Category The First Men on the Moon

VEHICLE PREPARATION

Apollo spacecraft CSM-107 was built by North American Rockwell at its plant at Downey, California. The conical command module was 11 feet 5 inches high, 12 feet 10 inches in diameter, and provided a habitable volume of 210 cubic feet. The cylindrical service module was 12 feet 10 inches in diameter and 24 feet 7 inches tall. Radial beams divided it into a central tunnel, which contained tanks of helium pressurant, and six outer compartments, four of which held propellant tanks, one contained the fuel cell system and the sixth was unused.9 The systems tests on the individual modules were completed on 12 October 1968, and the integrated tests on 6 December. The modules were flown to the Cape on 23 January 1969 by a ‘Super Guppy’ aircraft of Aerospace Lines. They were mated on 29 January, passed their combined systems testing on 17 February and altitude chamber tests on 24 March. At the Grumman Aircraft Engineering plant at Bethpage on Long Island, LM-5 completed its integrated test on 21 October 1968, and its factory acceptance test on 13 December. The ascent stage arrived at the Cape on 8 January 1969 and the descent stage on 12 January. After acceptance checks, the stages were mated on 14 February, passed their integrated systems tests on 17 February, and altitude chamber tests on 25 March. Overall, the vehicle stood 22 feet 11 inches tall. The descent stage was 10 feet 7 inches high and had a diagonal span of 31 feet across its foot pads. Two layers of parallel beams in a cruciform shape gave it a central cubic compartment (housing the descent engine), four cubic side compartments (each housing a propellant tank) and four triangular side compartments (carrying apparatus the astronauts would require during their moonwalk). The ascent stage comprised a pressurised crew compartment and midsection with a total volume of 235 cubic feet, and an unpressurised aft equipment bay.

The 138-foot-long, 33-foot-diameter S-IC first stage of the sixth launch vehicle in the Saturn V series was fabricated by Boeing at the Michoud Assembly Facility in Louisiana, and moved in a horizontal configuration by barge up the Intracoastal Waterway to the Mississippi Test Facility, arriving on 6 August 1968. It was then shipped around the southern tip of Florida, to the Kennedy Space Center. On arrival on 20 February 1969 the 24-wheeled trailer bearing the stage was offloaded by a

The fuel cell system had three fuel cells, two tanks of cryogenic oxygen and two tanks of cryogenic hydrogen, and provided 28 volts.

prime mover and driven into the ‘low bay’ annex of the Vehicle Assembly Building. The S-II second stage had the same diameter as the S-IC, but was only 81 feet 6 inches in length. After assembly at the North American Rockwell plant at Seal Beach in California, it was shipped via the Panama Canal to the Mississippi Test Facility, where it was tested on 3 October 1968. On arriving at the Cape on 6 February 1969, the S-II, complete with its 18-foot-tall aft interstage ‘skirt’, was driven on its 12­wheeled trailer to the low bay. After tests at the Douglas Aircraft Corporation facility in Sacramento, California, the S-IVB third stage was flown to the Cape by ‘Super Guppy’ on 19 January 1969. In all, some 12,000 companies across America participated in the production of the launch vehicle.

The principal structure of the Vehicle Assembly Building was 718 feet long, 517 feet wide and 525 feet tall. Its internal volume of almost 130 million cubic feet required a 10,000-ton air-conditioning system to prevent a ‘weather system’ with its own rainfall developing. The cavernous interior provided four ‘high bays’ for simultaneous assembly of Saturn V vehicles. Each pair of bays shared a bridge crane located 462 feet above the floor. The operator was in walkie-talkie contact with his colleagues at the work sites, and used a computer to move loads of up to 250 tons with a tolerance of 1/228th of an inch. Mobile Launch Platform 1 was a two-level steel structure 160 feet long, 135 feet wide and 25 feet high. At one end was the Launch Umbilical Tower, which rose 398 feet above the deck, and offset towards the other end of the platform was a 45-foot-square hole to allow launch vehicle exhaust to pass through. On 21 February the S-IC was hoisted, turned to vertical, and clamped to the supporting arms, one on each side of the hole. The S-II was added on 4 March. The next day the 260-inch-diameter S-IVB, now with its flared aft skirt fitted, was added, and the Instrument Unit containing the guidance system for the launch vehicle (which had arrived on 27 February) was placed on top. The 28-foot – long truncated-cone to house the LM and support the 154-inch-diameter CSM was fabricated at the North American Rockwell plant in Tulsa, Oklahoma, and delivered on 10 January. The integrated CSM, LM, adapter and launch escape system tower was referred to as the ‘spacecraft’ because it was the payload of the three-stage launch vehicle. Its addition on 14 April completed the ‘stack’. From the aperture of the F-1 engines of the first stage to the tip of the escape tower, the ‘space vehicle’, as the integrated launch vehicle and spacecraft was known, stood 363 feet tall. Nine hydraulically operated arms on the umbilical tower provided access to key sections of the vehicle.[17] The combined systems test of LM-5 was finished on 18 April. The integrated systems test of CSM-107 was completed on 22 April, and the spacecraft was electrically mated with the launch vehicle on 5 May. The overall test of the space vehicle was accomplished on 14 May.

The 6-million-pound transporter for the mobile launch system was 131 feet long,

VHF ANTENNA(2)

TRANSFcR TUNNEL AND OVERHEAD HATCH

EVA ANTENNA

AFT EQUIPMENT BAY

REPLACEABLE ELECTRONIC ASSEMBLY

FUEL TANK (REACTION CONTROL)

REACTION CONTROL

INGRESS/EGRESS HATCH

CREW COMPARTMENT

LAND NG

PAD (4)

LUNAR SURFACE SENSING PROBE

A cutaway diagram of the two LM stages.

Launch Escape System (LES)

ty, ‘ у Command module (CM)

Service module (SM)

Spacecraft/LM adapter (SLA)

Lunar Module (LM)

Instrument Unit (IU)

S-IVB

From the point of view of the Saturn V launch vehicle, the ‘spacecraft’ comprises the Launch Escape System, the CSM, and the LM contained within the adapter.

– –

CSM-107 is mated with the adapter of the Apollo 11 launch vehicle on 11 April 1969.

The space vehicle for Apollo 11 is ‘stacked’ in the Vehicle Assembly Building (clockwise from top left): a crane hoists the S-IC on 21 February; the S-II is added on 4 March; the S-IVB is added on 5 March; and the spacecraft is added on 14 April 1969.

On 20 May 1969 the Apollo 11 space vehicle starts up the incline to Pad 39A.

On 22 May 1969 the Mobile Service Structure is driven up to Pad 39A.

114 feet wide, and travelled on four independent double-tracked crawlers, each ‘shoe’ of which weighed about 1 ton. The access road was comparable in width to an 8-lane highway. It comprised three layers, averaging a total depth of 7 feet. The base was a 2-foot-6-inch-thick layer of hydraulic fill. Next was a 3-foot-thick layer of crushed rock. This was sealed by asphalt. On top was an 8-inch layer of river rock to reduce friction during steering. The vehicle was operated jointly by drivers in cabs located on opposite diagonals, who communicated by intercom. On 20 May the Apollo 11 space vehicle was driven to Pad A, the southernmost of the two launch sites of Launch Complex 39. Because the concrete pad was built above ground level to accommodate a 43-foot-tall flame deflector in the flame trench, the transporter had to climb a 5 per cent gradient while tilting the platform such that the tip of the launch escape system tower did not diverge more than 1 foot from the vertical alignment. Once in position, hydraulic jacks lowered the platform to emplace it on six 22-foot-high steel pedestals on the pad. In all, the ‘roll out’ lasted 6 hours. In its final orientation, the umbilical tower stood towards the north, with the axis of the central trench aligned north and south. After the transporter had withdrawn, the flame deflector was rolled in beneath the hole in the platform. On 22 May, the transporter collected the Mobile Service Structure from its parking place alongside the access road, and delivered it to the pad. The flight readiness test was completed on 6 June. The countdown demonstration test started on 27 June; the ‘wet’ phase was completed on 2 July, and the ‘dry’ phase on 3 July. As Kurt H. Debus, Director of the Kennedy Space Center, once said in jest, ‘‘When the weight of the paperwork equals the weight of the stack, it is time to launch!’’

FRA MAURO FORMATION

The flight dynamics team felt sufficiently confident to further reduce the size of the target ellipse and reject the requirement that the landing site be free of terrain relief, to permit the next mission to tackle a more confined site in rougher terrain. In 1962 Gene Shoemaker and R. J. Hackman had issued a stratigraphic map of part of the Imbrium Basin’s rim. In extending this map, R. E. Eggleton classified the peripheral hummocky terrain as ejecta from the Imbrium impact, and called it the Fra Mauro Formation. Although one geological unit, this terrain was distributed in isolated patches around the periphery of the basin. In terms of total area, it was the largest distinct stratigraphic unit on the near side. Contemporary understanding of lunar history was based on how the ejecta from the Imbrium impact had splattered across thousands of miles. Dating this impact was the single most important item on the lunar science agenda, as it would ‘lock in’ many other structures. It was not just a matter of learning about the Moon. The lunar basins indicated that the early Solar System was an extremely violent place. If the Moon had suffered such an intense bombardment so, too, must Earth. Studying the Moon would provide insight into the early history of our own planet. The terrestrial record of this age is missing, in part because of erosion but mainly because the crust is recycled by plate tectonics. The Moon, however, is so endogenically inert that its face has remained essentially unchanged for billions of years. The task was to find a crater in the hummocky Fra Mauro Formation which had a rocky rim, offered a safe line of approach from the east, and was within a mile of a landing site. A 1,200-foot-diameter pit situated 22 nautical miles north of the large crater Fra Mauro, south of the Imbrium Basin, was chosen. As a result of its shape, the ‘drill hole’ crater to be sampled was named Cone. The best landing site was on the undulatory plain 1,000 yards further west, but the target was set twice as far out in order to avoid the fringe of Cone’s ejecta. So great were the results to be gained from this site that after Apollo 13 had to abort and make an emergency return to Earth, Apollo 14 was reassigned this site and the target moved to the optimal landing place.

On 5 February 1971 Al Shepard and Ed Mitchell landed their LM, ‘Antares’. Following the pattern, they deployed their ALSEP on the first day and made the traverse on the second. Since the rocks were consolidations of shattered precursors (i. e. breccias) the analysis was rather more complicated than for previous missions. The primary objective was to date when the fragments had been bound together, in order to date the impact that applied the shock. This was achieved by exploiting the fact that the isotopic ‘clocks’ used to measure formation date are ‘reset’ when a rock is melted. This was not an issue for basalts from the dark plains, but the study of a breccia involved dating its individual clasts. The samples tended to cluster in two age ranges, one spanning the interval 3.96 to 3.87 billion years and the other spanning the interval 3.85 to 3.82 billion years. It was therefore inferred that the breccias

formed around 3.84 billion years ago as ejecta splashed from the Imbrium impact. The older dates provided the formation ages of the rocks shattered by that impact. It had been hoped that samples taken from right on Cone’s rim would characterise the basement on which the Fra Mauro Formation resided, which was expected (by some) to be volcanic. At first, several intriguing samples did look as if they might represent such volcanism, but they proved to be the first instances of another type of breccia. In fact, there proved to be many forms of breccia. The terms ‘fragmental breccia’ was coined for clasts of shattered rock bound up in a matrix of pulverised rock. As further samples were studied, it was found that fragments of individual minerals could become bound into breccias, showing that not all clasts were lithic. Also, since breccias themselves could be caught in impacts, there were ‘breccias of breccias’ in which the clasts of one breccia were fragments of earlier breccias, and the term ‘one-rock’ and ‘two-rock’ were coined to reflect this history. The samples initially thought to be volcanic were a type of breccia in which clasts were bound in impact-melt.4 Despite the violence of the shock-melting, the breccias contained very fragile crystals that could only have been formed by diffusion as mineral-rich vapour escaped from the ejecta. This crystallisation process was very similar to sulphur encrustation of volcanic vents on Earth, but in this case the gas was released by the ejecta itself rather than from the ground on which the ejecta sat, indicating that the rubble was hot when it was deposited and then fused as it congealed. Intriguingly, the impact-melt breccias proved to be KREEPy. Analysis revealed that they were originally a gabbro (i. e. a basalt that solidified deep underground rather than on the surface) that derived from the magma ocean. In the process of crystallisation, an element is accepted or rejected according to whether it fits the crystalline structure; elements that do not fit are known as ‘incompatibles’. As trace elements tend not to participate in mineralisation, they remain in the melt as the ‘compatible’ elements are extracted, with the result that their concentration progressively increases. The radioactives at depth helped to maintain this reservoir molten, and were locked in when it finally solidified. The impact that made the Imbrium Basin had penetrated sufficiently deep to excavate and scatter some of this material across the surface; mystery solved.

THE END OF THE BEGINNING

Apollo 14 drew to a conclusion the initial phase of the exploration of the Moon in which astronauts traversed on foot. Even before Apollo 11, NASA had ordered the design of a battery powered Lunar Roving Vehicle to enable the so-called ‘J’-class missions to range far and wide across their sites, carry a variety of tools, and return a large amount of material. . . but the stories of these missions are for another book.

Impact melt resembles basalt to the extent that it is a solidified rock melt, but endogenic basalt is homogeneous.

On 14 April 1969 Neil Armstrong, Buzz Aldrin and Mike Collins donned their training suits to have their Apollo 11 portrait taken in front of a 5-foot-diameter picture of the Moon.

As Apollo 11 lifts off, the lower arms of the tower swing away.

Apollo 11 clears the tower.

A view from Apollo 11 while in ‘parking orbit’ around Earth.

Following undocking, Collins inspected Eagle’s landing gear.

Frames from the 16-millimetre camera showing Neil Armstrong collecting the contingency sample alongside Eagle, setting up the television camera, and, with Buzz Aldrin, erecting the Stars and Stripes.

The commemorative plaque on Eagle’s forward leg.

Buzz Aldrin stands alongside the SWC. The rim of the crater that Eagle passed over immediately prior to landing forms the horizon, marred by the glare of the Sun.

Part of a panoramic sequence taken by Buzz Aldrin looking north across Eagle’s shadow, showing the television tripod, the Stars and Stripes and Neil Armstrong working at the MESA.

An impromptu (but iconic) picture of Buzz Aldrin.

A view of Eagle and the SWC taken by Buzz Aldrin while taking a panoramic sequence from a position north of the vehicle.

Having left the ALSCC where he took the previous picture, Neil Armstrong moved further out to take a panoramic sequence, catching Buzz Aldrin placing the PSE on the ground. The LRRR is still in the SEQ bay. Notice the ‘washed out’ landscape down-Sun, due to backscattered sunlight and the fact that shadows are masked by the objects that cast them.

Лі.

Neil Armstrong photographed Buzz Aldrin in the process of deploying the PSE.

Buzz Aldrin working on the first ‘core’ sample.

The view from Aldrin’s window after the moonwalk.

As Eagle completed its rendezvous with Columbia, Mike Collins took this picture with Earth in the background.

With the three BIG-clad astronauts safely in a raft, Clancey Hatleberg tends to Columbia’s hatch.

[1] Madalyn Murray O’Hair, a militant atheist, described by Life magazine in 1964 as “the most hated woman in America’’, sued the federal government over Apollo 8’s reading from Genesis, arguing that this violated the separation of state and church. This was rejected by the Supreme Court.

[2] In 1967 North American Aviation merged with the Rockwell Standard Corporation, as North American Rockwell; in 1973 this became Rockwell International.

[3] The Stars and Stripes shoulder patch was introduced by Jim McDivitt and Ed White after being prohibited from naming their Gemini 4 spacecraft ‘American Eagle’. In addition to retaining the flag, for their Gemini 5 flight Gordon Cooper and Pete Conrad introduced a mission patch. Both became standard adornments.

[4] Asa treat, in his personal preference kit Armstrong had an opal that Wendt had supplied, which, upon its return to Earth, Wendt intended to give to his wife Herma.

[5] Wendt kept the trout in his deep freeze until having it remounted in a more conventional way.

[6] Britain’s ambassador to Washington, John Freeman, having attended the launch of Apollo 10, declined his invitation to Apollo 11 on the basis that – as an embassy spokesman put it – ‘‘when you’ve seen one Apollo launch, you’ve seen them all’’.

[7] The Saturn V was so much more powerful than its predecessors that the sound of the first launch on 9 November 1967 took everyone by surprise. ft not only rattled the tin roof of the VfP bleacher but also threatened to collapse the booth from which Walter Cronkite was providing his television commentary.

[8] NASA preferred to use nautical rather than statute miles for space missions. One nautical mile is 2,000 yards, or 6,000 feet; whereas a statute mile is only 1,760 yards or 5,280 feet.

[9] Three of these names were coined by Gus Grissom to celebrate his Apollo 1 crew (‘Navi’ was his middle name, ‘Ivan’, spelt in reverse; ‘Dnoces’ was the reverse spelling of ‘second’, as in Edward H. White II; and ‘Regor’ was the reverse spelling of ‘Roger’, as in Roger B. Chaffee) and, as far as the International Astronomical Union was concerned, they were unofficial.

[10] Of the ‘Original Seven’ astronauts, Wally Schirra, Gus Grissom and Gordon Cooper were on the active list; Deke Slayton and Al Shepard had been grounded for medical reasons; Scott Carpenter had returned to the Navy; and John Glenn, who had been grounded on the basis that as a national icon he was too valuable to risk on a second mission, had left to pursue a political career.

[11] Being detachable, the magazine of a Hasselblad is traditionally referred to simply as a ‘back’.

[12] The engine did not ‘burn’ its propellant; instead a silver catalyst in the chamber converted the H2O2 to superheated steam and oxygen, and the gas passed through the nozzle to produce thrust.

[13] The Lunar Landing Research Facility at the Langley Research Center became operational on 30 June 1965. It was a 260-foot-tall 400-foot-long frame structure with a system of travelling pulleys to suspend a vehicle in such a manner as to balance five-sixths of its weight. It provided a ‘flying volume’ 180 feet in height and 360 feet in length, with a lateral range of 42 feet. Its main role was to test instruments and software to be used by the LM during the final 150 feet of a lunar descent, but astronauts used it to familiarise themselves with flying in one-sixth gravity prior to advancing to the LLTV.

[14] Based on an account in First on the Moon: A Voyage with Neil Armstrong, Michael Collins and Edwin E. Aldrin Jr, by Gene Farmer and Dora Jane Hamblin. Michael Joseph, pp. 216­218, 1970.

[15] In his debriefing after Apollo 11, Armstrong confirmed the fidelity of the LLTV, and thereafter each mission commander trained with it.

[16] The hypergolic propellants were nitrogen tetroxide oxidiser and a fuel comprising a 50:50 mix of hydrazine with monomethyl hydrazine. The RCS of the CSM required 300 pounds, the SPS of the CSM required 41,000 pounds, and the LM’s propulsion systems required a total of 23,245 pounds.

[17] The swing arm numbers and their interface points are: 1, S-IC intertank; 2, S-IC forward; 3, S-II aft; 4, S-II intermediate; 5, S-II forward; 6, S-IVB aft; 7, S-IVB/IU forward; 8, SM; 9,

crew access.

[18] The eagle that attracted Collins’s interest appeared on p. 236 of the book, Water, Prey, and Game Birds of North America, published by the National Geographic Society in 1965. In fact, the plate in the book was a mirror image of the original painting by Walter Alios Weber, which was published in the July 1950 issue of National Geographic Magazine. The eagle on the mission patch matches the orientation in the original.

[19] Telemetry showed the RCS propellant supply to be about 20 pounds below nominal following the transposition manoeuvre.

[20] In some ways, the most unfortunate person involved in the mission was the man who opened the hatch immediately following splashdown!

[21] Prior to the dawning of the space age, astronomers had defined lunar longitudes in terms of their view of the Moon in the terrestrial sky, with the leading limb being east. However, in 1961 the International Astronomical Union had redefined the system to place east in the direction of sunrise as seen from the lunar surface, which reversed the old scheme.

[22] At the post-flight party, the flight controllers voted Bill Tindall an honorary flight director, with the team colour grey.

[23] As was realised later, however, although the impulse from the tunnel venting was cancelled, this manoeuvre, and others made while ‘displaying’ Eagle to Collins, imparted slight residuals which, when propagated forward in time through the DOI manoeuvre, nudged Eagle’s trajectory slightly ‘off at the PDI point.

[24] Some at NASA would later suggest doing precisely this for later missions.

[25] The ground level of Mission Control held the Real-Time Computer Complex, and each of the two upper levels held a Mission Operations Control Room. Apollo 11 was managed from the top level.

[26] What no one realised was that the program driving the antenna was flawed, with the result that at certain times what was expected to be a clear line of sight to Earth was blocked by the structure of the vehicle.

[27] For the LM, yaw was a rotation around the thrust axis.

[28] There was a spare Maurer body, and Aldrin had tested both cameras during his inspection earlier in the mission; the spare was not needed (and was jettisoned with the trash after the moonwalk).

[29] This was long before the advent of computer-generated imagery, so the animations now appear quaint!

[30] Post-mission analysis established that several interrelated factors contributed to the position-velocity error at PDI – including uncoupled attitude manoeuvres such as station­keeping, hot-fire thruster testing, and venting of the sublimator cooling system – but most of these perturbations were more or less self-cancelling. The principal error was the propagation forward of the impulse imparted at undocking due to the incomplete venting of the tunnel; this was not a mistake by Collins, it was an oversight in planning. Due to the ‘vertical’ attitude of the stack at undocking, the perturbation was to the radial component of Eagle’s velocity.

[31] The down-Sun line was called the ‘zero phase’. With the Sun low in the east, the shadows of rocks and craters were hidden when looking west, and coherent backscatter from cleavage planes in the fractured crystalline rocks produced a very strong solar reflection that tended to ‘wash out’ the scene.

[32] At the time of Apollo 11, the law suit brought by Madalyn Murray O’Hair regarding the reading from Genesis by the Apollo 8 crew was still pending.

[33] Due to Armstrong’s manner of speech, he appears to have appended the ‘a’ to ‘for’, which came out as ‘for-a’, thereby giving the impression that he misspoke and uttered something meaningless!

[34] The time in Houston was 9.56 pm on Sunday, 20 July 1969.

[35] Vesicles were a characteristic of igneous rock in which the melt contained bubbles of gas that left spherical holes in the solidified rock. Since this occurs more readily in lava that has been extruded onto the surface or is at shallow depth, it supported the inference that the landing site was a basalt lava flow. Armstrong would expand on this observation later in the excursion.

[36] Phenocrysts were crystals embedded in the finely grained matrix of an igneous rock.

[37] These accounts are derived from interviews compiled by Glen E. Swanson in Before this Decade is Out… Personal Reflections on the Apollo Program, SP-4223, NASA, 1999.

[38] As indeed would happen at this point in the mission of Apollo 12.

[39] Engineers in Houston designed a ‘stand’ which, when deployed, would display the flags of the member states of the United Nations in the style of a tree.

[40] This picture of Aldrin became the iconic Apollo 11 ‘Man on the Moon’ image. It is on the front cover of this book.

[41] Although McCandless was told that a laser reflection had been detected while Eagle was still on the surface, and he relayed this news to Collins, this was not so.

[42] The seismometer included a detector to measure dust accumulation and radiation damage to the solar cells, and an isotope heater to keep the electronics warm during the long lunar night. Despite operating temperatures that exceeded the planned maximum by 30°C, the instrument functioned normally through the maximum heating around lunar noon. With the power output from the solar arrays in decline about 5 hours before local sunset (on 3 August 1969) transmission was halted by command from Earth. ft was turned on again on the next lunar day, but (on 27 August) near noon of this second lunar day the instrument ceased to accept commands and the experiment was terminated.

[43] The platform began to be unusable after 4 hours, and the computer failed just over 3 hours later. Both items had operated for considerably longer than had been predicted. The other systems were still functioning. The last contact with Eagle was at 137:55, when the battery output dipped below that required for the AGS to maintain the vehicle’s attitude within the antenna’s requirements for communication with Earth. Although Eagle was released in an almost circular orbit, perturbations by the mascons would soon have caused it to strike the surface, but it is not known when or where this occurred.

[44] On subsequent missions, crews would tease Duke about this misidentification.

[45] In fact, Armstrong was in error because Columbiad was the name of the giant cannon that fired Verne’s spaceship to the Moon; the ship did not have a name, always being referred to simply as ‘‘the projectile”.

[46] Note that there was a presumption that the astronauts would not get sea sick while wearing their suits, as the mask would have to have been removed in order to vomit, which would have violated the isolation.

[47] There are several Hasselblad pictures of Armstrong on the lunar surface, but he is in shadow and it was some time before his presence on these frames was noted.

[48] The aim point was at 0°42’50"N, 23°42’28"E.

[49] Actually, as Apollo 11 was heading home, NASA decided to withdraw one Saturn V from the lunar program in order to launch the Skylab space station, but this had not yet been announced.

[50] This is what Pete Conrad and Al Bean did after walking on the Moon on Apollo 12. Their CMP, Dick Gordon, remained in the lunar program in the hope of commanding Apollo 18, but this flight was cancelled.

[51] The name ‘armalcolite’ was derived from the first letters of the astronauts’ surnames. Some years later this mineral was found on Earth, too.

[52] These could be characterised in terms of their terrestrial equivalents as olivine basalt, pyroxene basalt, ilmenite basalt and feldspathic basalt.

The First Men on the Moon

On 17 December 1903 on the beach at Kitty Hawk, North Carolina, Orville Wright achieved the first flight in a ‘heavier than air’ machine. On 20 May 1927 Charles Augustus Lindbergh took off in Spirit of St Louis at the start of the first successful solo flight across the Atlantic, tracing the ‘great circle’ route from New York to Paris. On 12 April 1961 Yuri Alekseyevich Gagarin became the first man to orbit Earth. In response, the following month President John F. Kennedy challenged his own nation to land a man on the Moon before the decade was out – and on 16 July 1969 Apollo 11 set off to do so.

By demonstrating that it was feasible to land on the Moon, it cleared the way for the later missions that undertook more ambitious lunar surface activities. Yet Apollo was an anachronism – an element of 21st century exploration provoked by the geopolitical tensions of the 1960s. When Sir Arthur C. Clarke was asked what event in the 20th century he would never have predicted, he said: ‘‘That we would have gone to the Moon and then stopped.’’ Nevertheless, at the time of Apollo 11 the Moon was viewed merely as the first step. At a press conference just beforehand, Thomas O. Paine, NASA’s Administrator, said: ‘‘While the Moon has been the focus of our efforts, the true goal is far more than being first to land men on the Moon, as though it were a celestial Mount Everest to be climbed. The real goal is to develop and demonstrate the capability for interplanetary travel.’’ This task remains to be fulfilled. In 2004 President George W. Bush directed NASA to resume human lunar exploration as a stepping stone to Mars. Perhaps by the time of the 50th anniversary of Apollo 11, mankind will once again be able to enjoy the excitement of a lunar landing.

As the mission of Apollo 11 is a story of exciting times, f have drawn on the mission transcript to recreate the drama. Quotations have been edited for clarity, for brevity, and to eliminate the intermingling that is characteristic of spontaneous conversation, but f have endeavoured to preserve the sense of the moment.

David M Harland July 2006

Acknowledgements

I would like to thank: Frank O’Brien, W. David Woods, Robert Andrepont, Ken MacTaggart, Hamish Lindsay, Gene Kranz, Gerry Griffin, Dave Scott, Mark Gray, Mick Hyde, Rich Orloff, Mike Gentry, Ed Hengeveld, Eric Jones, Stanley Lebar, Kipp Teague, Marc Rayman and, last but not least, Clive Horwood of Praxis.

OVER THE HILL

Jack Riley was the Public Affairs Officer in Mission Control. “We’ve just had loss of signal as Apollo 11 passed behind the Moon. At that time we were showing its distance from the Moon as 309 nautical miles and its velocity with respect to the Moon as 7,664 feet per second. Here in the Control Center, two members of the backup crew, Bill Anders and Jim Lovell, have joined Bruce McCandless at the CapCom console. Fred Haise, the third member of the backup crew, just came in, too. And Deke Slayton, Director of Flight Crew Operations, is also present. The viewing room is filling up: among those on the front row are Tom Stafford, John Glenn, Gene Cernan, Dave Scott, Al Worden and Jack Swigert.’’

The inertial attitude of the vehicle was such that at its closest point of approach to the Moon the SPS engine would be facing the direction of motion, to serve as a brake. The CSM had redundant power buses, but in preparation for the burn these were ‘tied’ together to ensure that if one power supply were to fail this would not disrupt the operation of the systems at a critical time.

‘‘I’ve turned the S-Band volume down to get rid of that background noise,’’ Collins announced, ‘‘so don’t forget that we have to turn it back up on the other side!’’

With 2 minutes to go, they emerged from the Moon’s shadow. As they had been flying ‘on instruments’, Collins looked out of the window to visually confirm that they were in the correct attitude. ‘‘Yes, the Moon’s there, in all its splendour.’’

As they raced across the terminator, the deeply shadowed terrain appeared to be extremely rough. ‘‘Man,’’ exclaimed Aldrin, ‘‘look at it!’’

‘‘Don’t look at it!’’ said Armstrong, drawing their attention back inside. ‘‘Here we come up to ignition.’’

At 5 seconds to go, the computer flashed ‘99’ in the Verb display of the DSKY, to ask the crew whether they wished to go ahead with the burn as specified. ‘‘99’’, noted Collins.

‘‘Proceed,’’ commanded Armstrong.

Collins hit the PROCEED key to tell the computer to execute the manoeuvre. ‘‘Stand by for ignition.’’ Armstrong’s heart rate was 106 beats per minute, Collins’s was 66, and Aldrin’s was 70.

Two RCS thrusters fired briefly to settle the propellants in the main tanks, and then at the appointed time the computer ignited the SPS engine.

‘‘Burning!’’ confirmed Armstrong.

‘‘What’s our chamber pressure?’’ Collins asked.

The gauge was below the left FDAI. ‘‘It’s good, 95,’’ confirmed Armstrong.

‘‘The PUGS is oscillating around,’’ noted Aldrin. The Propellant Utilisation Gauging System measured how the engine was drawing fuel and oxidiser. Aldrin was to use a knob to maintain the correct combustion mixture, but this was tricky due to the lag in response.

‘‘Okay, we’re steering,’’ noted Collins. ‘‘The gimbals are a little busier than I’d have expected, but everything’s looking good.’’ The engine gave a load equivalent to one-fifth gravity. ‘‘The g feels sort of pleasant.’’

‘‘Tank pressures are good,’’ Aldrin confirmed.

“The chamber pressure is building up a little bit; 96 now,” Armstrong noted as he monitored the gauge.

“That’s a little more chamber pressure than they were predicting,” pointed out Collins, thinking of the miscalibration.

“Chamber pressure is continuing to rise,’’ added Armstrong a moment later, “it’s up to about 98 psi.’’

“We’re wandering off a little bit in roll, but that’s to be expected,’’ observed Collins. “It’s coming back.’’

The high chamber pressure would reduce the duration of the burn, but that was not the critical issue; what mattered was the change in velocity, and the computer would shut down the engine when the required 2,917.3-foot-per-second change in velocity had been attained. “Cutoff is going to be about 3 seconds early,’’ warned Aldrin.

“Nominal cutoff is at 6 + 02,’’ Collins noted, “so expect it around 6 minutes even, huh?’’

“I’m predicting 5 + 58, 4 seconds early,’’ said Armstrong. “Maybe 5 seconds.’’

“She’s steering like a champ,’’ Collins said. “The rates are wandering, but in all three axes they’re plus or minus 0.1 degree.’’

“Five seconds early, at 5 + 57,’’ Armstrong updated. “The chamber pressure is 100 psi even.’’

Collins counted down the seconds to the predicted cutoff.

“Shutdown!’’ confirmed Armstrong.

As they ran through the post-burn checklist, Collins prompted the computer to display the discrepancies between the desired and achieved velocity as measured in the three-coordinate system. “Minus 1, minus 1, plus 1; Jesus!’’ The ‘residuals’ were only 0.1 foot per second; the burn was essentially perfect. ‘‘I take back any bad things I ever said about MIT – which, of course, I never have.’’

Aldrin glanced out at the Moon. They were now well past the terminator and the terrain was well lit. ‘‘I have to vote with the Apollo 10 crew that the surface is brown.’’

‘‘It sure is,’’ agreed Collins.

‘‘It looks tan to me,’’ said Armstrong.

‘‘But when I first saw it, at the other Sun angle it looked grey,’’ Aldrin noted, referring to just prior to the burn. ‘‘It got more brown with increasing Sun angle.’’

Armstrong again drew his colleagues’ attention inside, ‘‘Alright, now we’ve got some things to do.’’

As they continued through the checklist, Collins said, ‘‘Well, I don’t know if we’re 60 miles or not, but at least we haven’t hit that mother.’’

The computer displayed the parameters of their orbit. ‘‘Look at that!’’ Aldrin exclaimed, ‘‘169.6 by 60.9.’’

‘‘Beautiful, beautiful, beautiful, beautiful!’’ enthused Collins. ‘‘Write it down just for the hell of it: 170 by 60, like gangbusters.’’

‘‘We only missed [apolune] by a couple of tenths of a mile,’’ Aldrin added in amazement.

It is not possible to orbit Earth at an altitude of 60 nautical miles, as this would be subject to the drag of the upper atmosphere. However, the Moon is airless. It is also smaller and less massive and, since its gravity is weaker, a spacecraft in orbit is not required to travel so fast. On the other hand, because the orbit is smaller, the period – at about 2 hours in this case – is only marginally longer than for a low orbit around Earth.

“Hello, Moon,” Collins greeted. “How’s the old back side?”

“Now,” said Armstrong, “the flight plan says we roll 180 degrees and pitch down 70 degrees.’’

“What are we pitching down for?’’ Collins asked. Then he laughed. “I don’t know what we’re doing.’’

Armstrong enlightened his CMP, “We’re going to roll over and pitch down so that we can look out the front windows down at the Moon!’’

“Oh, yes, okay,’’ Collins acknowledged.

As the spacecraft slowly executed the 180-degree roll, Collins asked, “Can we see the Earth on the horizon from here?’’

“We should be able to,’’ Armstrong replied.

Collins decided they should take a picture of their first Earthrise. “Big lens or small one?’’

“For the Earth coming up, we want the 250-millimetre,’’ decided Aldrin, as he started to assemble the Hasselblad. “Infinity, at f/11 and 1/250th, huh?’’

“Is it loaded with black-and-white, or colour?’’ asked Collins.

“Colour.’’

“Alrighty!’’ said Collins, satisfied.

“We ought to wash this window,’’ Aldrin said. “Anybody got a Kleenex?’’

Both Armstrong and Collins offered towels.

“Well, one more SPS burn,’’ Collins mused, thinking of completing the lunar orbit insertion sequence.

“Two more!’’ corrected Aldrin, remembering that the engine would also have to make the transearth injection burn if they were to get home.

Meanwhile, at home

Jan Armstrong had Barbara Young over for lunch. Having been through lunar orbit insertion on Apollo 10, Barbara described how she had had an anxious wait when her husband’s flight had reported back fully two minutes later than expected, raising the prospect of the burn having slowed that vehicle so much that it would crash. However, Jan was more concerned that AOS might be early, indicating that the burn had not occurred and the spacecraft was heading back to Earth on the free-return trajectory, because she knew that to lose the opportunity to attempt to land would be devastating for the crew’s morale. “Don’t you dare come around,’’ she muttered as the no-burn time approached. “Don’t you dare!’’ When that moment passed with no signal, she delightedly exclaimed “Yippee!’’

Back in space

“Look at those craters in a row. Something really peppered that one,’’ Collins said, drawing attention to the lunar surface. “There’s a lot less variation in colour than I would have thought, you know, looking down?’’

“But you’d say it’s brownish?” Aldrin asked.

“Sure.”

“Oh, golly, there’s a huge, magnificent crater over here,’’ exclaimed Aldrin. “I wish I had the other lens on. God, that’s a big beauty. You should look at that guy, Neil.’’

“I see him,’’ Armstrong said.

“Well,” said Collins, “there’s really no doubt that the Moon is a little smaller than the Earth; look at that curvature.’’

Aldrin suggested that as they still had about 10 minutes to AOS, they ought to switch the Hasselblad to a ‘wider’ lens in order to shoot the lunar landscape.

“Just don’t miss that first one,’’ urged Collins, eager that they should record their first Earthrise.

The landscape passing below was fascinating.

‘‘What a spectacular view!’’ remarked Armstrong.

‘‘There’s a hole down here you just wouldn’t believe,’’ Collins pointed out. ‘‘And there’s the biggest one yet. God, it’s huge! It’s enormous! It’s so damned big I can’t even get it in the window! You want to look at that? That’s the biggest one you ever seen in your life. Neil? God, look at this central mountain peak.’’

Meanwhile in Houston, Jack Riley, continuing his public commentary, noted, ‘‘It’s very quiet here in Mission Control. Most of the controllers are seated at their consoles, several are standing up. We’re now 7 minutes from the acquisition time for the nominal burn. If Apollo 11 attained only a partial burn, we could receive a signal at any time.’’

‘‘Isn’t that a huge one?’’ Collins exclaimed, indicating another crater as they continued around the Moon’s far side. ‘‘It’s fantastic! Oh, boy, you could spend a lifetime just geologising that one crater alone!’’ After pausing to reflect, he added, ‘‘Although that’s not how I would like to spend my lifetime!’’

‘‘There’s a big mother over here, too,’’ Aldrin pointed out.

‘‘Come on now, Buzz,’’ Collins chastised, ‘‘don’t refer to them as ‘big mothers’ – give them some scientific names.’’

‘‘It sure looks like a lot of them have slumped down,’’ noted Aldrin, referring to the terraced rims of the craters, which had indeed slumped into the pit.

‘‘A slumping big mother!’’ exclaimed Collins. ‘‘Well, you see those every once in a while.’’

‘‘Most of them are slumping,’’ continued Aldrin, ignoring Collins. ‘‘The bigger they are, the more they slump.’’

‘‘We’re at 180 degrees,’’ announced Armstrong as he terminated the roll, ‘‘and now we start a slow pitch down about 70 degrees.’’

‘‘We’ve got 4 minutes to get pitched down before AOS,’’ pointed out Aldrin. ‘‘We’ll never make it.’’

‘‘Goddamn, a geologist up here would just go crazy,’’ suggested Collins. ‘‘We shouldn’t take any more pictures on this roll until we get Earth.’’

‘‘We might make it in time,’’ said Armstrong, referring to the timing of their pitch manoeuvre.

‘‘There it is,’’ exclaimed Aldrin. ‘‘It’s coming up!’’

“What is?” Collins asked.

“The Earth!” explained Aldrin. “See it?”

“Yes. Beautiful.”

“It’s halfway up already,” Aldrin noted. He snapped a picture, but not having changed back to the 250-millimetre lens it was not the close up Collins desired. “We ought to have AOS now,’’ Armstrong pointed out.

The antenna in Madrid acquired the carrier signal right on time, indicating a good burn.

“AOS!” Riley announced to the public.

“Apollo 11, this is Houston. Do you read?’’ prompted McCandless. Although Armstrong replied with a full burn report, the high-gain antenna had yet to lock on and the transmission by omnidirectional antenna was so noisy that he was mostly unintelligible. “Could you repeat your burn status report?’’ McCandless requested. “It was perfect!’’ Armstrong replied simply.

Once the high-gain link had been established, the flight controllers examined the telemetry. Going ‘over the hill’, the combined mass of the two spacecraft was 96,012 pounds. The LOI-1 burn had consumed 24,008 pounds of propellant.

Meanwhile, at home

Joan Aldrin, who was at the hair-dresser, was listening to the radio coverage of the mission. In her house, Rusty Schweickart was explaining to the assembled crowd that the manoeuvre had gone to plan.

FLIGHT DIRECTORS

Clifford E. Charlesworth was appointed as lead flight director for Apollo 11. Cool headed with an easy smile, he had been nicknamed the Mississippi Gambler by the flight controllers on account of the fact that, although he always appeared relaxed, he was focused and confident. As planning firmed up in early 1969, he shared the principal tasks among the available flight directors. Of the eight major phases of the mission, five had either been demonstrated by Apollo 8 or soon were to be by Apollo 10, and the three unrehearsed phases were the powered descent to the lunar surface, the moonwalk, and the lunar liftoff. As, by Apollo 11, Charlesworth would be most familiar with the Saturn V, he took launch on through to the translunar injection manoeuvre, plus the subsequent surface excursion. Eugene F. Kranz had most experience with the LM, including its unmanned test on Apollo 5 and manned test on Apollo 9, and was therefore assigned the lunar landing and transearth injection manoeuvre. As Glynn S. Lunney would have been to the Moon twice, both times focusing on the CSM, he was given responsibility for the lunar liftoff and rendezvous. Gerald D. Griffin and Milton L. Windler were assigned to other miscellaneous tasks. The flight directors met the branch chiefs of the flight control division to create their teams of flight controllers, balancing their individual areas of expertise to each phase of the mission.

The flag ceremony

On 31 January 1969 Apollo Program Director Samuel C. Phillips asked Robert R. Gilruth of the Manned Spacecraft Center, Wernher von Braun of the Marshall Space Flight Center and Kurt H. Debus of the Kennedy Space Center to suggest symbolic activities that might be undertaken on the first lunar landing mission that would illustrate international agreements regarding the exploration of the Moon. The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space that was signed by the United States and the Soviet Union on 27 January 1967 (and, incidentally, witnessed by some of the astronauts, among them

The SWC sheet was designed in metric units, so these have been used here to enhance fidelity.

Buzz Aldrin deploys the SWC.

Neil Armstrong) stated, in part, that the spacefaring powers agreed not to stake territorial claims on celestial bodies. When NASA proposed that the flag of the United Nations be raised, this was rejected by Congress, which directed that the US flag be flown. Phillips proposed that they also either raise the flag of the United Nations alongside the American flag, place decal flags of the member nations of the UN on the descent stage, or just deposit an appropriate information capsule on the surface.[39] However, Congress ordered that only the flag of the United States be raised. In order to preclude any manufacturer claiming to have made the flag used on the Moon, George M. Low ordered that a 3-foot-by-5-foot Stars and Stripes be purchased (at the average price of $3) from every official supplier, that their labels be removed, and that a secretary select a flag at random; the other flags would not go to waste, because if ever there was a mission to prompt the waving of a flag this would be it!

Having returned to Eagle, Armstrong and Aldrin retrieved the flag assembly from stowage in a thermal shroud by the left-hand ladder rail. They then set off northwest, in the general direction of the television camera, Aldrin carrying the lower part of the aluminium staff and Armstrong the upper part of the staff with the crossbar attached at its top by a locking hinge, incorporating the flag itself. Once they were in position, Armstrong rotated the crossbar into position and the two men grasped opposite ends of the telescoping rod in order to draw it out, but it became stuck just short of its full extension.

At this point Columbia appeared around the limb. “How’s it going?” asked Collins. Joan Aldrin sympathised with him, “He doesn’t know what’s going on, poor Mike!’’

“The EVA is progressing beautifully,” McCandless replied. “I believe they are setting up the flag now.’’

“Great!” Collins said.

“I guess you’re about the only person around that doesn’t have TV coverage of the scene,’’ McCandless consoled.

“That’s all right,’’ Collins insisted. “I don’t mind a bit. How is the quality of the television?’’

“Oh, it’s beautiful, Mike. It really is,’’ McCandless assured.

“Oh, gee, that’s great!’’ said Collins. “Is the lighting half-way decent?’’

“Yes, indeed,’’ McCandless confirmed.

Having accepted that the crossbar would deploy no further, Armstrong set out to drive the lower section of the staff into the ground. As in the case of the staff of the SWC, the ground resisted penetration. Frustratingly, the surficial material gave little lateral support to hold the staff upright. On placing the flag assembly on top of the staff, Aldrin stepped back to salute and the flight control team stood, cheered and applauded.

The Mission Operations Control Room during the moonwalk.

“They’ve got the flag up now,” McCandless informed Collins, “and you can see the Stars and Stripes on the lunar surface!’’

“Beautiful,” replied Collins.

While Armstrong held the staff, Aldrin gripped the top and bottom of the flag and attempted to straighten it, in vain. They left it with a ‘permanent wave’ which, in retrospect, gave it a more natural appearance than if they had been able to draw it out totally flat. To finish off, Armstrong snapped two pictures of Aldrin standing by the flag.

Moving to his next checklist assignment, Aldrin set about evaluating modes of mobility. To enable the engineers to monitor his progress, he was to perform this exercise in front of the television camera. When asked, McCandless verified that he was in the field of view. He tested (1) a ‘loping gait’ in which he alternated his feet; (2) a ‘skipping stride’ that always led with the same foot; and (3) a ‘kangaroo hop’ in which both feet acted together. The conventional walking gait proved to be the most effective. On Earth he could easily halt his motion with a single step, but on the Moon it took several steps to slow down because the ratio of mass-to-weight had changed by a factor of 6. Similarly, changing direction while in motion had to be done in stages, stressing the outside leg in order to force the turn. As Aldrin paraded in front of the television camera, his wife laughed so much that her eyes wept. Pat Collins, watching with Barbara Gordon and Sue Bean, was amused by his antics. Jan Armstrong, who was ticking off items on her list, doubted they would achieve all of their assigned tasks in the time available.

Meanwhile, Armstrong had dismounted the Hasselblad and placed it on the MESA in order to start to prepare the equipment with which he was to collect what field geologists call a ‘bulk’ sample of the loose ground mass with embedded rock fragments.

A long-distance phone call

‘‘Tranquility Base, this is Houston,’’ McCandless called formally. ‘‘Could we get both of you on the camera for a minute, please.’’

‘‘Say again, Houston,’’ said Armstrong.

After repeating the request, McCandless added, ‘‘Neil and Buzz, the President of the United States is in his office now and would like to say a few words to you.’’

‘‘That would be an honour,’’ Armstrong said.

Richard Nixon had been watching them on television with Frank Borman in his private office in the White House. After the flag had been raised, Nixon went next door to the Oval Office to place a telephone call to the lunar surface. With a camera set up in the Oval Office, the television networks presented this historic call in split­screen fashion. Deke Slayton had alerted Armstrong that at some time during the moonwalk (the obvious moment being just after the flag was raised) they might receive a ‘‘special communication”, which they both took to mean a call from Nixon. However, it came as a surprise to Aldrin.

‘‘Go ahead, Mr President,’’ said McCandless.

‘‘Neil and Buzz,’’ Nixon began, ‘‘I’m talking to you by telephone from the Oval Room at the White House, and this certainly has to be the most historic telephone call ever made. I just can’t tell you how proud we all are of what you have done. For every American, this has to be the proudest day of our lives. And for people all over the world. I am sure they, too, join with Americans in recognising what an immense feat this is. Because of what you have done, the heavens have become a part of man’s world. And as you talk to us from the Sea of Tranquility, it inspires us to redouble our efforts to bring peace and tranquillity to Earth. For one priceless moment in the whole history of man, all the people on this Earth are truly one; one in their pride in what you have done, and one in our prayers that you will return safely to Earth.’’ “Thank you, Mr President,’’ Armstrong acknowledged. “It’s a great honour and privilege for us to be here representing not only the United States but men of peace of all nations, and with interest and a curiosity and a vision for the future. It’s an honour for us to be able to participate here today.’’

“And thank you very much,’’ added Nixon, “and I look forward – all of us look forward – to seeing you on the Hornet on Thursday.’’

“I look forward to that very much, sir,’’ replied Armstrong, signing off.

Both astronauts had remained in place throughout the call. Aldrin remained silent and left it to his commander to make the responses.

In the Collins house, Rusty Schweickart said there would be scientists around the world urging the astronauts to push on and collect some rocks. Indeed, Nixon was later criticised by some in the scientific community for having ‘wasted’ the limited time available to the astronauts. Aldrin, following his checklist, shuffled around repeatedly scuffing the surface with his boot to observe how the material dispersed. When sand on a terrestrial beach is scuffed, it disperses in an arc with some of the grains travelling further than others. On the Moon, in the absence of air-drag to sort the particles by size, all the grains landed at the same radius, which depended upon the impulse imparted and the weak lunar gravity. As this phenomenon marked a striking difference between training and reality, Aldrin found it fascinating. On returning to Eagle, Aldrin was struck by the sharpness of the vehicle’s shadow. On standing in sunlight and projecting his arm into the shadow, it seemed to vanish. Furthermore, as he recalled later, ‘‘The light was sometimes annoying, because when it struck our helmets from a side angle it would enter the face plate and make a glare that reflected all over it. As we penetrated a shadow we would get a reflection of our own face, which would obscure anything else. Once when my face went into shadow it took maybe 20 seconds before my pupils dilated out again and I could see details.’’

SMALL DETAILS

When NASA began to launch pairs of spacecraft during a single Apollo mission, it became necessary to introduce individual call signs while the vehicles were being operated independently. On seeing their CM arrive at the Cape tightly wrapped in a blue sheet, like a sweet, the Apollo 9 crew decided to name the CSM ‘Gumdrop’, and the LM was named ‘Spider’ for its arachnid appearance. In March 1969, after the Apollo 10 crew decided to name their vehicles ‘Charlie Brown’ and ‘Snoopy’ – characters in Charles L. Schulz’s comic strip Peanuts – Julian Scheer, Assistant Administrator for Public Affairs, wrote to George M. Low, Manager of the Apollo Spacecraft Program Office in Houston, to suggest that the next mission, which was to try to land on the Moon, should use more dignified names. The Apollo 11 crew, of course, were fully aware of the historical significance of their mission. As Michael Collins recalled:11

Based on accounts in Carrying the Fire: An Astronaut’s Journeys, by Michael Collins, W. H. Allen, p. 332, 1975, and ‘All we did was fly to the Moon’: Astronaut Insignias and Call Signs, by Richard L. Lattimer, The Whispering Eagle Press, Florida, p. 66, 1985.

“We had a variety of non-technical chores, such as thinking up names for our spacecraft and designing a mission emblem. We felt Apollo 11 was no ordinary flight, and we wanted no ordinary design, yet we were not professional designers. NASA offered to help us along these lines – wisely, I think. On Gemini 10, which [I flew with John Young, and] in my view has the best­looking insignia of the Gemini series, artistic Barbara Young had developed one of John’s ideas and come up with a graceful design, an aerodynamic ‘X’ devoid of names and machines. This was the approach we wanted to take on Apollo 11. We wanted to keep our three names off it, because we wanted the design to be representative of everyone who had worked toward the lunar landing – and there were thousands who could take a proprietary interest in it, yet who would never see their names woven into the fabric of a patch. Further, we wanted the design to be symbolic rather than explicit. On Apollo 7, Wally Schirra’s patch showed the Earth and an orbiting CSM trailing fire. On Apollo 9, Jim McDivitt produced a Saturn V, a CSM, and a LM. Apollo 10’s was even busier! Apollo 8’s was closer to our way of thinking, showing a figure of eight looping around Earth and Moon, on a command-module-shaped patch, but it had, like all the rest, three names printed on it. We needed something simpler, yet something which unmistakably indicated a peaceful lunar landing by the United States. Jim Lovell, Neil’s backup, introduced an American eagle into the conversation. Of course! What better symbol – eagles landed, didn’t they? At home I skimmed through my library and finally found what I wanted in a National Geographic book on birds: a bald eagle, landing gear extended, wings partially folded, coming in for a landing.[18]1 traced it on a piece of tissue paper, and sketched in an oblique view of a pockmarked lunar surface. Thus the Apollo 11 patch was born – although it had a long way to go before final approval. I added a small Earth in the background and drew the sunshine coming from the wrong direction, so that to this day our official insignia shows the Earth [incorrectly oriented] over the lunar horizon. I pencilled ‘APOLLO’ around the top of my circular design and ‘ELEVEN’ around the bottom. Neil didn’t like the ‘ELEVEN’ because it wouldn’t be understandable to foreigners, so after trying ‘XI’ and ‘11’, we settled on the latter, and put ‘APOLLO 11’ around the top. One day, outside the simulator, I was describing my efforts to Jim Lovell, and he and I both agreed that the eagle alone really didn’t convey the entire message we wanted. The Americans were about to land, but so what? Thomas L. Wilson, our computer expert and simulator instructor, overheard us and said to add an olive branch as a symbol of our peaceful expedition.

Beautiful! Where do eagles carry olive branches? In their beaks, naturally. So I sketched one in, and after a few discussions with Neil and Buzz over colour schemes, we were ready to go to press. The sky would be black, not blue, but absolute black, as in the real case. The eagle would be eagle-coloured, the Moon Moon-coloured, as described by Apollo 8, and the Earth also. So all we had left to play with, really, were the colours of the border and the lettering. We picked blue and gold, and then Stan Jacobsen in Houston assigned James R. Cooper, an illustrator at MSC, to do the artwork for us. We photographed the finished design and sent a copy through channels to Washington for approval. Washington usually rubber-stamped everything. Only this time they didn’t, and our design came back disapproved. The reason? The eagle’s landing gear – powerful talons extended stiffly below him – was unacceptable. It was too hostile, too warlike; it made the eagle appear to be swooping down on the Moon in a very menacing fashion – according to Bob Gilruth [Director of the Manned Spacecraft Center]. What to do? A gear-up approach was unthink­able. Perhaps the talons could be relaxed and softened a bit? Then someone had a brainstorm: just transfer the olive branch from beak to claw, and the menace disappeared. The eagle looked slightly uncomfortable clutching his branches tightly with both feet, but we resubmitted it anyway, and it greased on through channels and won final approval.’’

As regards the call signs, when it became apparent that Apollo 11 would be the mission, the crew began to receive suggestions for naming their spacecraft, some of which comprised pairs, others not. Names from mythology were dismissed for the simple reason that investigation invariably turned up something inappropriate. Romantic name pairings such as ‘Romeo’ and ‘Juliet’ were also rejected. ‘Castor’ and ‘Pollux’ were appealing, but were too suggestive of the Gemini program. Pat Collins argued for ‘Owl’ and ‘Pussycat’. An important factor was that the names selected should have clarity in radio transmission. For Scott Carpenter’s Mercury flight, his wife, Rene, had suggested ‘Rampart’, after the mountain range of his native Colorado, but he chose ‘Aurora’, which, lacking hard consonants, proved indistinct on the radio. It was decided that while the names must reflect American pride in the mission, they must do so with subtlety. To paraphrase Collins’s account:

‘‘The choice of an eagle as a motif for the landing led swiftly to naming the landing craft Eagle. One day, I was chatting long-distance with Julian Scheer, Assistant Administrator for Public Affairs in Washington, who suggested the name Columbia for our CSM. It sounded a bit pompous to me, but it had a lot going for it – the close similarity of Jules Verne’s mythical moon-ship cannon, the Columbiad, and the close relationship between the word ‘Columbia’ and our national origins: Columbia had almost become the name of our country. Finally, the lyrics ‘Columbia, the Gem of the Ocean’ kept popping into my mind and they argued well for the recovery of the spacecraft, which hopefully would float on the ocean. Since Neil and Buzz had no objections, and since I couldn’t come up with anything better, Columbia it was.’’

The ‘Apollo 11’ call sign would be used until such time it became necessary to discriminate, whereupon the two vehicles would employ their own names. Prior to the mission, Armstrong and Aldrin had given some thought to whether they should continue to refer to themselves by the call sign ‘Eagle’ while on the lunar surface, or introduce some other name. As Aldrin recalls:13

‘‘It would be somewhat similar to a radio call sign, but we wanted to give it added significance. Moon One? Base Camp? Moon Base? When we made our choice, we told only Charlie Duke, who would be our Capsule Communicator back in Houston, who we felt should know the exact name in case transmission was garbled. I cannot remember which of us originated the selection, but once we had thought it over it was an obvious choice. We were landing in an area known as the Sea of Tranquility, and would call our landing site Tranquility Base.’’

Approval of the call signs was not forthcoming from headquarters until the beginning of July.

The Apollo 11 crew

THE HAND OF FATE

It was Saturday, 21 December 1968, and some 2 hours 27 minutes into the mission when astronaut Mike Collins made the call, “Apollo 8, you’re Go for TLI.” This cryptic one-liner relayed the momentous decision that Frank Borman, Jim Lovell and Bill Anders were cleared to attempt the translunar injection (TLI) manoeuvre that would make them the first humans to head out to the vicinity of the Moon. If all went to plan, in three days the spacecraft would enter lunar orbit to conduct a reconnaissance for the missions that would follow, one of which would hopefully accomplish the challenge made by President John F. Kennedy on 25 May 1961 “to achieving the goal, before this decade is out, of landing a man on the Moon, and returning him, safely, to the Earth’’.

By a cruel irony, Collins had been assigned to Apollo 8. In early 1968 he had been the astronauts’ handball champion, but his game had deteriorated. “My legs felt peculiar, as if they did not belong 100 per cent to me. I had heard prize-fighters talk about their legs going, and I thought, well, instant old age.’’ On seeking medical advice, he was told that a disk had worked completely loose from its vertebra, fallen down into the spinal tunnel, and was impinging on his spinal cord. He suspected this derived from ejecting in 1956 from an F-86 which caught fire. Not only would it be necessary to undergo surgery, but if he was to retain flight status in jet aircraft then the adjacent vertebrae would have to be fused together to enable his weakened neck to withstand another ejection. The surgery in July was completely successful. In the meantime, he had been dropped from the Apollo 8 crew and replaced by his backup, Lovell. While recovering, Collins read in a newspaper that NASA had decided to send Apollo 8 out to orbit the Moon at Christmas, instead of simply orbiting Earth. On returning to work in October, he was assigned as one of the CapComs for the mission.

The commander of the backup crew was Neil Armstrong. On 23 December, as Apollo 8 was nearing the Moon, Deke Slayton, Director of Flight Crew Operations at the Manned Spacecraft Center in Houston, Texas, took Armstrong aside in the Mission Operations Control Room and enquired whether he wished to command Apollo 11; the answer was enthusiastically in the affirmative. To the next question – What did he think of flying with Buzz Aldrin, who was also on the Apollo 8 backup

crew? – Armstrong had no objection. Finally, Armstrong was asked if he would retain Fred Haise, who was the third member of the backup crew, or would he prefer Mike Collins? When the assignments had been made Aldrin had been the lunar module pilot (LMP), but when Lovell replaced Collins as the command module pilot (CMP) and Fred Haise was added, the fact that Haise was a lunar module specialist had resulted in Aldrin being reassigned to back up the CMP. If Haise were to fly on Apollo 11, Aldrin would remain as CMP, but if Collins were to join the crew then he would do so as CMP and Aldrin would revert to LMP. Armstrong first had a word with Collins, who was very enthusiastic, then he told Slayton, who submitted his recommendation for the Apollo 11 prime crew of Armstrong, Collins and Aldrin. This crew was endorsed by Robert R. Gilruth, Director of the Manned Spacecraft Center.

When Apollo 8 entered lunar orbit as planned, the crew were awed by the spectacle of Earth rising over the lunar horizon. Prior to heading home, they marked Christmas Eve by reciting the opening verses of the Book of Genesis.[1] On their return, Lovell and Anders were teamed with Haise to back up Apollo 11; but as Anders intended to leave NASA soon after this assignment, Ken Mattingly was assigned to shadow him, with a view to joining Lovell and Haise as the prime crew of a subsequent mission.

On Monday, 6 January 1969, Slayton called Armstrong, Collins and Aldrin to his office, confirmed their flight assignments, and told them to assume that their mission would involve a lunar landing. Thomas O. Paine, NASA’s Administrator, made the announcement three days later in Washington, and the following day, in Houston, the crew gave their first press conference.

At that time, Armstrong was by no means confident that Apollo 11 would make the first lunar landing. The lunar module (LM), whose development had been so protracted, had yet to be tested in its manned configuration, Mission Control had yet to show that it could operate the LM in parallel with the command and service modules (CSM), and Apollo 9 and Apollo 10 would have to demonstrate many procedures and systems before Armstrong’s own mission could be finally specified. Collins estimated that Apollo 10 had a 10 per cent chance of attempting the historic landing, while Apollos 11 and 12 had, respectively, a 50 and a 40 per cent chance.

SIGHTSEEING

As Apollo 11 started across the near side of the Moon, essentially in the equatorial plane and going east to west,[21] Armstrong called, ‘‘Apollo 11 is getting its first view of the landing approach. We’re going over the Taruntius crater.’’ This crater, some 30 nautical miles in diameter, was in the northwestern part of the Sea of Fertility. It had a flat floor and a complex of several low peaks at its centre. ‘‘The pictures and maps brought back by Apollos 8 and 10 have given us a very good preview of what to look at here – it looks very much like the pictures, but like the difference between watching a real football game and watching it on television.’’ The clarity of viewing by eye-ball far exceeded that of the pictures. ‘‘There’s no substitute for actually being here.’’

‘‘We’re going over the Messier series of craters now, looking vertically down on them,’’ announced Aldrin, ‘‘and we can see good-sized blocks in the bottom of

Messier-A.” This was a pair of craters, each about 6 nautical miles across. They had originally been known as Messier and Pickering, after French and American astronomers, but Pickering had been renamed Messier-A. The craters were notable for having produced a pair of divergent bright streaks that ran westward across the dark plain of the Sea of Fertility for a distance of about 60 nautical miles.

“And there’s Secchi,” added Armstrong. Named after an Italian astronomer, it was 14 nautical miles in diameter.

Having crossed the Sea of Fertility, they started across the Sea of Tranquility, where they were to land. “We’re going over Mount Marilyn at the present time,’’ said Aldrin. “That’s the ignition point.’’

“Jim’s smiling,’’ pointed out McCandless. Jim Lovell had named the peak after his wife.

Tom Stafford, who had reconnoitred this route on Apollo 10, explained to Jan Armstrong how the astronauts had assigned names they would readily remember to various features that they intended to use as landmarks. However, such names were unofficial. In 1961 the International Astronomical Union had specified how features were to be named: the flat plains would be named in Latin after states of mind, using the traditional (if inaccurate) terms oceanus (ocean), mare (sea), sinus (bay), lacus (lake) and palus (marsh); mountain ranges were to be named after their terrestrial counterparts; and craters were to be named after deceased scientists. In 1967 the IAU had met to discuss the assignment of specific names, but decided to defer naming until the next meeting in 1970. Meanwhile, of course, the crews of Apollo 8 and Apollo 10 had named some features. As the Moon was progressively transformed from an object studied by astronomers using telescopes into a world that was being explored by astronauts, it was inevitable the astronomers would lose ‘ownership’ over it.

As soon as the spacecraft appeared around the limb, the Manned Space Flight Network had begun to track it, to determine its orbit independently of the onboard navigation. ‘‘Our preliminary tracking data for the first few minutes shows you in a 61.6 by 169.5 orbit,’’ McCandless announced. At this time, the spacecraft was at an altitude of 127 nautical miles, and climbing towards apolune. The period of the elliptical orbit was 2 hours 8 minutes 37 seconds.

Armstrong called out landmarks on the line of approach. ‘‘We’re going over Maskelyne, Boot Hill, Duke Island, Maskelyne-W – our yaw-around checkpoint – and Sidewinder.’’ Boot Hill, Duke Island and Sidewinder were unofficial names. The crater Maskelyne, named after an Astronomer Royal, was 13 nautical miles in diameter. Maskelyne-W followed the IAU convention that small craters close to a ‘named’ crater were identified by a letter postfix. The astronauts had dubbed it the Wash Basin. ‘‘Now we’re coming up to the terminator. The landing site is well into the dark.’’ By design, they had arrived prior to sunrise at the landing site. The landing was 26 hours away, and with the Sun rising at 12 degrees per day, it would be some 10 degrees elevation at the time of landing. On the question of the colour of the surface, Armstrong noted that it had appeared tan in the vicinity of the subsolar point, where the Sun shone straight down, and had then faded to grey until, at the terminator, it was ashen.

While the spacecraft had been behind the Moon, its telemetry was taped and, on AOS, was downloaded to Earth. The flight controller responsible for the CSM promptly studied the performance of the SPS during the burn, and noticed that the tank pressure for the nitrogen used to drive the propellant feed valves of Bank-B was anomalously low, although it was holding steady now. Bank-A appeared nominal. McCandless sought clarification. “When you have a free moment, could you give us an onboard readout of nitrogen tank Bravo.”

“We’re showing the pressure in tank Bravo to be 1,960 psi, something like that,” replied Aldrin, “and Alfa is about 2,250 psi.’’ These matched the telemetry, which showed corresponding values of 1,946 and 2,249. Now able to eliminate a telemetry problem, the flight controller delved deeper into the record to further characterise the problem, with a sense of urgency because the SPS engine would soon be called upon to perform the second burn of the lunar orbit insertion sequence.

As the spacecraft passed over the Ocean of Storms on the darkened part of the near side, McCandless made an unscheduled request. “We’ve got an observation you might make – if you’ve time. There’s been a lunar ‘transient event’ reported in the vicinity of Aristarchus.” An astronomer had suggested that the astronauts take a look at the 22-nautical-mile-wide crater Aristarchus which, although far to the north of the ground track, should be on the near side of the horizon at their current altitude of 167 nautical miles. For many years, astronomers had been actively watching for transient lunar phenomena such as glows in the night. Of course, the sightings were disputed. The best evidence was by the Russian astronomer Nikolai A. Kozyrev of the Crimean Astrophysical Observatory on 3 November 1958, when he secured a spectrogram of a ‘red glow’ that persisted for almost an hour near the central peak of the large crater Alphonsus, but even this was disputed. The Ranger 9 probe was sent diving into this crater in 1965 to investigate the possibility that the peak was a volcano. In fact, the origin of lunar craters was disputed: the traditional theory was they were volcanic calderas, but there was mounting evidence that they were made by large impacts.

‘‘With Earthshine, the visibility is pretty fair,’’ Aldrin pointed out.

‘‘Take a look, and see if you see anything worth noting up there,’’ McCandless said.

‘‘You might give us the time that we’ll cross 45°W,’’ called Aldrin, ‘‘and then we’ll know when to start searching for Aristarchus.”

McCandless had the times at hand, ‘‘Aristarchus should become visible over your horizon at 077:04, and the point of closest approach will be at 077:12.’’

As they passed due south of the crater, Collins reported, ‘‘I’m looking north up toward Aristarchus now, and there’s an area that is considerably more illuminated than the surrounding area.’’

‘‘It does seem to be reflecting some of the Earthshine,’’ Aldrin said. In fact, as Aristarchus has a high albedo (it is one of the brightest features on the near side) it was visible to telescopic observers. ‘‘There is one wall of the crater that seems to be more illuminated and – if we are lining up with Earth correctly – that does seem to place it near to the ‘zero phase’.’’ He suspected that the ‘bright patch’ was merely selective reflection of Earthshine.

“Is that the inner or the outer wall?” McCandless asked. “And can you discern any difference in colour of the illumination.”

“That’s an inner wall of the crater,” Aldrin confirmed. “There doesn’t appear to be any colour.’’

“Have you used the monocular on this?’’ McCandless persisted.

“We’ll give it a try if we have the opportunity next time around,’’ Armstrong promised. “We’re in the middle of lunch.’’

“We’ve about 6 minutes remaining until LOS,’’ McCandless called 15 minutes later, “and to enable us to configure our ground lines, we’d like to know if you’re still planning to have the television up at the start of the next pass.’’

“It never was our plan to do so,’’ noted Armstrong, recalling a debate during mission planning, “but it’s in the flight plan and so I guess we’ll do it.’’ A telecast was to begin as soon as communication was re-established following the far-side passage.

Passing behind the Moon for the second time, the astronauts connected up the television camera. “Which window are we going to use,’’ Aldrin asked, “so that I can figure out how to put the monitor on?’’

“I suppose the best one would be the centre window,’’ Armstrong said. “Don’t you think?’’

“Probably,’’ Aldrin said.

Armstrong, being practical, decided, “Let’s get into attitude, and see what we think.’’

“We’re not going to have much of a television show unless we get high-gain,’’ pointed out Aldrin. Once they were in attitude, he steered the antenna to point at where Earth should rise over the lunar horizon.

“We’ve had AOS by Goldstone,’’ announced Riley publicly. “Television is now on.’’

“We have a good clear television picture,’’ reported McCandless. “We can see the horizon against the blackness of space, and without getting into the question of greys and browns, it looks, at least on our monitor, sort of a brownish-grey.’’

“That’s a good, reasonable way of describing it,’’ agreed Aldrin. “I’d say we’re about 95°E, coming up on Smyth’s Sea.’’

“For your information, your altitude is about 92 nautical miles,’’ McCandless advised.

“We’ll try and pick up some of the landmarks that we’ll be seeing during our approach to the powered descent,’’ Aldrin explained.

“Smyth’s Sea doesn’t look much like a sea,’’ observed Collins. “The area that is devoid of craters, of which there’s not very much, is sort of hilly looking.’’

“We’re now at about 83°E, which is equivalent to 13 minutes before ignition,’’ said Armstrong.

“Of course, you’ll be considerably lower at the initiation of powered descent,’’ McCandless pointed out.

“We’re coming up on the Foaming Sea,’’ said Collins.

The main wall display in the Mission Operations Control Room showed a map of the spacecraft’s ground track across the Moon, with a moving symbol showing its progress. “We show you coming up on landmark Alfa 1 shortly,’’ McCandless noted.

“Alfa 1 isn’t large,” Collins pointed out, “but it’s extremely bright.” The small bright-rayed crater designated A-1/11 was one of four craters in a featureless part of the small dark plain known as the Foaming Sea. If provided sextant sightings on landmarks of known positions, program P22 would calculate the parameters of the spacecraft’s orbit and, if so instructed, update the state vector. Alternatively, with knowledge of the orbit, it could process the sightings to calculate the positions and elevations of the terrain. Collins was to track this crater as practice for supporting the subsequent powered descent by Eagle.

“We show you over the Sea of Fertility now,’’ McCandless prompted.

“The crater that’s in the centre of the screen now is Webb,’’ explained Aldrin. “We will be looking straight down into it about 6 minutes before the powered descent.’’ This crater, named after a British astronomer, was 11 nautical miles in diameter and was located on the eastern part of the Sea of Fertility. Aldrin moved the camera to a side window to show an oblique view to the south of their ground track.

“We’re getting a beautiful picture of Langrenus, with its rather conspicuous central peak,’’ noted McCandless.

“The Sea of Fertility doesn’t look very fertile to me,’’ mused Collins. “I don’t know who named it.’’

Armstrong speculated, “It may have been named by the gentleman this crater was named after – Langrenus – who was a cartographer to the King of Spain and made one of the early reasonably accurate maps of the Moon.’’ On Earth, his wife at home exclaimed, “So that’s what he was doing with the World Book in his study!’’ In 1645 Michel Florent Van Langren (Langrenus in Latin) issued the first map of the Moon to include names, although his successors rejected most of his names. The crater later named in his honour was 74 nautical miles across. In fact, the Sea of Fertility was named by the Jesuit priest Giovanni Battista Riccioli, who, working with Francesco Grimaldi in Italy, published a map of the Moon in 1651. They had their own craters near the western limb.

Aldrin changed window again in order to view straight down, and announced, “Crater Secchi.’’

“We’re getting a good view of the track leading into the landing site now,’’ said McCandless.

“This is very close to the ignition point for the powered descent,’’ Aldrin noted. “We’re passing Mount Marilyn, that triangular-shaped mountain in the centre of the screen at the present time, with crater Secchi-Theta on its far northern edge.’’ And then, as another crater came into view, “The bright, sharp-rimmed crater at the right edge of the screen is Censorinus-T. We’re now at the 1-minute point in the powered descent.’’ Continuing west, they passed from the Sea of Fertility onto the Sea of Tranquility.

“For your information, your altitude is 148 nautical miles,’’ said McCandless.

“I’m unable to determine altitude at all by looking out the window,’’ Collins remarked.

“I bet you could tell if you were down at 50,000 feet,’’ quipped McCandless.

“There’s a good picture of Boot Hill,’’ said Aldrin. “That’ll be 3 minutes 15 seconds into the descent.’’ Then, “That’s Duke Island to the left. The biggest of the

craters near the centre of the picture right now is Maskelyne-W. It’ll be a position check in the descent at about 3 minutes 39 seconds; it’ll be our downrange position check and crossrange position check prior to the yaw-around to acquire the landing radar. Past this point, we’ll be unable to see the surface until very near the landing area.’’ Nearing the terminator, the illumination highlighted the shallow undulations on the Sea of Tranquility, in particular a pair of sinuous rilles whose snake-like appearance had prompted their names of Sidewinder and Diamondback. “The landing point is just barely in the darkness.’’ The crater Moltke was named after the nineteenth-century Prussian strategist Count H. K.B. von Moltke, who arranged for the publication in 1874 of a map of the Moon prepared by J. F.J. Schmidt. The crater was 3.5 nautical miles in diameter, and situated about 28 nautical miles southeast of where Apollo 11 hoped to land. The eastern crest of its raised rim was catching the Sun’s rays, but the rest of it was still in darkness.

Collins, who was doing the ‘flying’, had observed that after he set the docked vehicles into a given attitude, the main axis tended to drift (despite counteracting thruster firings) towards vertical with the LM on the bottom, and he thought this instability might be a gravity-gradient effect produced by the mascons. ‘‘It looks like that LM just wants to head down towards the surface.’’

‘‘That’s what the LM was built for!’’ McCandless retorted.

Now in darkness, Aldrin switched off the television, and communication with the spacecraft lapsed as the crew prepared for the second manoeuvre of the lunar orbit insertion sequence, which was to occur on the far side of the Moon at the end of the current revolution.

Meanwhile, at home

It was an excellent telecast, lasting over 30 minutes. Joan Aldrin had returned from the hairdresser in time to watch it. She had been accompanied by Jeannie Bassett who, driving, had tried in vain to evade the photographers. As the lunar landscape passed by, Joan lost interest. When they crossed the terminator into darkness, she said, ‘‘Well, now I just have to get through the next 24 hours.’’ Lurton Scott had taken the Collins children to the cinema while Pat Collins and Clare Schweickart reviewed newspaper coverage of the mission; they broke off to watch the telecast. After watching, Jan Armstrong spread a large-scale map on the floor and reviewed the features on the approach route and in the immediate vicinity of the landing site.

REHEARSAL

The original concept for Apollo 10 called for the spacecraft to enter lunar orbit and for LM-4 to undock, enter a slightly different orbit, return and redock as a test of operating in lunar orbit. In December 1968, however, the mission planning and analysis division of Mission Control successfully argued the case for putting the descent propulsion system through a realistic rehearsal in which the perilune would be lower. This would test the ability of the landing radar to lock onto the surface, with the illumination on the low passes exactly as it would be on the landing mission in order to document the primary site and identify landmarks on the approach route. Howard W. ‘Bill’ Tindall, the assistant division chief, had also suggested that the LM should initiate the powered descent and abort by ‘fire-in-the-hole’ staging, but this was not pursued. After three outstandingly successful manned missions, considera­tion was given to assigning Apollo 10 the landing mission. However, because LM-4 was incapable of landing – the software was not ready for either the simulator or the

vehicle, and in any case LM-4 was too heavy to carry sufficient propellant to lift off again – Apollo 10 commander Tom Stafford argued against waiting for LM-5. “There are too many ‘unknowns’ up there,” he insisted. “We can’t get rid of the risk element for the men who will land on the Moon but we can minimise it; our job is to find out everything we can in order that only a small amount of ‘unknown’ is left.’’ The plans, procedures, mission rules, manoeuvres, thermal regime and communica­tions would provide a high-fidelity rehearsal of the landing mission. On 24 March 1969 it was announced that Apollo 10 would conduct this dress rehearsal, and if it achieved its primary objectives then Apollo 11 would attempt to land.

One aspect of the Apollo 10 mission was to assess the operation, tracking and communications of two spacecraft in lunar orbit. Apollo 8 had confirmed that the mascons significantly perturbed the orbit of a spacecraft. By having Apollo 10 fly the profile planned for the landing mission, it would be possible to assess how the guidance and navigation system of the LM coped with these gravitational effects while making the low passes of the descent orbit. Apollo 10 lifted off on schedule on 18 May, and on the fifth day the LM separated in a circular parking orbit at an altitude of 60 nautical miles, entered an elliptical orbit with a 50,000-foot perilune, made two low passes, discarded the descent stage, and made a perfect rendezvous. The first low pass rehearsed an approach to ALS-2 (site ‘A3’, later 2P-6), and while the aim point itself was acceptable, the western end of the ‘landing ellipse’ was rougher, and Stafford told Armstrong that if he were to find himself coming in ‘long’, his best option might be to abort.

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Preparations

SIMULATION

With Apollo 10 having mitigated the risks, Armstrong and Aldrin were able to focus their training on the powered descent and lunar lift off. However, because Apollo 10 had first call on the simulators until early May, Clifford Charlesworth initiated training in April with the Saturn V launch phase. Two months then remained in which to conduct the specialised training because, with a target launch date of 16 July, the most intensive training using the simulators would be completed about 10 days earlier in order to enable the crew and flight control teams to finish other activities. Simulation explored two basic scenarios: ‘nominal’ and ‘contingency’. The nominal part occupied only a few days, and defined the Go/No-Go decision points, the procedures, and the timings for the interactions between the crew and the flight controllers. The first full set of mission rules for Apollo 11 was issued on 16 May, but was preliminary pending methodical testing by simulation. Because the nominal powered descent was to last only 12 minutes, it was possible to perform many runs and debriefings during a single day’s training. While Apollo 10 was performing its rehearsal in lunar orbit, Armstrong and Aldrin were routinely landing by flying the nominal profile. Contingency training was designed to test how the crew and flight controllers dealt with departures from the nominal profile involving trajectory and systems problems. The Simulation Supervisor (SimSup) for the powered descent was Dick Koos, an early recruit of the Space Task Group to train control teams. As there were then no graduates with computer degrees, NASA had hired engineers with experience, and his background was the computerisation of ground-to-air missiles for the Army Missile Command at Fort Bliss, Texas. Koos and his five support staff occupied a glassed-in partition at the front of the Mission Operations Control Room, and their role was to develop realistic mission scenarios that would assess the mission strategy, rules and procedures, the knowledge and coordination of the individual flight controllers, the ability of the team as a whole to develop real-time solutions to technical difficulties, and generally to probe the psyches of everyone involved. It was considered that a fully trained team of flight controllers ought to be able to function as a single ‘mind’.

The first contingency training was on 10 June. A succession of runs introduced a