Category The First Men on the Moon


General James L. Collins was a career officer who served in the Philippines, in the 1916 Mexican campaign, and in France in World War One. He married Virginia Stewart, whose family had British roots; his own family came from Ireland. Michael Collins was born on 31 October 1930 while his father was Army attache to Rome, joining siblings James L. Collins Jr, who was 13 years older, and sisters Agnes and Virginia, 10 and 6 years older respectively. The family returned to the USA in 1932. As a child, Michael read a lot, was athletic, and had fun, but in contrast to most of his contemporaries did not develop any great passion for airplanes. His father had graduated from West Point Military Academy, as had his brother, but Michael was inclined towards medicine. His mother suggested a career in the State Department. Although his father put no pressure on him to attend West Point, Louisiana congressman Edward Hebert, a family friend, urged him to follow in the family tradition, which, on leaving high school in 1948, Michael decided to do – more for the free education than for any desire to join the military. After graduating in 1952 he joined the Air Force, gained his ‘wings’ in the summer of 1953, and was sent to Nellis Air Force Base, Nevada, for advanced fighter training, followed by training for ground attack using nuclear bombs. In December 1954 he was posted to an F-86 fighter squadron at a NATO base in France. In 1956 he met 21-year-old Patricia

Finnegan, a civilian worker in the Air Force who had arrived the previous year and was the eldest of the eight children of Joseph and Julia Finnegan of Boston, Massachusetts. Michael and Patricia were soon engaged, but did not marry until 28 April 1957. On returning to the USA a few months later, Collins was assigned as an instructor, and as he considered a test pilot to be more an engineer than a seat-of – the-pants fighter pilot, in August I960 he enrolled at the Experimental Test Pilot School at Edwards Air Force Base. When NASA sought a second intake of astronauts in April 1962 he applied, but was rejected. When the agency made another call in June 1963 he applied again, and on 17 October was announced as one of 14 new astronauts. The family moved to Nassau Bay, buying a house not far from that of the Aldrins.

As his specialism Collins was assigned to track the development of space suits and miscellaneous equipment for extravehicular activity. On 18 July 1966, John Young and Collins were launched for the Gemini 10 mission, during which, over a three-day period, they rendezvoused with an Agena target vehicle which was then used to rendezvous with the Agena left by Gemini 8. Collins made two spacewalks, one standing in the hatch and the other involving floating across to the old Agena in order to retrieve an experiment which, if Gemini 8 had not been cut short, Dave Scott would have retrieved.

On being assigned to Apollo 11, Collins was asked whether he was frustrated by having to remain in lunar orbit while his colleagues attempted the landing. “I’d either be a liar or a fool if I said that I think I have the best of the three seats on the mission. On the other hand, all three seats are necessary. I would very much like to see the lunar surface – who wouldn’t!? – but I am an integral part of the operation, and am happy to be going in any capacity. I am going 99.9 per cent of the way, and I don’t feel frustrated at all.’’

At the time of Apollo 11, the Collins family comprised Mike and Pat, son Michael, aged 6, and daughters Kathleen, 10, and Ann, 7.


The crew of Apollo 11 did not become close friends, as some crews did during training, but this was not a prerequisite for mission success – it was required only that each man should know his job, trust his colleagues to do likewise, and work together as part of a team. Collins later described the trio as “amiable strangers’’. In a sense, they were no more than military men assigned to a mission. Of Armstrong, Collins observed, “Among the dozen test pilots who flew the X-15 rocket ship, Neil was considered one of the weaker stick-and-rudder men, but the very best when it came to understanding the machine’s design and how it operated.’’ He was “notable for making decisions slowly, but making them well’’. Collins considered him “far and away the most experienced test pilot among the astronauts’’, and the best choice to command the first attempt to land on the Moon.

The abandoned vehicle fell straight down

“The ejection system threw me somewhat east of the crash, but the wind was from the east and at the time my chute opened I was a bit concerned that I might be drifting down into the fire, but the wind was strong and I actually missed the flames by several hundred feet. After I landed, I got up and walked away. The only damage to me was that I bit my tongue.’’

As Armstrong had abandoned a stricken Panther jet over Korea, this was his second ejection. Most astronauts would have sought out colleagues and related an enthusiastic account of the event, but Armstrong returned to his office to catch up on paperwork. At the time, observers speculated that there had been an explosion, but they had been misled by the steam issuing from the thrusters as Armstrong was attempting to recover. LLTV A2, which was not yet in operation, was grounded pending an investigation led by Algranti, which concluded that a design flaw had enabled the helium pressurisation of the peroxide system to decay, rendering the thrusters ineffective.

The first В model LLTV was delivered to Ellington in December 1967, but did not become available until mid-1968. A Flight Readiness Review on 26 November declared LLTV В1 ready for astronaut training. On 8 December 1968, on its tenth flight, the vehicle developed an uncontrollable lateral control oscillation, obliging Algranti to eject at an altitude of 200 feet. Kraft and Robert R. Gilruth, Director of the Manned Spacecraft Center, suggested that the LLTV was too dangerous, but the

astronauts, particularly Armstrong, who had most experience with it, insisted it was essential. On 13 June 1969 LLTV B2 was declared ready for astronaut training. As commander of the mission that was to attempt a lunar landing, Armstrong had first call, and he flew it on 14, 15 and 16 June. Since the vehicle carried propellant only for about 6 minutes of flight and it took several minutes to climb and establish the required profile, a descent test lasted at most 4 minutes and often was concluded with only seconds to spare. Although dangerous, the LLTV was the only effective training for flying the LM in a manual mode.[15]


On 17 June the Apollo 11 crew had their T-30-day medicals and transferred to the Manned Spacecraft Operations Building, located on the industrial facility 5 miles south of the Vehicle Assembly Building. The third-floor crew quarters, which had a ventilation system designed to maintain a germ-free environment, comprised a living room, dining room, kitchen, briefing room, bathroom, exercise room, equipment room, and a number of small windowless bedrooms. Lewis Hartzell had been hired to cook for the Gemini crews and remained, not for the money, but for the honour of cooking for the astronauts. As a former Marine and a cook on tugboats, Hartzell only did plain cooking, which raised no objections from the astronauts.

A flight readiness review later on 17 June authorised loading the hypergolic propellants into the LM and CSM tanks. This represented a major decision point, because if a mid-July launch should prove impracticable, it would not be safe to retain such corrosive chemicals in the tanks for an additional month – not only would the tanks have to be drained, but certain components would require to be removed and returned to the vendor for refurbishment. Worse, there would be no guarantee that the vehicles could be reassembled in time for the August launch window. The loading operation began on 18 June and, despite delays caused by weather conditions at the Cape, was completed on 23 June.[16]

On 26 June Armstrong, Aldrin and Collins had medical examinations that were not only to confirm their physical state, but also to catalogue the organisms in their systems to provide a ‘baseline’ for spotting any infections that they might contract during the final stages of preparation. After a countdown demonstration test that concluded with a simulated launch at 9.32 am local time on Wednesday, 3 July, they flew to Houston for the Fourth of July weekend. Life magazine published an issue

with the cover ‘Off To The Moon’, with stories about their home lives. NASA would have loved to have scheduled the lunar landing for 4 July, but operational constraints did not permit this.

Gene Kranz’s flight control team took 4 July off, but returned to work the next day for their ‘graduation’ simulations. As Armstrong and Aldrin were unavailable, Pete Conrad and Al Bean took their places as a welcome training opportunity for Apollo 12. The flight controllers successfully overcame six tough scenarios during the morning. The afternoon sessions were to be ‘flown’ by the Apollo 12 backup crew of Dave Scott and Jim Irwin, the rationale being that a less-experienced crew would increase the pressure on the flight controllers. Three minutes into the first run, Koos prompted the LM’s computer to issue an alarm. A caution and warning light illuminated, and the computer flashed the numerical identifier for that particular problem. Computer alarms could result from a hardware fault, a software issue, out- of-tolerance data, or a procedural error either by the crew or the ground. Steve Bales, the guidance officer, was monitoring the LM’s computer to ensure that it received the correct data from Earth and that its guidance, navigation and control tasks were being properly executed. In this case the alarm was a 12-01. Bales had previously seen it during functional tests of the computer on the ground, but never in a simulation, and certainly not in flight. While the LM crew awaited advice, he checked his manual: the 12-01 alarm was ‘executive overflow’, which meant that the computer was overloaded. The computer’s executive was to repeatedly cycle through a list of tasks in a given interval of time, and evidently the time available was no longer sufficient to finish the tasks before it was obliged to begin the next cycle. Bales called Jack Garman, a support room colleague and software expert, and they agreed that the alarm was serious, especially since it was recurrent. With no mission rules to inform his decision-making, Bales called Kranz, told him that there was something amiss with the computer, although he could not say what, and recommended an abort. This call came out of the blue as Kranz had not been party to the discussion between Bales and Garman, but as a flight director must trust the judgement of his controllers – especially on abort calls – he confirmed it. Charlie Duke, serving as CapCom, relayed the abort to the crew, who performed the manoeuvre and made as if to rendezvous with their mother ship (which was not actually in the simulation). At the debriefing, Koos pointed out that the 12-01 had not necessitated an abort; in the absence of a positive indication that the computer was failing they should have continued. Shocked that he had made a bad call, Bales got together with the people from the Massachusetts Institute of Technology who had written the software, in order to investigate the alarm. Later that evening, he called Kranz and conceded there had been no need to abort. The next day, 6 July, Koos triggered a range of computer alarms to enable Bales’ team to record data on the ability of the computer to continue to function. On 11 July Bales added a new mission rule listing the alarms that would require an immediate abort; in all other cases the powered descent was to continue pending a positive indication of a critical failure.

In 1966 Slayton had told George E. Mueller, Director of the Office of Manned Space Flight, that an Apollo crew would require 140 hours of training in the CSM simulator, with a lunar landing crew spending an additional 180 hours in the LM. In

fact, as they completed their training, Collins had spent 400 hours in the CSM; Armstrong had spent 164 hours in the CSM, 383 hours in the LM, and a total of 34 hours in the Lunar Landing Research Facility at Langley and flying the LLTV; and Aldrin had spent 182 hours in the CSM and 411 hours in the LM, but had not used the other facilities. Training for lunar surface activities accounted for no more than 14 per cent of their time.


After breakfast Aldrin went into the lower equipment bay, removed his constant – wear garment, reinstalled his urine-collection and fecal-containment utilities and put on his liquid-cooled garment, the fishnet fabric of which had a network of narrow flexible plastic tubes sewn into it through which cold water would be pumped to manage the heat generated by the exertion of the moonwalk. It had to be donned now, since they were to remain suited while in the LM. Aldrin then went into the LM, vacating the lower equipment bay to Armstrong, who suited up with Collins assisting with the zippers and checking fixtures – a process that took 30 minutes. When Armstrong went into the LM, Aldrin returned to suit up. Collins also suited up as a precaution against inadvertent decompression during undocking, or the need for an early abort in which Eagle’s crew would conduct an external transfer using the side hatch.4

At AOS on revolution 11, Aldrin was well into powering up Eagle’s systems. When Duke requested a status report, it became evident that Aldrin was running about 30 minutes ahead of the flight plan. When the steerable high-gain antenna mounted on a boom on the right-hand side of the roof was pointed to Earth, the LM flight controllers received their first significant telemetry of the mission.

The two crews worked independently in their preparations, but certain events required coordination. One item was setting Eagle’s clock, which was to be done by synchronising it with its counterpart in Columbia.

‘‘I have 097:03:30 set in,’’ called Armstrong.

Collins counted down, ‘‘15 seconds to go. 10, 5, 4, 3, 2, 1. MARK.’’

‘‘Got it,’’ confirmed Armstrong.

Another task, some time later, was to coarsely align the platform of Eagle’s

Only once Eagle was safely on the surface would Collins remove his suit, and he would don it again shortly prior to liftoff.

inertial navigation system. In essence, two humans acted as an interface between two machines.

“I’m ready to start on a docked IMU coarse-align,’’ Armstrong said. “When you’re ready, go to Attitude Hold with Minimum Deadband.’’ Once Collins had confirmed that he was holding the docked vehicles stea­dy, Armstrong said, “I need your Noun 20.’’

“I’ve got Verb 06, Noun 20. Give me a Mark on it,’’ Collins replied. “MARK!” called Armstrong. “Register 1, plus 11202, plus 20741, plus 00211,’’ said Collins, reading the display on his DSKY. The numbers represented the CSM’s attitude with respect to the current REFSMMAT.

Armstrong gave a read-back for confirmation, “11202, 20741, 00211.’’ “That’s correct,’’ Collins agreed. After performing an arithmetical transformation to allow for the fact that the designers of the vehicles had specified their Cartesian axes differently, Armstrong keyed the attitude into his DSKY.

The alignment showed up in the telemetry, and Duke reported, “That coarse align looks good to us.’’

“Okay, Mike,’’ said Armstrong. “Your Attitude Hold is no longer required.’’

If necessary, Eagle would later make star sightings for its equivalent of a P52 to refine the alignment.

Once he had installed the probe and drogue assemblies in the tunnel and fully extended the probe, Collins called to Eagle, “The capture latches are engaged in the drogue. Would you like to check them from your side?’’

“Stand by,’’ Armstrong replied. He looked up through the open hatch to verify that the tip of the probe projected through the hole in the centre of the drogue and the three small latches, each no larger than a finger nail, were engaged. “Mike, the capture latches look good.’’ Armstrong then closed the upper hatch to make Eagle air-tight.

At this point, Apollo 11 passed around the far side of the Moon. They were to continue with the preparations during revolution 12, and undock prior to AOS on revolution 13.

Collins slowly retracted the probe until the latches established a firm grip of the drogue. The next task was to release the main latches in the docking units. To guard against the possibility of depressurisation, he donned his helmet and gloves.

Five minutes later, Aldrin called, “Mike, let us know how you’re coming up there, now and then.’’

“I’m doing just fine,’’ Collins replied. He was physically priming the latches, imparting the stored energy they would need to re-engage on the redocking. “I’ve cocked eight latches, and everything is going nominally.’’ And then a minute later, “All 12 docking latches are cocked.’’

“Okay,” acknowledged Aldrin.

“I’m ready to button up the hatch,’’ Collins announced.

Although the vehicles were now held together only by the capture latches, these were able to maintain the hermetic seal in the tunnel because the interface had been compressed by the hard docking. “Mike, have you got to the Tunnel Vent step yet?’’ Aldrin asked.

“I’m just coming to that,’’ replied Collins. “What can I do for you?’’

“Well, we’re waiting on you,’’ Aldrin noted. Although ahead of schedule, the LM crew had to wait for Collins to vent the tunnel before they could proceed.

Two minutes later, Collins reported, “I’m ready to go to LM Tunnel Vent.’’ He opened the valve to space. The process was expected to take about 8 minutes.

“How’re you doing, Mike?’’ Armstrong asked several minutes after that time had elapsed.

“Stand by, and I’ll give you the delta-P reading,’’ replied Collins. He reset the valve to enable a nearby gauge to measure the difference in pressure between the tunnel and the command module, which was at about 5 psi. “It’s 3.0 psi.’’ There was still a significant amount of air remaining in the tunnel.

In Eagle, Armstrong and Aldrin donned their helmets and gloves to check the hermetic integrity of their suits.

Meanwhile, Collins started to manoeuvre into the attitude required for the next P22 landmark tracking, which would be Site 130-prime, a crater inside Crater 130 in the Foaming Sea. Because this had been selected as a reference by John Young on Apollo 10 for the reason that it was both readily identified and small enough to be accurately marked using the sextant, it was also referred to as John Young’s crater. The sightings were to be used to update Houston’s knowledge of the orbit, and where the spacecraft was in that orbit, in order to calculate the precise time at which to initiate Eagle’s powered descent.

When the manoeuvre was finished, Armstrong called Collins, “We’re going to put our gear down.’’

“Master Arm,’’ said Aldrin on intercom, reading the checklist. “Landing Gear Deploy, Fire.’’

“Here we go, Mike,’’ Armstrong warned before detonating the pyrotechnics to release the spring-loaded legs.

“Bam, it’s out. There ain’t no doubt about that,’’ Aldrin mused. “Master Arm, Off.’’

“The gear went down okay, Mike,’’ Armstrong called. There were redundant circuits, but the primary had successfully fired the pyrotechnics to deploy the legs. The 67-inch-long probes, whose tips had been latched against the inner parts of the legs, hinged on the undersides of the lateral and rear foot pads to project ‘straight down’. For Apollo 5 in February 1968, a Saturn IB had launched LM-1 absent its legs for an unmanned test. LM-3 had demonstrated the deployment of the legs on Apollo 9 in March 1969. At that time the design had included a probe on each of the pads but, at Armstrong’s request, it had been decided to delete the probe from the forward leg lest it be bent on touchdown in such a manner as to cause him to slip (or worse, puncture his suit) as he jumped backwards down off the ladder.

As Apollo 11 appeared around the trailing limb on revolution 12, Duke made them aware that communications had been restored. “Apollo 11, Houston. We’re standing by.’’ There was a lot of static on the downlinks. With no response, in all likelihood owing to the fact that he had not directed his call to a specific vehicle, Duke persisted. “Columbia, Houston. Do you read?’’

“Loud and clear,’’ Collins acknowledged.

“Eagle, Houston. Do you read?’’ No response.

“Eagle, do you read Columbia?’’ asked Collins.

“Yes,’’ acknowledged Aldrin. “I’m working on the high-gain right now.’’ He slewed the steerable dish as per the flight plan, but could not establish contact with Earth. “Are you in the right attitude, Mike?’’

“That’s affirm.’’

“Columbia, Houston,’’ called Duke.

“Houston, Columbia. You’re loud and clear.’’

“Eagle, Houston. Will you verify you are on the forward omni?’’ No response. “Columbia, Houston. We have no voice with Eagle. Would you please verify that Eagle is on the forward omni.’’

“Buzz,’’ Collins called. “Are you on the forward omni?’’ When there was no response, he repeated the call.

“Roger. I am,’’ confirmed Aldrin.

“Houston, Columbia. Eagle is on the forward omni.’’

Duke tried again, “Eagle, Houston.’’

“Roger, I’ve got you now,’’ acknowledged Aldrin. “I fed in those angles for the S – Band, and couldn’t get a lock-on. It appears as though the antenna would have to be looking through the LM in order to reach the Earth.’’

Because the docked vehicles were oriented to facilitate P22 landmark tracking shortly after flying around the limb, it was difficult for the boom-mounted S-Band antenna cluster on Columbia to point at Earth, and the body of the LM blocked the line of sight of its steerable dish. In this attitude the vehicles would have to rely on their respective omnidirectional antennas.

“Eagle, Houston. Could you give us an idea where you are in the activation?’’

“We’re just sitting around waiting for something to do,’’ Aldrin replied. “We need a state vector and a REFSMMAT before we can proceed to the AGS calibration, and we need you to watch our digital autopilot data load, the gimbal drive check and the throttle test.’’

Although Armstrong and Aldrin were well ahead in their LM activation, they were again obliged to wait until Houston was able to upload information and monitor their telemetry, which could not be done until they could use their high-gain antenna, which in turn meant waiting until Collins had performed his landmark

tracking. While getting ahead created a margin against encountering a problem that might slip them behind schedule, the need to do certain tasks at given times meant that being ahead early on did not in itself enable the process to be completed ahead of the flight plan.

“It’ll be about another 10 minutes or so before we get the P22 and manoeuvre to an attitude for the high-gain,’’ Duke pointed out.

Armstrong and Aldrin proceeded with those items that could be done using the low data-rate provided by an omnidirectional antenna.

“We’re ready to pressurise the RCS,’’ Aldrin announced.

“You can go ahead with RCS pressurisation,’’ Duke agreed, “but we’d like to hold off on the RCS hot-fire checks until we get the high bit-rate.’’

“Eagle, Columbia. My P22 is complete,’’ Collins reported. He manoeuvred to let the high-gain antennas on both of the vehicles see Earth, and communications markedly improved. With high data-rates on both its uplink and downlink, Eagle was able to complete data uploading and checkout.

“Houston, Eagle,’’ Aldrin called. “Both RCS helium pressures are 2,900 psi.’’ “Let me know when you come to your RCS hot-fire checks,’’ said Collins, “so I can disable my roll thrusters.’’

Fifteen seconds later, Aldrin announced that they were ready. “Columbia,’’ he called, “We’d like Attitude Hold with Wide Deadband.’’

“You got it,’’ Collins replied. A wide deadband on the Attitude Hold would allow the testing of Eagle’s thrusters to disturb the attitude of the docked vehicles without prompting Columbia’s control system to waste propellant in attempting to intervene. “My roll is disabled. Give me a call as soon as your hot-fire is complete, please.’’ “Houston, Eagle,’’ Aldrin called several minutes later. “The RCS hot-fire test is complete. How did you observe it?’’

“It looked super to us,’’ Duke confirmed.

“I’ve got my roll jets back on now,’’ Collins announced.

At this point, Kranz polled his flight controllers, and Duke relayed the result, “Apollo 11 Houston. You’re Go for undocking.’’

“Understand,’’ replied Aldrin.


Apollo 11 had proved the ability of the LM to land on the Moon, but the fact that it came down off target was frustrating. The ability to land within about 1,000 feet of a specific point was a prerequisite to being able to undertake a planned geological traverse. After the flight dynamics team had devised a simple method to correct for the perturbations of the mascons, they were so confident that they reduced the size of the target ellipse. In addition, it was decided to cut the number of backup sites from two to one. There were five prime sites on the short-list for the first landing. The easterly ALS-1 and ALS-2 sites in the Sea of Tranquility had been backed up by ALS-3 in the Meridian Bay, with ALS-4 and ALS-5 in the Ocean of Storms in reserve against a major launch delay. It would have been natural to send Apollo 12 to one of these sites, but the conservative constraints had resulted in the choice of ‘open’ sites, and the geologists were eager to sample the ejecta of a sizeable crater. In fact, even before Apollo 11, the site selectors had re-examined sites rejected due to the inconvenient proximity of a crater, and listed them for a later mission. In the end, however, in order to convincingly demonstrate the ability to address a ‘pin-point’ target it was decided to land alongside an unmanned probe. The relaxation of the operational constraints allowed the reinstatement of the Surveyor 1 site (ALS-6) in the Ocean of Storms. However, because this was so far west that it did not permit a backup, it was decided instead to visit Surveyor 3 in the eastern Ocean of Storms. Originally designated 3P-9, this site became ALS-7. Pete Conrad and Al Bean landed their LM, ‘Intrepid’, within 600 feet of Surveyor 3 on 19 November 1969. On their first excursion they deployed the deferred ALSEP, and during a 3-hour traverse the next day they ranged 1,200 feet from home, collected samples, and cut parts off the Surveyor as trophies. Meanwhile, in orbit, Dick Gordon photographed the site being considered for the next mission.

A pre-mission investigation of the morphology of the craters at the Apollo 12 site predicted that the regolith would not exceed 6 feet in thickness, and that the large impacts would have excavated bedrock. Whereas breccias and basalts were represented equally by number in the Apollo 11 samples, just two of the 34 rocks returned by Apollo 12 were breccias. The crystalline rocks were coarser and more texturally diverse. In view of the fact that they contained less titanium, it appeared, on reflection, that the basalt of the Sea of Tranquility was unusually enriched in this element. This chemical variation confirmed that the dark plains were not from a single source. Indeed, the fact that four kinds of basalt were identified at the Apollo 12 site meant that there had been several distinct flows in this local area.[52] However, the crystallisation dates clustered within a fairly narrow window, which suggested that the extrusions were the result of partial melting of pockets of rock at shallow depth. The initial results were confusing, but it was immediately recognised that something profound had been discovered concerning early lunar history. The first measurement yielded an age of 2.7 (±0.2) billion years, which meant a billion years had elapsed between the extrusions in the Sea of Tranquility and the Ocean of Storms. The next result pushed this up to 3.4 billion years, but as the analyses continued the dates converged on 3.2 billion years. This 500-million-year span in ages for the lavas at the two landing sites indicated that the driving process had been persistent. Geochemist Paul W. Gast made a surprising discovery in the basalts, in the form of an abundance of potassium, phosphorus and some of the ‘rare earth’ elements. By linking their chemical symbols, Gast coined the label ‘KREEP’. On trying to isolate this material, he realised that it was not present as a mineral. The term is an adjective, and it is more correct to describe the Ocean of Storms basalts as being KREEPy. By way of an ‘instant science’ explanation for the media, Gast suggested this chemical additive might have been picked up from the ancient crust that some scientists believed formed the ‘basement’ of the dark plains, and he even speculated that it might be associated with the putative light-toned basalt believed (by some) to be prevalent in the highlands, but when the material proved to be rich in radioactive elements, in particular thorium and uranium, it was realised that this could not be typical of the crust because the heat of radioactive decay would have prevented the crust from solidifying. This KREEPy additive became a mystery for a subsequent mission to resolve.

After being discarded, the ascent stage of the LM was deliberately de-orbited, and the ALSEP seismometer recorded the crust ‘ringing’ for nearly an hour with a signature quite unlike a terrestrial signal. At the Lunar Science Conference, Gary V. Latham, the principal investigator for the seismic instruments, noted it had been difficult to tell the difference between a moonquake and an impact until this strike had provided a point of reference, whereupon it was found that surprisingly few of the 150 seismic events on record were internal quakes. It seemed that the crust was brecciated to a depth of about 18 nautical miles, indicating that, after the crust had solidified, further impacts had churned this up to a considerable depth, forming a

‘megaregolith’. In order to probe to greater depths, it was decided that on future missions the spent S-IVB should be made to impact the Moon.



During a meeting in the summer of 1964 at Woods Hole, Massachusetts, the Space Science Board of the National Academy of Sciences listed basic questions relating to the Moon that ought to be studied either by spacecraft placed into lunar orbit or by instruments emplaced on the lunar surface.

On 19 November 1964, after tests conducted on an aircraft providing one-sixth gravity established that astronauts would be able to offload scientific instruments from the descent stage of the LM onto the lunar surface, the Manned Spacecraft Center began to study how instruments might be powered. It was decided that the best source would be a radioisotope thermal generator (RTG) in which heat was converted by thermocouples into electricity. The Grumman Aircraft Engineering Corporation of Bethpage, New York, which was developing the LM, was asked to give some thought to how an RTG might be packaged and carried. Grumman was also asked to develop a prototype for a container in which to return to Earth samples of lunar material. This would require to be carried on the exterior of the vehicle, accessed while on the surface, loaded, hermetically sealed, transferred into the ascent stage, and later passed through the tunnel into the command module and stowed for the flight home.

In January 1965 NASA undertook a time-and-motion investigation in order to assess how best to use the limited time that would be available to the first Apollo crew to land on the Moon. In May, a preliminary list of surface experiments was drawn up, and George E. Mueller, Director of the Office of Manned Space Flight, initiated a two-phase procurement process: the definition phase was to be done in parallel by a number of companies, one of which would be selected to develop the hardware for flight. In June the Manned Spacecraft Center set up the Experiments Program Office within its Engineering Development Directorate to manage all experiments for manned spacecraft, and Robert O. Piland, formerly deputy manager of the Apollo Spacecraft Program Office, was selected to head it. On 7 June Mueller approved the procurement of the Lunar Surface Experiments Package (LSEP) and assigned responsibility for its development to the Experiments Program Office. It was to be an RTG-powered suite of instruments that had to be able to be deployed

by two men in 1 hour, and was to transmit data to Earth for 1 year. Overall, it was envisaged as a passive seismometer to monitor moonquakes; an active seismometer that would detonate calibrated explosive charges in order to seismically probe the shallow subsurface; a gravimeter to measure tidal effects that might shed light on the deep interior; an instrument to measure the heat flowing from the interior; radiation and meteoroid detectors; and an instrument to analyse the composition of any lunar atmosphere. The instruments would be electrically connected to a central station that would transmit to Earth. Mueller specified that the package should be available for the first landing mission. On 3 August NASA announced that Bendix Systems, TRW Systems and Space-General Corporation had each been given a 6-month contract worth $500,000 to propose designs. On 14 October NASA contracted the General Electric Company to supply the RTG under the supervision of the Atomic Energy Commission. An instrument to investigate any lunar magnetic field was added to the suite on 15 December. By early 1966 the instrument suite had been renamed the Apollo Lunar Surface Experiments Package (ALSEP). On 16 March NASA Administrator James E. Webb decided that, in view of the company’s experience in developing experiments for automated lunar spacecraft, Bendix of Ann Arbor, Michigan, would receive the contract to design, manufacture, test and supply four ALSEPs (three flight units and one in reserve), the first of which was to be delivered no later than 1 July 1967.

Homer E. Newell, Associate Administrator for Space Science and Applications, wrote to Mueller on 6 July 1966, “the highest scientific priority for the Apollo mission is the return to Earth of lunar surface material’’, with the position of each sample being carefully documented prior to sampling. Newell recommended that on the first moonwalk the astronauts start by collecting an assortment of readily accessible samples (a ‘grab bag’ in the vernacular of field geology), deploy the ALSEP, and end with a ‘traverse’ to collect a number of ‘documented samples’, utilising a range of tools, including core tubes.

By the autumn of 1966 the magnetometer was having serious developmental problems, and the central data-processor was in a critical state. At the end of the year, NASA headquarters suggested that an instrument on the second ALSEP be brought forward as a replacement for the magnetometer, but as the scientists said that the magnetometer would be required to properly interpret the data from the other instruments, it was decided to develop a simpler magnetometer as a stand-by. It was also necessary to consider the ‘fuel cask’ of plutonium-238 for the RTG. The cask gave structural support and thermal insulation to the fuel capsule: in the case of the SNAP-27 unit for the ALSEP this comprised 8.4 pounds of plutonium. On the Moon, an astronaut would require to remove the 500°C fuel capsule from the cask on the exterior of the LM and insert it into the thermocouple assembly. When simulations revealed flaws in this procedure, the design had to be modified, and after several launch failures unrelated to the Apollo program the cask had also to be ‘hardened’ to ensure that it would not spill its contents. The Manned Spacecraft Center established the Science and Applications Directorate in December, which took over the activities of the Experiments Program Office and, as Newell had long urged, put science on a par with engineering and operations. Wilmot N. Hess, formerly of the Goddard Space Flight Center, was appointed as Director of the Science and Applications Directorate, with Piland as his deputy.

On 4 January 1967 Christopher C. Kraft, Director of Flight Operations at the Manned Spacecraft Center, said that if a lunar landing was to involve two surface excursions, the first outing should facilitate lunar environment familiarisation, an inspection of the vehicle, photographic documentation and contingency sampling. The ALSEP should be deployed on the second outing, and be followed by a more systematic geological survey. Conversely, if only one excursion was planned, that mission should not be provided with an ALSEP since its deployment would use a disproportionate amount of the time. This rationale applied particularly to the first landing, when the mass saved by deleting the instruments would undoubtedly be able to be put to good use. It was also decided that the astronauts should be provided with a rough time line but be allowed to make real-time decisions; the surface operations must not be micro-managed by Mission Control, at least not on the first mission, when there would be so many unknowns and the people on the spot would be best positioned to make decisions. On 16 March NASA announced that 110 scientists, including 27 working in laboratories outside the USA, had been selected to receive lunar samples. In June, Apollo Program Director Samuel C. Phillips formed an ad hoc team to review the status of the magnetometer. It was concluded that while the technical problems were certain to be resolved, the instrument was unlikely to be ready for the first landing, which at that time was thought might occur in the latter part of 1968. Unfortunately, neither would the simpler magnetometer be ready for that date, so work on this was terminated. Leonard Reiffel, on Phillips’s science staff, recommended on 20 June that in view of the uncertainties concerning an astronaut’s ability to work in one-sixth gravity, “an uncrowded time line’’ would be “more contributory to the advance of science than attempting to do so much that we do none of it well’’.

By mid-September 1967, on the basis of the LM spending 22.5 hours on the lunar surface, the planners recommended that two excursions should be defined, but the second, to follow a sleep period, should not be listed as a primary objective. The decision on whether to conduct the second excursion – on which the ALSEP would be deployed – should be made on the basis of the astronauts’ performance during the first outing. However, one year later, on 6 September 1968, with the LM significantly overweight and the development of the RTG behind schedule, Robert R. Gilruth, Director of the Manned Spacecraft Center, recommended that the first landing should make a single excursion of 2.5 hours; the ALSEP should not be carried (as it could not function without the RTG); the high-gain antenna for the television should not be carried (instead, the 210-foot-diameter antenna at Goldstone in California could receive a transmission from a smaller antenna on the LM); and the geological activities be restricted to the ‘minimum lunar sample’. As Gilruth put it, “I’m sure all will agree that if we successfully land on the Moon, transmit television directly from the surface, and return with lunar samples and detailed photographic coverage, our achievement will have been tremendous by both scientific and technological standards.’’ However, Hess argued for a compromise in which, in view of the development problems of the ALSEP, a smaller package should be assigned to this

mission using instruments that would be easier to deploy, with the duration of the outing being open ended. On 9 October the Manned Space Flight Management Council, chaired by Mueller, agreed to the development of three lightweight experiments for the first landing mission – a solar-powered passive seismometer, an unpowered laser reflector, and a solar wind composition experiment that would be deployed and later retrieved for return to Earth. It was decided to carry the erectable antenna for the television transmission in case the time of the moonwalk did not coincide with a line-of-sight to Goldstone. The mass saved by not carrying the ALSEP would allow more fuel to be carried, and thereby increase the time available for the hovering phase of the descent. In effect, the first landing was to be an ‘operational pathfinder’ for its successors. On 5 November Bendix was told to make the three-instrument Early Apollo Surface Experiments Package (EASEP), which was to be shipped by mid-May 1969. On 6 December Phillips said that if the special tools under development for the geological investigation were ready, and if the astronauts had sufficient time to train in their use, they would be carried. One such item was a camera designed by Thomas Gold, an astronomer at Cornell University. In the early 1960s he had argued, on the basis of radar reflections, that the lunar surface was a thick blanket of extremely fine dust into which a spacecraft would sink without trace, and he maintained this position even after automated landers settled on firm ground. His camera was designed to take stereoscopic close-up pictures of the lunar dust.


At the press conference in Houston on 10 January 1969 that introduced the crew of Apollo 11, a reporter enquired about which of them would be first to set foot on the Moon. Armstrong turned to Deke Slayton, Director of Flight Crew Operations, for guidance. Slayton said the matter had not yet been decided, but would be resolved by the training exercises. This ambiguity provoked much speculation in the media. The Gemini precedent was that a commander remained in the spacecraft while his copilot undertook extravehicular activity. In March, after the success of Apollo 9 increased the likelihood of Apollo 11 being assigned the first lunar landing, Kraft and George M. Low, Manager of the Apollo Spacecraft Program Office in Houston, had an informal discussion and both felt that since the first man to set foot on the Moon should be a Lindbergh-like figure, Armstrong would be preferable to Aldrin. On hearing a rumour that Armstrong had been chosen to egress first because (despite his being a former naval aviator) he was ‘‘a civilian’’, Aldrin discussed the issue with Armstrong, who said simply that since it was not their decision to make they must wait and see. Several days later, Aldrin went to Low and urged that a decision be made in order to facilitate training. This was a reasonable request, because one of Aldrin’s assignments in planning the mission was to refine procedural issues. Low and Kraft then met with Gilruth and Slayton, and they formally decided that the first man to exit the LM would be Armstrong, if only for the fact that the hatch was hinged to open towards the man on the right, meaning that the man on the left, the

Portable life-support system 17

commander, must exit first. When Slayton called the astronauts into his office, he cited the hinge on the hatch as the reason for Armstrong being first out and last in.1 On Monday, 14 April, Low announced to the press that if all went well, Armstrong would be the first man to set foot on the lunar surface.


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,











PAD (4)


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)


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!’’


After the P22 landmark tracking, Collins had initiated a manoeuvre to orient the docked vehicles to enable Eagle to calibrate its abort guidance system (AGS). As he waited for this to finish, he noted that there was an advantage to being behind the Moon, as they then were, “It’s nice and quiet over here, isn’t it?’’

“You bet,’’ agreed Aldrin.

On finishing the manoeuvre, Collins nulled out the rates and then went ‘free’ while Eagle performed the calibration. After five minutes Collins asked, ‘‘How’s the Czar over there? He’s so quiet.’’

‘‘I’m punching buttons,’’ replied Armstrong, referring to the DSKY activity.

A few minutes later, Collins, having been thinking ahead, urged, ‘‘You cats take it easy on the lunar surface. If I hear you huffing and puffing, I’m going to start bitching at you.’’

“Okay, Mike,’’ Aldrin promised.

During the calibration, the only tasks that could be performed were those that would not induce vibrations. One permissible operation was to open the helium valves to pressurise the DPS propellant tanks. Once the calibration was finished, Collins called, “I’m going to manoeuvre to the undocking attitude.’’ He aligned the docked vehicles ‘vertically’, with the CSM beneath. “How about 100 hours and 12 minutes as an undocking time? Does that suit your fancy?’’

“That’ll be fine,’’ agreed Armstrong.

‘‘Are you guys all set?’’ Collins asked, as the clock ticked down.

‘‘We’re all set when you are, Mike,’’ Armstrong confirmed.

‘‘15 seconds,’’ called Collins. He released the capture latches. If these were to fail to release, the design allowed for a suited crewman to manually release them, either by Collins pulling a handle or by a LM crewman pushing a button on the tip of the probe; in either case, the cabin would require to be depressurised and the appropriate hatch opened to gain access to the mechanism. The latches, however, did release. As the residual air in the tunnel escaped, it made the vehicles slowly drift apart.

Since it was desired that the LM remain in the orbit resulting from the LOI-2 manoeuvre, the parameters of which had been precisely defined by Manned Space Flight Network tracking, the same state vector had been loaded into both vehicles and as soon as Eagle was free Armstrong cancelled the 0.4-foot-per-second rate of separation that the PGNS indicated had resulted from the undocking.[23]

‘‘I’ve killed my rates, Mike,’’ Armstrong announced, ‘‘so you drift on out to the distance you like and then stop.’’

When Collins was about 65 feet away, he halted to station-keep.

Meanwhile, in the Aldrin home, son Andrew wondered aloud why NASA had not installed a communications satellite to relay while the spacecraft was behind the Moon.[24] In the Collins home, Joe and Mary Engle were looking after the children. Pat Collins, flight plan on her lap, was eager for AOS to find out if the undocking had occurred. Jan Armstrong was also at home with her flight plan, thinking the same thoughts.

‘‘Eagle. Houston. We’re standing by,’’ called Duke as the vehicles appeared on revolution 13.

‘‘The Eagle has wings,’’ replied Armstrong.

Collins had installed his 16-millimetre Maurer in window 4 to document this part of the mission. On the flight plan, the television camera was to have been set up

alongside it to provide ‘live’ television, but about 57 hours into the translunar coast Houston had cancelled this telecast owing to the lack of an available channel on a geostationary satellite to relay the transmission from the Madrid receiving station to Houston for conversion. In any case, as Collins had said shortly prior to LOS, he was too busy to set up the television system. The loss of ‘live’ views of Eagle in flight was a disappointment to the national television networks, which had hoped to use it to introduce their uninterrupted coverage of the next phase of the mission.

Several minutes into the near-side pass, Armstrong yawed Eagle around and pitched it up in order to place it ‘side on’ to Columbia, and then slowly yawed it through 360 degrees to enable Collins to visually confirm that the legs had fully deployed and the probes were in position. An unusual sound late in the translunar coast had prompted Armstrong to speculate that the hinged panel on the right side of the vehicle had prematurely deployed, but Collins confirmed that this was in its stowed configuration. ‘‘You’ve got a fine-looking flying machine,’’ he assured.

‘‘See you later,’’ promised Armstrong, as the separation manoeuvre loomed.

‘‘You guys take care,’’ said Collins. With his spacecraft oriented apex-up, he fired his forward-facing RCS for 8 seconds to impart a downward radial thrust in order to withdraw at 2.5 feet per second, during which time the rendezvous radar mounted on Eagle’s ‘forehead’ tracked Columbia as a test of the radar’s ability to lock onto the transponder on the other vehicle, and Columbia tested its VHF ranging apparatus; these tests being designed to verify the rendezvous systems prior to Eagle entering the descent orbit. The separation burn occurred about 10 degrees east of the landing site, and placed Columbia into an equi-period orbit with its perilune 90 degrees later, and some 5 nautical miles lower.

Meanwhile, at home

Astronauts cycled back and forth between the Armstrong and Aldrin homes, as indeed did their wives, although rarely together because their efforts were divided between the families – it was a routine that Jan and Joan understood, as they had done the same thing themselves, and there was no need to play host because it was a self-organising process.


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.


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.


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.


On 15 October 1962 Hamilton Standard of Windsor Locks, Connecticut, initiated development of the Portable Life-Support System (PLSS) for use by an astronaut on the lunar surface. It had to be able to accommodate the metabolic heat liberated by a man doing the equivalent of shovelling sand and, for short periods, sawing wood without overheating or fogging the visor. An attempt to use the oxygen circulation system of the space suit proved to be inadequate, and in September 1964 it was decided to develop an undergarment incorporating a network of fine tubes through which cool water could be pumped. In 1965, with the PLSS growing in size and complexity, consideration was given to cancelling it in favour of just providing the astronauts with 50-foot umbilicals that would snake out of the hatch, even though this would have restricted lunar surface activity to the immediate vicinity of the LM. Fortunately, the pace of development promptly improved. The backpack was 26 inches high, 18 inches wide and 10 inches deep, and contained: (a) a primary oxygen system to regulate the suit at 3.7 pounds per square inch; (b) a ventilator to circulate oxygen, both for breathing and to cool, dehumidify, and cleanse the suit of carbon dioxide and other contaminants; (c) a loop to circulate 4 pounds of water per minute through the liquid-coolant garment; (d) a sublimator to shed waste heat to vacuum; and (e) a communications system to provide primary and backup voice relay via the LM. Each internal system was covered by a thermal insulator of fire-resistant beta cloth, and the entire pack was covered with aluminised kapton to minimise heat transfer and fibre-glass as protection against incidental damage. It had sufficient water and oxygen for 4 hours of nominal operation, but this would begin at the time of disconnecting from the LM’s life-support system, prior to egress, and run on after ingress until switching back to the LM. However, as no one could be certain of the metabolic rate of a man on the lunar surface, and therefore of the rate at which oxygen and coolant would be consumed, it was decided to limit the first moonwalk to half of this time. If a second moonwalk were to be scheduled then the PLSS would be replenished as necessary from the LM’s resources.

When Apollo 9 lifted off on 3 March 1969 with LM-3, mission commander Jim McDivitt thought that if they achieved only 50 per cent of their demanding program they would still be able to declare the mission a success. Rusty Schweickart was to test the PLSS by emerging from the forward hatch of the LM, translating along a

Nevertheless, if it had been decided that Aldrin should egress first, it would have been possible for them to switch places prior to donning their bulky backpacks.

handrail onto the roof of the vehicle, grasping a shorter rail on the CSM and entering the command module through its side hatch, so rehearsing the external transfer that would be used in the event of a returning lunar crew being unable to employ the tunnel in the docking system. However, when Schweickart suffered ‘space sickness’ early in the flight his spacewalk was limited to the ‘porch’ of the LM. Nevertheless, the 38-minute excursion was sufficient to demonstrate the PLSS in the space environment, and no one seriously doubted that an external transfer between vehicles was feasible.


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.