Category Soviet Robots in the Solar System

MINISTER

Подпись:Afanasyev, Sergey Aleksandrovich 1918-2001 ‘

First Minister of General Machine Building 1965-1983

Sergey Afanasyev’s organization managed the institutions and workforce that built ballistic missiles and satellites vital to the defense of the Soviet Union, as well as the spacecraft and launch vehicles for their politically important space ex­ploration program. Leonid Brezhnev once told him,

“We believe in you, but if you fail w;e will put you against a brick wall and shoot you.” Known as “the big hammer”, he could be a very rude and intimidating man but he had a talent for orches­trating immense projects. He was among the most powerful people involved in the USSR’s space program, which included Korolev and his rival Glushko. His criticism of Korolev’s management of the manned space program resulted in the separation of the robotic program from Korolev’s bailiwick to that of Georgi Babakin in 1965. He oversaw the Soviet Union’s response to the Apollo project and was ultimately responsible for canceling it after many setbacks.

Spacecraft

LUNAR SPACECRAFT

Russian lunar spacecraft can be divided into families according to their evolution from the very first simple flyby and impactor spacecraft in 1958-1960, exemplified by Luna 1 to 3, to the first modular designs built for soft-landing culminating with Luna 9 and 13, to the final series of complex sample return and lunar rover missions beginning with Luna 15 and continuing through to Luna 24. After the first success at soft-landing, some of these spacecraft were modified to carry lunar orbital payloads, in particular to perform tasks in support of an eventual manned lunar landing. These modifications were easily and quickly accomplished because of the modular design. The final series were essentially large soft-landcrs with interchangeable payloads. Although they were complex, they achieved the first robotic sample return missions and first lunar rovers in addition to a pair of orbiters.

Luna Ye-1 series, І958-1959

in the summer of 1958, the Americans and the Russians were racing to launch the first spacecraft to the Moon as a major signal of strength in rocket technology. The spacecraft were small and lightly instrumented and were flown opportunistically on what were mainly test flights of military rockets. The goals were more technological and political than scientific.

The Americans tried eight times to reach the Moon without success in 1958 1960. Only one spacecraft, Pioneer 4, was launched successfully to Earth escape velocity, but it missed the Moon by a wide margin.

To counter the American lunar campaign, the Soviet Union built the Ye-1 lunar impactor spacecraft for launch on a new’ three-stage Luna rocket derived from the R-7 that launched Sputnik. The Yc-1 wras a very simple spherical payload similar to Sputnik, spin-stabilized, with several protruding antennas. Six such spacecraft w’crc launched during the 12 months between September 1958 and 1959. All but two were

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 5,

© Springer Science+Business Media, LLC 2011

image35

Figure 5.1 Examples to scale from the Luna series of spacecraft: Luna 1 and 2 Ye-1 impactor spacecraft; Luna 3 Ye-2 flyby spacecraft; Luna 9 and 13 Ye-6 soft-lander spacecraft; Luna 10 Yc-6S orbiter spacecraft; Luna 12 Ye-6LF orbiter spacecraft; and Luna 16, 18 and 20 Ye-8-5 sample return spacecraft in landed configuration without in­flight drop tanks (from Space Travel Encyclopedia).

lost to launch vehicle mishaps, but owing to the Soviet way of not naming a mission until it was successfully underway, these were Luna 1 and Luna 2. Although Luna 1 missed the Moon on January 4, 1959, it was the first spacecraft to achieve escape velocity – two months before Pioneer 4. The final spacecraft to be launched in this series, Luna 2, became the first spacecraft to impact the Moon on September 14, 1959. Tn effect, the Soviets had kept launching until their goal was achieved, and then they moved on.

Launching to Mars and Venus

TIMELINE: OCT 1960-FEB 1961

The Moon had been the principal target for the USSR in 1958 and 1959, and for the US as well through 1960, hut both had ambitions to send spacecraft to the planets. Venus was the closest and most accessible, but Mars, slightly farther away, was the most fascinating. Having been successful at the Moon, the Soviet Union was ready to start launching planetary missions in 1960. The US, struggling to achieve success at the Moon, decided to put off attempting planetary missions.

Korolev developed a four-stage version of the R-7 rocket to launch missions to the planets, and a spacecraft quite different from the initial Luna series to meet the challenges of interplanetary flight. The new rocket and spacecraft were ready for the launch opportunities for Mars in late 1960 and for Venus in early 1961. The first attempts to send a spacecraft to Mars were on October 10 and 14, 1960. and in both cases the third stage failed, giving the new fourth stage and spacecraft no chance to perform. Later on February 4, 1961, the first attempt to send a spacecraft to Venus was foiled when the engine of the new fourth stage failed to ignite. Finally, on its fourth launch on February 12, 1961, the new rocket succeeded in sending its payload on a trajectory towards the planet Venus. Unfortunately, the Venera 1 spacecraft had a number of problems and failed early in its flight.

Launch date

1960

10 Oct

Mars flyby

Third stage failure

14 Oct

Mars flyby

Third stage failure

15 Dec

Pioneer lunar orb iter

Booster exploded

1961

4 Feb

Venera impactor

Fourth stage failure

12 Feb

Venera 1 impactor

Communications lost in transit

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 7,

© Springer Science+Business Media, LLC 2011

THE FIRST LAUNCH TO MARS: 1960

Robotic achievements in the shadow of Apollo

TIMELINE: DEC 1968-APR 1970

The flight of Apollo 8 in December 1968 marked the beginning of the end for the Soviet Union’s campaign to put cosmonauts on the Moon. The Zond circumlunar flight test series had been plagued by problems. Even the successful flight of Zond 5 suffered so many subsystem anomalies that engineers were very reluctant to trust a spacecraft to a manned mission. The crash of Zond 6 made beating Apollo 8 to the Moon almost impossible, and the circumlunar program endured a further setback on January 20, 1969, when the next Zond test flight fell victim to yet another launcher failure. Any chance that cosmonauts could reach the Moon in competition with the Americans was dealt a severe blow on February 21, 1969, when the counterpart of the Saturn V, the N-l, failed spectacularly on its maiden flight. It had been intended to deliver a modified Zond into lunar orbit. The second attempt to qualify the N-l on July 3, 1969, less than a fortnight ahead of the launch of Apollo 11, resulted in the biggest explosion in the history of rocketry and destroyed the pad facilities. The last of the scheduled Zond flight tests, Zond 7, was a success in August, 1969, but by then the race was over. Instead of following up with a manned circumlunar mission the Soviets added another automated flight, which flew successfully in October 1970 as Zond 8. After two further attempts to qualify the N-l in June 1971 and November 1972 also failed, the manned lunar program vras canceled.

However, the Soviets countered the Apollo program with a series of robotic lunar missions using a new, large spacecraft that was originally designed to land a rover for a cosmonaut to employ on the lunar surface. When in late 1968 and early 1969 it became clear that the Americans were likely to beat them to the Moon, the Soviets opted to use this robotic landing system to try and upstage Apollo by being the first to return a lunar sample to Earth.

While the sample return system was being developed for use with the lander, the first launch of the new’ lander with a rover was attempted on February 19, 1969, but it was lost when the payload shroud failed shortly after the Proton launcher lifted off’. The first sample return spacecraft was launched on June 14, but lost when the

W. T. Huntress and M. Y. Marov, Soviet Robots in the Solar System: Mission Technologies and Discoveries, Springer Praxis Books 1, DOl 10.1007/978-1-4419-7898-111,

© Springer Science 4-Business Media, LLC 2011

Подпись: Launch date 1968 21 Dec Apollo 8 lunar orbiter 1969 5 Jan Venera 5 entry probe 10 Jan. Venera 6 entry probe 20 Jan Zond Earth orbital test flight 19 Feb Luna rover 21 Feb N-I Moon Rocket test 2S Feb Mariner 6 Mars flyby 27 Mar Mariner 7 Mars flyby 27 Mar Mars orbiter 2 Apr Mars orbiter 18 May Apollo 10 lunar orbit test 14 Jun Luna sample return 3 Jul N-l Moon Rocket test 13 Jul Luna 15 sample return 16 Jul Apollo 11 lunar landing 7 Aug Zond 7 eircumlunar test 23 Sep Luna sample return 22 Oct Luna sample return 14 Nov Apollo 12 lunar landing 1970 6 Feb Luna sample return 11 Apr Apollo 13 lunar landing
Подпись: Success, first men to orbit the Moon Entry successful, didn’t reach surface Entry successful, didn't reach surface Second stage failed Launcher shroud failed First stage failed in flight Success on Jul 31 Success on Aug 4 Third stage exploded Booster exploded Success Fourth stage failed First stage exploded at liftoff Crashed on Moon on Jul 21 Success, first men on Moon on Jul 20 Success, returned to Earth on Aug 14 Fourth stage failed Fourth stage failed Success Second stage premature shutdown Explosion damage enroute, safe return

fourth stage failed. Rushing to beat Apollo 11 to the Moon, another sample return mission was launched on July 13, 1969, ten days after the devastating N’-l explosion and 3 days before Apollo 11 was launched. This spacecraft, Luna 15, successfully reached lunar orbit 2 days ahead of Apollo 11 and Westerners, uninformed of its intentions, viewed it with suspicion. Shortly after the lunar module of Apollo 11 set down on the Moon on July 20 and its astronauts made their historic moonwalk, the Soviet spacecraft crashed attempting to land in the Sea of Crises, some distance cast of the Apollo 11 site in the Sea of Tranquility. The next three attempts through the middle of 1970 to return samples from the Moon with this type of spacecraft were all lost to launch vehicle failures.

In early January 1969 the Soviets followed up their 1967 success at Venus with two launches of spacecraft similar to Venera 4 but modified to descend through the atmosphere more rapidly, and thereby provide data from deeper levels than before. Although Venera 5 and Venera 6 worked well, they imploded far above the surface.

The Soviets were ready with a new spacecraft designed for Mars in March 1969. Like the new Luna for delivering rovers and sample return spacecraft, these were heavy spacecraft that needed the Proton launcher. They had been designed Lo be able
to enter orbit around Mars and dispatch a lander, but for the 1969 window they were to release a probe to get the data on the atmosphere that was required to design that lander. When the probe was deleted owing to development and test problems it was decided to equip the two spacecraft for this window as orbiters. Neither survived its launcher. These spacecraft and their launch attempts were virtually unknown in the West until after the Cold War. Blissfully unaware of this potentially overwhelming competition, the IJS dispatched two more flyby missions to Mars in 1969, Mariners 6 and 7, both of which were successful.

A MASSIVE ASSAULT ON MARS FAILS: 1973

Campaign objectives:

In planning of their 1973 campaign for Mars the Soviets were aware of the IJS plan to send orbiter/landers to the planet in 1975. They also knew that these Vikings were considerably more capable than their own 1971 lander. Adding to this problem, the 1973 opportunity required more energy than that of 1971 and they could not repeat the M-71 orbiter /lander strategy. If they were to send landers to Mars in 1973. then the carrier spacecraft would have to fly past the planet. Their spacecraft were too massive and the Proton-K launcher did not have enough capability to combine an orbiter and a lander in 1973. Chagrined by the poor performance of their spacecraft in 1971 in comparison to the success of the Mariner 9 orbiter, yet encouraged by the near-success of the Mars 3 lander, the Soviets w ere determined to score a success at Mars ahead of the Viking missions. In fact the US had hoped to launch these in 1973 but financial problems forced a postponement to 1975. Knowing there would be no American competition in 1973, the Soviets decided upon four launches to send an armada consisting of two or biters and two flyby landers. The or biters would be sent first so that they could act as communications relays for the landers on the surface. After releasing its lander, a carrier spacecraft would relay telemetry from the entry system to Earth in real-time during the entry and descent, and then perform its own remote-sensing observations of the planet in making its flyby.

Spacecraft launched

First spacecraft:

Mars 4 (M-73 No.52S)

Mission Type:

Mars Orbiter

Country! Builder:

USSR/NPO-Lavoclikin

Launch Vehicle:

Proton-K

Launch Date ‘: і ime:

July 21, 1973 at 19:30:59 IJT (Baikonur)

Em ounter Da te l Time:

February 10, 1974

Out come:

Failed orbit inserted burn, flew past planet.

Second spacecraft:

Mars 5 (M-73 No.53S)

Mission Type:

Mars Orbit er

Country і Builder::

USSR/NPO-Lavochkin

Launch Vehicle:

Proton-K

Launch Date; Time:

July 25, 1973 at 18:55:48 UT (Baikonur)

Encounter Date/ Time:

February 12, 1974

Mission End:

February 28, 1974

Outcome:

Successful, but short-lived.

Third spacecraft:

Mars 6 (M-73 No.50P)

Mission Type:

Mars Flyby,’Lander

Country I Builder:

USSR/NPO-Lavochkin

Launch Vehicle:

Proton-K

Launch Date! 7 ime:

August 5. 1973 at 17:45:48 UT (Baikonur)

Enc ounter Da tel Time:

March 12, 1974

Outcome:

Successful descent, but lander lost at touchdown.

Fourth spacecraft:

Mars 7 (M-73 No.5IP)

Mission Type:

Mars Flyby.’Lander

Country і Builder:

USSR/NPO-Lavochkin

Launch Vehicle:

Proton-K

Launch Date: Time:

August 9, 1973 at 17:00:17 UT (Baikonur)

Encounter Date/7 ime:

March 9, 1974

Outcome:

Entry system failed. Hew past Mars.

By 1973 the US and USSR were in a period of detente, and cooperation between the two space programs had increased with a number of joint working groups and a joint Apollo-Sovuz mission scheduled for 1975. The Soviets gave the US the data from Mars 2 and 3 and from Venera 8 in return for an accurate ephemeris for Mars, models of its atmosphere, and Mariner 9 orbital imagery of the zones chosen for the Mars 6 and 7 landers.

In order to save cost and reduce risk, Soviet engineers used the same spacecraft as in 1971 with minimum changes. But they were plagued with electronics problems in test and in flight. One crucial difference between the 1971 electronics packages and those built for 1973 were that gold leads had been replaced with aluminum on a key transistor used throughout the spacecraft. This difference was discovered very late in the integration and test program, wiien some of the new 2T-312 transistors suffered failures. The difficulties with the 2T-312 transistor were to be the Achilles’ heel of the 1973 campaign. They were in almost every engineering subsystem and science instrument on the spacecraft. Tests showed that these transistors generally failed 1.5 to 2 years after production. This would correspond to Mars arrival, and they could not all be replaced in time to meet the launch window. An analysis estimated a 50% likelihood of a complete mission failure owing to these transistors. In a US program this would have mandated postponing the mission, but the Soviet decision makers, in their rush to beat the Amerieans to the surface of Mars, dismissed the concerns of the engineers and opted to take the risk and launch with the suspect transistors.

The problem of the transistors became manifest almost immediately after launch, and plagued the entire campaign. All four spacecraft reached Mars but with three in a seriously crippled state. One orbiter flew past the planet, one lander missed and the other lander was lost just before touchdown after returning a degraded set of descent data. Mars 5 was able to achieve orbit, but then failed after less than a month.

The paucity of data from this flotilla compared to the mass of data returned from the single long-lived Mariner 9 orbiter, considered together with the lack of a viable competitor to the forthcoming Viking missions, led the Soviets to abandon Mars in favor of Venus for the foreseeable future – and it would be 15 years before they tried again.

Spacecraft:

The overall design and subsystems of the spacecraft for the 1973 Mars campaign were the same as before, although the scientific instruments were slightly different. The most signifieam engineering difference was the installation of a new telemetry system solely to enable the flyby carrier to relay data from its entry system to Earth in real-time; this would prove crucial in the ease of Mars 6. The landers telemetry system remained the same and communications from the surface would be through the or biters.

The M-73 orbiters were almost identical to the M-71S spacecraft. Their function was to enter into orbit around Mars, communicate with the landers, and obtain their own information on the composition, structure, and properties of the atmosphere and surface of the planet. The science payload was mounted on top of the spacecraft, in the same place as the entry systems of the flyby spacecraft. The principal function of the flyby carrier was to release the entry system on a proper entry trajectory and provide a real-time telemetry relay during the descent. It had science instruments for cruise and Mars flyby observations. Because the Mars 3 lander had made it to the surface, the entry systems were the same. However, the science payload of the landers was upgraded.

Mars 4 and 5 launch mass: 3,440 kg (orbiter; dry mass 2,270 kg)

Mars 6 and 7 launch mass: 3,260 kg (flyby vehicle)

1,210 kg (entry vehicle)

635 kg (lander system on descent)

358 kg (lander)

4,470 kg (total)

image173

Figure 13.5 Mars 4 and Mars 5 spacecraft diagram: 1. Science instrument compartment; 2. Parabolic high-gain antenna; 3. Attitude control system; 4. Spiral antennas; 5. Mars sensor; 6. Star sensor; 7. Sun sensor; 8. Fuel tank and propulsion system; 9. Avionics compartment; 10. Attitude control gas tanks; 11. Thermal control radiators; 12. Earth sensor; 13. Solar panels; 14. Magnetometer.

image174

Figure 13.6 Mars 4 and Mars 5.

image175

Figure 13.7 Mars 6 and Mars 7 spacecraft diagram (from Space Travel Encyclopedia): 1. Lander; 2. Parabolic antenna; 3. Attitude control gas jets; 4. Spiral antenna; 5. Mars sensor; 6. Star sensor; 7. Sun sensor; 8. Propulsion system; 9. Instrument compartment; 10. Attitude control gas tanks; 11. Radiators; 12. Earth sensor; 13. Solar panels; 14. ‘STEREO’ radio emission antennae.

image176

Figure 13.8 Mars 6 and Mars 7,

image177

Figure 13.9 Mars 6 entry system in test.

Payloads:

Some of the M-73 scientific instruments were redesigned forms of those carried by Mars 2 and 3, but others were new. The Mars 4 and 5 orbiters and the Mars 6 and 7 flyby spacecraft were equipped as follows:

1. FTU facsimile imaging system

2. Optical-mechanical panoramic imaging system

3. Infrared radiometer (8 to 40 microns) for measurement of surface temperature (Mars 5 only)

4. Infrared photometer in five carbon dioxide bands around 2 microns to obtain surface altitude profiles

5. Microwave polarimeter (3.5 cm) for measurement of dielectric constant and subsurface temperatures

6. Two polarimeters in ten bands from 0.32 to 0.70 microns to characterize surface texture (French-Soviet)

7. Four band visible photometer in range 0.37 to 0.6 microns for measurement of color and albedo of the surface and atmosphere (Mars 5 only)

8. Infrared narrow-band 1.38 micron photometer for measurement of water vapor content in the atmosphere

9. Ultraviolet photometer (0.260 and 0.280 microns) for measurement of ozone

10. Scanning photometer (0.3 to 0.9 microns) to study emissions in the upper atmosphere (Mars 5 only)

11. Gamma-ray spectrometer for surface elemental composition

12. Micrometeoroid sensors (Mars 6 and 7 only)

13. Lyman-alpha photometer for measurement of upper atmosphere hydrogen (French-Soviet)

14. Solar wind plasma sensors (8) for measurement of speed, temperature and composition in the 30 eV to 10 keV energy range (Mars 4 and 7 only)

15. Boom mounted three-axis lluxgate magnetometer (Mars 4 and 7 only)

16. STHRHO-2 to study solar radio emissions (French-Soviet. Mars 7 only)

17. ZIIEMO to study solar protons and electrons (French-Soviet, Mars 6 and 7 only)

18. Multichannel electrostatic analy/cr (Mars 4 and 5 only)

19. Dual-frequency radio occultation experiment to profile ionospheric electrons and tropospheric density.

Two types of imaging system were employed. The first was a version of the M-71 FTU camera with various technical improvements and more film and faster scanning rates. The second was a single line push-broom panoramic imager that was to scan a 30 degree field of view from horizon to horizon and was sensitive in both the visible and near-infra red. It stored its data on a 90 minute analog tape recorder for replay to Earth.

The FTLT optics were as before: two bore-sighted cameras, one an f/2.8 lens with a focal length of 52 mm and a 35.7 degree field of view, and the other an 174.5 lens with a 350 mm focal length and a 5.67 degree field of view. They each weighed about 9 kg. The wide angle camera was equipped with red. green, blue and orange filters, and the narrow angle one used an orange long-pass filter. Twenty meters of 25.4 mm film was contained in a radiation-shielded magazine. This was sufficient for at most 480 frames. Exposure times alternated between 1 50th and 1/150th of a second. Each camera produced a 23 x 22.5 mm frame and the film could be scanned at up to ten resolutions, only three of which were used actually: 235 x 220,940 x 800, and 1.880 x 1,760 pixels. The scanned images were transmitted at either 512 or 1.024 pixels per second by the dedicated impulse transmitter. At the intended operating altitude these cameras would provide resolutions of between 100 and 1,000 meters.

The push-broom panoramic camera system was first used by Luna 19 in 1971. It comprised two optical-mechanical cameras, each with a single photomultiplier tube and a rotating prism to scan a 30 degree field of view aeross the spacecraft’s track. One camera had red and orange filters and was sensitive across the visible spectrum and the other used a red long-pass filter with a photomultiplier that was sensitive in the infrared. They scanned at 4 lines/seeond and produced 250 cycles line for video recording on magnetic tape at 1,000 IIz. The readout rate was 1 line/second and the transmission was commanded at 256 or 512 pixels line resolution.

The payload of the entry system and lander w as essentially the same as flown on Mars 2 and 3, but with upgraded imagers, mass spectrometer, and temperature and pressure sensors. The Doppler experimeni to measure winds during the descent was new. Most significantly, it was nowr possible to transmit the descent data in real-time rather than storing it for transmission after landing. They were equipped as follow s:

1. Accelerometer for atmospheric density during entry

2. Doppler experiment for winds and turbulence on descent

3. Temperature and pressure sensors on descent and landing

4. Radio altimeter for providing altitudes on descent

5. Mass spectrometer for atmospheric composition on descent and landing

6. Atmospheric density and wind velocity on the surface

7. Two panoramic television cameras for stereo viewing of the surface

8. Gamma-ray spectrometer for soil composition mounted in a petal

9. X-ray spectrometer for soil composition deployed to the surface from a petal

10. PrOP-M walking robot deployed to the surface from this same petal with

onboard gamma-ray densitometer and conical penetrometer.

Doppler measurements and the radio altimeter, accelerometer, temperature, and pressure sensors operated from the beginning of parachute deployment right down to the surface.

Mission descriptions:

All four spacecraft were dispatched successfully but predictably and inevitably first Mars 6, then Mars 7, then Mars 4 suffered system-wide failures within a matter of weeks owing to the faulty transistor. Only Mars 5 arrived relatively trouble free and was able to enter orbit around Mars, but it suffered a pressure leak and shortly thereafter fell silent.

Mars 4:

Mars 4 was launched on July 21, 1973. It made a midcourse correction on July 30, but the computer developed problems that prevented a second midcourse correction. It reached the planet on February 10, 1974, but the engine failed to ignite for the orbit insertion maneuver and the spacecraft flew? past the planet at a range of 1,844 km.

Mars 5:

Mars 5 was launched on July 25, 1973. It made midcoursc corrections on August 3 and on February 2, 1974, and followed through with the orbit insertion maneuver at 15:44:25 UT on February 12 to achieve a 1,760 km x 32,585 km orbit with a period of 24.88 hours inclined at 35.3 degrees to the equator. Some unknown event during orbit insertion triggered a slow leak in the instrument compartment. An accelerated plan of observations w as prepared that focused on obtaining high resolution imagery of the surface. But when the pressure fell below operating levels in the transmitter housing on February 28 after only 22 orbits, this prematurely ended the mission and ruled out the use of this spacecraft as a relay for the landers that were scheduled to arrive in early March.

Mars 6:

Mars 6 was launched on August 4, 1973, and conducted a midcourse correction on August 13. At the end of September the science and operations dow nlink was lost, almost certainly due to the failure of a 21-312 transistor. Only two channels in the telemetry system remained operational, neither of which provided any information on spacecraft status. Refusing to give up, the engineers continued to send commands to the spacecraft in the hope that the receivers might still be functioning. As it turned out the command uplink was unaffected, and Mars 6 dutifully obeyed the commands and executed its autonomous functions. Unable to report to Earth, in February 1974 it autonomously determined its position, calculated the second midcourse correction and carried this out. Upon approaching the planet on March 12, it properly executed the optical navigation and targeting, and then released its entry system at a range of

48,0 km from the planet with just 3 hours remaining to atmospheric entry.

Ground controllers first realized that Mars 6 had done its job shortly thereafter, at 08:39.07 UT, when data began to arrive through the dedicated relay channel. At that time the entry system was 4.800 km from its target. The spacecraft was able to relay data throughout entry and descent, and then continued past the planet, passing within 1,600 km of the surface. This performance was a monumental achievement in spacecraft autonomy for the Soviet program so early in the history of planetary exploration.

The entry system penetrated the atmosphere at 09:05:53 UT at a speed of 5.6 km/s and an 11.7 degree angle of attack. Loss of signal due to plasma effects occurred at 09:06:20 at an altitude of 75 km. The signal was regained at 09:07:20 at 29 km. with the start of the data transmission. The main parachute was deployed at 09:08:32 after the entry system had slowed to 600 m/s at an altitude of 20 km. The canopy opened fully at 09:08:44. and the capsule started to transmit data on altitudes, temperatures and pressures. The mass spectrometry was stored for transmission after the landing. The Doppler shifts on the signal were noted. The capsule appeared to be swaying under the parachute more than expected, impairing the transmission quality. Ignition of the rocket engines was confirmed but the transmission cut off at 09:11:05 when the lander was "in direct proximity to the surface’*, probably when it hit the surface. The velocity at the time of signal loss was 61 m/s, which was excessive for a safe touchdown. The transmitter was programmed to turn off after the lander had been released in order to switch over to a different set of VHF antennas on the lander. No further signals were received. The fate of the lander is unknown. It lies at 23.90 S 19.42 W in the Margaritifer Sinus region, in the vicinity of Samara Valley, where the landscape is characterized by steep slopes.

Mars 7:

Mars 7 was launched 4 days after Mars 6 but flew a faster trajectory which arrived at the planet 3 days earlier. It made only one course correction on August 16, 1973. An early failure in the communications system cost it one transmitter, but it was able to remain in contact. At Mars the targeting maneuvers to set up the entry system were executed properly and the entry system was released on March 9. 1974. However, most likely owing to a failed 2T-312 transistor, the entry system computer did not issue the command to fire the retro-rocket, with the result that it missed the planet by 1,300 km. The intended target was in the crater Galle at 51.2 S 30.9 W. The carrier spacecraft provided some data during its flyby.

Results:

Orbiters:

Imagery

After Mars 4 failed to execute its orbit insertion maneuver it flew past the planet and continued to return interplanetary data from solar orbit. During the flyby it returned one swath of twelve pictures and two panoramas in a 6 minute imaging cycle from a range of 1,900 to 2Л 00 km. Two dual-frequency radio occultation profiles were also obtained, one on passing behind the planet as viewed from Earth and the other upon exiting and these supplied the first indication of a night-side ionosphere.

The Mars 5 orbiter operated for only 25 days after orbit insertion, and returned atmospheric data and images of a small portion of the southern hemisphere of Mars. In all it returned 108 pictures, but the narrow angle ones were motion blurred. The useful data included 43 wide angle images and five panoramas which were returned in five imaging sessions over a 9 day period, all of roughly the same area, which was near the imaging track of Mariner 6 and showed swaths of the area south of Valles Marineris from 5 N 330 W to 20 S 130"W. Measurements by other remote sensing instruments were also made near periapsis along seven adjacent arcs in this region. High cirrus clouds and yellow clouds of fine dust w ere identified.

Surface properties

Data returned from orbit by the infrared radiometer on Mars 5 showed a maximum surface temperature of-Г C, -43 C near the terminator, and -73°C at night. It gave a thermal inertia for the soil that was consistent with grains 0.1 to 0.5 mm in size, and polarization data in the visible spectrum implied grain sizes smaller than 0.04 mm in aeolian deposits of variable cover. The polarization at 3.5 cm suggested a dielectric constant of 2.5 to 4 at depths of several tens of cm. The oxygen, silicon, aluminum, iron, uranium, thorium, and potassium sensed by the gamma-ray spectrometer from orbit suggested a surface similar to terrestrial mafic rocks.

Lo wer atmosphere

Six altitude profiles were measured by the carbon dioxide photometer along a path between 20 and 120 :W in longitude and spanning 20 to 40r’S in latitude, and these were in general agreement with the Mariner 9 ultraviolet spectrometer data. Surface pressures as high as 6.7 millibars were determined. Mars 3 had found only 10 to 20 precipitable microns of water vapor while the dust storm was raging in 1971. Two years later. M ars 5 found abundances as high as 100 precipitable microns south of the Tharsis region. The water vapor content was variable by a factor of 4 to 5 across the planet. An ozone layer about 7 km thick was detected at 40 km altitude in the equatorial region, not near the surface as anticipated, with a concentration of about 1/1,000th that of Earth’s ozone layer. The Mariners were able to detect ozone only at the poles where it is more abundant. The existence of argon in the atmosphere was confirmed.

image178

Figure 13.10 Pictures from Mars 4 during its flyby and from Mars 5 once it was in orbit. Left: cratered terrain at 35.5eS 14.5’W taken hv Mars 4 from 1,800 km range through a red filter. From lower left the large craters are Lohse, Hartwig and Vogel. Right: the crater Lampland at Зб^ 79"W taken by Mars 5 from 1,700 km range.

image179

image180

Figure 13.12 Picture from the Mars 5 panoramic imager (processing by Ted Stryk).

Upper atmosphere and ionosphere

The Lyman-alpha instrument found the exosphere temperature to be 295 to 355K. with the temperatures in the altitude range 87 to 200 km being 10 degrees lower. No upper atmosphere emissions were noted by the visible spectrometer in the range 0.3 to 0.8 microns. Mars 5 also performed a radio occulta lion experiment on one orbit and its results, with those from the flyby occupation measurements for Mars 4 and 6. showed the existence of a night-side ionosphere with a maximum electron density of 4,600/cc at an altitude of 110 km, and an atmospheric pressure near the surface of 6.7 millibars.

The fields and particles instruments returned a significant data set to complement the M-71 orbiter data. Two distinct plasma zones were found inside the bow shock between the undisturbed solar wind and the planetary magnetosphere: a thermalized plasma behind the bow shock, and a small electrical current carried by protons in the magnetotail. The bow shock was held at an altitude of 350 km. The plasma results and magnetometer measurements were consistent with the planet having an intrinsic magnetic field of about 0.0003 times the strength of Earth’s field, and inclined 15 or 20 degrees from the rotational axis which, as in the case of Earth, is tilted 23 degrees from the perpendicular to the plane of its orbit.

Flyby spacecraft:

The radio occupation made by the Mars 6 carrier spacecraft verified the detection by Mars 4 and 5 of a night-side ionosphere. The French STEREO instrument on Mars 7 w orked satisfactorily throughout the cruise to Mars but the spacecraft did not return any useful science during the flyby. It was the last of the armada to fall silent, wiiieh it did in September 1974.

Entry systems:

The Mars 6 entry system transmitted for 224 seconds during its descent before it fell silent, providing the first in-situ measurements of this atmosphere. Although a lot of it was unreadable due to the degradation of another 2T-312 transistor, enough data w’as obtained to profile the temperature and pressure from an altitude of about 29 km down to the surface. The density of the atmosphere from 82 km down to this level was inferred from accelerometer data. Winds of 12 to 15 m s were measured from an altitude of 7 km dowm to near the surface. A surface pressure of 6.1 millibars and a temperature of -28 C were derived from temperature, pressure, accelerometer and Doppler data. The surface winds were 8 to 12m/s. Other parameters included a lapse rate of 2.5K/km, the presence of the tropopause at an altitude of 25 to 30 km. and an almost isothermal stratosphere at a temperature of 150 to 160K. These values were consistent with measurements by the Mars 5 orbiter, and were later confirmed by the Viking missions. Instruments also indicated "several times" more atmospheric water vapor than previously reported. The mass spectrometer data were stored during the descent for transmission after landing, and so were lost. However, the current to the vacuum pump was transmitted during the descent as an engineering parameter, and a sleep increase in current was interpreted as an indication of argon at an abundance of 25 to 45%. which was implausibly large; the actual value was found by the Vikings to be a more reasonable 1.6%.

Landers:

Ко transmissions were ever received from the Mars 6 lander and no results w’ere obtained from the surface. The Mars 7 entry system missed the planet entirely.

THE GOOD, THE BAD AND THE SAD

The Soviet and American enterprises to explore space were created as a by-product of the Cold War, specifically the development of intercontinental ballistic missiles and their modification to put spacecraft on interplanetary trajectories. While aiming their nuclear-tipped missiles at each other, the iwo opposed societies competed for the minds of the rest of the world by demonstrating their technological prowess by exploits in civilian space exploration. The Soviet space exploration program was noi entirely divorced from the military, as it was in the US. As a result. Soviet robotic missions to the Moon and planets were cloaked in secrecy until the early 1980s, and only after the collapse of the USSR has reliable information become available on the full history of the Soviet lunar and planetary exploration program. The key leaders and institutions involved, and almost all decisions and events, were state secrets and unknown outside the closed circle of Soviet secrecy. Launches were not announced, and the Soviets rarely revealed the purpose of their spacecraft except for human missions where this eould not be hidden. This policy hid embarrassing failures, and only when a success could be claimed was its purpose revealed.

The heavily cloaked Soviet robotic exploration program provided mystery and a challenge to the Americans. State secrecy concealed the fact that the Soviet robotic space exploration program was bolder, more innovative, and more tragic than any observers in the West could have imagined at the lime. As eaeh planetary launch window approached, the Americans would get very anxious about what spectacular the Soviets might be planning. The subliminal pressure to outdo the Soviets added to this anxiety, particularly in the first decade of the space race when the USSR always appeared to have the upper hand. Imagine the despair on the American side in the late 1960s if it had been known that the Soviets were planning landings on Mars in 1969 while the US was still conducting flybys. Over the long run, the Soviets were tragically jinxed at Mars, never gaining a true success despite expending enormous effort and resourees on a resolute and more aggressive attack on the planet than was the case in the US. They were the first to launch at Mars in 1960, failed with their next generation spacecraft in the 1960s, fared poorly with their massive grand fleets in 1971 and 1973. fell tragically short with the Phobos missions in 1988, and ended abysmally with Mars-96. Yet many Soviet achievements endure the lunar rovers and sample returns, the Vega missions, and the extensive and very successful in-situ exploration of Venus are all accomplishments that were never equaled by the US.

і’he story of the Soviet lunar and planetary exploration program is a tale of great adventure, excitement, suspense, and tragedy; a tale of courage and the patience to overcome obstacles and failure; a tale of fantastic accomplishment and debilitating loss; a tale of courage and enthusiasm to try the previously impossible. To carry it out they exhibited superb expertise in engineering design and development. They were very innovative in utilizing the technology available to produce engineering systems that accomplished the task. Their rocket engines are testimony to mastery of materials development and propulsion system engineering. Their innovative lunar mission design and return trajectories and their terminal optical navigation scheme for the M-71 and M-73 missions demonstrate excellence in celestial mechanics, navigation, and guidance and control. The automation of the midcourse maneuvers and optical navigation scheme for Mars were applied successfully well before the US even contemplated such complexity a clear demonstration of superior skill in automation and software which unfortunately was to unravel in later missions. The

success of any enterprise is ultimately the result of people, and the Soviet Union had excellent engineers, scientists and managers who faced immense difficulties with the heavy-handed, personality-driven, complex and entangled national system of control and supply, and succeeded thanks to an intense devotion to the space exploration enterprise and a strong sense of competition with America.

The successes of the Soviet robotic exploration program were achieved at a heavy price. The Luna, Venera and Mars programs all endured an enormous number of losses from launch vehicle and spacecraft failures – far more than would have been tolerated in a US program. Soviet persistence in pursuing their goals, particularly in the early years, would have appeared maniacal to an American. During one stretch between 1963 and 1965, the Soviets suffered eleven straight failures in attempting a lunar soft landing. Korolev had to exercise considerable political skill to save his lunar lander program after such a long string of disasters. This w ould have brought dow n an American program w here no such commanding personality existed for the robotic program. The worst string of losses in an American robotic exploration program occurred roughly contemporaneously and was only about half this number. The Americans suffered six straight failures from 1961 to 1964 in their Ranger lunar impact or program. At one time they were very close to terminating both the program and its implementing organization. Thereafter the Americans never tolerated more than an occasional failure in their program, whereas the Soviets tolerated relatively large failure rates as a matter of course.

The poor reliability of Soviet rockets was the primary cause of failures until the mid-1970s, but it was these very same rockets that enabled the Soviet Union to be so bold in executing their program. The Molniya was capable of lifting many times the weight of American rockets. It was produced in quantity, and readily available from the military on short notice and at no apparent cost. This characteristic was essential since the Soviets, in contrast to the Americans, tested their spacecraft by Hying them – resulting in many more attempts to launch Soviet spacecraft than American: 106 versus 51 through 1996. This may have been a consequence of the readier access to Soviet launch vehicles before cost became an issue, but in any case Soviet engineers also lacked discipline in ground testing. They rushed their designs through assembly with insufficient system test time in low quality clean facilities with loose ground test procedures. This showed in the poor performance of their spacecraft in flight. By the end of 1965, they had lost all four of their spacecraft launched to Venus, both of their spacecraft launched to Mars, and five of nine lunar spacecraft. In that same time, they lost an additional 24 of their 39 missions to launch vehicle failures. w7hich w’as not only a very large number in itself but also a huge percentage loss from an American point of view. The situation improved with time, but failures continued to plague the program. The inflight failure rate dropped from over 70% through 1965 to 39% by 1976, and the launch vehicle failure rate dropped from over 60% to 48% over that same period of time. After 1976 the inflight failure rate fell to 10% and the launch vehicle failure rate dropped to 9%.

The absence of strong ground test discipline w as symptomatic of a weakness in systems engineering. The Americans learned their skill in this discipline through the trouble-plagued Ranger lunar program in the early 1960s, and rarely had an inflight failure afterwards. The Soviets were much slower in applying this discipline, and suffered continuing inflight failures. Their problems were exaeerbated by a handicap in electronics technology. Decades after vacuum electronics had become standard in Western spacecraft the Soviets eontinued to fly pressurized spacecraft – in fact, right up to Mars-96. One impetus for continuing this practice was that Soviet rockets were so large that the mass penalty of old electronics was not a major consideration, but another problem was that Soviet industry did not produce vacuum qualified complex electronic systems for its exploration missions. The reliability and operating lifetime of Soviet space avionics systems were a problem throughout the program and were a principal reason why the USSR never attempted a mission to the outer planets. Their Mars spacecraft were for some reason particularly prone to inflight avionics failures from start to finish.

The sad part of the story is the disappearance of Russia from the scene after the fiasco of Mars-96. This has been a great loss of vision, enterprise and expertise in robotic space exploration. The Soviet enterprise was born as part of the Cold War. and seemingly expired with it. After 1991 the Russian space program turned almost exclusively to humans-in-orbit. The Academy of Sciences had a great deal of trouble acquiring funds to keep its robotic space exploration program alive. After Mars-96 failed and government interest in robotic space exploration plummeted, it increased its investment in human spaceflight and partnership with the US in the International Space Station. Now7, after a long hiatus, the Russians are reviving their robotic space exploration program with the Phobos-Grunt mission.

FOUNDER AND CHIEF DESIGNER OF THE SOVIET SPACE PROGRAM

Подпись:Подпись: to wear his medals. His identityKorolev, Sergey Pavlovich 1907-1966

Founder of the Soviet Space Program Chief Designer OKB-1 1946-1966

Chief Designer Sergey Korolev (this common spelling is not phonetically correct, Korolyov is proper) was the behind-the-scenes Soviet equivalent of von Braun in the US. His Experimental Design Bureau No. l (OKB-1) led the development of first military and, shortly thereafter, peaceful applica­tions of rocketry in the USSR. His identity was a state secret known only to an inner circle; to others he was simply the ‘Chief Designer’. While von Braun was openly engaged with the public and served as an enthusiastic communicator on the American civilian space program, Korolev worked under heavy state security. He V”as not even allowed w’as not made public until after his death.

A passionate advocate of space exploration. Korolev began as a young engineer leading a research group, GIRD, that built small rockets in the 1930s at the same time as Robert Goddard was making his rockets in the US. Korolev became a victim of one of Staling purges in the late 1930s. eonfessing to trumped up charges under duress. He was sent initially to a gulag before being transferred to the ‘sharashkas’. slave labor camps for scientists and engineers, where he could continue to work on rockets in exile for the military. As a result of the eonsiderable hardship he endured, he developed health issues that would persist for the rest of his life. He was released near the end of WW-II to evaluate the captured German V-2 missile and build a Soviet rocket capability.

In 1946 Korolev was appointed Chief Designer of a new department in Scientific Research Institute No.88 (N11-88) to develop long-range missiles. The R-l, which was basically a Soviet-built V-2, led to a succession of ever more powerful rockets named R-2, R-3 and R-5. He proved himself to be a very talented technical designer and manager, and in 1950 his department was upgraded to a design bureau, and then in 1956 was separated from N11-88 to become OKB-1. He began work in 1953 on an I CBM to deliver the heavy 5-ton nuclear warhead. This would require a rocket of unprecedented size and power. The resulting massive multi-stage R-7 (which NATO referred to as the SS-6 Sapwood) was first tested in the spring of 1957. long after technology had reduced the size of the warheads. It was overly large and awkward as a weapon, taking 20 hours to prepare for launch, and only a few were deployed before more praetical delivery systems were produced by competing organizations. However, the R-7N lifting power allowed Korolev to adapt it for space exploration purposes, including Sputnik, which proved to a reluctant Kremlin the political value of non-military uses for large missiles. Like von Braun, Korolev’s passion was the exploration of space, but he needed the military business to build his rockets. Thus his designs owed as much to his dreams as to hard military requirements. Korolev s lobbying to use the R-7 for space exploration, and his insistence on the large and militarily impractical cryogenic rockets best suited to this role, drew impatience from the military, which reacted by plaeing contracts with competitors, in particular Mikhail Yangefs OKB-586 and Vladimir ChelomeyN OKB-52.

Korolev was a charismatic man who through sheer perseverance, political savvy, technical expertise, and talent for leadership established the Soviet space exploration program on the backs of the military, with consequent resentment. Nevertheless, he triumphed because his space spectaculars won him the support of the Soviet political hierarchy and in particular Nikita Khrushchev. The R-7 in its various incarnations became the most reliable and most used space exploration launch vehicle in the 20th Century. The Soyuz version continues in use today to launch cosmonauts into low Earth orbit. The Molniya version launched all of the early Soviet lunar and planetary missions until the more powerful Proton developed by Chelomey became available, and later versions are still used for this purpose. His sudden death in January 1966 was a severe shock, and without his leadership the Soviet lunar program devolved into rivalry between factions, impeding progress and dashing any chance the Soviet Union may have had after their late start.

President of the Soviet Academy of Sciences 11

Luna Ye-2 and Ye-3 series, 1959-1960

These series were the second generation of simple, single-module lunar spacecraft, designed for a more complex payload and flight mission. Instead of a direct flight to impact the Moon, they were placed into a highly elliptical orbit that would take them beyond the far side of the Moon, which they would photograph, and upon returning to the vicinity of Farth they would scan and transmit the pictures. The Ye-2 was the first three-axis stabilized spacecraft. It flew to the Moon in spin-stabilized mode, and then switched to three-axis stabilization and control for lunar photography. The Ye – 3 had a modified attitude control system and an improved camera. One Ye-2 and two Ye-3 spacecraft were launched in the six-month period between the start of October 1959 and the end of April 1960 using the Luna launcher. Only the Ye-2 spacecraft, Luna 3, was successful. Both Ye-3 spacecraft were lost to launch vehicle failures.

Campaign objectives

Mankind’s first venture to the planets began in I960, known only to those in the Soviet Union who performed the task and to the elite in the American spy services. The first Mars space flight campaign consisted of two identical spacecraft built for flyby exploration of the planet. They were launched in October 1960 and preceded the first US attempt at Mars by four years. Two similar spacecraft for Venus were launched in February 1961. These four spacecraft were the first designed to directly investigate our neighboring planets.

Chief Designer and Academician S. P. Korolev began work on Mars and Venus missions at OKB-1 in late 1958, during a hectic time in w’hich not only was his R-7 ICBM being developed and tested but also the second silo-based R-9ICBM. Despite flight tests often occurring at a rate of several per month, he worked on adapting the R-7 for the non-military space exploration role that had always been his dream. He created a small third stage to attain Earth escape velocity, and was ready for the first lunar launch attempts in late 1958. With the successful impact of Luna 2 and far side photography of Luna 3 in 1959, the objectives of the initial lunar spacecraft series were satisfied and Korolev was able to move on to Mars and Venus. He had planned to use an upgraded form of the third stage of the R-7F Luna launcher for planetary spacecraft later in 1959 and 1960, but the Institute of Applied Mathematics of the Soviet Academy of Sciences convinced him that a four-stage rocket would be much more efficient and robust. When American plans for a Venus launch w ere postponed to 1962, Korolev decided to skip the 1959 60 planetary window s in order to gain the time to develop a four-stage R-7 that would have a third stage derived from the R-9 second stage and a wholly new’ fourth stage with a restartable engine. The first three stages and the initial burn of the fourth stage w ould insert the fourth stage into a low’ orbit around Earth. At the appropriate time, the fourth stage would restart to gain the desired interplanetary trajectory and release its payload. This 8K78 vehicle became known as the ‘Molniya’ launcher. It was capable of sending 1.5 tons to the Moon or just over 1 ton to either Mars or Venus.

In early January 1960, Khrushchev aired his concern about the growing US space program at a meeting with Korolev and other space leaders. Pushed by his political master to send a spacecraft to Mars, by the end of February Korolev had a schedule for launching to Mars in that fall. His team balked at the 8-month timescale because the four-stage R-7 was still a ‘paper’ vehicle and the spacecraft was not yet designed there were not even any working drawings. By today’s standards the schedule was ludicrous, but Korolev and his team had, as they put it "a fervent desire to beat the Americans…and were in a desperate hurry’7

The 1M (Mars) and IV (Venus) spacecraft originally envisioned in 1958 were far more complex than the Luna missions. They were fully З-axis stabilized spacecraft with attitude control and propulsion systems, solar arrays and battery power, thermal control, and long range communications. Korolev’s plan called for three

launches in the Mars window to dispatch two flyby spacecraft and one lander, with the optimum date being September 27. A lander had to undertake the most difficult of planetary missions – to pass through the atmosphere, survive impact with the surface, and take photographs. But at that time information on the atmospheric properties of the tw o planets w as unreliable, particularly for Mars. Korolev assumed a surface pressure for Mars between 60 and 120 millibars, which was thin but feasible, and that Venus had an atmosphere more like Earth’s. Experiments in the summer of 1960 using the R-l 1A scientific suborbital rocket (a version of the ‘Scud’ military rocket) took test entry vehicles up an altitude of 50 km for drop tests using parachutes. But designing to the uncertainties, in so short a time, forced the engineers to give up on a lander for Mars and to settle for the simpler flyby task, and for Venus it was decided to design a probe to report on conditions in the atmosphere without the need to survive impact with the surface. Nevertheless, even these simpler missions were very challenging, not least owing to the large uncertainties in the ephemerides of the two planets, wiiich for Mars exceeded the diameter of the planet itself.

The scientific objectives for the Mars flyby spacecraft were specified by Mstislav Keldysh in a document dated March 15, 1960:

1. Photograph the planet from a range of 5.000 to 30.000 km at a surface resolution of 3 to 6 km with the coverage including of one of the polar regions

2. Coverage of the infrared C-II band in the reflection spectrum, to search for plant or other organic material on the surface

3. Research into the ultraviolet band of the Martian spectrum.

The instruments and spacecraft were rushed through development in order to meet the deadline. There were many problems at the factories. The spacecraft delivered to the launch site at the end of August were a shambles. Korolev s team worked around the clock to solve the numerous technical problems, constantly taking subsystems apart for repair and retesting. The communications system gave the most trouble. In fact, full scale integrated testing did not begin until September 27, which w? as the optimum launch date!

Korolev also raced to assemble his first four-stage R-7. The new third stage was a conversion from another vehicle, so the real task was to rapidly develop the entirely new; fourth stage with its restartable engine. The pressure on the rocket team was not eased by knowing that the first test launch would be a full-fledged attempt at Mars.

Ultimately, the payload had to be slashed in order to make mass available for test instrumentation on the new upper stage combination. The heaviest instruments – the camera, infrared spectrophotometer and ultraviolet spectrometer – were deleted. The two spacecraft did not reach the launch pad until well after the optimum launch date, which meant they would not be able to approach as close to Mars as intended. But in the event this w as of no consequence because they w ere both victims of their launch vehicles.

Had these Mars spacecraft and the Venus spacecraft in February 1961 succeeded, then the world w’ould have been treated to a spectacular planetary exploration coup in May 1961. The Venus probes would have arrived at their destination on May 11

Подпись: First spacecraft: Mission Type: Country! Builder: Launch Vehicle: Launch Date ': 7 ime: Outcome:Подпись:

Подпись: Spacecraft launched

1M No. l [Mars 1960Л. Marsnik 1]

Mars Flyby USSR OKB-1 Molniya

October 10. 1960 at 14:27:49 UT (Baikonur) Launch failure, third stage malfunction.

1M No.2 [Mars 1960B. Marsnik 2]

Mars Flyby USSR OKB-1 Molniya

October 14. 1960 at 13:51:03 UT (Baikonur) Launch failure, third stage did not ignite.

and 19. and the Mars flybys would have occurred on May 13 and 15. Following only one month after Gagarin’s orbital flight in April, the effect of these triumphs on the West would have exceeded even Sputnik.

The fact that the new four-stage R-7 and Mars spacecraft were even launched is a testament to the can-do attitude of Korolev’s team against almost impossible odds. Nevertheless, a typical Russian sense of resignation ran underneath the optimism. In early September, during the scramble to make the launch date, a spacecraft engineer remarked. "‘Forget about that radio unit and all the Mars problems. The first time wc won’t fly any farther than Siberia!” He was right.

Spacecraft:

The spacecraft was essentially a cylindrical container, 2.035 meters long and with a diameter of 1.05 meters, pressurized to 1.2 bar with nitrogen for the avionics and instruments, with a dome on top housing the propulsion system, which was a fixed 1.96 kN К DU-414 res tar table liquid hypergolic rocket engine that burned nitric acid and dimethylhydrazine. The engine was capable of making one or more trajectory correction maneuvers with a total firing time of 40 seconds.

The pow er system consisted of two fixed 1.6 x 1.0 meter solar panels populated by a total of 2 square meters of solar cells, and had silver-zinc batteries for storage. Thermal control was achieved using internal circulation fans in association with shutters on the exterior to stabilize the internal temperature to 30 C.

The avionics included a telemetry tape recorder and a program timer (actually a clockw ork event sequencer) that had to be preset for a specific time of launch. The communication system consisted of three units. Л directional system used a high – gain 2.33 meter diameter fine copper net parabolic dish for 8 cm (3.7 GHz) and 32 an (922 MHz) band transmitters. This antenna was to open automatically when the spacecraft separated from the fourth stage of the launcher. Two cross-shaped semi-

image61

Figure 7.1 Diagram of the 1M spacecraft: 1. Propulsion system nozzle; 2. Sun and star sensors; 3. Earth sensor (1VA only); 4. Parabolic high gain antenna; 5. Attitude control jets; 6. Thermal sensors; 7. Medium gain antenna; 8. Boom omni antenna.

image62

Figure 7.2 The 1M Mars spacecraft.

directional medium-gain antennas were mounted on the back of the solar panels for the command receiver and for low bandwidth telemetry at 922.8 МН/. A low-gain omnidirectional antenna was affixed to the end of the 2.2 meter magnetometer boom Гог use near Earth in the 1.6 meier band. Commands were sent at 768.6 MHz at 1.6 bits/s. Before executing an uplinked command sequence, the spacecraft repeated it back and awaited acknowledgement from the ground.

Attitude sensing was achieved using fixed Sun and star sensors in combination with gyroscopes and accelerometers, and a system of nitrogen gas jets adopted from Luna 3 provided attitude control and З-axis stabilization. In cruise mode the solar panels were maintained within 10 degrees of perpendicular to the Sun. For telemetry sessions, the spacecraft used radio bearings to turn and lock onto Earth. For the 1VA Venus spacecraft, this mode was improved by using a separate Earth optical sensor.

Launch mass: 650 kg (dry mass —480 kg)

Payload:

1. Boom mounted triaxial fiuxgaLe magnetometer to search for a Martian magnetic field

2. Ion trap charged panicle detectors to investigate the interplanetary plasma medium

3. Micrometeoroid detector to investigate interplanetary spacecraft hazards

4. Cosmic ray detectors to measure radiation hazards in space

5. Infrared radiometer to measure the Martian surface temperature

6. Facsimile film camera system to image the surface (not down)

7. Infrared 3 to 4 micron C-II band spectrometer to search for organic compounds (not flown)

8. Ultraviolet spectrometer to detenu і ne atmospheric composition (not flown)

Most of the instruments were externally mounted. 1 he camera and spectrometer were inside the pressurized module with their optics observing through a port. The camera was the same facsimile film system as that flown on Luna 3 to photograph the Moon and used the 3.7 GHz channel for transmission. It would be triggered by a Mars sensor.

The interplanetary cruise instruments were derived from balloon and sounding- rocket experiments. Shmaia Dolginov supplied the magnetometer and Konstantin Gringauz the two ion traps. The cosmic ray detectors consisted of two Geiger counters and one sodium iodide scintillator inside the pressurized container, and one cesium iodide scintillator mounted externally, all of which were supplied by Sergey Vernov. Tatiana Nazarova provided the mierometeoroid sensor.

All three key planetary instruments outlined in Keldysh’s memo in March were ultimately deleted. The schedule was set in February and the launch window opened on September 20, leaving very little time to build the instruments. The spacecraft itself had a large number of problems in development and testing. On September 20 the radio was still at the factory and the electrical system was not working. The radio

had further problems after it arrived for integration with the spacecraft. By now the minimum energy launch date on September 27 had passed, and every day thereafter the mass that could be launched diminished. To save mass as the days passed, the camera system was deleted. It had suffered test and integration problems of its own. Finally, as the end of the launch window approached, the infrared spectrometer, which had failed to detect life during a field test in Kazakhstan, and the ultraviolet spectrometer were deleted. Pressure integrity tests of the avionics compartment were never done. After the launch of the first spacecraft failed and the mass constraint tightened, the entire science payload and midcourse engine were removed. As it was too late in the launch window to attempt the desired close flyby of Mars, the goal of the mission was reduced to simply gaining flight experience with the spacecraft.

Payload mass: 10 kg

Mission description:

Spacecraft 1M No. l arrived at the pad on October 8 and was launched on October 10, towards the end of the launch window. It did not achieve Earth orbit. Resonant vibrations in the launcher during the second stage burn caused a gyroscope in the avionics to malfunction. At 309 seconds into the Fight, after third stage ignition, the vehicle pitched over beyond permissible limits and the engine was shut down. The stack crashed in eastern Siberia.

image63

Figure 7.3 Preparing for the first test of the new four-stage R-7 on October 10, 1960, carrying the 1M Mars flyby spacecraft.

1M No.2 did not achieve Earth orbit either. Its launcher failed after 290 seconds, when the third stage engine failed to ignite. An oxidi/er leak on the pad had frozen the kerosene in the feed pipes. The launch window closed before the planned third spacecraft could be launched. The failure of the third stage on both launches robbed the new fourth stage and the spacecraft of any chance to perform.

The Soviets made no announcement of either launch, since they had not reached orbit. But the IJS was cognizant, having tracked them from its surveillance station in Turkey and from a reconnaissance aircraft flying between Turkey and Iran. Tracking stations along the southern borders of the USSR readily picked up radio traffic prior to launches, and the telemetry from early Soviet launch vehicles was unencrypted. The deployment of tracking ships was a further indication that a launch attempt was imminent, and in any ease planetary launch windows were well known. Only a few lunar and planetary launches escaped detection by the Americans.

Nikita Khrushchev was in New York for a United Nations meeting during the launch period. He had a model of the 1M Mars probe with him as a bragging piece. After the first failure, instead of boasting w ith his model, he made his famous speech with accompanying shoe-banging on October 12. When the second launch failed, he was on his way back to the USSR with his model.

Results:

None.

FOLLOWING UP AT VENUS: 1969

Campaign objectives:

In 1967 Venera 4 worked as well as could be expected considering the unknown environment to which it was sent. The US had only managed a flyby in this launch window for Venus* while the first successful Soviet planetary mission had achieved the impressive technical challenge of descending through the planetary atmosphere and sending back critical data on its characteristics. Knowing the US had no plans to return to Venus because it desired to focus on Mars, the USSR set out to develop an unassailable lead in the investigation of Venus.

NPO-Lavochkin built two new 3MV spacecraft for the 1969 launch opportunity. Venera 4 w7as high above the surface wlien it fell silent after 93 minutes of descent, either when it was crushed or when the battery ran out. It was decided that the new capsules must fall more rapidly in order to reach a deeper level in the time allowed by the battery. The capsules were similar to that of Venera 4, but modified to endure a higher entry velocity and with a smaller parachute for a faster descent.

Spacecraft launched

First spacecraft:

Venera 5 (2V No.330)

Mission Type:

Venus Atmosphere/Surface Probe

Country і Builder:

USSR NPO-Lavochkin

Launch Vehicle:

Molniya-M

Launch Date: Time:

January 5, 1969 at 06:28:08 UT (Baikonur)

Encoitn ter Dale і 7 ‘і me:

May 16, 1969

Outcome:

Successful.

Second spacecraft:

Venera 6 (2V No.331)

Mission Type:

Venus Atmosphere/Surface Probe

Countryi Builder:

USSR.’NPO-Lavochkin

Launch Vehicle:

Molniya-M

Launch Date: Time:

January 10, 1969 at 05:51:52 UT (Baikonur)

Encounter Date/Time:

May 17, 1969

Outcome:

Successful.

Taken together, data from the Venera 4 and Mariner 5 missions in 1967 and from terrestrial measurements of the planet’s radio brightness indicated that the surface pressure on Venus greatly exceeded the design tolerance of the descent capsule. But the debate about whether Venera 4 had reached the surface raged on for 2 years. In 1968 Soviet and American scientists met first in Tucson in March, then again at the COSPAR meeting in Tokyo in May. and for a third time at a symposium in Kiev in October. The result was general agreement that the surface conditions were 427C and 90 bar. But this long debate did not reach consensus soon enough to influence the short construction schedule available for the 1969 probes. Knowing only that the pressure exceeded 18 bar, NPO-Lavochkin increased the tolerance to 25 bar for the new missions. By the time Venera 5 and 6 were launched, however, it was accepted that the surface pressure was much greater. With no time for further improvement, the missions were treated simply as an opportunity to obtain data using more precise instruments while new higher pressure designs were created for the next window .

Both missions were successful in descending through the atmosphere and. just as expected, the capsules imploded at altitude. The Soviet media had played down any expectations of reaching the surface. Venera 5 and 6 firmly set the stage for the next mission, which would attempt to reach the surface. This was the first 100% success rate for multiple launches and the first 100% success rate for multiple spacecraft.

Spacecraft:

The carrier vehicle was essentially the same as Venera 4, but the descent probe was strengthened to handle the higher velocity of approach in 1969, which would impose a higher deceleration load of 450 G, and also to withstand a pressure of 25 bar. This used up the buoyancy mass allocation. A lower velocity of 210 in. s was preset for the deployment of the pilot parachute, wath smaller parachutes employed to descend more quickly and obtain measurements nearer to the surface before either the battery expired or the internal temperatures became lethal. The pilot parachute was reduced in size from 2.2 to 1.9 square meters, and the main chute from 55 to just 12 square meters.

Figure 11.1 (right) shows the Venera 6 spacecraft folded in launch configuration. The entry system is at the bottom covered with its dark ablation material. Most 3MV pictures are taken with the probe painted white and bearing the letters "СССР’. The antenna and solar panels are folded to fit into the launcher shroud and the spiral gas cooling pipes are visible on the back of the high gain antenna dish which, by facing in the opposite direction to the solar panels, acts as a radiator. The Venera 5 and 6 spacecraft w ere identical.

image114

Figure 11.1 Venera 5 on display and Venera 6 folded for launch.

Payload:

Carrier spacecraft:

1. Solar wind charged particle detector

2. Lyman-alpha and atomic oxygen photometers

3. Cosmic ray gas discharge and solid state detectors

These are the same as on Venera 4.

Descent/landing capsule:

1. Temperature, pressure and density sensors

2. Atmospheric chemical gas analyzers

3. Visible airglow photometer

4. Radio altimeter

5. Doppler experiment

Atmospheric density was measured during entry by a combination of Doppler tracking and the probe’s accelerometers. In the parachute descent the atmospheric structure experiment measured temperature, pressure and density. This instrument was improved over Venera 4 with three platinum wire resistance thermometers for more precision, two redundant sets of three aneroid barometers covering the ranges

0. 13 to 6.6 bar, 0.66 to 26 bar and 1 to 39 bar, and a tuning fork densitometer for the

image115

Figure 11.2 Venera 5 and Venera 6 entry capsule diagram: 1. Drogue parachute; 2. Main parachute; 3. Pyro piston lid; 4. Transmitter antenna; 5. Density sensor; 6. Gas fill valve;

7. Deliumidifier; 8. Thermal control fan; 9. Pressurization valve; 10. Commutation block; 11. Accelerometer; 12. Transmitter; 13. Oscillation damper; 14. Battery; 15. Redundant transmitter; 16. Accelerometer; 17. Timer; 18-20. External insulation; 21. Internal insulation; 22. Thermal control system; 23. Lander cover; 24. Pyro piston; 25. Parachute compartment lid; 26. Radio altimeter antenna; 27. Gas analyzer.

wider range of 0.0005 to 0.040 g/cc. The atmospheric gas analyzers were improved and reconfigured to benefit from the experience of Venera 4. A getter was added to measure the total inert gases including molecular nitrogen, and refinements were introduced to make better measurements of molecular oxygen and water. Accuracies were improved by transmitting a pressure reading at the same time as a composition analysis. Venera 5 would make its composition measurements at higher altitudes and Venera 6 at lower altitudes. A number of improvements were made to the radar altimeter to avoid the problems on Venera 4, and three semaphores were provided for altitudes of 45, 35, and 25 km at an accuracy of about 1.3 km. Even though these were night-lime landings, a visible photometer was included to measure light levels during the descent because the dark hemisphere of the planet was known to exhibit an airglow phenomenon of unknown origin.

Mission description:

Venera 5 was launched on January 5, 1969, performed a course correction maneuver on March 14 when 15.5 million km from Earth, and reached Venus on May 16. The entry capsule was released at a distance of 37,000 km and at 06:01 UT it entered the atmosphere at 11.17 km/s at an approach angle of 65 degrees. During the parachute descent at 3°S 18°E on the night side, it provided a set of instrument readouts every 45 seconds for 53 minutes. The transmission ceased at an altitude of about 18 km when the pressure exceeded 27 bar. At that time the external temperature was 320 :C and internal temperatures had reached 28 C. It was 4:12 Venus solar time and the solar zenith angle was 117 degrees.

Venera 6 was launched on January 10, 1969, conducted a midcourse correction on March 16 at 15.7 million km, and arrived on May 17 (one day after its partner). The entry capsule was released at a distance of 25,000 km and it entered the atmosphere at 06:05 UT. It descended over 5 S 23 E on the night side and transmitted for 51 minutes. Signals ceased at an altitude of about 18 km and a pressure of 27 bar, thereby confirming the results from its partner. It was 4:18 Venus solar time and the solar zenith angle was 115 degrees.

The Venera 5 and 6 carrier spacecraft both provided measurements on the upper atmosphere and ionosphere prior to breaking up in the atmosphere.

Results:

The Venera 5 and 6 entry capsules transmitted in excess of 70 temperature readings and 50 pressure readings during the descent from about 55 km altitude to their crush depth. Atmospheric density was derived from the temperature and pressure data by using the hydrostatic equation and verified against parachute descent characteristics inferred from the radio altimeter. Doppler data provided altitude profiles of wind speed and direction, both horizontal and vertical. While there was initially confusion about the altimetry, these instruments did work properly and the temperatures and pressures measured near the radio altimeter marks were a good match to the current engineering model of the planet’s atmosphere:

Venera 5 Venera 6

altitude (km)

36

25

18

34

22

pressure (bar)

6.6

14.8

27.5

6.8

19.8

temperature (C)

177

266

327

188

294

Each capsule made two readings of atmospheric composition: at 0.6 and 5 bar for

Подпись: carbon dioxide nitrogen and other noble gases molecular oxygen water vapor

Подпись: Venera 5 97 ± 4% less than 3.5% less than 0.1 % about 1.1% (11 mg/T)
Подпись: Venera 6 greater than 56% less than 2.5% less than 0.1% about 0.6% (6 mg/T)

Venera 5. and at 2 and 10 bar for Venera 6. Their readings were consistent and in good agreement with the Venera 4 data:

Neither photometer registered anything except darkness, although the photo­meter on Venera 5 did report a large reading just before termination. This eould have been a flash of lightning but. given the timing, it may merely have been an electrical transient caused by the imminent breakup.

The Venera 5 and 6 carrier spacecraft returned measurements on the solar wind in the vicinity of Venus and its interaction with the planet.