extensive internationalization was unprecedented for the historically closed Soviet space program. And internally the perestroika initiative enabled him to overcome resistance by the Soviet bureaucracy.

But the final credit must go to Chief Designer Vyacheslav Kovtunenko and the NPO-Lavochkin scientists and engineers wTo, by building the most comprehensive and successful deep space mission in their history, created a legacy for Soviet lunar and planetary exploration.

Подпись: First spacecraft: Mission Type: Country! Builder: Launch Vehicle: Launch Date ': 7 ime: Venus Encounter: I la lley Encounter: Outcome: Подпись:

Подпись: Spacecraft launched

Vega 1 (5VK No. 901)

Venus Flyby/Lander/Balloon and Halley Flyby USSR, NPO-Lavochkin ’ ‘ ‘

Proton-K

December 15, 1984 at 09:16:24 UT (Baikonur) June 11, 1985 March 6, 1986 Successful.

Vega 2 (5VK No.902)

Venus Flyby/Lander/Balloon and Halley Flyby USSR, NPO-Lavochkin ’ ’ ‘

Proton-K

December 21, 1984 at 09:13:52 UT (Baikonur) June 15, 1985 March 9, 1986 Successful.

The Vega missions became an integral part of the International Halley Mission (IHM) organized initially by the European Space Agency to coordinate operations and data analysis for the various Halley missions being planned by Europe, Japan, the IJS and the Soviet Union. An Interagency Consultative Group consisting of high level representatives of the space agencies overseeing the IIIM provided cover for US participation in the midst of the Cold War, effectively ci re um venting the absence of a formal agreement between the US and USSR. Ironically spacecraft were sent to Halley by all these nations except the US, whose formal involvement was ultimately limited to providing tracking and science support.

With lander, balloon, and flyby components the Vega missions were both very ambitious, and by involving a host of international interfaces including a large array of international instruments were extraordinarily complex. The nations participating included Austria, Bulgaria, Czechoslovakia, East Germany, France, Hungary. West Germany, Poland, and the United States. The Hungarians built part of the navigation system and the Czechs supplied the optical system for the automated scan platform. Foreign investigators were allowed into the country to participate fully and actively in the project from beginning to end; not passively as previously by delivering their completed instruments in advance and waiting at home to find out what happened to them. Team meetings were held in the USSR and foreign contributors were allowed into Soviet facilities for development, testing and integration activities. This style of cooperation w ith the USSR w7as unprecedented. An organization called Intercosmos had existed since the 1960s for coordination of cooperation in space research mainly among Eastern Bloc nations and with France, but this was the first time the activity assumed such a large scale and included Western nations to such a degree.

The 1984 launches gave the Soviets enormous influence in the international space
community. With such a bold move to internationalization, leadership in planetary exploration passed to the USSR. After the busy era of Mariner, Pioneer. Viking and Voyager launches in the 1970s, the US launch rate had fallen precipitously to zero in the 1980s. The USSR continued to reap a harvest from its Venera series, and began its transition from a closed program to an open program far more international than any flight project in the US. The Soviets now issued open calls for participation in its science missions. US science missions would not become more international than ”participation by invitation onlv*

The Vega missions were highly successful in meeting all their science objectives, and a major achievement for the Soviet robotic lunar and planetary program. They concluded the run of ten consecutive highly successful heavy-class Venera missions that started with Venera 9 in 1975. and they were the final Soviet missions to Venus after twenty-nine launch attempts since 1961. During this 24 year period only three of sixteen windows for Venus were not used. Nineteen of the twenty-nine launches sent spacecraft on trajectories to Venus, of w hich fifteen successfully delivered three entry probes, ten landers, tw’o balloons, and four or biters. The Soviet scientists and engineers participating in the Vega missions would have dismissed as ridiculous the prospect of there being only two more campaigns in the Soviet planetary exploration program, both of w’hich would be embarrassing failures.

Spacecraft:

Flyby spacecraft:

The flyby spacecraft was nearly identical to Venera 9 to 14 but used the larger solar panels of Venera 15 and 16 to handle the pow er demand and w^as loaded w ith 590 kg of propellant instead of the usual 245 kg. It w’as protected from hypervelocity comet dust impacts by an aluminum shield consisting of an outer multi-layer sheet of 100 micrometers thickness mounted at a standoff distance of 20 to 30 cm.

A data rate of 65 к bits/s was provided for the comet encounter, but a slower mode would be used in the cruise phase. Approximately half of the spacecraft w as devoted to the Halley science instruments and half to the Venus entry system. In making the flyby of Venus in the manner required to set up the Halley encounter, the spacecraft would relay to Earth the transmission from the lander during its descent and surface operations as previously. However, the balloon would transmit its telemetry directly to Earth.

The spacecraft was fitted with an 82 kg articulated scan platform that could rotate from -147 to +126 degrees in azimuth and from -60 to +20 degrees in declination for a pointing accuracy of 5 minutes of arc and a stability of 1 minute of arc per second. Its automated tracking would enable instruments to be continuously pointed at the nucleus of the comet during the rapid flyby while the spacecraft held an orientation that permitted its high gain antenna to point at Earth for real-time transmission. The pointing was controlled either by an eight-element photometer or by using the wide angle camera, and gyroscopic attitude control was provided as a

image214

Figure 18.1 Vega spacecraft (courtesy NPO-Lavochkin). Scan platform folded on left, parabolic antenna on the right, toroidal instrument compartment on the bottom with external instruments.

image215

Figure 18.2 Museum model Vega spacecraft without insulation and dust shields. Front side at right shows solar panels, parabolic antenna, and navigation instruments. Back side at left show’s camera platform hanging down below toroidal instrument section, radiator panels and black disks where helical lander relay antennas were mounted.

precaution against comet dust upsetting the optical sensors. The scan platform carried the narrow and wide angle cameras, an infrared sounder, and a three – channel spectrometer. All other experiments were body-mounted except for two magnetometer sensors and various plasma probes and plasma wave analyzers which were mounted on a 5 meter boom. The total science payload for Halley weighed 130 kg.

image216

Figure 18.3 Vega 1 folded and ready to launch. Note scan platform, insulation and metal shielding.

Entry system:

The entry system was virtually identical to the recent Venera missions, consisting of an insulated sphere 2.4 meters in diameter whose upper and a lower hemispheres were joined non-hermetically. In this case, however, the lander was installed in the lower half and the balloon in the upper half.

image217

Figure 18.4 Entry capsule cross-section (by James Garry): 1. Antenna; 2. Balloon compartment; 3. Helium inflation tank; 4. Lander aerodynamic stabilizer; 5. Gas chromatograph; 6. Spectrophotometer; 7. Entry heat shield; 8. Thermal insulation; 9. Oscillation damper; 10. Battery; 11. Stabilizing vanes; 12. Crushable impact torus; 13. Drill and sample collector; 14. Coolant delivery piping: 15. Balloon aerobrake; 16. Science instrument bay; 17 Parachute.

Lander:

The Vega landers were almost identical to the Venera 13 and 14 landers with some aerodynamic modifications for increased stability while free falling. These included spoke-like blades interior to the landing ring to reduce spinning and a thin collar-like sleeve installed beneath the disk of the aerobrake to minimize the turbulence which would be induced by the externally mounted instruments.

Figure 18.5 (left) show’s the sleeve and the blades. Tn view on the landing ring are the two white hygrometer compartments, the temperature and pressure unit offset to its right, and also the drill. Figure 18.5 (right) shows the large shiny cylindrical gas chromatograph on the ring to the left, the horizontal drill vacuum reservoir, and the penetrometer and the hydrometers on the far right. The impact velocity of 8 m/s was to be cushioned by the shock absorbers that support the main spherical pressurized compartment.

image218

Figure 18.5 Venera 13 and Venera 14 landers during tests at Lavochkin

 

Strap to balloon

 

Semi-Directional / Antenna

 

Straps

 

Radio Transmitter and Electronics

 

Temperature

Sensors

 

Photometer

Pressure Sensor

Lithium Batten"

„ Nephelometer Windows

 

r-3

——— lb

кґ 4 ,—^

 

Anemometer

 

image219image220

Figure 18.6 Gondola diagram (from Don Mitchell) and testing on a short tether.

Balloon:

The balloons were a new component, and were to be carried in and deployed by the upper hemisphere of the entry system. The super-pressure helium aerostat with its attached gondola w as designed to float in the middle layer of cloud at an altitude of 54 km, where the temperature was a mild 32’C and the pressure was 5.35 millibars.

Each radio-transparent balloon had a mass of 11.7 kg and when inflated it wfas 3.4 meters in diameter and held 19.4 cubic meters of helium that had a mass of 2 kg. A 13 meter long tether suspended the 7.0 kg gondola (including 1.6 kg for the tether). The entire system weighed a little over 20.7 kg. The rate of helium diffusion w’as sufficiently low to sustain pressure for about 5 days.

The 1.2 meter long 14 cm wide gondola contained a transmitter with a stabilized oscillator for Doppler tracking, a conical antenna, a vertical anemometer, sensors for ambient temperature and pressure, a light photometer, a nephelometer. a eontrol and ballast system, and sixteen lithium batteries for 300 wratt-hours of power. The 1 kg battery package w as designed for 46 to 52 hours of life. To simplify the task for the network of radio telescopes wdiich would track the balloons, the 4.5 W transmitter operated in the 18 cm astronomical band at 1.6679 GHz. It transmitted direct to Earth via the conical antenna at either 1 or 4 к bits, s. Except for the lightning counter which was sampled every 10 minutes and the photometer twice every 30 minutes, all the other instruments were sampled once every 75 seconds. The data w as stored on a 1,024 bit memory. A 5.5 minute burst of data was sent to Earth every 30 minutes, alternating between two transmission inodes in a predetermined sequence. In the first mode, 852 bits of data collected from the instruments were transmitted in a 270 second burst preceded and followed by 30 seconds of carrier for VLB1 velocity measurements. In the alternative 330 second mode, only two tones were transmitted for VLBI position and velocity.

The balloon system had to be folded up during cruise and entry, survive the forces of deployment, and then withstand the corrosive atmosphere of sulfuric acid aerosol. The envelopes were made using a woven teflon and cloth matrix, the gondola was covered with a white paint resistant to sulfuric acid, and the tethers were made of a type of nylon. Timing, as determined by pressure sensors, was critical to successful deployment: if the envelope were inflated at too high an altitude it would burst in the low pressure; if it were inflated at too low’ an altitude it w ould not gain the necessary buoyancy, would penetrate too deep and be destroyed by the high temperature. The inflation system had 2 kg of helium, and altitude control would be by the release of ballast.

The balloon system was carried in the upper hemisphere of the entry system, in a toroidal canister that surrounded the helical antenna of the lander. In addition to the folded balloon and gondola, this canister contained a 35 square meter parachute and the spheres of pressurized helium to inflate the balloon. The deployment began at an altitude of 64 km by separating the hemispheres while on the drogue parachute. This released the lower hemisphere containing the lander. Separation deployed a braking parachute for the lander, which then performed its own deployment sequence as on previous missions. The upper hemisphere then released the toroidal balloon package

I – 0

JtQ-

 

Entry H – us

 

Open parachute

 

Drop entry shell begin telemetry

 

II – *2 KM

V – $• м/с

 

II • 43 km V-INW(

 

//

 

Deploy balloon package main parachute

II – 57 km

V – M м/с

 

Release chute

 

II – 47 km

V – !ft м/с

 

Begin balloon inflation

H • 95 KM

V ■ I м/с

 

€ a

 

Landing

1*41 мни

v – a м/с

 

image221image222image223image224image225image226

THE VENUS-IIALLEY CAMPAIGN: 1984

Scientific instruments

 

THE VENUS-IIALLEY CAMPAIGN: 1984

Navigation sensors

 

Scan platforms

 

Oust shield

 

Scientific instruments

 

Figure 18.8 The Vega spacecraft configured for Halley encounter (courtesy NPO – Lavochkm).

 

image227

at 62 km, deploying its parachute in the process. At 57 km the package deployed the balloon system. At 55 km the inflation system was activated. By the 53 km level the envelope had inflated and the package on the parachute released the balloon system. At 50 km the balloon system released its ballast, deployed the boom that carried the temperature sensors and anemometer, and then rose to 54 km to travel wherever the prevailing wind took it. Since the temperatures in this altitude range w’ere benign there was no requirement for thermal control.

On Earth, a global distribution of twenty international antennas consisting of two networks was ready to perform Doppler tracking and receive the scientific data from the balloons – one at a time, as they were to arrive at the planel several days apart. One network was led by 1K1 and used six Soviet antennas including a new 70 meter dish that was built for the Vega missions. The second network was led by CNES and used the three 64 meter antennas of the Deep Space Network in the US, Australia and Spain, and astronomical antennas in Brazil, Canada, England, Germany, Puerto

Rico, South Africa, and Sweden. Doppler tracking by each antenna gave the range and velocity along the Earth-Vcnus line, but lateral motion of the balloons required interferometry that combined phase information from antennas located far apart and linked electronically. In addition, the network simultaneously tracked carrier wave signals provided by one or other of the two flyby spacecraft to provide a third leg to greatly increase the precision of distance and velocity measurements in a differential interferometry technique developed by the IJS for the Apollo lunar missions.

THE VENUS-IIALLEY CAMPAIGN: 1984 Подпись: 4,924 kg (Vega X. fuel mass 155 kg) 4,926 kg (Vega 2. fuel mass 766 kg) 3,222 kg (Vega 1. dry mass 2.466 kg) 3,228 kg (Vega 2. dry mass 2.462 kg) 1,702 kg (Vega 1) * ~ 1,698 kg (Vega 2) 716 kg (both) 122.75 kg at entry with parachutes, fill system, ballast etc. 21.74 kg at float

Vega spacecraft system mass

Payload:

flyby spacecraft:

Mounted on the scan platform:

1. TV imaging system (TVS, USSR-France-Hungary)

2. Three-channel (ultraviolet, visible and near-infrared) spectrometer (IKS. France-USSR-Bulgaria)

3. Infrared spectrometer (IKS, France)

Body mounted:

1. Dust mass spectrometer (PUMA, FRG-USSR-France)

2. Dust particle counter (SP-1)

3. Dust particle counter (SP-2)

4. Dust particle detector (DUCMA, USA)

5. Dust particle detector (FOTON)

6. Neutral gas mass spectrometer (ING, FRG)

7. Plasma spectrometer (PLASMAG)

8. Energetic particle analyzer (TUNDE-M. Hungary-USSR-FRG-ESA)

9. Energetic particles (MSU-TASPD)

10. Magnetometer (MISCHA, Austria)

11. Low frequency wave and plasma analyzer (APV-N, USSR-Poland-Czecho – slovakia)

12. High frequency wave and plasma analyzer (APV-V, USSR-France-ESA)

Three instruments for remote sensing of Halley were mounted on the ASP-G scan platform; the 32 kg TVS camera, the 14 kg TKS three-channel spectrometer, and the

18 kg IKS far-infrared spectrometer. The camera was Russian and the spectrometers were provided by France. The far-infrared spectrometer was cryogenically cooled by a Joule-Thompson cryostat and operated in the range 2.5 to 12.0 microns. The three – channel instrument operated in the ultraviolet 120 to 290 nm, visible 275 to 715 nm, and near-infrared 950 to 1,200 nm. The flyby range at Ilailey was deliberately large to avoid damaging to the spacecraft, so to obtain the desired view of the nucleus the camera required a narrow angle optical system capable of a resolution of 150 meters at a range of 10,000 km. The computers for the science instruments were enhanced by using Western electronics. Hoivever. because CCD technology was restricted the Soviets had to develop their ота 512 x 512 device for the camera. The optics were built by the French, and comprised a 150 mm f/3 wide angle lens that was limited to the red, and a 1,200 mm f/6.5 narrow angle lens with six filters from the visible to infrared. The Hungarians were responsible for the camera electronics with assistance from the Soviets.

The five instruments to study the dust issued by the nucleus of the comet were the

19 kg PUMA dust particle impact mass spectrometer to measure the composition of

A

image228

individual dust particles, the 2 kg SP-1, 4 kg SP-2, and 3 kg DUCMA dust particle counters to determine the flux and mass distribution of dust particle in different si/e ranges, and the FOTON dust particle detector that was installed to measure the large particles that punched through the standoff shield. In-situ measurements by the 7 kg INC neutral gas mass spectrometer would analyse gas in the space through which the spacecraft was traveling. The composition and energy spectrum of ions would be determined by the 9 kg PLASMAG plasma spectrometer, and the flux and energy of ions would be measured by the 5 kg TUNDE-M energetic particle analyzer. It also had the 4 kg MISCHA magnetometer, two plasma w*ave analyzers, the 5 kg APV-N for ion flux and frequencies below 1 kHz, and the 3 kg APV-V for plasma density, temperature and frequencies in the range 0 to 300 kHz.

Including the scan platform and its supporting structure, the instrument payload of the flyby spacecraft was 253 kg.

Lander:

Entry and descent:

1. Temperature, pressure and wind sensors (МЕТЕО, USSR-France)

2. Hydrometer for water vapor concentrations ( VM-4)

3. Ultraviolet spectrometer for atmospheric SO2 and sulfur measurements (ISAV-S)

4. Optical nephelometer-seatterometer for aerosol size and properties (ISAV-A)

5. Particle si/e spectrometer for aerosols (LSA)

6. X-ray fluorescence spectrometer for aerosol elemental analysis (IFP)

7. Gas chromatograph for aerosol chemical analysis (SIGMA-3)

8. Mass spectrometer for aerosol chemical analysis (MALAKIIIT-V. USSR – France)

9. Doppler experiment for wind and turbulence

The deseent instruments focused on aerosols in particular. There were two particle size instruments for measuring the physical properties of aerosols, two instruments for aerosol chemistry, and one instrument for an elemental analysis of the aerosols. These five instruments had externally mounted components with limited insulation from the ambient temperature and pressure, but since the aerosols were confined to the upper atmosphere they were required to function only above 35 km. The aerosols were carried into the instruments by inlet tubes. Some instruments analyzed the light scattered by the aerosol partieles in these tubes to determine their si/e. The ISAV-A instrument also included a nephelometer to determine the cloud density by shining a beam of light through a window’ in the pressure vessel and measuring the light returned through this window. It shared electronics with the ultraviolet spectro­meter.

The gas chromatograph instrument was specifically designed for Vega to measure sulfuric acid aerosol by trapping the droplets in a carbon saturated filter that reacted with sulfuric acid to produce sulfur dioxide and carbon dioxide.

The x-ray spectrometer was a significant improvement on the ones carried by the

Venera 13 and 14 landers. It distinguished grain size using laser imaging. The mass spectrometer sampling system used an aerodynamic inertial separator to segregate grains into small and large sizes on two separate filters. These were then vaporized and analyzed in the mass spectrometer.

The ultraviolet spectrometer was an active experiment, particularly effective for a descent in darkness. It had an ultraviolet lamp and a 1.7 meter path length absorption cell into which the atmosphere was admitted in order to measure the absorption at 512 points between 230 and 400 nm. The objective was to determine the nature of the mysterious ultraviolet absorber’ deduced from remote sensing measurements. The spectrometer was inside the lander, but there was a pipe through the hull to allow the atmosphere into the instrument. It was operated from 62.5 km down to the surface.

The temperature and pressure instruments were similar to those of the Venera 13 and 14 landers but revised for greater accuracy. They comprised two platinum wire thermometers and three pressure sensors covering the ranges 0 to 2, 0 to 20 and 2 to 110 bar. The hydrometer was also improved.

Surface:

1. Drill and surface sampler (SSCA)

2. X-ray fluorescence speciromcter (BDRP)

3. Gamma-ray spectrometer (GS-15STsV)

4. Dynamic penetrometer (PrOP-V)

As both the gravity-assist to deflect the flyby trajectory for Halley and the mission of the balloons required the Vega entries to occur on the night-side, the landers were not given cameras or optical instruments, and those instruments they did carry w’ere similar to those utilized previously. I he Vega landers were focused mainly on solving mysteries about the atmosphere and rectifying problems with instruments on previous missions that were caused by the hostile atmosphere. The gamma-ray soil spectrometer had been deleted after Venera 9 and 10 in favor of the combined drill and x-ray fluorescence spectrometer; this time they were all carried. And since there were no imagers the penetrometer was upgraded to provide an electrical readout.

Lander instrument mass 117 kg.

Balloon:

1. Temperature and pressure sensors (‘USSR-France)

2. Vertical wind velocity anemometer

3. Nephelometer for density and particle size of local aerosols (USA)

4. Light level photometer and lightning detector

5. Stable oscillator for VLBI measurements

A boom w as deployed from the side of the gondola to expose sensors. One w as a propeller anemometer. It measured vertical winds as fast as 2.0 m/s. The horizontal winds were measured by VLBI analysis of radio tracking. The ambient temperature

was measured by two thin-film resistance thermometers with a range of 0 to 7Cf’C and an accuracy of 0.5°C mounted at separate positions on the boom. Pressure was measured by a vibrating quartz beam sensor with a range of 0.2 to 1.5 bar and an accuracy of 0.25 millibar. The photometer consisted of a silicon PIN diode sensitive in the 400 to 1,100 nm range with a 60 degree field of view at the nadir. It was also designed to detect lightning by counting short bursts of abnormally bright intensity. The ncphelomcter was a simple backscatter instrument similar to those of previous missions.

Mission description:

Flyby spacecraft:

In keeping with the international nature of the project. Westerners were allowed to visit Baikonur and view the launches of Vega 1 on December 15. 1984, and Vega 2 on December 21. This was also the first time that Soviet television showed a Proton launch. And although the US routinely tracked Soviet spacecraft, this w’as the first time that this was done officially. The announcement that an American instrument was onboard prompted a small furor in the US. One of the booms for the plasma wave experiment initially failed to deploy on each spacecraft, but these both sprung out after the first midcourse maneuver.

Vega 1 arrived at Venus in early June 1985, only weeks after Venera 16 had been switched off. The spacecraft released their entry systems 2 days out from the planet,

image229

on June 9 for Vega 1 and on June 14 for Vega 2. The points at which they were to enter the atmosphere were on the night-side in order to enable the spacecraft to head for Halley and to maximize the cruising lifetime of the balloons before they suffered solar heating. After releasing its entry system Vega 1 maneuvered to pass the planet at a range of 39,000 km for the gravitv-assist to llallev and to relay the data from its lander. Vega 2 did likewise at a range of 24.500 km. Each spacecraft turned off-Sun to receive the transmission from its lander at a rate of 33)72 hits/s in the meter band and to relay it to Earth in the centimeter and decimeter bands. They did not conduct any science observations at Venus. On finishing the relay, each spacecraft resumed cruise operations. The gravity-assist of the flyby did most of the work in deflecting the path of each spacecraft toward Halley, but maneuvers were needed to refine the final approach.

Vega 1 flew past the nucleus of the comet at a range of 8.890 km on March 6. 1986. and Vega 2 did likewise at a range of 8,030 km on March 9. Both made highly successful scientific measurements. Two Japanese spacecraft had been observing the comet at extreme distance and Europe’s Giotto was scheduled to arrive on March 13 for a daring close flyby at a range of only 500 km. By combining tracking data with imaging, the Vega spacecraft gave a more precise position for Halley in space than was possible using terrestrial telescopes. This was used to improve the accuracy of Giotto’s terminal maneuvers, both to reduce the targeting error in order to obtain the intended observations and to reduce the potential risk to that spacecraft. Both Vega spacecraft flew through the tail of the comet and were pummeled by small grains impacting at 80 km s. The shields installed on one side of each vehicle protected it from damage. The solar panels suffered both dust impacts and electrical discharges induced by the comet plasma. Vega 1 lost 40% of its power supply and Vega 2 lost 80%. After a circuit around the Sun, both spacecraft passed through the tail again in 1987. providing further data. Vega 1 ran out of attitude control gas on January 30 of that year and then on March 24 contact with Vega 2 was discontinued.

Entry system:

The Vega 1 capsule entered the night-side atmosphere at 01:59:49 UT on June 11. 1985, at a speed of 10.75 kin/s and at an angle of 17.5 degrees. The Vega 2 capsule entered at 01:59:30 UT on June 15, at 10.80 km/s and at an angle of 18.13 degrees. The pilot parachutes were deployed at an altitude of 65 km. Eleven seconds later, at

64.5 km, the capsules split into hemispheres and the pilot parachutes drew the upper hemispheres containing the balloon systems away, in the process deploying the main parachutes of the landers in the lower hemispheres. Hour seconds later, at 64.2 km. the landers shed their hemispheres. Having slowly descended to 47 km. each lander released its parachute in order to free-fall to the surface. The new aerodynamic drag devices successfully reduced both vibration and spin, thereby increasing the stability of the descending landers.

Meanwhile, the balloon packages were released from their hemispheres at 62 km. in the process deploying the pilot parachute of each balloon package. At 57 km the

main parachute was deployed. At 55 km the inflation of the envelope was initiated. With the balloon fully inflated, the main parachute was released at 53 km. At 50 km the inflation system and ballast was released and the balloon system rose to 54 km in the middle of the cloud layers with its gondola deployed to make measurements.

Landers:

The Vega 1 lander settled at 7.11 N 177.48 E. just north of eastern Aphrodite Terra and 0.6 + 0.1 km below the planetary mean radius. It was 03:02:54 IJT on 11 June. 0:24 local time, and the solar zenith angle was 169.3 degrees. The measured surface temperature was 467’C and the pressure was 97 bar. The transmission was curtailed 20 minutes after landing in order to conserve energy on the flyby spacecraft, which was not facing its solar panels at the Sun. and to ensure readiness for the subsequent Halley trajectory maneuver.

At an altitude of 17 km the Vega 1 lander experienced electrical spikes and the Doppler tracking data showed violent upward excursions. This shock triggered the accelerometer that was to indicate contact with the ground, causing a premature start to the surface activity sequence, including deployment and operation of the drill and x-ray spectrometer. As the x-ray soil analysis instrument had failed its pre­launch tests and been flown regardless, this may not have mattered. Venera 11 to 14 and the four IJS Pioneer probes also experienced electrical anomalies in the altitude region 12 to 18 km, but Venera 9 and 10 and Vega 2 did not. The cause of these anomalies remains unknown.

The Vega 2 lander touched down at 7.52°S 179.4 E, 1,300 to 1,500 km southeast of Vega 1 and 0.1 +0.1 km above the planetary mean radius. It was 03:00:50 UT on 15 June, 1:01 local time, and the solar zenith angle was 164.5 degrees. The surface temperature was 462°C and the pressure was 90 bar. The transmission was truncated 22 minutes after landing to preserve energy on the flyby spacecraft. There were no anomalies during the descent and the surface operations were performed nominally.

Balloons:

The Vega balloons were both successfully deployed at the anti-solar point (i. e. local midnight) and drifted with the wind at an altitude of about 53 km where the pressure was about 0.5 bar, right in the middle of the three cloud layers. They were carried longitudinally by zonal winds through the night-side atmosphere for 30 hours before crossing the dawn terminator. No latitude measurements could be made, and it was assumed that the balloons remained at a constant latitude. 8°K in the case of Vega 1 and 7 S for Vega 2. Each balloon transmitted for 46.5 hours until its batteries were exhausted. Loss of signal occurred in the early morning hours on Venus after having traveled some 10.000 km. about one-third the way around the planet. The balloons continued silently into the day-side where they would eventually have succumbed to solar heating and burst their envelopes.

Results at Venus:

Landers on descent:

A telemetry problem prevented Vega 1 temperatures from being transmitted during the descent, but the Vega 2 data indicated the presence of a sharp thermal inversion that reached a minimum temperature of -20°C at an altitude of 62 km. The optical spectrometers operated between 63 and 30 km and reported an atmospheric structure similar to that seen by earlier landers and confirming a three layer cloud deck. But on this mission, as for Venera 8, no sharp lower cloud boundary was observed. Aerosol particle size measurements were taken down to 47 km, and were in general agreement with earlier Soviet results and the data from the Pioneer entry probes and confirmed that there were at least two layers of differing particle sizes. The measurements from Vega 1 and 2 were highly consistent, indicating the cloud layers to be very similar at their entry points except in the uppermost layer where Vega 2 found less dense aerosols than Vega 1. The smallest ‘mode Г particles were speculated to be aluminum and/or ferric chloride. About 80% of the larger ‘mode T particles were shown to be spherical with a refractive index of 1.4, a characteristic consistent with sulfuric acid, wdiile the remaining 20% had a refractive index of 1.7, suggestive of solid sulfur, The highest particle counts wrere in the altitude range 58 to 50 km. The Vega instruments were insensitive to the largest ‘mode 3’ particles reported by Pioneer probes.

The Vega 1 and 2 gas chromatographs and the Vega 1 mass spectrometer were the first to make an in-situ detection of sulfuric acid, confirming remote sensing results and yielding a density for the altitude range 63 to 48 km of about 1 milligram of sulfuric acid per cubic meter. The Vega 1 mass spectrometer heavy particle sample contained sulfur trioxide (sulfuric acid anhydride) and chlorine. Unfortunately, the Vega 2 mass spectrometer failed. The x-ray fluorescence spectrometer on Vega 2 detected sulfur (—1.5 mg/m3), chlorine ( — 1.5 mg/m3), and iron (0.2 + 0.1 mg/’mJ). It also made the first detection of phosphorus (—6 mg/m3), this possibly in the form of phosphoric acid, and explaining the persistence of a small amount of aerosol in the sub-cloud region with a base at 33 km. Iron was also reported by the x-ray

image230

Figure 18.11 Chlorine, sulfur and phosphorus profiles from the descent x-ray aerosol analyzer (from Don Mitchell).

analysis, perhaps as ferric chloride in the aerosols. The Vega 1 x-ray fluorescence instrument failed. The ultraviolet speetrometcrs gave vertical profiles for sulfur dioxide mixing ratios with upper region abundances in general agreement with remote sensing and other sources, and generally deer easing towards /его at the surface. The possibility of elemental sulfur vapor was also noted. Solar ultraviolet was completely absorbed below an altitude of 10 km. although this was probably due to aerosols coating the instrument. The hydrometer reported a water vapor abundance of 0.15% at high altitudes (60 to 55 km) decreasing by a factor of ten at lower altitudes (30 to 25 km). The fact that this large abundance is inconsistent with other measures may indicate that the instrument was confused by other atmospheric constituents. The water vapor profile on Venus remains poorly determined.

Landers on the surface:

The Vega 1 lander conducted a gamma-ray soil analysis but the drill had failed and so no x-ray soil analysis could be performed. The Vega 2 gamma-ray spectrometer, drill, and x-ray fluorescence experiments all worked well.

X-ray fluorescence results from Vega 2 (as oxides):

silicon

47%

titanium

0.2%

aluminum

16%

iron

8.5%

manganese

0.14%

magnesium

11%

calcium

7.3%

potassium

0.1%

sulfur

4.7%

chlorine

<0.3%

These analyses showed rocks poor in iron and magnesium but rich in silicon and aluminum, indicating a composition similar to lunar highland rocks. The fairly high sulfur abundance may be an indicator of older rocks.

Подпись:

THE VENUS-IIALLEY CAMPAIGN: 1984

Gamma-г а г results:

The potassium, uranium and thorium values were very similar to Venera 9 and 10. in contrast to the Venera 8 results that showed significantly higher concentrations of all three elements.

Balloons:

Even although this was the first attempt at deploying a planetary aerostat, both of the balloons succeeded. They made the first measurements of the horizontal structure of the atmosphere to complement the many vertical profiles from descent probes. The temperature in the Vega 1 air mass was a constant 40°C. It was about 6°C cooler for the Vega 2 balloon. The atmosphere was more turbulent than expected. At times the balloons precipitously plunged in downdrafts of 1 to 3 m/s by hundreds of meters, sometimes several kilometers. The Vega 1 balloon encountered heavy turbulence at the start of its run and then again towards its end. Shortly after sunrise, passing over the Aphrodite Terra highlands, the Vega 2 balloon plunged more than 3 km to a pressure level of 0.9 bar, very close to the lower limit of its buoyant zone, before it rebounded.

atm

km

0.6

——-

53

0.7

*

V 1 „

52

o.8

__ t___ i____ 1___ I___ i____ l____ I___ i___

5i

Ю 20 30 40 hOlirS

Подпись: Figure 18.13 Flight profile of the Vega 2 balloon (from Don Mitchell).

Figure 18.12 Flight profile of the Vega 1 balloon (from Don Mitchell).

The nephelometer on the Vega 1 balloon was hard to interpret due to calibration problems but generally seemed to agree with particle data from the nephelometers on the descent probes, showing the middle cloud in which the balloon drifted to be horizontally homogeneous with no clear regions. Unfortunately, the Vega 2 balloon nephelometer failed. In their cruise to the dawn terminator, the photometers noted some variation in light levels that may have been due to variations in the underlying clouds, and although there were some light flashes there was no strong evidence for lightning. Vega 1 crossed the terminator into daylight 34 hours into the flight, and its photometer registered dawn 2 hours prior to sunrise. The Vega 2 photometer did not
function correctly, but indicated dawn 3 hours before the terminator crossing. The anemometers reported downdrafts of 1 m s. The VLB! Doppler measurements found horizontal winds of up to 240 km/hr, made the first in-situ observations of the ‘super-rotation’ of the atmosphere at this altitude, and made measurements of atmospheric turbulence.

Results at Halley:

The results of the Vega Halley encounter were more than just scientific, they were also cultural and political. The project would be the first to image the nucleus of the world-famous Comet Halley. For the first time, a Soviet mission and its purpose was made known well in advance. The portion of the Vega mission at Venus went barely noticed outside scientific circles, but the whole world was waiting in expectation for the spectacle of the Halley encounter and the Soviets were well aware that this was unlike any other space mission they had ever conducted.

The Vega 1 spacecraft closed in on the comet at the blazing speed of 79.2 km/s in early March 1986. It performed a final trajectory correction on February 10. Its scan platform locked onto the comet on February 14 and began tracking. Far encounter images on March 4 and 5 demonstrated the camera’s performance. On March 6, the day of close encounter, the world’s press was present in the IKI control room for the first time, disturbing the usual professional calm with a bustling jumble of people eager to experience a Soviet mission event as it happened, including US television and media with both Roald Sagdeev and Carl Sagan providing commentary. Sagan as commentator for a Soviet spacecraft encounter in real-time was clear evidence that perestroika had become reality. Vega 1 switched to high rate telemetry 2 hours before closest approach and took over 500 images during the 3 hour encounter. The raw images looked overexposed and fuzzy. It was hard to pick out the nucleus from the obvious dust jets. But the IKI press room was filled with awe and applause. The images and other data streamed in for another 2 days.

Vega 2 closed in 3 days later at 76.8 km s. It did not require a final correction but 30 minutes before the encounter on March 9 it gave its controllers a scare when the computer guidance system failed. However, the spacecraft quickly switched over to the backup system and the observations began as planned. By the time the encounter was over on March 11 the spacecraft had provided over 700 images.

The images of Halley revealed a potato-shaped nucleus 14 x 7 km with a very dark albedo of 4%. a rotation rate of 53 hours, and at least five dust jets that could be counted on its sunward side. The environmental sensors on board the two spacecraft made pioneering measurements of the plasma fields in the vicinity of the comet, and defined the interaction of the solar w ind with the out-flowing eometary gases. Some of the constituents of the gas were identified and measured. The size and flux of dust particles varied enormously as the spacecraft flew through and in between the jets of dust and gas. A number of instruments were lost during the encounter, and the solar panels were extensively damaged by impacts and the electrical discharges that were induced by the cometary plasma.

image232

Figure 18.14 Vega 2 image of Halley (processing by Ted Slryk).

The infrared spectrometer on Vega 2 failed due to a leak in the cryogenic system. The Vega 1 infrared spectrometer was sent an erroneous command which put it into calibration mode during the 30 minutes at closest approach, which was unfortunate, but it did report data taken at greater distances. The C-TT band of hydrocarbons was detected. The fact that the temperature of the nucleus was 300 to 400K meant that it had an insulating layer at its surface. The dust and gas were jetting through fissures in this crust opened by the heating of volatiles contained within. The three-channel spectrometer on Vega 1 was crippled by an electrical fault, and despite its partner on Vega 2 losing the ultraviolet channel this was able to detect water, carbon dioxide, the hydroxyl radical and the cyano radical, various other products of hydrocarbon photolysis, ammonia and other organic materials in the coma. It was concluded that the principal components of the gas were water containing carbon monoxide and carbon dioxide molecules, as well as photo-produced radicals and atomic hydrogen, oxygen and carbon.

Analysis of the dust in the jets revealed grains in the submicron-lo-micron size range of compositions varying from metallic to siliceous to carbonaceous. The dust mass spectrometers returned results showing three families of materials: one very similar Lo the carbonaceous chondrile meteorites which are thought to be the most primitive of Solar System material, another enriched in carbon and nitrogen, and the third enriched with water and carbon dioxide ice.

Thus ended one of the most daring, innovative, complex and successful missions in the history of robotic space exploration to that time. It established the USSR as the leader in the field; a distinction that was sadly short-lived and later forgotten.

Lunar Soyuz (Zond), 1967-1970

As early as 1959 the Soviets had a plan for manned circumlunar flights. When the Americans decided in mid-1961 to go to the Moon, Korolev was already designing the Soyuz spacecraft for these missions. It was the same three-module arrangement with w’hich we are all familiar, with a support module containing all the resources required for power, propulsion, communication, navigation and consumables for the cosmonauts, a descent module to carry them aloft and to return them to Earth, and a compartment to provide more room for the cosmonauts on long flights. After the Vostok and Voskhod manned capsules, this system was introduced and remains the reliable Russian system still in use today.

wwamttw* ■mv w:*5i’

f-WW fjr. "A’.WJ

Figure 5.4 Soyuz 7K-L1 ‘Zond’ circumlunar spacecraft (from Space Travel Encyclope­dia).

The Soyuz 7K-L1 was a version of the 7K-LOK lunar orbital spacecraft modified to perform a circuit! lunar mission. Although the three-stage R-7 used for Soyuz flights in Earth orbit was replaced by the more powerful four-stage Proton, mass limitations meant that the 7K-L1 did not have the ‘orbital’ module and was designed to carry only two cosmonauts. The idea was to fly circumlunar missions with two astronauts using the 7K-L1 as a precursor to performing a lunar landing using the 7K-LOK version of the Soyuz (which would have an orbital module) and the LK lunar lander, all launched by the massive N-l rocket. To prepare for the manned circumlunar missions, several automated flights of the 7K-L1 were conducted, the first two in Earth orbit and then nine others over the years 1967-1970 either to lunar distance or performing actual circumlunar flights. Zond 4 reached lunar distance before returning to Earth, but in a direction away from the Moon in order to simplify navigation, and Zond 5 to 8 each made circumlunar flights. Zond 4 self – destructed on re-entry, Zond 5 had significant but non-fatal problems with on board systems, and Zond 6 crashed on landing only a few weeks before the Apollo 8 mission. Although Zond 7 and Zond 8 were complete successes, the Soviets never used the system for a manned circumlunar flight.

A BOLD, NEW PROGRAM FOR MARS: 1969

Campaign objectives:

Since their origins in 1960 the Soviet Mars and Venus programs had been strongly intertwined, using slightly different versions of the same spacecraft. When NPO – Lavochkin took over the planetary program it set out to transform OKB-l’s 3MV-3 design into a 1,000 kg spacecraft to be launched on an upgraded Molniya-M at the 1967 flight opportunity to Mars. But this approach was soon abandoned. The Mars program had been a disaster. Seven attempts in the period 1960 through to 1964 had failed, including one test mission. Then the Zond 2 Mars flyby spaeeeraft created an embarrassment by failing as Mariner 4, launched by the US at almost the same time, went on to make a successful flyby in July 1965. In that same month Zond 3, after operating successfully at the Moon, failed its Mars deep space test flight objectives. Aware that the US was turning away from Venus in favor of Mars, starting with dual flybys planned in 1969 and with orbiters and landers to follow, perhaps as early as 1973. the Soviets decided to perfect a Mars lander that would outdo the American flyby missions.

Spacecraft launched

First spacecraft:

М-69 Ко. 521

Mission Type:

Mars Orbitcr

Country; Builder:

l JSSR NPO-L avoc h к і п

Launch Vehicle:

Proton-K

Launch Date; Time:

March 27, 1969 at 10:40:45 UT (Baikonur)

Outcome:

Launch failure, 3rd stage explosion.

Second spacecraft:

М-69 Ко.522

Mission Type:

Mars Orbiter

Country і Builder:

USSR, NPO-Lavochkin

Launch Vehicle:

Proton-K

launch Date ‘: 1 їте:

April 2, 1969 at 10:33:00 UT (Baikonur)

Outcome:

Launch failure, booster explosion.

The entry vehicle for the 3MV Mars spacecraft had been designed in the early 1960s on the presumption that the atmospheric pressure at the surface was between 80 and 300 millibars. The Mariner 4 flyby in July 1965 showed it to be a mere 4 to 7 millibars. The design of the 3MV entry probe was therefore fatally flawed. A new technique would be required to perform entry, descent and landing in such a rarefied atmosphere. In October 1965 NPO-Lavochkin abandoned the 3MV for Mars, but retained it for Venus because it was suitable for that dense atmosphere. The Soviets skipped the 1967 Mars launch opportunity to develop a more capable spacecraft for the 1969 opportunity.

The powerful Proton launch vehicle made its debut in 1965. It doubled the mass that could be delivered to low Earth orbit compared to the three-stage Molniya. and when augmented by the Block D fourth stage (as the Proton-K) it facilitated a whole new generation of heavier, more capable and complex lunar and planetary spacecraft than the Molniya-launched 3MV. Capable of dispatching over 4 metric tons onto an interplanetary trajectory, the Proton-K became the standard launcher for lunar and Mars missions after 1966, and for Venus missions after 1972.

The engineering requirements for new Mars and Venus missions during the time period 1969 73 were defined in March 1966 by the head of NPO-Lavochkin, Georgi Bab akin:

1. Use of the Proton-K to achieve parking orbit and escape onto an interplanetary trajectory

2. IJsc of a "universal” multi-purpose, modular on board propulsion system for trajectory correction while coasting and then insertion into an orbit around the target with a pericenter about 2,000 km and apocenter not exceeding

40.0 km

3. Use of descent-from-flyby and descent-from-orbit mission designs for soft landers to place instruments on the surface

4. Use of the main spacecraft as either a flyby vehicle or an orbiter to relay information from the lander at about 100 bits/s to the Earth

5. IJsc of a telemetry system capable of transmission from the main spacecraft of about 4,000 bits/s.

It was decided that in addition to trajectory correction maneuvers, entry vehicle targeting and planetary orbit insertion and trim maneuvers, the universal propulsion system should also participate in establishing the desired interplanetary trajectory by firing after the spent Block D stage was jettisoned.

These requirements were not applied to Venus until the successful Venera type of the 3MV had fulfilled all of the objectives for that planet in 1972, but they were applied immediately to Mars for the 1969 opportunity. Also, it was decided that for the initial Mars mission the descent module would be an atmospheric probe to obtain the data required for designing a landing system for that rarefied atmosphere. Another key objective was to improve the ephemeris for Mars for future missions. The science objectives for Mars missions using this new spacecraft system were: [1] [2] [3] [4] [5] [6] [7] [8] [9] opportunity that was only 33 months away, an incredibly short period of time in which to try to develop a spacecraft of such an unprecedented complexity. And by devoting part of this time to modifying the 3MV to score a success at Venus in 1967 they left themselves with only 20 months to develop the new spacecraft. Then problems with the design left them with only 13 months. Given the intense pressure to outdo the US at Mars, the risks taken were enormous.

The workload was intense during the last years of the 1960s as the Soviets tried to compete with Apollo. NPO-Lavochkin was overloaded developing the Luna rover and sample return missions, continuing to milk the successful Venus missions, and making a valiant effort on M-69. This was a brand new spacecraft like none built before, and the rushed development showed. Nothing went smoothly. The spacecraft suffered from the same development problems as OKB-l’s early rushed designs and engineers were not terribly optimistic about its chances. The winter of 1968-69 was exceedingly harsh, pipes burst and heating systems failed, creating near-impossible working conditions. Control and telemetry systems were plagued with troubles and the design of the spacecraft actually prevented easy access for servicing. The entry probe had to be deleted very late in the process due to insufficient time and system mass growth, and was replaced by a compartment for additional orbital instruments.

The Soviets were to fail in their first attempt with this new spacecraft in 1969, but the engineering and science requirements for the M-69 program set a precedent for all of the Mars mission designs that were to follow7. At that time almost nothing was known of these missions in the West, and 30 years would elapse before they were described in any detail.

Spacecraft:

The initial design:

As Babakins engineers worked with their OKB-1 colleagues in 1966-67 to prepare a 3MV spacecraft for what would become the successful Venera 4 mission, others at NPO-Lavochkin were working on a new7 spacecraft for the Luna series that would be launched by the Proton-K instead of the Molniya. Unlike the previous 2MV, 3MV and Luna series spacecraft where the avionics compartment was the main structural element, this time a quartet of spherical propellant tanks connected together in the shape of a square using cylindrical inter-tank sections became the element on w7hich everything else was mounted.

Given the short period of time available for the development of a Proton – launched Mars spacecraft, it was decided to exploit this work. The initial M-69 design had the entry probe attached to the tank assembly where the lunar rover w7ould otherwise be carried, and the remaining systems attached to the underside’. The two solar panels were spread out from opposite sides of the square, and the antenna and engine were opposite each other on the remaining sides. This design could meet the schedule, but was not easily reconfigured and failed to satisfy some of the requirements. Also, the designers struggled with a number of engineering

image130

figure 11.17 Drawing of the original Mars-69 concept.

problems in trying to adapt a lunar spacecraft for Mars exploration. The main issues centered on the fundamental tank design, and ultimately it was abandoned, forcing a total redesign 13 months before the launch date.

The final design:

The new design used a single large spherical tank at the center of the spacecraft as the main structural element. The tank had an internal baffle to separate the UDMH fuel from the nitrogen tetroxide oxidizer. The Isayev engine was attached to the base of the tank. A cylindrical interstage with a pressurized container for electronics was attached to the top of the tank, and the entry vehicle was installed above that. Two hermetically sealed cylindrical modules were attached on opposite sides of the tank, one for communication, navigation systems and optical orientation sensors, and the other for science instruments including the cameras. There were also science sensors attached to the outside of ihe spacecraft.

The antenna system, including both a large high gain and small conical antennas, was affixed to the cylindrical interstage. The two 3.5 square meter solar panels were mounted outboard of the instrument modules. The panels were supplemented with a NiCad. battery that delivered power at 12 amps with a 110 amp-hour capacity. Both passive insulation and active thermal control vrere employed. The active system operated in the pressurized compartments and consisted of a ventilation and air circulation system to route air between two radiators, one exposed to sunlight and the other to shadow. The thermal control radiators were inboard of the solar panels, between the modules across the main tank. The avionics of the M-69 spacecraft were

image131

Figure 11.18 Final Mars-69 spacecraft design: 1. Parabolic high-gain antenna; 2. Entry system (not flown); 3. Fuel tank; 4. Solar Panels; 5. Propulsion system; 6. Attitude control; 7. Thermal control-cooling side nozzles; 8. Camera viewports; 9. Instrument compartment; 10. Thermal control-heating side; 11. Omni antenna; 12. Navigation system.

much improved over the 3MV series. It was the first Soviet planetary spacecraft to carry a computer. .An advanced data processing system weighing only II kg was provided that could program the instruments and acquire, process and compress the data from both engineering and science systems for transmission to Earth.

A new telemetry system was provided that consisted of a transponder-receiver for

image132

Figure 11.19 Mars-69 spacecraft under test.

non-imaging data and an impulse transmitter for images, a 2.8 meter parabolic high gain directional antenna and a trio of low gain semi-directional conical antennas for decimeter and centimeter bands. The arrangement of the conical antennas was such that when the solar panels were pointed at the Sun, they would be pointing at Earth. The transponder-receiver had two transmitters and three receivers in the decimeter band at 790 to 940 MHz with 100 W of power, and facilitated Doppler tracking at a transmitted data rate of 128 bits/s with 500 data channels. These transmitters and receivers could use either the conical antennas or the high gam. One receiver was always on and connected to one of the conical antennas for continuous reception. The remaining receivers and the transmitters were cycled through these antennas by timers in order to ensure the reliability of the system. As part of the payload, a new film camera system with facsimile processing was developed. The imaging system had a 5 cm impulse 50 W transmitter for a data rate of 6 kbits/s using short pulses at 25 kW.

For the attitude control system, new Sun and star sensor systems and new nitrogen gas micro-engines were developed. There were two Sun sensors, two star sensors, two Earth sensors, and two Mars sensors. Nine helium-pressurized tanks provided nitrogen gas stored in ten separate tanks to eight attitude control thrusters,
two each for pitch and yaw and the other four for roll. The nitrogen lank pressure of 350 bar was regulated to 6 bar for maneuvering and 2 bar for attitude maintenance. During cruise and routine operations the vehicle used one set of sensors to maintain itself in a rough attitude that faced the solar panels towards the Sun. For high gain antenna operations, midcourse maneuvers, and orbital mapping, it used a more accurate set of sensors for precise З-axis stabilization. Both optical sensors and gyroscope control were provided for the altitude control system.

The entry system was a prototype of that which would be used in 1971, and was to have been deployed w hile 2 days from Mars. But it was ultimately deleted from the 1969 mission due to mass growth of the spacecraft and insufficient time to test the parachute descent system in balloon drops. The entry probe w as designed around a large spherical tank with three attached pressurized compartments. No other details are available.

Подпись: 4,850 kg (fueled but without probe) 3,574 kg 260 kgLaunch mass:

Or hi ter mass:

Probe mass:

Payload:

Or biter:

1. Facsimile imaging system (FTU)

2. Infrared Fourier spectrometer (UTV1) for atmosphere and surface studies

3. Infrared radiometer (RA69) for surface temperature

4. Ultraviolet spectrometer (USZ) for reflected radiation

5. Water vapor detector (I VI)

6. Mass spectrometer for ionosphere composition and hydrogen, helium detection (UMR2M)

7. Multi-channel gamma-ray spectrometer (GSZ)

8. Low – energy ion spectrometer (RIB803)

9. Charged particle deteetor (KM69) for solar electrons and protons

10. Magnetometer

11. Micrometeoroid detector

12. Low frequency radiation detector

13. Cosmic ray and radiation belt detector

14. X-ray radiometer

15. Gamma-ray burst detector

Total mass: 85 kg.

The new FTU was an advanced film facsimile imaging system consisting of three cameras, each with red, green and blue color filters. The image format was 1,024 x 1,024 pixels. One camera had a 35 mm lens, a second had a 50 mm lens and a field of view of 1,500 x 1,500 km, and the third had a 250 mm lens and a field of view of 100 x 100 km with a best resolution of 200 to 500 meters. The film was processed on

board, encoded digitally and supplied to the impulse transmitter. The film was to be chemically activated upon arrival at Mars in order to avoid damage by radiation in cruise. Each camera had sufficient film for 160 images.

Atmosphere probe (deleted):

1. Pressure sensors

2. Temperature sensors

3. Accelerometers for atmospheric density

4. Chemical gas analyzer

Total mass: 15 kg.

Mission Description:

The plan was to use the first three stages of the Proton and the Block D upper stage to achieve parking orbit. After one orbit, the Block D would be reignited for the first part of the escape sequence under the control of the spacecraft. After burnout of the Block D and separation, the spacecraft would fire its main engine for the final boost onto the interplanetary trajectory. This would be the first time that this new scheme was used, adding more risk to an already challenging project. The spacecraft engine w ould also be used for two trajectory corrections during the 6 month cruise to Mars, one 40 days out from Earth and the other 10 to 15 days prior to arrival. The fourth burn of the engine would be made at the closest point of approach to Mars in order to enter a 1.700 x 34,000 km orbit inclined at 40 degrees to the equator with a period of 24 hours. No immediate trim burns were planned, despite the expectation that the errors would be considerable. After some photography and other science from this initial orbit over several weeks, the periapsis would be lowered to about 600 km for an additional 3 months of imaging and data collection. At that point the mission was expected to be concluded.

Unfortunately, neither spacecraft even reached Earth orbit. М-69Л was lost to a third-stage explosion when a rotor bearing malfunction caused a turbopump to fail and catch fire. The engine shut down at the 438 second mark and the stage exploded. M-69B was lost when one of the six first stage engines exploded just at launch. The vehicle continued to climb on the five remaining engines until the 25 second mark, at which time it tipped over to the horizontal at an altitude of 1 km. The remaining engines shut down and 41 seconds into the flight the vehicle fell to the ground 3km from the pad and exploded. Remarkably, the second stage landed intact.

The failure of the Soviets to exploit the 1969 opportunity for Mars passed largely unnoticed in the West, mainly because the two attempted launehes failed so early in flight. But the Protons may have saved the Soviets from the larger embarrassment of another Mars mission failing due to the spacecraft being rushed too hard through its design and development. As one of its designers remarked, M-69 was an example of how’ not to build a spacecraft.

Results:

None.

The Proton was experiencing its worst period in development at this time, with a very high failure rate. It was responsible for the loss of many spacecraft including a large number of lunar missions. The failure of the M-69 launches was a bitter pill for the spacecraft team to swallow after all the difficult and frantic work that had gone into the preparation. To rub salt into the wound, soon thereafter the US achieved the Apollo 11 lunar landing and the successful Mariner 6 and 7 flybys of Mars.

Key players

INTRODUCTION

Any great enterprise is the product of people. It is people who make things happen. Institutions are the means by which great enterprises are realized, but it is the people in these institutions, and in particular the leaders of these institutions, that drive the mechanisms to create great products. And so it is in the space exploration enterprise. We begin the story of the Soviet Union’s space exploration program in the 20th Century with a description of the people who led the development of this great enterprise. While there were many administrators, engineers and scientists who were essential, we have room here only to describe those at the top of the enterprise, those whose personal and institutional power created the USSR’s space program. At the top are the Communist Party leaders and government ministers who had control over selecting and funding national projects; second, and most particularly, the individual Chief Designers of the space program who proposed the projects; third the directors of the design bureaus which were responsible for building rockets and spacecraft for the projects; and finally the President of the Soviet Academy of Sciences, who besides his own leadership of the space program provided academic resources via the directors of the Academy’s research institutes where space mission goals were developed using the rockets and spacecraft built by the design bureaus.

The single most important individual in the development of the Soviet space program after WW-II was Sergey Pavlovich Korolev. After. Toseph Stalin decided to make rocket development a national priority at the end of the war, Korolev was retrieved from exile in a labor camp, together with others from his small band of engineers that built research rockets before the war. They started with the V-2 and a group of captured German engineers, just as occurred in the US. During the 1940s and 1950s Korolev’s design bureau developed the USSR’s first long range rockets using the German rocket engineers’ expertise to build their own design skills. By the mid-1950s the German engineers had been generally dismissed, and the enterprise was entirely Russian. Korolev began testing his R-7 ICBM in the spring of 1957, the rocket that would launch not only Sputnik and other early Earth satellites, but

W. T. Huntress and M. Y. Marov, Soviet Robots in the Solar System: Mission Technologies 5

and Discoveries, Springer Praxis Books 1, DOl 10.1007/978-1-4419-7898-1_2,

© Springer Science+Business Media, LLC 2011

almost all of the Soviet lunar and planetary missions throughout the 1960s and all Soviet cosmonauts, in upgraded and modified versions, this venerable rocket has become the core of the Soyuz launcher that is used commercially today for both manned and unmanned missions.

Korolev was an excellent engineer and designer, with considerable leadership and political skills. These qualities and his mission successes made him the darling of the Soviet space program. His identity was kept secret and he became known as ‘Chief Designer’, a term invented for the titular head of the Soviet space program. There were only two others that followed him after his death in 1966, but neither man had the full measure of qualities possessed by Korolev and the program seemed to lose much of its driving force. Had Korolev remained in charge, the USSR may have landed a cosmonaut on the Moon – even if later than planned and after the Americans. The Chief Designer of the Soviet space program, the de-facto leader inside Kremlin circles, was at the same time a director of one of the implementing design bureaus. There was no equivalent in the US: Wernher von Braun had a similar leadership role but was not at the same time the Administrator of NASA. In the USSR, there was no equivalent of NASA. The space enterprise was only a portion of the government’s Ministry of General Machine Building, which had wide control over all of Soviet space industry and the design bureaus that implemented the policies of the ministry.

The design bureaus and research institutes were the places where all the hardware

image3

Figure 2.1 Korolev’s Council of Chief Designers in 1959. Left to right: A. F. Bogomolov, M. S. Ryazansky, N. A. Pilyugin. S. P. Korolev, V. F. Glushko, V. P. Barmin, Y. I. Kuznetsov.

was developed and built to execute the Soviet space program, except for the science instruments supplied by the Soviet Academy of Seiences. The directors, also known as ‘Chief Designers’, of the several design bureaus and research institutes were the key ‘movers and shakers’ of the program. At the beginning of the Soviet rocket and space enterprise, Korolev established a Council of Chief Designers to coordinate all efforts in rocket development and space exploration. The members of the Council are shown in Figure 2.1. Council member Academician Valentin Petrovich Glushko (1908-1989) was an early colleague of Korolev’s before WW-II and supplied the rocket engines for the R-7, but later he became a dedicated rival to Korolev. He was one of the most important figures in the history of the Soviet program, and his role following Korolev’s death is described later in this chapter. Academician Nikolay Alexeevich Pilyugin (1908-1982) was Chief Designer of МІР and responsible for autonomous control systems (avionics) for rockets and spacecraft. Pilyugin was one of Korolev’s closest colleagues and pioneered the development of flight computers and precision avionics for autonomous navigation. Corresponding member Mikhail Sergeevich Ryazansky (1909 1987) was Director and Chief Designer of N11-885 and developed radio systems including on board transmitters, receivers, radio command links and terrestrial antennas for rockets and deep space missions. In particular, he pioneered the study of radio systems to facilitate autonomous navigation by vehicles in deep space and the development of imaging systems for spacecraft. Academician Alexey Fedorovich Bogomolov (1913 2009) w’as Director of Design Bureau OKB МЫ (until 1989) and principally responsible for the development of on board radio telemetry and trajectory tracking, in addition to terrestrial antennas for rockets and spacecraft. He also greatly contributed to radar remote-sensing techniques including the instrument Гог mapping of Venus by Venera 15 and 16. Academician Vladimir Pavlovich Barmin (1909 1993) was Chief Designer of all ground complexes for ballistic missiles and space launchers. He also contributed to the development of soil – sample devices for Luna and Venera missions. Academician Victor Ivanovich Kuznetsov (1913 1991) w as Chief Designer and Director of N11-10, and as such he developed gyroscopes for rockets and spacecraft and pioneered inertial navigation systems in the USSR.

The design bureaus were all in competition with one another. One or the other of the directors, such as Korolev, was by force of personality and political connection the LChief Designer’ of the whole space program. With no dedicated governmental space administration to marshal the competition between design bureaus, the Soviet space program was rife with rivalry, animosity and political intrigue. The resulting inefficiencies were wasteful of resources and a cause for much delay and many a failure. After Korolev died, there was no one with all the personal skills necessary to hold it all in check.

Almost equivalent in stature to Korolev was Mstislav Vsevolodovich Keldysh, head of the Institute of Applied Mathematics and after 1961 President of the Soviet Academy of Sciences. While Korolev w as the ‘Chief Designer’ of the Soviet space program, Keldysh was ‘Chief Theoretician’. They worked together both to advocate and implement the space exploration program. From 1956 until his death in 1978. Keldysh was the Chair of the highly recognized In ter-Departmental Scientific and

image4

Figure 2.2 Sergey Pavlovich Korolev (left) and Mstislav Vsevolodovich Keldysh (right).

Technical Council on Space Research (MNTS KI; Mezhduvcdomstvennyi Nauchno-Tekhnicheskii Soviet po Kosmicheskim Issledovaniyam) which was responsible for space science and technology development in the Soviet Union. The Council and the Academy determined the objectives for the space program, advised the government and recommended individual projects, provided expertise in space navigation, and supplied scientific investigations for flight missions. Acting together, Korolev and Keldysh were responsible for many of the achievements of the space program.

The final highly influential group were the directors of research institutes of the Soviet Academy of Sciences. The two leading space science organizations were the Vernadsky Institute of Geochemistry and Analytical Chemistry established in 1947 and the Institute for Space Research set up in 1965. The Academy’s science institutes devised the science objectives and instruments for space missions. The leading design bureau and science institute directors were strong individuals who advised Korolev and Keldysh on which missions to fly and determined what science investigations would be carried.

.Minister 9