Chapter 2

The Transmutation of Mercury

During January 1961, NASA’s manned space flight program altered course. At the policy-making level in Headquarters, thinking shifted from lunar reconnaissance to lunar landing. This change was crucial, not only for the lunar program itself but also for what was to become Project Gemini; before 1961 was over that shift would provide justification for a rendezvous development program. In the field, the newly independent Space Task Group stopped talking about an improved Mercury capsule and began working on it. Plans for a lunar landing mission and work on an advanced Mercury proceeded through the summer of 1961 at different levels and varying rates. These separate paths converged in the autumn to give birth to a new program.

Whether these efforts would have borne fruit without a sharp change in the political climate is anyone’s guess. The past two years had seen their share of false starts, dashed hopes, and aborted plans. But the climate did change. Within months after taking office, President Kennedy and his advisors found compelling reasons to support an American manned space flight program far larger than Project Mercury. One factor was certainly the renewed clamor about a space race between the United States and the Soviet Union. Informed opinion might discount Soviet accomplishments or stress American sophistication against Russian brute force; that smacked of quibbling to the American public, especially after 12 April 1961, when Cosmonaut Yuri A. Gagarin aboard Vostok I became first human being to orbit in space. Two days later, the chairman of the House Committee on Science and Astronautics was not merely speaking for himself when he asserted, “My objective … is to beat the Russians.” The President announced his decision on 25 May 1961, in a speech to Congress on “Urgent National Needs.” He committed the United States to landing an American on the Moon before the end of the decade.¹

New Directions

NASA had long since begun to lay plans for lunar flights, although throughout 1960 it had tended to focus on flying around, rather than landing on, the Moon. A new direction in NASA thinking surfaced at the quarterly meeting of the Space Exploration Program Council (SEPC) on 5-6 January 1961. The council was a NASA device for smoothing out technical and managerial problems at the highest level. Its members were the heads of the field development centers and Headquarters program offices,* ² with the Associate Administrator serving as chairman.³ The January meeting was the first presided over by Robert Seamans in his new assignment, and it marked a decisive turning point in the manned space flight program. The first day was devoted to manned lunar landing.

The meeting began with a series of presentations arranged by George Low, Chief of Manned Space Flight in the Office of Space Flight Programs, to provide “a ‘first cut’ at a NASA Manned Lunar Landing Program.”⁴ Low, an early advocate of orbital staging techniques as an alternative to the Nova direct approach, made sure that the council heard about Earth orbit and lunar orbit rendezvous as well as direct ascent.** ⁵ The next step was setting up a study team to devise a more complete plan. This the council did, naming Low its chairman. Unable to agree on the best approach, the council simply asked for “an answer to the question ‘What is NASA’s Manned Lunar Landing Program?’"⁶

The Low Committee began its work a week later.*** Low himself drafted its report, revised it on the basis of comments from other members, and submitted it to Seamans early in February.⁷ The report set out the two themes that came to dominate NASA lunar-mission planning throughout 1961. First, Low argued that both orbital operations and large boosters were going to be needed in the long run. NASA must include Nova-class boosters in the national space program, but “orbital operation techniques must be developed as part of the space program, whether or not the manned lunar landing mission is consider.” Second, he insisted that, barring unforeseen problems, rendezvous “could allow us to develop a capability for the manned lunar mission in less time than by any other means.”⁸

In Space Task Group, the question of rendezvous took a different form. It was seen as one of several classes of missions around which a follow-on Mercury program might be built. This was one of the subjects at a meeting on 20 January 1961 between Director Robert Gilruth and his chief lieutenants.** Max Faget, aided by his Flight Systems Division staff, led the discussion and outlined hardware and booster requirements for several possible types of missions.⁹ Two broad classes came in for particular attention: one was labeled extended time in orbit, the other was rendezvous.

Extended time in orbit covered two possible missions. The first was an 18-orbit manned Mercury mission based on augmented capsule and environmental control systems. The standard Atlas but Gilruth suggested that the group think about using an Atlas-Agena. Atlas-Agena was a two-stage vehicle. The Atlas, which served as first stage, was a product of the Astronautics Division of General Dynamics Corporation in San Diego, California, and the Agena was built by the Lockheed Missiles& Space Company, Sunnyvale, California. Agena development began in 1957 under the Air Force Ballistic Missile Division. An improved model, Agena B, with a restartable engine and larger propellant tanks, entered development in June 1959 and flew on 12 November 1960.¹⁰ Atlas might or might not have enough power to carry aloft the capsule modified for the mission; but if a primate were to pave the way for a manned mission of 7 to 14 days, then Atlas was clearly lacking. It could not lift the required weight.

Atlas was even more doubtful for rendezvous missions. Faget and his colleagues discussed two types, which differed chiefly in their targets. Both used Mercury capsules modified to make them maneuverable, but the target in the first instance was Saint; in the second, an as-yet-undeveloped space laboratory. Discussion centered on the need for a much “refined capsule with better operational and maintenance capabilities, better door, better wiring, possibly a bi-propellant control system, etc.” All this meant weight, more than an Atlas could lift. But the basic objection to the rendezvous mission was that it “might be considered too hazardous for a one-man operation.”¹¹

Whatever their merits, all these possibilities were too vague. Before proposing a Mercury follow-on program to NASA Headquarters, STG had to be “more specific with regard to particular flights needed, funding, management, etc.” This was the task assigned to Faget,# who had only a week to complete it before a scheduled visit to STG on 26-27 January by Abe Silverstein, head of Space Flight Programs in NASA Headquarters. The meetings with Silverstein resulted in a shift in focus to “the question of capsule redesign to speed up check-out and maintenance.”¹²

With a good deal more work clearly needed, Gilruth turned to James A. Chamberlin. Canadian-born and trained at the University of Toronto and the Imperial College of Science and Technology in London, Chamberlin had been working in aeronautical engineering and design since 1939 for several Canadian firms. By March 1959 he had become chief of design for AVRO Aircraft, Inc., of Toronto, where he worked on the CF-105 Arrow, an advanced interceptor aircraft.¹³ When that project was canceled, NASA was able to recruit Chamberlin and several of his colleagues.¹⁴

Chamberlin joined STG in April 1959; by August he had become acting chief of the Engineering and Contract Administration Division.¹⁵ For the next year and half, he directed STG’s technical monitoring of Mercury development and production. When, on 1 February 1961, Gilruth assigned him to work on an improved Mercury, Chamberlin remained titular chief of what had since become the Engineering Division but turned over most of his organization’s administrative, technical, and operational matters to his assistants, André J. Meyer, Jr., and William M. Bland, Jr.¹⁶ Chamberlin himself went to St. Louis in mid-February; during the next months he actually worked from an office in the McDonnell Aircraft Corporation plant two or three days a week.¹⁷

STG’s change in status at the beginning of 1961 may have sparked its renewed pursuit of a post-Mercury program. Although located at Langley Research Center in Virginia, STG belonged administratively to Goddard Space Flight Center in Maryland. This clumsy arrangement served no very useful purpose, since the Space Task Group was largely self-directed in any case. So NASA Administrator Keith Glennan announced on 3 January 1961 that STG was henceforth an independent field element, charged not only with managing Mercury but also with planning and carrying out programs “in the general area of manned space flight.”¹⁸ This was more hope than fact, however; Mercury was still the only approved program, and independence was largely formal. STG stayed at Langley, on which it still depended for much of its support, both technical and administrative.

The union with Langley was the next to go, for a number of compelling reasons: the threatened impact on Langley research of a full-fledged development effort, the strain of fitting a much expanded STG into already cramped Langley quarters, the chance to spread NASA more widely across the country, and the need to move before new programs had progressed to the point where moving would disrupt them.¹⁹ These reasons anticipated, rightly as it proved, the President’s lunar landing decision. Where to move was settled during the summer of 1961, after a special committee visited 19 possible sites.## ²⁰ Houston won the prize, and the booming space agency joined forces with the booming city.

That massive expansion, which saw the tripling of both the manned space flight program and the center in charge of it, had been well prepared. NASA’s first two years had seen most of the relevant issues raised, many of the answers suggested. Nothing had been decided beyond recall, but the channels were carved into which later events flowed. In the first half of 1961, some channels broadened, others dwindled and vanished. Before the summer was over, a far larger, far more complex, and far more costly manned space Right program emerged. An enormous lunar project had joined Mercury and a third project stood in the wings, justified by the needs of Apollo but growing out of the technology of Mercury.

STG Plunges Ahead

The report of the Low Committee early in February 1961 produced no immediate action. As outgoing Administrator Glennan had warned his colleagues in the January meeting of the Space Exploration Program Council, lunar landing was not something NASA could undertake on its own hook; so large and costly a program needed backing at the highest levels.²¹ In the uncertain political climate of early 1961, planning for a lunar landing remained temporarily in abeyance, though work on the Apollo spacecraft went ahead in STG. But renewed interest in rendezvous and orbital operations in NASA Headquarters, as shown in the Low report, led to a second inter-center meeting on rendezvous at the end of February. This time the site was Washington, instead of one of the field centers. The agenda reflected the changing nature of rendezvous research within NASA. Though Langley still dominated the discussions on rendezvous studies, Marshall took a full session to describe aspects of the rendezvous and orbital operations program it had under contract. This meeting saw the lunar orbit rendezvous idea introduced to NASA as a whole.²² Until then, it had been limited to Langley circles and NASA Headquarters.

Rendezvous and orbital operations also figured prominently in congressional hearings on NASA’s proposed budget for fiscal year 1962 during the first months of 1961.²³ The House Committee on Science and Astronautics, in particular, displayed a marked interest in the prospect of orbital rendezvous and scheduled a special hearing on the subject for May.²⁴ NASA’s budget included some $2 million for further rendezvous studies. This was much less than NASA had wanted, but the Bureau of the Budget had sliced $6 million from the agency’s initial request. The House committee recommended the full $8 million and NASA did eventually get the money.²⁵ In sharp contrast to the marked concern for space station logistics in 1959 hearings, the testimony in 1961 consistently stressed the role of rendezvous in mounting lunar and planetary expeditions and the broad value of rendezvous applications.²⁶

While NASA spokesmen were telling Congress how important rendezvous was going to be, a working group in NASA Headquarters was drawing up guidelines for a full-fledged orbital operations development program. The resulting staff paper, ready in May, presented the case for the immediate “establishment of an integrated research, development and applied orbital operations program.” Stressing the need for orbital operations in future space programs, the report urged NASA to set up “an aggressive program,” coordinated with other NASA programs and with the Department of Defense, but separate from either. Such a program, the report concluded, would buy for the United States at a cost of roughly $1 billion three important skills: the ability to intercept and inspect orbiting satellites, to support a space station, and to launch from orbit.

Bernard Maggin, who had arranged the first NASA rendezvous meeting a year earlier, headed the working group.* He sent copies of the report to the program office directors in NASA Headquarters and to the director of Program Planning and Evaluation. His request for comments, however, went unanswered.²⁷ By early May, NASA knew that President Kennedy was ready to approve a lunar landing program. The decision for a speeded up and expanded program transformed the context of NASA planning and made the kind of program Maggin suggested seem far too modest.

In the meantime, James Chamberlin followed his own course. He had arrived in St. Louis in February convinced that his job was to redesign the Mercury capsule from the bottom up. This was a belief not widely shared. The common view had it that Mercury only needed to be improved. Chamberlin felt, and as engineering director of Project Mercury he was surpassingly well qualified to judge, that the Mercury design precluded simple upgrading.²⁸ The Mercury capsule was merely a first try at a manned spacecraft. It clearly took too long to build, test, check out, and launch. The heart of the trouble was Mercury’s integrated design, which packed the most equipment into the least space with the smallest weight. This could hardly have been avoided, given the limited weight-lifting capacity of the boosters available for the Mercury program. But integration also meant that reaching parts to test, repair, or replace was harder than it should be.

Chamberlin first met with McDonnell engineers to discuss the improved Mercury on 13 February. Little more than a month later, he had the chance to present some of his ideas to the head of Space Flight Programs, Abe Silverstein. On 17 March, Gilruth and his top-ranking staff journeyed to Wallops Island, Virginia, for a weekend retreat, where they were joined by Silverstein.²⁹ Mercury problems took up some time, but the meeting’s main purpose was to discuss advanced programs. This chiefly meant Apollo. Chamberlin did, however, have a chance to describe his approach to redesigning the Mercury capsule.

He had attended the meeting mainly to discuss Mercury’s progress. But after Silverstein outlined a series of desirable future Mercury missions, ranging from the one- and three-orbit manned missions already planned to rendezvous development, Chamberlin launched into a largely impromptu blackboard lecture on the program’s future, which he saw as very limited. The trouble with trying anything more ambitious with Mercury than had been planned was that even these relatively modest goals could only be achieved at the expense of the most painstaking and arduous care in testing and checkout. This was not a manned spacecraft problem so much as it was a Mercury design problem. Drawing on his experience with fire control and weapons delivery systems for fighter aircraft, Chamberlin sketched a new capsule structure with its equipment located outside the cockpit in self-contained modules easy to install and check out. Although Chamberlin focused his remarks on capsule modification, he had obviously given some thought to a suitable mission for the new design. He had, in fact, prepared a brochure dealing with an audacious circumlunar flight for the improved Mercury, which Silverstein looked at and dismissed without comment.³⁰

Both Silverstein and Gilruth, however, saw the need for changes along the lines Chamberlin had suggested. Gilruth asked Chamberlin to pursue the ideas in more detail with McDonnell, as the basis for specific proposals. Silverstein authorized STG to prepare a work statement to cover a McDonnell study of modifying the Mercury capsule for enhanced equipment accessibility. STG was also to place an order with McDonnell for parts to be used in several capsules beyond the 20 already contracted for. Looking back, Chamberlin was sure that was where it started: “As far as I was concerned, the meeting at Wallops was the initiation of Gemini.”³¹

On 14 April STG and McDonnell signed an amendment to the original contract for the Mercury capsule. This amendment authorized McDonnell to procure so-called long-lead-time items - those parts that took longest to get - for six extra Mercury capsules. The parts and material so obtained would be used in what was now termed the Mercury Mark II spacecraft, once the design had been agreed upon by NASA and McDonnell. Specifically excluded from this procurement effort were capsule structure, ablation heatshield, and escape-tower systems, but all other capsule systems were covered up to a cost of $2.5 million.³²

The design of the Mark II spacecraft was the subject of a second contract. After talks with STG, McDonnell submitted a study proposal on 12 April.³³ McDonnell proposed to spend $126,385 for 9,000 hours of engineering study, with two objectives: first, to reduce the time needed to build and check out a Mark II capsule by improving the location of equipment and the way it was installed; second, by means of these changes to make the new capsule easy to modify to meet new program objectives. Capsule shape and heat protection were not to be altered, nor were capsule systems to be replaced or greatly modified. The focus of change was to be rearrangement; moving equipment from inside to outside the cabin and putting it in modular subassemblies, with special concern for escape, retrograde, and recovery systems.³⁴ McDonnell was authorized on 14 April to proceed with the engineering study, and a contract for $98,621 was signed on 24 April.³⁵

By then, the study was already well under way. Chamberlin began calling on others in STG to help him. The first was James T. Rose, a recent transfer to Engineering from Flight Systems Division.³⁶ McDonnell created a small project group for the study, headed by William J. Blatz, with Winston D. Nold as chief assistant project engineer. Although they brought with them several engineers from McDonnell’s advanced design section, the new group drew most heavily on Project Mercury, particularly a team led by Fred J. Sanders, for its staff.³⁷ Chamberlin regarded Mercury experience as indispensable. “That was the point,” he recalled, “to use and build on experience, to gain and not to start over again . . . without the benefit of the detailed hardware experience.”³⁸

The guiding idea shared by Chamberlin and his McDonnell colleagues was “to make a better mechanical design"; capsule parts would be more accessible, leading to “a more reliable, more workable, more practical capsule.”³⁹ The experimental Mercury capsule was to be transformed into an operational spacecraft. At this point, neither Chamberlin nor the McDonnell group were much concerned with the purpose such a redesigned capsule might serve. The subject arose, of course, as Chamberlin’s lunar scheme shows, but it took a back seat. For the moment, the urgent question was strictly one of improving the engineering design. Working out the objectives for a program based on the improved capsule could wait.

Direct Ascent Versus Rendezvous

While Chamberlin, Blatz, and their co-workers were eyeing the Mercury capsule and seeing, as engineers always can, any number of ways to make it better, events in the upper reaches of NASA were moving during the spring of 1961 toward the conclusion that would eventually give the engineers their chance to put ideas into practice. Enough of a case had been made for rendezvous in the lunar program during the past year to make it seem worth a closer look. But President Kennedy’s decision to call for a lunar landing before the end of the decade transformed the context of lunar mission planning.

When NASA planning had first focused on flight around the Moon rather than landing on it, rendezvous lacked any urgency. Orbital operations seemed a matter of expedience, a way of making do with smaller boosters than direct ascent demanded. Circumlunar flight, too, could be launched with smaller boosters, but without any need for rendezvous, and a lunar landing appeared to be a long way off. Nobody denied that larger launch vehicles would be an asset to the American space program, and nothing suggested that building such vehicles would pose any special problem other than time and money. Rendezvous, on the other hand, was an unknown. How hard it might be, how dangerous, could not be predicted. Nobody denied that rendezvous could be a useful and important technique, but planning the lunar mission around it appeared unnecessarily risky. Under the circumstances, direct ascent could be defended as more prudent.

Kennedy’s decision changed all that. Gone were the long stretches of time that had allowed the choice between rendezvous and direct ascent to seem less than urgent. NASA now had to select the method that offered the best prospect for meeting the deadline. Even before it was announced, but knowing that a decision was imminent, NASA began seeking the answer.

On 2 May, Associate Administrator Seamans formed a task group to explore “for NASA in detail a feasible and complete approach to the accomplishment of an early manned lunar mission.”⁴⁰ Most members of the ad hoc group came from NASA Headquarters, as did its chairman, William A. Fleming, then acting as Assistant Administrator for Programs.* ⁴¹ Fleming had been working closely with Seamans for several months and had, in fact, drafted the Seamans memorandum that created the task group.

The Fleming Committee had four weeks to size up the scope of the task that NASA faced. This was a tall order for so short a time, and the committee felt compelled to limit itself to one approach.⁴² It elected direct ascent as “the simplest possible approach - the approach of least assumptions and least unknowns.”⁴³ Rendezvous, much the biggest unknown, had no place in the lunar landing program, although it was “an essential program in its own right.”⁴⁴ Having dismissed rendezvous, the Fleming group devoted most of its effort to choosing between solid and liquid propellants for the first stages of Nova-class boosters.⁴⁵ While this did permit the group to pinpoint some crucial decisions that needed to be made quickly - especially the importance of an early choice of sites for the large ground facilities the lunar mission required⁴⁶ - it merely avoided the question of rendezvous versus direct ascent. Convinced, as Fleming later remarked, “that it was always possible to ‘build something bigger and make it work,’"⁴⁷ his committee saw no reason to base its study on a risky and untried alternative.

Others in NASA were not so sure. On 19 May, while the Fleming Committee was still meeting, John Houbolt wrote Seamans from Langley deploring the state of the launch vehicle program and urging more serious attention to rendezvous. He denied any wish to argue for rendezvous against direct ascent but insisted that, “because of the lag in launch vehicle development, it would appear that the only way that will be available to us in the next few years is the rendezvous way. For this very reason I feel it mandatory that rendezvous be as much in future plans as any item, and that it be attacked vigorously.”⁴⁸

This was a viewpoint that Seamans, long a student of orbital rendezvous and openly receptive to such ideas since joining NASA, must have shared. On 25 May, he called on Don R. Ostrander, Director of Launch Vehicle Programs, and Ira H. A. Abbott, Director of Advanced Research Programs, to name “a group of qualified people . . . to assess a wide variety of possible ways for executing a manned lunar landing.” Seamans wanted their report quickly, “at about the same time as the one under way by the Ad Hoc Task Group on Manned Lunar Landing.” NASA Headquarters furnished none of the six members of this committee, led by Bruce T. Lundin of Lewis Research Center.** ⁴⁹ Lundin regarded his committee as speaking for the field centers, in contrast to the Headquarters viewpoint expressed by the Fleming group.⁵⁰ The Lundin report was ready by 10 June, a week before the Fleming report.

Although Lundin’s committee discussed other matters, its main concern was to compare the several rendezvous schemes with each other. It pointedly excluded any specific comparison of rendezvous with direct ascent but noted two inherent advantages in rendezvous that promised an earlier manned lunar landing. One was the relative capacity of a rendezvous-based program to absorb increases in a payload weight, which meant that early decisions on booster design and development might not so critically affect the program. The other was the smaller size of launch vehicles required by a rendezvous mission, a size which would not call for the development of large new engines.⁵¹

Time limited the Lundin Committee to a brief qualitative survey, which could not compare in scope or detail to the elaborate quantitative assessment provided by the Fleming Committee.** ⁵² Clearly, however, the choice between solid or liquid propellants in the first stage or two of a Nova booster was too restricted; the proper alternative to direct ascent was some form of rendezvous. This proposition won unanimous agreement at a meeting between Seamans and the program directors.** On 18 June, though only after considerable discussion, they decided to pursue two courses. Ostrander would form a team from NASA Headquarters and Marshall to define an overall plan for using orbital operations to achieve manned lunar landing. At the same time, the Fleming Committee study of direct ascent would be paralleled by an equally intensive investigation of the rendezvous and orbital operations approach.⁵³

The first line of action under Ostrander produced a preliminary project development plan for orbital operations by mid-September.⁵⁴ For the second, Seamans formed still another ad hoc group that was “to establish program plans and supporting resources necessary to accomplish the manned lunar landing mission by the use of rendezvous techniques” with as much rigor as the Fleming report. He named Donald H. Heaton, his former assistant who had become Assistant Director for Vehicles in Ostrander’s office, as chairman of the new group.⁵⁵

Heaton’s group was about the same size as Fleming’s, but its members were more evenly divided between Headquarters and the field centers.# Its findings, issued late in August, concluded that “rendezvous offers the earliest possibility for a successful manned lunar landing.”⁵⁶ Despite this parade of studies, as future events were to show, the issue had only been joined, not settled. But the view that rendezvous techniques were important enough to pursue “whether or not rendezvous is selected as an operating mode” for the lunar mission⁵⁷ was clearly gaining strength. And this viewpoint was crucial to the fate of Mercury Mark II, which had in the meantime taken on a much more sharply defined form.

The Advanced Capsule Design

Chamberlin and Blatz were ready to report progress toward an advanced capsule design early in June 1961. Chamberlin had conceived his task in terms that diverged widely from what was generally expected. Adept at keeping his ideas to himself until they matured, he was not much of a talker. As far as Space Task Group knew, at least officially, McDonnell was studying an advanced version of the Mercury capsule for just two reasons: to extend the capsule’s lifetime in orbit to one day (or 18 orbits) and to make the capsule easier to check out and test before flight.⁵⁸ The extent of the changes that Chamberlin and Blatz revealed to STG leaders on Friday afternoon, 9 June, took some of them aback.* Chamberlin explained that the primary aim “of the design was to increase component and system accessibility to reduce manufacturing and checkout time.” That was no surprise. But to do it, he had packaged and relocated almost every capsule system. Those closest to Project Mercury tended to share Chamberlin’s view that the Mercury capsule was inherently limited because of its design - making it better meant making it over. This was, after all, the heart of the case Chamberlin had presented at the Wallops Island meeting in March, and he had followed through along the lines he had then suggested. But others in STG, more distant from the daily problems of working with Mercury, were likely to assume that the capsule needed only relatively minor changes to improve it, not the nearly complete new design that Chamberlin offered.⁵⁹

Chamberlin later justified this approach in an enlightening lecture on the design philosophy of the Gemini spacecraft (which Mercury Mark II was to become).⁶⁰ The main trouble with the Mercury capsule was that

most system components were in the pilot’s cabin; and often, to pack them in this very confined space, they had to be stacked like a layer cake and components of one system had to be scattered about the craft to use all available space. This arrangement generated a maze of interconnecting wires, tubing, and mechanical linkages. To replace one malfunctioning system, other systems had to be disturbed; and then, after the trouble had been corrected, the systems that had been disturbed as well as the malfunctioning system had to be checked out again.⁶¹

Mercury designers had been preoccupied with solving such basic problems of manned space flight as reentry heating and human tolerance of both high acceleration and zero gravity, for “the sole purpose of placing a man in orbit in a minimum time.” Thus they paid no great attention to making a convenient, serviceable spacecraft. That, however, was precisely what the new design offered. In it,

systems are modularized and all pieces of each system are in compact packages. The packages are so arranged that any system can be removed without tampering with any other system, and most of the packages ride on the outside walls of the pressurized cabin for easy access. This arrangement allows many technicians to work on different systems simultaneously.⁶²

The Mercury capsule, in contrast, could only be worked on from the inside, which meant, as a rule, only one person working at a time.

The new design attacked a number of other Mercury trouble spots. Perhaps the most troublesome was the sequencing system. Chamberlin argued that one of his chief motives for keeping systems in the new design separated was to avoid the endless complications Mercury experienced because so many sequentially controlled operations were built into it. Most of Mercury’s flight operations could be controlled by the pilot, but safety demanded that they also be automatic, each complex series of events triggered by an appropriate signal and ordered through a predetermined sequence by a tangle of electrical circuitry.⁶³ So complex was Mercury sequencing that Chamberlin recalled it as “the root of all evil and anybody that really worked on Mercury - that’s all they talked about.”⁶⁴ The new design relied on pilot control, instead of merely allowing it and backing it up with automatic sequencing. The result was a much simpler machine; the 220 relays in Mercury, for example, were reduced to 60 in Mark II.⁶⁵

What may have been the most complex sequencing of all was demanded by the automatic abort modes in Mercury, which depended on a rocket-propelled escape tower to pull the capsule away from the booster in an emergency during or just after liftoff.⁶⁶ In Chamberlin’s mind, “the sequencing of the escape system was one of the major problem areas in Mercury in all its aspects - its mechanical aspects in the first part of the program, and the electronic aspects later.”⁶⁷ What made this peculiarly frustrating was that the escape tower added hundreds of kilograms to the capsule’s weight, even though it was essentially irrelevant to the function of the capsule itself; in a successful flight it was jettisoned shortly after launch. Yet its many relays and complex wiring, besides making it inherently untrustworthy, were major factors in prolonging checkout time. To make matters worse, the Mercury abort modes - NASA shorthand for the methods that allowed the pilot to escape when a booster malfunction threatened his life - were automatic. Some circumstances not actually calling for an aborted mission - including a malfunction of the abort system itself - could trigger one, as happened more than once in the Mercury development program.⁶⁸

The new design put the pilot in an ejection seat and eliminated the escape tower.⁶⁹ This change, if installed, excluded Atlas as a booster for the new capsule. Atlas propelled itself with liquid oxygen and a mixture of hydrocarbons called RP-1, a highly explosive combination if the booster broke up. No ejection seat had the power to kick a pilot away from an exploding Atlas quickly enough, particularly if escape were not automatically triggered. Safety was thus a key reason for the escape tower and for its automatic features in Mercury. But Chamberlin had just become aware of a new booster that might relax these constraints.

Its name was Titan II, and the Martin Company was developing it as an intercontinental ballistic missile for the Air Force and as a manned booster in the Air Force Dyna-Soar program.⁷⁰ Albert C. Hall, general manager of Martin’s Baltimore Division, had proposed it to Associate Administrator Seamans, an old MIT classmate, for a role in NASA’s lunar mission. Although Seamans was skeptical, he arranged for Martin spokesmen to present their case at NASA Headquarters on 8 May 1961. The visit was strictly unofficial, since Titan II was an Air Force project. Any formal contact between NASA and Martin required Air Force sanction. Among those who heard about Titan II that day was Abe Silverstein, who saw enough in the new missile to ask Gilruth to look into the possibility of using it somewhere in the manned space flight program.⁷¹ Silverstein dismissed any thought of a role for Titan II in the lunar program.

To Chamberlin, however, Titan II looked very good for the improved Mercury. Weight was the most serious constraint in spacecraft design. An improved Mercury meant a heavier Mercury, since the price for packaged components was extra kilograms. This, in turn, meant that the new design called for a launcher more powerful than Atlas. Titan II had power to spare, its total thrust being almost two and a half times that of Atlas. Not only could it easily lift the heavier spacecraft, but it could also carry the redundant systems that would make it a safer booster for manned space flight. This, in a way, merely augmented what may have been Titan II’s outstanding features - simplicity and reliability.⁷²

Titan II ran on storable hypergolic propellants: a blend of hydrazine and unsymmetrical dimethyl hydrazine (UDMH) as fuel with nitrogen tetroxide as oxidizer. Because this combination is hypergolic - fuel and oxidizer burn spontaneously on contact - Titan II needed no ignition system. Since both fuel and oxidizer can be stored and used at normal temperatures - instead of the supercold required by the liquid oxygen of Atlas or Titan I - Titan II required no cold storage and handling facilities. The design and the lessons learned from Titan I combined to reduce the 172 relays, umbilicals, valves, and regulators in the first version of the missile to 27 in Titan II.⁷³ This simplification struck a responsive chord in Chamberlin, who saw in it something to match what he had been trying to achieve in redesigning the Mercury capsule. Booster and spacecraft seemed almost to have been made for each other.⁷⁴

Titan II’s self-igniting propellants had still another advantage. They reacted much less violently with each other than did the cryogenic propellants of Atlas or Titan I. In June 1961, there was still some question about whether a Titan II explosion would be sufficiently less violent, compared to Atlas, to permit the use of an ejection seat. Chamberlin was not yet ready to spell out his plans for using Titan II, but that was the way he was thinking. And his active distaste for escape towers made him eager to include ejection seats in his design.

Ejection seats not only promised to relieve a major source of trouble by getting rid of the escape tower, but they also furthered the concept of modularization, keeping each spacecraft system, so far as possible, independent. “The paramount objective in the program,” according to Chamberlin, “was to dissociate systems.” Ejection seats, in what he called “very happy coincidence that was fully realized at the time,” also fitted in nicely with another design change, substituting paraglider for parachute recovery.⁷⁵

STG had not displayed much active interest in Francis Rogallo’s flexible wing concept after the initial flurry in early 1959.⁷⁶ Rogallo and his co-workers at Langley had pushed ahead with their studies in the meantime. By mid-1960, they had convinced themselves that a controllable, flexible wing could carry a returning spacecraft safely to land, thus providing “a lightweight controllable paraglider for manned space vehicles.”⁷⁷ STG rediscovered the paraglider at the start of 1961 as a by-product of work on Apollo. A technical liaison group on Apollo configuration and aerodynamics met at Langley on 12 January.** In the course of describing his center’s work for Apollo, the Langley representative mentioned the paraglider landing system: “The feeling at Langley is that if the paraglider shows the same type of reliability in large-scale tests . . . that it has achieved in small-scale tests, the potential advantages of this system outweigh other systems.” Engineering design of large paragliders appeared to be no problem and would be demonstrated in manned and unmanned drop tests.⁷⁸

Space Task Group engineers met informally with Rogallo and his colleagues in February, March, and April to explore the use of a paraglider in the Apollo program.** The STG team was less than enthusiastic. They believed much work was yet to be done before the device could be seriously considered as a landing system for Apollo. The biggest unknown was the deployment characteristics of an inflatable wing; no inflatable structure had ever been successfully deployed in flight. Other questions - how the paraglider was to be packaged, whether the pilot’s view from the capsule would be good enough for flying and landing with it - were nearly as important and also largely unanswered. The STG team advised gathering at least six months of data before awarding any paraglider development contract.⁷⁹ At the same time, however, McDonnell engineers were looking at a paraglider for the modified Mercury, and Marshall Space Flight Center had already let two contracts to study paraglider as a booster recovery system. The idea clearly had promise, and in May 1961 Gilruth decided to contract for further study.

Three contractors each got $100,000 for two and a half months to design a paraglider landing system and define potential problem areas.** The best design was expected later to become the basis for a development contract to “provide the modified [Mercury] spacecraft with the capability of achieving a controlled energy landing through the use of aerodynamic lift.”⁸⁰ In fact, the design studies soon received a new name - Phase I of the Paraglider Development Program.⁸¹ Observed by a small technical monitoring group from STG, the paraglider design studies were under way before May ended.# ⁸² McDonnell engineers also maintained close liaison with paraglider work, independent though it was of the Mercury Mark II study contract.⁸³ The redesigned Mercury, as presented by Chamberlin and Blatz to the Capsule Review Board in June, could he adapted to a paraglider landing system, once it was developed.⁸⁴

One other significant innovation marked the new design, an enlarged overhead mechanical hatch, which would allow the pilots to get in the spacecraft more easily and to get out more quickly in an emergency. It was another way of making the new spacecraft a truly operational machine, one that could be entered and left like an airplane. Such a hatch was also needed if ejection seats were to be used. But it also had a special virtue that its designers were well aware of, though they did not talk about it. A large mechanical hatch would enable the pilot to leave and return to the spacecraft while it was in orbit and thus permit what later became known as extravehicular activity, or EVA.⁸⁵

The many changes proposed by Chamberlin and Blatz did not make the redesigned spacecraft a totally new machine. Though somewhat enlarged, it retained the fully tested and proved shape and heat protection of the Mercury capsule. It was still to be a one-man craft, and its designers expected to use mostly Mercury parts, packaged and rearranged but not otherwise substantially altered. The new design would not be much longer- lived in orbit than Mercury, 18 orbits (or one day) being the most the designers were aiming at.⁸⁶ Nevertheless, members of the Capsule Review Board seemed staggered by the scope of the changes presented to them. They refused to accept the complete Chamberlin-Blatz package but agreed to reconvene after the weekend to decide if any of the new features might be worth pursuing.⁸⁷

Chamberlin came back again Monday morning, since he was a regular member of the board, but Blatz had returned to St. Louis.## The board talked over the design of the ejection seat and hatch, simpler sequencing, better accessibility, and an 18-orbit capability. Each of these ideas had its own appeal, but most of them carried a price tag far too high to fit within the scope of the follow-on Mercury program STG was then thinking about, a program budgeted for less than $10 million in the coming fiscal year.⁸⁸

Although reaching no clear-cut decision, the board still hesitated to endorse Chamberlin’s plans in full. Instead, he was allowed to continue working on alternative approaches to an improved Mercury, while McDonnell studied “the minimum modifications that could be made to the present capsule to provide 18-orbit capability” and looked into “a larger retro and posigrade pack.”⁸⁹ This amounted to little more than reviving an early Mercury objective, once the ultimate goal of the program. Growing capsule weight and power requirements, as well as the limitations of the manned space flight tracking network, had forced STG to scrap the 18-orbit mission by October 1959.⁹⁰ The idea lived on, however, in the form of a proposal to fit the capsule with its own rocket motors to provide the final increment of velocity needed to attain an orbit high enough to resist Earth’s gravity for 18 revolutions.⁹¹ This was the idea the Capsule Review Board again endorsed at its meeting on 12 June.

Modification or Transmutation

The matter of a post-Mercury manned space flight program was far from settled in the Capsule Review Board meetings of 9 and 12 June. Chamberlin was not giving up, and McDonnell, despite the board’s injunction to limit its work to minor modifications, was still pressing for a more radical effort. At the beginning of July 1961, top STG officials were looking at an ephemeral “Hermes Plan,” calling for a new Mark II design much along the lines proposed by Chamberlin and Blatz a few weeks before. This Mark II was contrasted with a minimally redesigned capsule for an 18-orbit mission, now termed Mark I. The question of Mark II design, as Gilruth’s special assistant Paul E. Purser noted, was still very much “up in the air.”⁹² Still unclear was the scope of a follow-on Mercury program. A choice in favor of the extensively redesigned Mark II would impose a far greater effort than the slightly altered Mark I.⁹³

A McDonnell group led by Mercury manager Walter F. Burke attended a senior staff meeting at STG on 7 July to outline the company’s studies of an advanced Mercury capsule that took three distinct forms. One version, the “minimum change capsule,” involved not much more than cutting some hatches in the side of the capsule for better access. Although it could be ready to launch relatively quickly and cheaply (II months, $79.3 million), it had some obvious drawbacks. Better access only accented the capsule’s cramped interior, and the hatches themselves weakened the capsule’s structure and heat protection. As Chamberlin later remarked, “It was clear that this mod was too little to inspire any additional confidence in the design, and hence make it worth doing. Thus, the merits of the greater modifications became apparent.”⁹⁴ The second McDonnell advanced design, called a “reconfigured Mercury capsule,” adhered closely to the Chamberlin Blatz proposal of June. It would take longer to build and cost more than the minimum change capsule (20 months and $91.303 million), but it might very well be worth the expense. And for another two months and $12.248 million, NASA might do even better with McDonnell’s third version, a “two-man Mercury capsule.”⁹⁵

The notion of putting more than one man in a modified Mercury capsule was not new, having been suggested at least as early as January 1959.⁹⁶ That idea had gone nowhere, but Faget revived the possibility at the review board meeting on 9 June 1961. Blatz recalled that, after he and Chamberlin had made their pitch, Faget’s comment was, “If we’re going to go to all of this trouble to redesign Mercury, why not make it a multiplace spacecraft in the process?"⁹⁷ Faget’s interest in a two-man spacecraft was prompted, in part, by the prospect of extra-vehicular operations. As early as March 1961, he had asked John F. Yardley, McDonnell’s manager for Mercury operations at Cape Canaveral, to look into the possibility “of expanding Mercury into a two-man version” for this purpose.⁹⁸ Others saw reason for a two-man spacecraft in the rigors of long missions. If the Mark II were to be in space for more than a few orbits, then having two men to share the strain and support each other’s activities made good sense.⁹⁹ There was also a certain compelling logic in building a two-man spacecraft for a program falling between the one-man Mercury and three-man Apollo.¹⁰⁰

NASA Headquarters seemed uncertain about the size of the changes STG was thinking about during July 1961. George Low told Associate Administrator Seamans and the Washington program directors on 6 July that McDonnell and STG were working on a minimally modified 18-orbit capsule. He reported that

McDonnell originally looked upon the 18-orbit capsule as a development of a new flight article with substantial increase in size and weight, and incorporating rendezvous capabilities. McDonnell has been advised, however, to proceed on the basis of minimal changes to the existing hardware and to approach design modifications on this basis.¹⁰¹

But a master plan for orbital operations, dated 19 July, included, besides four 18-orbit Mercury flights during 1963, eight one-man Mercury Mark II flights to be launched at two-month intervals - from October 1963 through December 1964 - and to perform rendezvous and docking tests in orbit.¹⁰²

Whatever confusion may have existed, however, was resolved before the end of the month. On 27 July, Abe Silverstein joined Gilruth and other STG leaders, as well as several astronauts, at the McDonnell plant in St. Louis. McDonnell engineers displayed quarter-scale models of four basic spacecraft configurations: an Eighteen Orbit MK I, a Minimum Change MK II, a Reconfigured MK II, and a Two Man MK II. Also on display was a full-size wood and plastic mockup of the cockpit for a two-man spacecraft - Astronaut Walter M. Schirra, Jr., sat in it and exclaimed, “You finally found a place for a left-handed astronaut!"* ¹⁰³

Although the ideas for an advanced Mercury presented by the McDonnell study team were much the same as they had been 20 days earlier,¹⁰⁴ the audience on 27 July now represented NASA Headquarters as well as STG. Silverstein had long been convinced of the importance of Mercury missions more ambitious than merely circling Earth three times. What he saw in St. Louis was apparently enough to tip the scales toward a decision that many in NASA were ready to welcome. On 28 July, during the second day of the St. Louis meeting, Silverstein directed McDonnell to focus all further effort to improve Mercury solely on the two-man approach.** ¹⁰⁵ The choice had been made for a larger, rather than a smaller, follow-on Mercury program.

In what was to become a familiar pattern, that program had already grown far beyond its original bounds. The McDonnell study contract, the basis for the company’s design work on advanced Mercury, had outlined a relatively modest effort. By the time that contract was signed, on 24 April, the work was well along. In just over three weeks, McDonnell requested and received a contract increase from $98,621 to $187,189.¹⁰⁶ McDonnell efforts soon far surpassed that limit. By 6 August, the company had assigned 45 engineers to the study, and the original 9,000 engineering manhours called for in the contract had climbed to almost 23,000; added to that figure were 6,000 shop manhours for building and testing models not even mentioned in the contract. The estimated cost now topped $535,000.¹⁰⁷

Since STG had agreed that advanced Mercury needed more study, McDonnell had not felt obliged to wait until its contract had been amended to provide the extra funds. The company spent its own money. This was the kind of initiative that earned the firm a good deal of respect in NASA circles. Where others refused to move without money in hand, McDonnell focused on the task and relied on the good faith of its customer to make up the cost. It was seldom disappointed. In this instance, the company proposed a new contract to cover the extra engineering study and shop work done since 19 June, when contract funds had been exhausted, and to pay its projected expenses through the end of September.¹⁰⁸ The original contract and the new request together totaled over $670,000, nearly seven times the figure first approved in April. STG did not issue a new contract but, instead, amended the procurement contract to authorize the additional funds.¹⁰⁹

A Technological Imperative

Before the end of July 1961, the joint efforts of Chamberlin, Blatz, and their co-workers in STG and McDonnell had produced the design of an advanced Mercury capsule, Mercury Mark II. Space Flight Programs Director Silverstein had endorsed it. Although the final verdict was not yet in, the larger program seemed to be in the works, something that could scarcely have been predicted when the year opened. The situation was transformed on 25 May, when the President asked the country to assume the burden and the glory of reaching for the Moon.

The metamorphosis of Space Task Group into Manned Spacecraft Center, followed by its move from Virginia to Texas, flowed directly from this decision. STG had been created solely to manage Project Mercury; as a single-purpose task force, it was outmoded. Project Mercury now became only the first step on the path that was to lead Americans to the Moon before 1970.

As always, the lunar mission, in whatever form, held center stage. This was just as true in Headquarters as it was in the field. Although Washington’s chief planning concern was the voyage to the Moon, research and development in the field focused on specific problems raised by a lunar mission and the hardware needed to surmount them. STG, of course, had Project Mercury to worry about; but when it had time to look ahead, what it looked at was the Moon. Even before the President’s decision for a lunar landing, STG engineers were hard at work on the spacecraft that would ultimately carry men there.

Once a deadline had been set, the question of rendezvous as part of the lunar mission took on a new guise. By holding out the prospect of using smaller and thus more quickly developed boosters, rendezvous offered a chance to reach the Moon sooner than did a direct approach. During the spring and summer of 1961, discussion of this promise became widespread, and support for some form of rendezvous mission gathered strength. Even those who objected to chancing a lunar mission on an unproved technique were quite willing to admit that the technique needed to be developed, if only for its intrinsic value in future manned space flight. The growing conviction of the need for rendezvous, still further bolster by studies during the fall of 1961, provided the framework for what became Project Gemini.

By the time NASA decided that it needed a rendezvous development program, a freshly designed spacecraft was on the drawing boards. Mercury Mark II was not so much the product of planning as it was of a kind of technological imperative, the ceaseless and unquenchable desire of working engineers to perfect their machines. Some features of Mark II did, of course, spring from thinking about the objectives of a program to follow Mercury. But most of the changes in the new design suggested improvement in the abstract, rather than means to defined goals.

When Chamberlin talked about the design, it was in terms of accessibility and convenience, serviceability and simplification, “a better mechanical design” that was “more reliable, more workable, more practical.” These are qualities that can never be absolutely realized, though they may be endlessly pursued. During the first half of 1961, Chamberlin, Blatz, and the others pursued them far beyond the intent of those who had set them the task. By July they had reached a point where they were willing to pause, although, as the later career of Gemini was to show, it was not a point at which they could long rest content.

When Silverstein endorsed the two-man Mark II, its designers faced a new task. The gap between a spacecraft design, whatever its merits, and a manned space flight project was a wide one. Early in 1961, NASA Headquarters had set up a formal procedure for planning and carrying out new projects.¹¹⁰ The first step for such large and complex projects at Mercury Mark II now promised to be was a preliminary project development plan. This was the task to which Chamberlin and his colleagues now turned.