Category Paving the Way for Apollo 11

NASA was well placed to exploit the new administration’s willingness to expand the space program. Its long-term planning was impressive for its detail, in particular

This report was excerpted in the New York Times on 12 January 1961, and is sometimes wrongly dated as such.

because George Low’s committee had costed the accelerated plan – concluding that it would require $7 billion to land a man on the Moon by the end of the decade. In January 1961 Low briefed Keith Glennan on the forthcoming hearings for NASA’s budget, but Glennan expected to be replaced by the new administration and so was in a weak position.

On Johnson becoming Kennedy’s Vice President, Robert S. Kerr took over from him the chairmanship of the Senate Committee on Aeronautical and Space Sciences. After consulting Kerr, Johnson recommended James E. Webb to succeed Glennan as NASA administrator, and Webb took over on 14 February. Whereas Glennan was a scientific administrator with a conservative outlook, Webb was a political operator. He had served as Director of the Bureau of the Budget between 1946 and 1949 and Undersecretary of State from then until 1952 in the Truman administration. He had been a director of Kerr’s oil and uranium conglomerate, Kerr-McGee Oil Industries, and simultaneously a director of the McDonnell Aircraft Company.

Webb immediately set out to obtain the funding that was earlier denied for Apollo and the Saturn launch vehicle. When the Bureau of Budget refused, Webb wrote to Kennedy in early March that Eisenhower had “emasculated the 10-Year Plan before it was one year old’’, and if the funding were not made available it would “guarantee that the Russians will, for the next five to ten years, beat us to every exploratory space flight’’. To ram home the message in terms that Kennedy would appreciate, Webb said, “We have already felt the effects of the fact that they were the first to place a satellite into orbit, have intercepted the Moon, photographed the back side of the Moon, and have sent a large spacecraft to Venus. They can now orbit seven and a half ton vehicles about the Earth, compared to our two and a half tons, and they have successfully recovered animals from flights of as much as 24 hours. Their present position is one from which further substantial accomplishments can be expected, and our best information points to a steadily increasing pace of successful effort on a realistic timetable.’’

On 23 March Kennedy met with Lyndon Johnson, Jerome Wiesner, David Bell of the Bureau of Budget and Edward C. Welsh, a former aide to Johnson who was now serving as Executive Director of the National Aeronautics and Space Council, of which Johnson was chairman. Kennedy agreed to increase funding for the Saturn launch vehicle, but said he would need to deliberate further on the Apollo spacecraft – he would decide in the autumn, he said.

Just when NASA began to think that it might beat the Soviets to a manned space flight, on 12 April 1961 Yuri Alexseyevich Gagarin made a single orbit and landed safely. Webb told Congress, in budget hearings then underway, that NASA could certainly work faster if its funding was increased.

The next evening Kennedy met at the White House with Jerome Wiesner, David Bell, James Webb, Hugh Dryden, Theodore Sorensen, who was a friend and advisor, and Hugh Sidey, a journalist for Life magazine who was one of Kennedy’s friends, and put to them the question, “at what point we can overtake the Russians’’. NASA opened with a space station to be assembled in Earth orbit to serve as a jumping off point for a future mission to the Moon. But, it pointed out, if the Soviets were on the same plan they would likely remain in the lead for some considerable time. Kennedy

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The Huntsville Times reports the first man in space.

wanted to minimise this period, either by accelerating or by short circuiting the plan. Dryden said a ‘crash’ program might land a man on the Moon ahead of the Soviets, but it might cost as much as $40 billion. ‘‘The cost! That’s what gets me,’’ Kennedy mused. ‘‘When we know more, I can decide if it’s worth it or not. If somebody can just tell me how to catch up.’’ As the meeting broke up, Sorensen remained behind to discuss what had been said, and upon emerging told the others, ‘‘We’re going to the Moon!’’

On 19 April Kennedy summoned Johnson and told him he had decided to issue a momentous challenge. The next day, Kennedy sent a memo to Johnson seeking ‘‘an overall survey of where we stand in space’’. Specifically:

1. Do we have a chance of beating the Soviets by putting a laboratory in space, or by a trip around the moon, or by a rocket to land on the moon, or by a rocket to go to the moon and back with a man. Is there any other space program which promises dramatic results in which we could win?

2. How much additional would it cost?

3. Are we working 24 hours a day on existing programs. If not, why not? If not, will you make recommendations to me as to how work can be speeded up.

4. In building large boosters should we put [our] emphasis on nuclear, chemical or liquid fuel, or a combination of these three?

5. Are we making maximum effort? Are we achieving necessary results?

On 21 April Kennedy told reporters that his administration was considering the options and cost of space, and said, ‘‘If we can get to the Moon before the Russians, we should.’’

Johnson consulted NASA first, which said there was little chance of beating the Russians to a space station; it might be possible to beat them to lunar orbit; the best bet was a lunar landing. This matched Johnson’s thinking. NASA suggested 1967 as a target date because it was expected that the Soviets would attempt to make a lunar landing then in order to mark the 50th anniversary of the Bolshevik Revolution. As a result of the additional analysis by Low, the costing had been increased from the $7 billion estimate for a landing in 1969 to $22 billion; but a landing in 1967 would be $34 billion. Next, Johnson consulted the Pentagon, and the Air Force agreed that a manned lunar landing would be appropriate – even although the Air Force would not be allowed to perform it. Finally, Johnson consulted three businessmen whose judgement he trusted: Frank Stanton of the Columbia Broadcasting System; Donald Cook of the American Electric Power Service Corporation; and George Brown of Brown and Root, which was a construction company in Texas. The fact that none of them was involved in the aerospace industry that would be called upon to build the hardware for the program was a point in their favour, since it meant they were unbiased. At the National Aeronautics and Space Council on 24 April, Johnson, as Wiesner later described it, ‘‘went around the room saying, ‘We’ve got a terribly important decision to make. Shall we put a man on the Moon?’ And everybody said ‘yes’. And he said ‘Thank you’.’’

The scientific community was represented in the White House by Wiesner. The majority of space scientists were interested in particles and fields, and because this

Chairman of the Space Council to be in charge of making an overall survey of where we stand in apace.

1. Do we have a chance of beating the Soviets by putting a laboratory in space, or by a trip around the moon, pr by a rocket to land on the moon, or by a rocket to go to the moon and back with a man. Is there any other space program which promises dramatic results in which we could win?

2. How much additional would it cost?

3. Are we working 24 hours a day on existing programs. If not, why not? If not, will you make reconmenda – tions to me as to how work can be speeded up.

Д. In building large boosters should we put out

emphasis on nuclear, chemical or liquid fuel, or a confcination of these three?

5. Are we making maximum effort? Are we achieving necessary results?

I have asked Jim Webb, Dr. Wiesner, Secretary McNamara

/в/ John F. Kennedy

The historic memo to Lyndon B. Johnson which led John F. Kennedy to challenge his nation to land a man on the Moon before the decade was out.

research did not require a human presence, money spent on sending men into space was by definition wasted. But Kennedy wanted “dramatic results” and the scientists were unable to offer this. To be fair, Kennedy invited Wiesner to suggest a terrestrial challenge that would serve the purpose, “… something with an overseas impact, like desalination or feeding the hungry”. However, Wiesner could see that the Moon was

shaping up to be the challenge, and advised the President “never to refer publicly to the Moon landing as a scientific enterprise”.

On 28 April Johnson submitted the National Aeronautics and Space Council’s recommendation:

Largely due to their concerted efforts and their earlier emphasis upon the development of large rocket engines, the Soviets are ahead of the United States in world prestige attained through impressive technological accomplishments in space. The US has greater resources than the USSR, etc. The country should be realistic and recognize that other nations, regardless of their appreciation of our idealistic values, will tend to align themselves with a country which they believe will be the world leader. The US can, if it will firm up its objectives and employ its resources, have a reasonable chance of attaining world leadership in space. If we don’t make a strong effort now, the time will soon be reached when the margin of control over space and other men’s minds through space accomplishment will have swung so far on the Russian side that we will not be able to catch up. Even in those areas in which the Soviets already have the capability to be first and are likely to improve upon such capability, the United States should make aggressive efforts, as the technological gains as well as the international rewards are essential steps in gaining leadership. Manned exploration of the Moon, for example, is not only an achievement with great national propaganda value, but is essential as an objective, whether or not we are first in its accomplishment – and we may be able to be first.

Kennedy was receptive to Johnson’s recommendation, but he postponed a formal decision until after the first manned Mercury mission, which came on Friday, 5 May 1961 when Al Shepard rode a Redstone missile on a suborbital arc.[19]

Over the weekend, Johnson met James Webb and Secretary of Defense Robert S. McNamara to draw up a formal recommendation to Kennedy’s memo of 20 April. Recommendations for our National Space Program: Changes, Policies and Goals, jointly authored by Webb and McNamara, said, “It is man, not merely machines, in space that captures the imagination of the world. All large-scale projects require the mobilization of resources on a national scale. They require the development and successful application of the most advanced technologies. Dramatic achievements in space, therefore, symbolize the technological power and organizing capacity of a nation. It is for reasons such as these that major achievements in space contribute to

After his successful Mercury flight, Alan B. Shepard shakes hands with John F. Kennedy at the White House.

In a speech to Congress on 25 May 1961 John F. Kennedy challenged his nation to land a man on the Moon before the decade was out.

national prestige.” They wrote, “even though the scientific, commercial or military value of [such an] undertaking may by ordinary standards be marginal or economically unjustified”, it nevertheless generated “national prestige”, which had value in its own right. Furthermore, “The non-military, non-commercial, non­scientific but ‘civilian’ projects such as lunar and planetary exploration are, in this sense, part of the battle along the fluid front of the Cold War.’’ This echoed Kennedy’s criticism of Eisenhower: whereas Eisenhower had been conscious of the cost and dismissive of national prestige, to Kennedy national prestige was the issue and the cost was secondary.

On 25 May Kennedy gave a speech to a joint session of Congress on the theme of Urgent National Needs. In view of recent space achievements by the Soviets, he proclaimed, ‘‘Now it is time to take longer strides, time for a great new American enterprise, time for this nation to take a clearly leading role in space achievement, which in many ways may hold the key to our future on Earth.’’ Having outlined the political background, he laid down the gauntlet. ‘‘I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon, and returning him, safely, to the Earth.’’ He had opted for a lunar landing precisely because it posed a great technical challenge. By literally ‘shooting for the Moon’, he was betting that America would not only catch up with the Soviet Union in space, but forge ahead. Having concluded that space was the arena of superpower politics, he was challenging his rival, Nikita Khrushchev, for world leadership. He had imposed the deadline to ensure that reaching the Moon was perceived as a race. He was also well aware of the magnitude of the task. ‘‘No single space project in this

period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish.” The sending of a man to the Moon was to be the modern form of the ancient practice of ‘single combat’, whereby opposing armies lined up and each dispatched a single warrior to decide the issue. To indicate that it was a matter of national honour, he added, ‘‘In a very real sense, it will not be one man going to the Moon; if we make this judgment affirmatively it will be an entire nation, for all of us must work to put him there.’’ And in order to emphasise what was at stake, he warned, ‘‘If we are to go only halfway, or reduce our sights in the face of difficulty, in my judgment it would be better not to go at all.’’

For Kennedy the Moon was a symbol and, in terms of what he wished to achieve it was an excellent symbol. He had the impression that the applause in Congress was ‘‘something less than enthusiastic”, as he told Sorensen immediately after giving the speech. But Johnson had read the mood well: there was only minor opposition in the House of Representatives, and the debate in the Senate lasted less than an hour – only five of the 96 senators spoke, and the floor was dominated by Robert Kerr, who was Johnson’s man. NASA’s budget was doubled without a formal vote being taken.

CHANGING HORSES

In January 1961 the Hughes Aircraft Company was selected to build the Surveyor spacecraft. With a planned mass of about 1,125 kg at translunar injection, it would require the Atlas-Centaur. The plan was for the orbital version to provide wide-area mapping and reconnaissance of potential landing sites for the surface Surveyors and, later, for Apollo. The mass at touchdown was expected to be about 340 kg, of which 114 kg would be scientific instruments which would not only transmit pictures but also provide data on the physical, chemical, mineralogical and biological properties of the surface material. The initial schedule called for the first flight in 1964. It was also envisaged that as the project matured, an orbital variant would be equipped to serve as a communications relay for landers investigating sites on the far-side of the Moon.

On 23 March the Lunar Science Subcommittee at the Office of Space Sciences recommended that the orbiter have a TV system which was capable of providing: (1) full coverage of the limb areas (highly foreshortened to terrestrial observers) and of the far-side at a resolution of 1 km, (2) wide-area reconnaissance at a resolution of 100 metres, and (3) stereoscopic pairs of selected areas with sufficient resolution to discern objects 10 metres in size. On 5 December Charles Sonett, Chief of Lunar and Planetary Sciences at the Office of Space Sciences, asked William Cunningham to determine the status of the orbiter. On 12 January 1962 Cunningham reported that JPL would not be able simply to adapt the vidicon system developed for Ranger; a new TV system would be required, the development of which had not yet begun.

NASA called for JPL to define the design requirements for the Surveyor orbiter, maximising its commonality with the lander, by 1 September 1962, but owing to the problems the laboratory was facing with Ranger the orbiter received little attention.

Meanwhile, on 15 June 1962 the Office of Manned Space Flight compiled a list of the data that it required the Office of Space Sciences to supply on the environment around the Moon and on its surface – i. e. Brainerd Holmes’s Requirements for Data in Support of Apollo. In view of the urgency to feed such information into the design

of the Apollo vehicles, the Office of Space Sciences asked JPL whether Ranger could serve as the basis for an orbiter. JPL in turn asked the Hughes Aircraft Company to consider the possibility of a 360-kg orbiter which could be launched by the Atlas – Agena. Hughes replied that in order to meet this mass limit, the scientific payload could not exceed 27 kg, which was unrealistic in view of the activity to be pursued. JPL calculated that if the solid-rocket motor that Surveyor was to use in the initial phase of its descent to the Moon were to be used to augment the Agena in the translunar injection, it would be possible to increase the scientific payload to 57 kg, but this was still too little. Even although the development of the Centaur stage was running behind schedule, the Office of Space Sciences decided to proceed with the Centaur-based orbiter.[26] To meet the Apollo requirements, the orbiter would require to provide photography of potential landing sites capable of revealing protuberances and pits as small as 1 metre in size and slopes as shallow as 7 degrees. But even the stereoscopic views from the Surveyor orbiter’s TV system would have a resolution no better than 10 metres. A photographic system employing film would be needed to meet the requirements of the Office of Manned Space Flight.

On 21 September 1962 Oran Nicks, Director of Lunar and Planetary Programs in the Office of Space Sciences, asked Lee R. Scherer to form a committee to evaluate proposals which had been submitted by the Space Technology Laboratories and the Radio Corporation of America for a ‘lightweight’ lunar orbiter compatible with the Atlas-Agena.

On 23 October Joseph Shea, the Deputy Director of the Office of Manned Space Flight, specified the relative priorities of the data that Apollo would require from the Office of Space Sciences. There was a greater need for the information which a soft – lander would provide, since this would feed into the design of the Apollo vehicles, whereas the information from an orbiter would not be required until later, in mission planning. Shea stressed that if funding was tight in Fiscal Year 1963, then the Office of Space Sciences should favour the lander over the orbiter.

Scherer reported to Nicks on the issue of an Agena-based orbiter on 25 October. The proposal by the Radio Corporation of America was for a Ranger bus to make a lunar flyby, dropping off a 200-kg package which would insert itself into orbit. The orbiter would be 3-axis stabilised and use a vidicon system (no doubt a development of the camera the company had provided for Ranger Block II) to provide pictures at a resolution of 130 metres in the wide-angle coverage and 30 metres in the narrow – angle coverage. The Space Technology Laboratories had envisaged an orbiter with a mass of 320 kg. It would have a monopropellant engine which was capable of firing several times. In addition to a midcourse manoeuvre and orbit insertion, this engine would permit changes to the orbit. One mission profile would be to enter a circular polar orbit at an altitude of 1,600 km and map the entire Moon, resolving objects as small as 18 metres in size. Alternatively, it could be placed into equatorial orbit at an altitude of 40 km to photograph that zone with a resolution of 0.5 metre. It would be spin-stabilised, and use a ‘spin scan’ camera of a design similar to that proposed by the RAND Corporation in 1958. It would use film to obtain a higher resolution than was obtainable using a vidicon. Scherer reported that only the proposal by the Space Technology Laboratories offered the prospect of meeting the requirements set by the Office of Manned Space Flight for imaging resolution, and he recommended that the company further refine the concept so as to enable the Office of Space Sciences ‘‘to establish the confidence needed [to consider] a flight program of this type, should it be deemed preferable to a Centaur-based orbiter’’. In fact, once the viability of an Agena-based reconnaissance orbiter had been established, this in itself undermined the case for pursuing the Surveyor orbiter.

On 26 October, Clifford Cummings, unaware of Scherer’s study, wrote to advise Oran Nicks that JPL was about to conduct a study to refine the configuration of the Surveyor orbiter in order to specify how it would perform its mission. In his reply on 8 November, Nicks pointed out that the Office of Space Sciences was looking into the possibility of an Agena-based orbiter.

On 2 January 1963 Nicks asked Floyd L. Thompson, the Director of the Langley Research Center, to consider the possibility of his staff taking on the development of a lightweight orbiter. Thompson set up an internal feasibility study. After the Space Technology Laboratories had refined its concept, a review was held at Langley on 25 February involving representatives of the company, the Office of Space Sciences, the Office of Manned Space Flight, Langley and Bellcomm. Lee Scherer and Gene Shoemaker reported on a study they had undertaken for Nicks to determine how a lightweight orbiter might satisfy the photographic requirements of Apollo. Dennis Jones of Bellcomm reported an assessment made for Shea on the degree to which an orbiter might support the manned and unmanned exploration of the Moon. A second meeting on 5 March agreed that not only was a lightweight orbiter viable, it would also significantly support Apollo. Langley then sent a delegation headed by Clinton E. Brown to brief Robert Seamans and present the case for Langley taking on such a project; Seamans authorised planning to proceed.

In order to assist Langley draw up the request for proposals, in April 1963 the Office of Manned Space Flight refined its requirements. The critical needs were: (1) data on the radiation flux in lunar space over a typical 2-week period; (2) a summary and analysis of all efforts for short-term prediction of severe solar proton events; (3) measurements of particles capable of penetrating 0.01 cm and 0.1 cm of aluminium in an average peak 2-week period of micrometeoroid activity; and (4) photographic data capable of showing protuberances 3.5 metres tall and slopes of 15 degrees in an area of the lunar surface with a radius of 60 metres (to be provided by the autumn of 1965) and then equivalent data showing 50-cm protuberances and 8-degree slopes in an area with a radius of 1,600 metres. Other needs were: (1) measurements of the distribution of slopes greater than 15 degrees in areas of 3.5 metres radius; and (2) the greatest possible coverage of the zone within 5 degrees of the lunar equator with a resolution of 25 metres or better.

On 25 April Edgar Cortright put it to Homer Newell that since one successful orbiter could be worth “dozens of successful Ranger TV impactors”, the three new Rangers which had recently been funded in order to obtain high-resolution pictures and gamma-ray and radar reflectance data on the Moon should be cancelled. Newell accepted this reasoning and passed the recommendation to Robert Seamans, who concurred on 12 July. Later in the year, the second batch of rough landing Rangers was also cancelled.

AS-201 was the first in a series of test flights to ‘man rate’ the Saturn IB and the Apollo spacecraft.8 It lifted off from Pad 34 at 16:12:01 GMT on 26 February 1966. After the booster cut off, the S-IVB stage separated cleanly and attained the planned suborbital arc. In releasing CSM-009, the stage splayed its four panels to an angle of 45 degrees to allow the service propulsion system engine an unobstructed exit. The spacecraft had neither a guidance and navigation system nor an S-Band transmission system. It was powered by batteries instead of fuel cells, had a 20 per cent propellant load, and an ad hoc electromechanical control sequencer. It began by firing its RCS thrusters for 18 seconds to withdraw from the S-IVB. Upon peaking at an altitude of 226 nautical miles, the spacecraft fired its thrusters again to provide ullage to settle the propellants in their tanks, then fired the service propulsion system. However, 80 seconds into the planned 184-second burn the thrust chamber pressure started to decline owing to inadvertent helium ingestion, and by the time the engine shut down the pressure had declined to 70 per cent. The thrusters were immediately fired for ullage and the engine was reignited for a 10-second burn, during which the chamber pressure oscillated from 70 per cent down to 12 per cent.

At this point, CSM-002 was the only production-line spacecraft to have flown – it was launched on 20 January 1966 at the White Sands Missile Range by a Little Joe II booster as a high-altitude abort test.

Although the manoeuvres on the descending side of the arc were designed to drive the spacecraft into the atmosphere at a speed significantly faster than a normal orbital entry, it was still not as fast as a trajectory returning from the Moon. Several seconds later, the thrusters began a pitch manoeuvre at a rate of 5 degrees per second for 18 seconds to yield a 90-degree change in attitude. On separating, the command module used its own thrusters to continue this pitch rotation for an additional 82.5 degrees and then rolled 180 degrees in order to orient its heat shield for atmospheric entry. The plan was to subject the heat shield to a high heating rate – meaning a high temperature for a comparatively short time – but the velocity at entry was 782 ft/sec slower than the planned 29,000 ft/sec and the flight path was 0.44 degree shallower, with the result that the heating rate was less than that intended. Although the deceleration peaked at 14.3 g rather than 16.0 g, it was still much greater than on an operational mission. A fault in the electrical power system ruled out aerodynamic steering, and the ‘rolling’ entry which resulted was 40 nautical miles short. Some 37 minutes after launch, the command module splashed into the South Atlantic. It was recovered 2.5 hours later by USS Boxer. To allow the time to diagnose and rectify the fault in the service propulsion system, AS-202 was rescheduled to follow AS-203, which, as an S-IVB development flight, would not carry a spacecraft.

The docking by Gemini 8 with its Agena target vehicle on 16 March lent support to the decision to try the AS-207/208 dual mission. On 21 March NASA announced that Gus Grissom was to command the first Apollo mission. He would fly CSM-012 with Ed White and Roger Chaffee. They were to be backed up by James McDivitt, David Scott and Rusty Schweickart respectively. In each case, the commander and senior pilot were Gemini veterans and the third man was a rookie. Deke Slayton earmarked Grissom for this role immediately after the Gemini 3 test flight in March 1965. After commanding Gemini 4 in June 1965, McDivitt was reassigned to back up Grissom. White, who flew with McDivitt on Gemini 4, backed up Gemini 7 in December 1965 and then joined Grissom’s crew. Although Slayton was introducing a ‘rotation’ for Gemini in which a pilot could progress through backup to command a later mission, after flying Gemini 8 Scott was immediately assigned to McDivitt’s crew to enable them to obtain early experience of Apollo training prior to attempting the AS-207/208 dual mission. If CSM-011 demonstrated that the problems suffered by CSM-009 had been fixed, then AS-204 would launch CSM-012 in the last quarter of 1966 on an ‘open ended’ mission of up to 14 days ‘‘to demonstrate spacecraft and crew operations and evaluate spacecraft hardware performance in Earth orbit’’, but if there were significant issues outstanding then CSM-012 would be modified for a third unmanned test.

On 4 April 1966 the Manned Spacecraft Center revised its senior management job titles, replacing ‘assistant director for’ with ‘director of’ in order to make explicit the fact that the post had primary rather than subordinate responsibility for that activity. Thus, for example, Kraft ceased to be the Assistant Director for Flight Operations and became the Director of Flight Operations. On 12 May NASA deleted the word ‘Excursion’ from ‘LEM’, to make the lander the Lunar Module ‘LM’. On 25 May, precisely 5 years after President Kennedy made his speech to Congress calling for a lunar landing, a diesel-powered crawler carried the 500-F engineering model of the

Apollo-Saturn V at a maximum speed of 1 mile per hour from the vast cube of the Vehicle Assembly Building a distance of 3.5 miles on a special causeway to Pad 39 on the Merritt Island Launch Area in order to verify the ground facilities and assist in the development of training procedures. It was an awesome demonstration of the ‘mobile launcher’ concept.

AS-203 lifted off from Pad 37 at 14:53:17 GMT on 5 July 1966 and the S-IVB inserted itself into the desired circular orbit at an altitude of 100 nautical miles. As it did not have a spacecraft, an aerodynamic nose cone was used. At orbit insertion the liquid hydrogen was ‘settled’ by a combination of tank baffles and deflectors and by ullage induced by venting liquid oxygen. A TV camera in the fuel tank then verified that continuous venting of liquid hydrogen could hold the fluid in this condition during a coasting phase that approximated a flight heading for translunar injection. The fact that the rise in the liquid hydrogen pressure in orbit was greater than predicted gave data on the heat transfer properties of the tank that would be applied in planning Saturn V missions. Radar tracking by ground stations monitored how the parameters of the orbit were changed by the thrusting effect of continuous venting. A simulated restart of the J-2 engine verified the charging of the restart bottles at orbital insertion cutoff, the fuel recirculation chill – down, the fuel antivortex screen, and the liquid oxygen recirculation chill-down. A subcritical cryogenic nitrogen experiment carried in the nose cap successfully maintained pressure control, with a progressive decrease in the fluid quantity indicating that vapour was being uniformly delivered from a two-phase mixture. To save weight, the S-IVB had been designed such that its propellant tanks shared a bulkhead. This sophisticated structure had to cope with the normal difference in pressure between the tanks and also insulate the liquid oxygen at -172°C from the liquid hydrogen at -253°C to preclude the oxygen solidifying. After the ullage trial of the first revolution, the hydrogen valves were closed and the oxygen valves opened to space in order to place an inverse pressure on the common bulkhead and assess its predicted failure point – when this occurred early on the fifth revolution it caused the vehicle to break up.

On 13 July 1966 Deke Slayton and Chris Kraft jointly wrote to Joseph Shea, the Apollo Spacecraft Program Manager: ‘‘A comprehensive examination of the Apollo missions leading to the lunar landing indicates there is a considerable discontinuity between the missions AS-205 and AS-207/208. Both missions AS-204 and AS-205 are essentially long-duration system validation flights. AS-207/208 is the first of a series of very complicated missions. A valid operational requirement [therefore] exists to include an optical equi-period rendezvous on AS-205.’’ If this Block I flight were to include a rendezvous with its spent S-IVB, it would offer an opportunity to evaluate the control dynamics, visibility, and piloting techniques for the rendezvous phase of AS-207/208. By this point, every spacecraft on Grumman’s production line through to LM-4 was late. The focus, of course, was on LM-1, but late shipments by subcontractors were impeding its assembly. Nevertheless, the ‘rate of slippage’ was slowing, and on 6 October Shea reported his expectation that the company would be able to deliver LM-1 early in 1967. By the end of 1966 LM-1 and LM-2 were in test stands, and LM-3 through LM-7 were in various stages of assembly, but by the end

of January 1967 it was clear that LM-1 would not be able to be shipped on schedule in February.

As its designation suggests, AS-202 was intended to be the second Saturn IB test, but it slipped behind AS-203 as a result of delays involving the spacecraft. CSM-011 was a fully functional Block I spacecraft, minus the crew equipment. But it carried a more sophisticated ad hoc sequencer than on AS-201, a 60 per cent propellant load, a variety of flight qualification instrumentation and four film cameras. It lifted off from Pad 34 at 17:15:32 GMT on 25 August 1966. A key objective was to verify the emergency detection system in closed-loop configuration. At cutoff, the S-IVB was at an altitude of 120 nautical miles and climbing on a ballistic arc. Eleven seconds after separating, the spacecraft fired its service propulsion system in order to place itself on a higher trajectory that would result in entry over the Pacific. As a thermal test, the spacecraft then turned to aim its apex towards the Earth and maintained this attitude through the peak altitude of 618 nautical miles above Africa. On descending over the Indian Ocean it realigned its apex to the velocity vector, then fired its main engine for 89.2 seconds to accelerate for atmospheric entry and concluded by firing it briefly twice more in rapid succession as a demonstration of rapid restart.

In contrast to the ‘rolling’ entry made by AS-201, this time the command module controlled its attitude to fly a trajectory that ‘skipped’ off the atmosphere to trace a ballistic arc which led to a second contact and full entry. A similar profile was to be used on returning from the Moon. The double peak in the heating rate was designed to expose the shield to low heat rates with high heat loads – lower temperatures, but applied for longer – than a ‘straight in’ lunar return. Although the temperature at the base of the shield peaked at 1,482°C, the cabin did not exceed 21 °C. After a flight of 93 minutes, the command module splashed into the Pacific and adopted the apex-up flotation attitude. But the flight path angle at entry of-3.53 degrees was steeper than the desired -3.48 degrees and the lift-to-drag ratio of 0.28 ( + 0.02) was less than the predicted 0.33 ( + 0.04), causing it to fall short by 205 nautical miles. It was 8 hours before USS Hornet recovered the capsule. The planners would have to take into account the lower than expected lift-to-drag ratio of the command module. This qualified the heat shield for Earth orbital missions, but additional tests would be required for a lunar return. Both the Saturn IB and the Block I spacecraft were declared ready for the first manned mission.

As 80 per cent of the objectives specified for CSM-002, CSM-009 and CSM-011 had (between them) been met, AS-204 was released for the manned Apollo 1.

As William Herschel was passing sunlight through a prism in 1800, he found that heat was refracted just beyond the red end of the visible spectrum, so he named this infrared radiation. The Estonian physicist Thomas Johann Seebeck discovered in 1821 that if two wires of different metal are made into a loop by soldering their ends together, then an electric current will flow if the joins are at different temperatures. In 1856 Charles Piazzi Smyth utilised such a thermocouple to detect solar infrared reflecting off the Moon. Laurence Parsons inherited the 72-inch reflecting telescope built by his father at Birr Castle in Ireland. ft was the largest telescope in the world at that time. The common view was that since the airless lunar surface was exposed to the intense cold of space, it simply must be covered by ice. fn fact, S. Ericsson of Norway had proposed in 1869 that the lunar landscape was shaped by glaciation. fn 1870 Parsons equipped his telescope with a thermocouple and found that at lunar noon the temperature of the equatorial zone – where the Sun would pass close to the zenith – exceeded that of the boiling point of water, which indicated that the surface could not be ice. Measurements of the angle of polarisation of the surface published by M. Landerum in 1890 confirmed that it could not be ice. Despite the measured high temperatures at lunar noon, P. J.H. Fauth in Germany endorsed the idea that the landscape was shaped by glaciation, and in 1913 he and Hans Horbiger announced the highly unorthodox theory that ice was the essence of the cosmos! However, the vapour pressure of ice would cause it to sublime in the vacuum. ff ice were indeed present, it would have to be subterranean. fn 1916 Pierre Puiseux in Paris pointed out that if ice were present in the amounts claimed by Fauth, then it should be most evident at high latitudes where the Sun did not rise far above the horizon – yet there were no polar caps. Nevertheless, W. H. Pickering speculated that there might be ice at the summits of lunar peaks. The outcome of these studies was therefore that the majority of the surface was not ice.

fn 1930 Edison Pettit and Seth B. Nicholson put a thermocouple on the 100-inch reflector on Mount Wilson, which at that time was the largest telescope in the world, and discovered that the surface temperature in the equatorial zone varied by several hundred degrees during the monthly cycle. At the onset of a lunar eclipse in 1939 they measured the temperature plunge by 120°C in the space of an hour as the Moon entered the Earth’s shadow. This implied that the material on the surface was poor at retaining heat. On making more sophisticated measurements, they found that at the equator the temperature was +101°C at noon, fell to -39°C at sunset and -160°C at midnight. fn 1948 A. J. Wesselink in Holland inferred from these cooling rates that the Moon could not be exposed solid rock but must be covered by a blanket of loose material.

After the Second World War, the Moon was investigated at radio wavelengths. fn 1946 Robert H. Dicke and Robert Beringer in America detected thermal emission from the Moon at a microwave wavelength of 1.25 cm. Using the same wavelength, in 1949 J. H. Piddington and H. C. Minnett in Australia measured the temperature of the whole disk at a variety of phases over three lunations. The variation proved to be less extreme than it was at infrared wavelengths. The fact that the radio temperature lagged behind the optical phase of the Moon by 3.5 days suggested the presence of a thin insulating layer with low thermal conductivity. fn 1950 John Conrad Jaeger in Australia matched materials to the microwave observations made by Piddington and Minnett. Agreeing with Wesselink’s inference of loose material, Jaeger argued for a layer of ‘dust’, typically only several millimetres thick, resting on top of a granular material. Observations of lunar eclipses on 29 January 1953 and 18 January 1954 at microwave wavelengths by the US Naval Research Laboratory implied that only the uppermost part of the surface underwent a large variation in temperature. This was consistent with a thin layer of dust on a loose granular material. In 1962 J. F. Denisse in France announced that for wavelengths exceeding 30 cm there was no variation in temperature over the monthly cycle.

Taken together, these investigations indicated that whereas an optical telescope fitted with a thermocouple measured the temperature of the surface itself, the radio temperatures were averages for granular material to depths corresponding to several times the wavelength. The constancy at wavelengths greater than 30 cm implied that the material in the uppermost metre or so was such a poor conductor of heat that even when the Sun was at the zenith its heat did not penetrate that far. And at night, although the surface rapidly radiated away the heat it had gained during the day, the poor conductivity of the deeper material served to insulate it. The temperature at a depth of about one metre was estimated to be a constant -40°C. Candidates for the uppermost metre of material were a porous volcanic rock like pumice or a granular conglomerate. A colloquium held in Dallas, Texas, in 1959 concluded that the fine dust that formed the actual surface was probably of meteoritic origin. It was initially believed that the Moon is particularly bright at its ‘full’ phase due to there being no shadows in view – the objects at the centre of the disk cast no shadows, and objects away from the centre mask their shadows to terrestrial observers. But the absence of appreciable darkening of the limb proved to be a result of the fact that the surface ‘scatters’ more light back towards its source than it does in other directions. It was inferred from this that the material at the surface was a porous vacuum-sintered dust, and that sunlight which penetrated a ‘cavity’ was not absorbed but reflected back out towards its source.

In 1955 Thomas Gold, an astronomer with a wide-ranging interest who was then at the Royal Greenwich Observatory in England, proposed that particles of dust on the lunar surface would become electrically charged by the harsh ionising ultraviolet radiation from the Sun, and that in making the grains of dust repel each other this would cause them to flow remorselessly ‘down hill’ and collect in low-lying areas. Tests using powdered cement in a vacuum had shown that this tended to form fragile ‘fairy castle’ structures full of voids, which was consistent with the inference that the surface material was porous. Gold claimed that the maria were accumulations of dust, possibly several kilometres thick, and were of low albedo because the dust had been darkened through exposure to radiation. But whilst dust moving down hill could bury craters in low-lying terrain, it could not explain the missing ‘seaward’ wall of a crater such as Le Monnier on the margin of Mare Serenitatis, nor the dark floors of Archimedes sitting on elevated terrain or Plato embedded in the lunar Alps.

A. Deutsch in Leningrad suggested in 1961 that there might be life in the granular material where the temperature was constant, and that it lived off gases leaking from the interior. Expanding on this, Carl Sagan in America speculated that if the granular material were tens of metres deep, then it might contain a considerable amount of ice and organic material.

As the space age dawned, therefore, there were already interesting insights and speculations into the nature of the lunar surface material.

When on 25 May 1961 President Kennedy challenged his nation to land a man on the Moon before the decade was out, the sky scientists were unimpressed but the geologists were delighted.

On 8 June Hugh Dryden advised the Senate Committee on Aeronautics and Space Sciences that NASA intended to make use of automated spacecraft to strengthen the manned lunar program. In particular, it was essential to find out whether the surface would support the weight of the Apollo lander. As Dryden put it, ‘‘We want to know something about the character of the surface on which the landing is to be made, and obtain as much information as we can before man actually gets there.’’ Following up, Abe Silverstein provided some details. For a start, Ranger would be extended by four Block III missions. Congress authorised the funding for these missions several weeks later.

Clifford Cummings, JPL’s Lunar Program Director, visited NASA on 21 June and told Edgar Cortright and Oran Nicks, the two managers in Silverstein’s office who were responsible for Ranger, that the greatest single contribution this project could make to Apollo would be to provide high-resolution imagery to enable the nature of the lunar surface to be characterised to provide the information needed to design the landing gear of the Apollo lander. For this, the Block III would replace the surface package subassembly with a TV system that was more sophisticated than that made for the Block II. In the interim, some insight would be provided by the Block II radar altimeter and the accelerometers of the surface capsule as this impacted and rolled to a halt.

JPL recommended that the contract to develop the high-resolution TV system go to the same company that supplied the camera for the Block II, and this was agreed.

On 5 July 1961 JPL discussed the design of the system with the Radio Corporation of America, and it was decided to use a shutter (which was not a standard feature on a continuous-scan TV system) to define a ‘frame’ on a vidicon tube. The contract was signed on 25 August. Responsibility for the design, fabrication and testing of the system was delegated to the company. Harris Schurmeier’s Systems Division would monitor the work. On 31 August, Cummings appointed Allen E. Wolfe as the Ranger Spacecraft Systems Manager to assist James Burke with the increased work. Wolfe had replaced Gordon Kautz as Project Engineer in the Systems Division when Kautz was made Burke’s deputy. Wolfe’s first responsibility would be to steer the remaining Block II spacecraft through all phases of assembly and testing, and then supervise the development of the Block III.

The design of the high-resolution TV subsystem was finished in September 1961. It had three major assemblies: a tower superstructure incorporating a thermal shield to stand on the top of the hexagonal bus; a central box to house the main electronics; and, above, a battery of six cameras and their individual electronic systems. It used two types of camera. The ‘A’ type had a lens with an aperture ratio of f/1 and a focal length of 25 mm. The ‘B’ type had an f/2 lens with a focal length of 75 mm. There were two ‘A’ cameras and four ‘B’ cameras. The vidicons were all the same, but the entire 11-mm square image would be used for the full (F) frame and only the central 3-mm square for the partial (P) frame. One ‘A’ and one ‘B’ camera would operate a 5.12-second cycle in which the shutter fired to expose its vidicon and this was read out over an interval of 2.56 seconds, then erased over the next 2.56 seconds. They were to operate out of phase so that a frame was taken every 2.56 seconds. The other cameras would require 0.2 second to fire the shutter and perform the readout, and 0.6 second to erase. The faster cycle time for these cameras was because a smaller

area was to be scanned. They were to be cycled to take a frame every 0.2 second, in the hope that one camera would be able to provide a close-up picture just prior to impact. The cameras were mounted at angles designed to provide overlap to enable the relationship of one frame to be related to those preceding and following. The TV subsystem would have its own battery, independent of the bus, and a pair of 60-watt transmitters. Unlike the Block II, whose flow of pictures would conclude when the separation of the surface package caused the high-gain antenna to lose its lock on Earth, the Block III would continue to send pictures until it hit the surface. In all, the high-resolution TV subsystem would be 160 kg.6

As in the case of the Block I, the low-gain antenna would be in a fixed position at the top of the tower. The designers of the Block III had the luxury of being able to exploit the full payload capacity of the Atlas-Agena B, and this allowed some degree of redundancy in the basic systems.

On 19 September 1961 NASA announced that the Block IIIs were to be launched in January, April, May and August 1963 – certainly they were to be over before the first soft-landing Surveyor, which was expected in 1964.

On 25 June 1963 Floyd Thompson went to Washington to define the terms of the request for proposals. In particular, he did not wish it to be stated that the spacecraft should be spin stabilised; he wished to see what the bidders proposed. It was agreed to say only that the primary requirement was photographic data at medium and high resolution in order to facilitate the selection of sites for Surveyor and Apollo landers. The secondary objectives were to provide information on the size and shape of the Moon and the properties of its gravitational field. Information would also be sought on conditions near the Moon, including the micrometeoroid flux and total exposure to energetic particles and gamma rays – the latter having been shown by Ranger 3 to exist. A key requirement of the photographic system was that it identify the altitude of the orbiter at the time of an exposure, the orientation of the line of sight (relative to lunar north) and the angle of the Sun to the surface. In particular, it was desired to be able to determine the location of any surface feature to an accuracy of 1 km.

On 23 August Lee Scherer presented the request for proposals to Oran Nicks and Edgar Cortright, who duly reviewed it with Robert Seamans. The Project Approval Document signed by Seamans on 30 August officially initiated Langley’s first deep – space project. It was given the mundane name of Lunar Orbiter. The Lunar Orbiter Project Office was set up at Langley, with Clifford H. Nelson as Project Manager,2 William J. Boyer as Operations Manager and Israel Taback as Spacecraft Manager. In Newell’s office, Lee Scherer was appointed as Lunar Orbiter Program Director, Leon J. Kosofsky as Program Engineer and Martin J. Swetnick as Program Scientist.

On 30 August 1963 NASA invited bids from industry. In September the Lunar Orbiter Project Office established a Source Evaluation Board chaired by Eugene C. Draley of Langley. Five bids were received. The evaluations began in October and ran to late-November.

A key factor in the requirements was that, where possible, off-the-shelf hardware be used to minimise the development effort. The Hughes Aircraft Company, which was prime contractor for Surveyor and would have built the 3-axis-stabilised orbiter for that project, proposed a spin-stabilised spacecraft that would use a solid rocket

In October 1964 Langley recruited James S. Martin from Republic Aviation as Assistant Project Manager.

Boeing wins 147

motor to enter lunar orbit. The Space Technology Laboratories submitted a refined version of its spin-stabilised design. The Martin Company, which supplied the Titan missile to the Air Force but had limited experience of spacecraft systems, offered a 3- axis-stablised design. The Lockheed Missile and Space Company, which had built the Agena as a 3-axis-stablised vehicle and integrated various payloads into it for the Air Force, including reconnaissance cameras, suggested that the Agena be adapted to operate in lunar orbit. Eliminating the need to develop a new vehicle satisfied the desire for off-the-shelf hardware, but the operational concept was flawed because it would require a lot of propellant to insert such a heavy rocket stage into lunar orbit. The Boeing Company’s expertise was aircraft, but it wished to gain experience with spacecraft systems. It proposed a 3-axis-stabilised spacecraft with a mass of 360 kg that would enter lunar orbit using a liquid rocket (just developed by Marquardt as an attitude control thruster for the Apollo spacecraft) and be powered by solar panels. The Source Evaluation Board was particularly impressed by Boeing’s plan to use a lightweight form of a photographic system developed by Eastman Kodak in I960 for a reconnaissance satellite. The camera used two lenses in a configuration that would take wide-angle and narrow-angle frames simultaneously and interleave them onto a single strip of film.[27] The film would be developed and fixed using the ‘semi-dry’ Bimat process introduced by Kodak in 1961, as this obviated the complication of handling ‘wet’ chemicals in weightlessness.[28] The clinching argument in favour of Boeing was the proposal to use Kodak SO-243 fine-grain aerial film to obtain the required high resolution. This film had an exceedingly ‘slow’ rating of 1.6 ASA, whereas the other bidders intended to use ‘fast’ film. In the case of the spin – stabilised designs, a high-speed film was essential. But adding up the time spent flying to the Moon, the time spent in orbit preparatory to imaging, the 10 days spent imaging, and the time spent scanning and transmitting the film, a mission might last up to a month. During this time there was a fair chance of the particle radiation from a solar storm ‘fogging’ a high-speed film, and the heavy shielding to protect it would be prohibitive. Boeing’s proposal to use slow film showed that the company had a better understanding than its competitors of the mission requirements. The Source Evaluation Board strongly recommended in favour of Boeing, and this was accepted. On 20 December 1963 James Webb announced that the contract would be awarded to Boeing of Seattle, Washington.

Boeing appointed Robert J. Helberg to manage the development of Lunar Orbiter. George H. Hage was Chief Engineer. Carl A. Krafft, the Business Manager, led the contract negotiations that began on 6 January 1964 and involved both Langley and the merged Office of Space Sciences and Applications. Boeing subcontracted Kodak to provide the photographic system, and the Radio Corporation of America for the communications system. In March, Boeing

suggested that the photographic data be processed into pictorial format at Kodak in Rochester, New York, where there was already the necessary equipment, but NASA decided that the processing, handling and distribution of all scientific data provided by Lunar Orbiter should be done at Langley – in the case of photographic data by utilising equipment and technicians supplied by Kodak. Langley appointed Calvin Broome as Chief of the Photographic Subsystem Section.

The plan called for five Lunar Orbiter missions to be launched by Atlas-Agena D, with the first in either late 1965 or early 1966. They were to photograph the lunar surface from a perilune of 40 km. As in the case of Ranger at JPL, Langley would be responsible for overall systems integration of the spacecraft and the launch vehicle, as well as the necessary ground support, but, significantly, by this point NASA had gained control of both the procurement of launch vehicles and of launch operations. Because JPL had established the Deep Space Network to track and communicate with spacecraft, the Lunar Orbiters would be run from the Space Flight Operations Facility. In April 1964, Langley discussed this collaboration with Eberhardt Rechtin. This was the first time that JPL had provided another NASA centre with deep-space support, and so, in effect, a ‘contract’ had to be negotiated to define what JPL would do. But since trajectory design was closely related to the design of the spacecraft’s communications system, and JPL had neither the manpower nor the computer time available to involve itself in this, the transit trajectory and operations in lunar orbit

would have to be planned by Langley and Boeing after JPL had educated Boeing’s engineers in the capabilities and procedures of the Deep Space Network.

Langley and Boeing signed the detailed contract on 16 April 1964. It was sent to NASA headquarters for ratification. James Webb agreed on 7 May, and the formal contract was signed on 10 May.

When NASA decided in 1962 that Apollo would use the lunar orbit rendezvous mission mode, many people doubted that orbital rendezvous would be feasible. The primary objective of the Gemini program was to explore the issues. The ten manned missions flown between March 1965 and November 1966 not only established that rendezvous and docking was feasible, by testing a variety of techniques it gave the Apollo planners the flexibility of options. This inspired a workaround to the fact that the combined Apollo vehicles exceeded the payload capacity of the Saturn IB, in the form of the dual AS-207/208 rendezvous. Gemini also showed that astronauts could endure the space environment for longer than any Apollo mission would require. Given that the longest American space flight at the time of President Kennedy’s commitment to Apollo was Al Shepard’s 15-minute suborbital arc, on which he was weightless for only a couple of minutes, this was welcome news. The fuel cells that were to power the Apollo spacecraft were tested on Gemini, as were a fully inertial reference platform for guidance and navigation, a spaceborne radar, a state-of-the-art digital computer to process the radar data for rendezvous, and bipropellant ablative thrusters. Gemini established that a spacecraft could be steered through re-entry for recovery at a specific location. This increased confidence in the ‘atmospheric skip’ manoeuvre that was to be used by an Apollo spacecraft returning from the Moon. By enabling astronauts to learn how to operate outside a spacecraft, Gemini inspired a rescue option for the crew of an Apollo lunar module that was unable to dock with its mothership. And, of course, by training a cadre astronauts and flight controllers Gemini allowed Apollo to get off to a running start.

As Robert Gilruth, Director of the Manned Spacecraft Center, observed: ‘‘In order to go to the Moon, we had to learn how to operate in space. We had to learn how to manoeuvre with precision to rendezvous and to dock; to work outside in the hard vacuum of space; to endure long-duration in the weightless environment; and to learn how to make precise landings from orbital flight – that is where the Gemini program came in.’’

EARLY IDEAS ABOUT LUNAR CRATERS

In 1662 Robert Hooke was made curator of the recently formed Royal Society of London. He was charged with devising demonstration experiments. As an extremely skilled technical artist, in 1665 he published Micrographica, which was profusely illustrated with his own observations using a telescope and a microscope. Although he included a detailed drawing of the lunar crater Hipparchus, which is at the centre of the Moon’s disk, he had no desire to map the Moon. However, he undertook a series of experiments to investigate how craters may have formed. First he dropped heavy balls into tightly packed wet clay, and examined the imprints that they made. He also heated alabaster until it bubbled, and then let it set so that the last bubbles to break the surface produced craters. However, just as Hooke could not imagine where the projectiles could have come from to scar the Moon so intensively, nor could he conceive how the surface could have been sufficiently hot to blister on such a scale.

Following the discovery of the first two asteroids in 1801 and 1802, Marshal von Bieberstein in Germany suggested that lunar craters were created by the impact of such bodies. This was reiterated independently in 1815 by Karl Ehrenbert von Moll. In 1829 Franz von Gruithuisen agreed. However, the idea was rejected by those who supported the anti-catastrophist paradigm of uniformitarianism in terrestrial geology which was developed in the 1830s and 1840s.[4] In 1873 Richard A. Proctor published The Moon. Although this book was largely devoted to the motions of the Moon, he revived the idea that the craters marked impacts. But when the second edition of the book was issued in 1878 this section had been deleted. What puzzled the nineteenth century proponents of the impact hypothesis was that the lunar

craters are almost all circular, whereas the majority of bodies must have struck at an oblique angle and, it was presumed, produced elliptical craters.

In 1874 James Nasmyth and James Carpenter in England published The Moon, in which they attempted to explain how the surface features may have formed. As had Hooke two centuries earlier, they made model craters in experiments. They came to the conclusion that the lunar craters were produced by ‘fountains’ of material. In the early part of an eruption, when the velocity of the material ejected from the vent was great, the material would spray out in an umbrella-shaped plume and fall back some distance away to build up a concentric ring that became the wall of the crater. In many cases, as the eruption declined the fallout formed a succession of terraces interior to the wall. They presumed that in some cases the final phase of the eruption either built up the central peak, or in the case of craters with dark floors and no peak, switched to fluid lava that was confined to the cavity and buried the vent. In view of the weak gravity and absence of an atmosphere, it seemed plausible that this process could have produced very large structures.

Other explanations were offered for the origin of lunar craters. In 1854 the Danish astronomer Peter Andreas Hansen argued that the Moon bulged towards Earth, that its centre of gravity was displaced 50 km towards the far-side, and that this had drawn all the air and water on the surface around to the far-side, to where the inhabitants had relocated. In 1917 D. P. Beard suggested that the Moon was once immersed in a deep ocean, that the craters were limestone structures similar to coral reefs, and they were left exposed when the water flowed to the far-side.

On 24 September 1961 NASA announced that the Manned Spacecraft Center to be built near Houston, Texas, would supersede the Space Task Group. It would not only design, develop, evaluate and test manned spacecraft, but also train astronauts and manage mission operations. Robert R. Gilruth, head of the Space Task Group, was made Director of this new centre.

On 1 November, NASA restructured its headquarters. As part of this review, the offices of Space Flight Programs and Launch Vehicle Programs were wrapped up, and new program offices were created for Manned Space Flight, Space Sciences, and Applications. This raised Manned Space Flight to office status, as opposed to a subdivision of Space Flight Programs. The effect was to put the administration of all the agency’s activities (some of which were aeronautical) on a par with the Office of Manned Space Flight, although that office had fully three-quarters of the budget. In effect, James Webb had gathered the power of decision-making into headquarters, since the directors of all the ‘offices’ and ‘centres’ would report to Robert Seamans, the Associate Administrator who, as the agency’s ‘general manager’, would have budgetary control.

The obvious candidates to be Director of the Office of Manned Space Flight were Abe Silverstein and Wernher von Braun, but because their relationship was stormy Webb had sought an outsider, and on 21 September hired Dyer Brainerd Holmes. As general manager of the Major Defense Systems Division of the Radio Corporation

Specifically, the cameras were designated Fa (25-mm), Fb (76-mm), P1/P2 (76-mm) and P3/P4 (25-mm).

of America, Holmes had built the Ballistic Missile Early Warning System on time and on budget, which was no mean feat.7 Silverstein returned to the Lewis Research Center, this time as its Director.

Homer Newell was promoted from Silverstein’s deputy to become Director of the Office of Space Sciences. Edgar Cortright became Newell’s deputy, and Oran Nicks superseded Cortright as Director of the Lunar and Planetary Programs Division. As one of his first acts, Nicks established individual offices in the Lunar and Planetary Programs Division for Ranger and Surveyor, and also for the Mariner interplanetary program. For Ranger, William Cunningham was Program Chief, Walter Jakobow – ski was Program Engineer and Charles Sonett served in an interim capacity as Program Scientist. James Burke at JPL was delighted with this structure, because it integrated engineering and science in a single program office and greatly simplified his relationship with NASA headquarters.

Holmes promptly assigned Joseph F. Shea, a systems engineer who had run the development of the inertial guidance system for the Titan intercontinental-range ballistic missile, to resolve the protracted debate about how Apollo would fly to the Moon – the ‘mission mode’ issue.

On 28 November, NASA announced that North American Aviation of Downey, California, had been awarded the contract to develop the Apollo spacecraft. On 21 December, Holmes set up the Manned Space Flight Management Council. Drawing on senior managers at headquarters and the field centres, this would set policy for manned space planning. At its first meeting, the Council decided on a launch vehicle which would become known as the Saturn V. A single launch would be capable of dispatching an Apollo circumlunar mission. It might even be possible to undertake a lunar landing with a single launch. A landing mission involving Earth orbit rendezvous could certainly be done using just two launches.

On 20 February 1962, America finally inserted a man into orbit, with John Glenn riding an Atlas missile to circle the globe three times. On 7 June NASA decided on lunar orbit rendezvous as the mode for Apollo. On 7 November, it announced that the Grumman Aircraft Engineering Corporation of Bethpage, New York, had been awarded the contract to develop the Apollo lunar module.

By the end of 1962, therefore, NASA had taken all the key decisions that defined how it would address Kennedy’s challenge.

BMEWS used large radar stations in Alaska, Greenland and England to provide the US with the famous ‘‘fifteen minute’’ warning of a Soviet ICBM strike over the north pole.

On 12 May 1964 the Office of Space Sciences and Applications announced how Lunar Orbiter would satisfy Apollo’s requirements for maps of the Moon, as agreed with William B. Taylor of the Advanced Manned Missions Program Directorate of the Office of Manned Space Flight. The Manned Spacecraft Center in Houston was interested primarily in the near-side within 5 degrees of latitude of the equator, and had specified stringent requirements for accuracy of selenodetic and topographic data in the vicinity of selected landmarks to assist in navigation in orbit and landing site selection. The US Geological Survey was to produce a variety of maps based on Lunar Orbiter photography.

Oran Nicks suggested to Sam Phillips on 23 September 1964 that the Office of Manned Space Flight should make a study of how Lunar Orbiter could best support Apollo. This would aid the Lunar Orbiter Project Office in developing guidelines for mission planning. Bellcomm was asked to make this study, and on 25 January 1965 Douglas D. Lloyd and Robert F. Fudali submitted the report Lunar Orbiter Mission Planning. This discussed the relative merits of clockwise and anticlockwise orbits of the Moon aligned near the lunar equator. It was confirmed that to achieve the specified 1-metre resolution in the H frames the pictures could be taken from an altitude no greater than 46 km. A strategy of obtaining contiguous high-resolution coverage of multiple targets was recommended. To avoid the possibility of orbital instability as a result of such a low perilune, it was recommended that the initial inclination of the orbit should not exceed 7 degrees to the lunar equator (because gravity perturbations would tend to increase the inclination) and that the spacecraft should have sufficient propellant to perform corrective manoeuvres. Bellcomm followed up on 30 March with Apollo Lunar Site Analysis and Selection, which recommended that the Office of Manned Space Flight and the Office of Space Sciences and Applications form a Site Survey Steering Committee with responsibility for choice of measurements and their relative priorities and instruments, target selection, launch schedules, control of data handling, and methods of data analysis for the Lunar Orbiter and Surveyor missions. On 10 May Bellcomm further recommended that the Office of Manned Space Flight and the Office of Space Sciences and Applications create a joint Lunar Surface Working Group to coordinate mutual planning activities concerning site survey requirements and the means by which these should be satisfied.

In May the Surveyor/Orbiter Utilisation Committee was formed. It was chaired by Edgar Cortright, and its membership comprised senior representatives of these two programs and their project offices: Oran Nicks of Lunar and Planetary

Programs, Urner Liddel of Lunar and Planetary Science, Lee Scherer of the Lunar Orbiter Program, and Benjamin Milwitsky of the Surveyor Program, all of whom were from the Office of Space Sciences and Applications; Israel Taback of the Lunar Orbiter Project Office at Langley; Victor Charles of the Surveyor Project Office at JPL; Sam Phillips, the Apollo Program Director and Everett E. Christensen of Manned Operations, both at the Office of Manned Space Flight; and William A. Lee of the Apollo Spacecraft Project Office and William E. Stoney of Data Analysis, both at the Manned Spacecraft Center. The Committee was to coordinate the Surveyor and Lunar Orbiter projects for their mutual benefit and in support of Apollo. In July, the Apollo Site Selection Board was established in the Office of Manned Space Flight. Although the Surveyor/Orbiter Utilisation Committee would gather engineering and science information and assess proposals for Lunar Orbiter imaging coverage and for Surveyor landing sites, and later recommend landing sites for Apollo, the Apollo Site Selection Board chaired by Sam Phillips would make the decisions.

The Surveyor/Orbiter Utilisation Committee’s first meeting on 20 August 1965 discussed four Lunar Orbiter mission options which had been developed by Langley and Boeing in response to Bellcomm’s report. In order of priority they were: type 1, to photograph ten evenly distributed target areas near the equator, each of which would be covered stereoscopically with both M and H frames; type 2, to photograph four areas in order to ‘screen’ for possible Surveyor landing sites near the equator; type 3, to photograph using H frames an area containing a landed Surveyor in order to study its context; type 4, to obtain topographic data which would not otherwise be obtained. It was decided to start with the type 1 mission, in order to provide as soon as possible the data that was required by the Apollo planners. If the Office of Space Sciences and Applications had not been obliged to support Apollo, the preferred first mission would have been to enter a high circular polar orbit for a global survey at a resolution better than that obtainable using a terrestrial telescope and, significantly, to view the limbs from a vertical perspective.5 In 1963, when the Office of Manned Space Flight began to specify its requirements for Apollo in terms of surface slopes, Gene Shoemaker had hired Jack McCauley to develop methods of photoclinometry. In June 1965 the Surveyor project asked McCauley to use this technique to suggest possible landing sites for their landers. He formed a small team and compiled a list of 74 sites. Owing to uncertainty in the accuracy of Surveyor’s approach trajectory, the sites were specified in terms of ‘target circles’ 25, 50 and 100 km in radius. After factoring in vertical descent and illumination constraints, they selected only circles of 25 and 50 km radius. McCauley presented the final list to the Surveyor/Orbiter Utilisation Committee on 20 August. There were 24 sites with 50-km-radius circles on the maria, and seven in the highlands. There were also 13 ‘scientific’ targets with 25-km-radius circles that would require greater landing accuracy.6

As yet, the only images of the far-side had been provided by Luna 3 in October 1959 and Zond 3 in July 1965.

In fact, all Surveyors except the last would be sent to sites on McCauley’s list.

Mission objectives 151

On 8-9 September 1965 Langley hosted a meeting which (in part) drew up lists of photographic targets judged compatible with Apollo, Surveyor and Lunar Orbiter constraints. James Sasser of the Apollo Spacecraft Project Office in Houston argued for distributed coverage which ‘sampled’ different types of terrain near the equator, although with the emphasis on apparently smooth areas. Lawrence Rowan of the US Geological Survey described an analysis based on a map produced by the Air Force Chart and Information Center on a scale of 1:1,000,000. This analysis identified the types of terrain available for ‘sampling’ by Lunar Orbiter: namely an ordinary mare, a dark mare, mare ridges, mare rays, crater rims, deformed crater floors, and several different types of terrain in the highlands. These discussions led to the ‘A’ mission plan which was formally presented to the Surveyor/Orbiter Utilisation Committee on 29 September. This called for a type 1 mission to inspect a number of areas in the ‘Apollo zone’ – defined as being within 5 degrees of the equator and 45 degrees of the central meridian – to assess their suitability for Apollo and Surveyor landings. It would start with test pictures taken in the high-perilune initial orbit of sites between 60°E and 110°E. Although not in the Apollo zone, these pictures would show a vertical perspective of the limb region in which landmarks would later be selected for Apollo orbital navigation. After the perilune had been lowered, ten sites, mostly in the zone, would each receive a single photographic pass timed to maintain a given angle of illumination as the terminator advanced westward. The targets would cover a variety of terrains, including the Flamsteed Ring in Oceanus Procellarum, which was the favoured site for the first Surveyor. In May, a team of photo-interpreters led by Lawrence Rowan had been created by the US Geological Survey to suggest sites for Apollo. Each site was subjected to a detailed analysis, drawing in data from all sources. This work continued through the Summer Study on Lunar Exploration and Science held 19-31 July 1965 in Falmouth, Massachusetts. Rowan presented a list of ten potential Apollo landing sites to the Surveyor/Orbiter Utilisation Committee on 29 September (just over a month after the Committee received McCauley’s list of candidate Surveyor sites – some sites were on both lists). The meeting approved the ‘A’ mission proposal with nine primary (P) sites, including several that were not on the smooth maria.

The Planetology Subcommittee of the Space Sciences Steering Committee met on 21-22 October to discuss the ‘A’ mission plan. The meeting was chaired by Urner Liddel, who was a member of the Surveyor/Orbiter Utilisation Committee. Harold Masursky of the US Geological Survey explained how the methods of structural and stratigraphic geological mapping would be applied to the pictures supplied by Lunar Orbiter. Liddel then wrote to Oran Nicks on 5 November to emphasise the merit of developing a Lunar Orbiter Block II for a multifaceted scientific study of the Moon to obtain the data which would be required to plan ‘advanced’ Apollo missions.[29]

The Apollo Site Selection Board held its inaugural meeting on 16 March 1966. Although the only materials available were telescopic studies and their interpretation on the basis of close-up views of three sites provided by the Ranger project, several potential areas were identified in the expectation that it would prove possible to land the first Apollo mission at one of them.

On 4 April Leonard Reiffel, representing Apollo, informed Oran Nicks of another Apollo requirement. The original plan had been to store all the data returned by the Lunar Orbiter missions on film, but magnetic tape had a greater dynamic range and was more readily processed by computer, and NASA wished the process of analysis to be as automated as possible – in particular the photoclinometry by which the US Geological Survey was to measure the slopes. Nicks duly ordered that state-of-the – art recorders be purchased to enable the data to be written directly onto tape.

By the time of the Apollo Site Selection Board’s second meeting on 1 June 1966, Surveyor 1 had landed on the Moon and the first Lunar Orbiter was soon to attempt to photograph it to provide a sense of context which would allow the ‘ground truth’ from the lander to be applied more generally.