Mercury Mark II Begins

Chamberlin finished the revised project development plan on 27 October 1961.35 The bulk of it followed the August versions word for word, although some new material appeared, some old ideas vanished, and some accents changed. Most striking was the greatly increased stress on the development of rendezvous techniques. Long duration retained first place on the list of objectives, but rendezvous had moved into second, with controlled land landing third, and astronaut training (still incidental) fourth.

Gone were the radiation study and the animal flights; no trace remained of a lunar mission, nor even of a deep-space sortie. The focus became developing the technique, rather than applying it. More of the text dwelt us, with several new paragraphs to describe in detail the special equipment needed for rendezvous navigation, maneuvering, and docking systems. A closing statement of expected [64] "Project Results," new in the October plan, clearly showed that rendezvous now had priority. The August plan ". . . . for an Advanced Manned Space Program Utilizing the Mark II Two Man Spacecraft" became, in October, a "Project . . . for Rendezvous Development."

The new flight plan also reflected the shift in focus. Although the total number of flights in the program only expanded from 10 to 12, the rendezvous flights doubled - from four to eight. The first flight had become strictly a qualification test of the unmanned spacecraft and booster, the spacecraft to be launched into a 160-kilometer circular orbit. An 18-orbit manned qualification was still second, followed as before by two extended manned missions, though these might now last up to 14 days. All other flights were designed to develop and test rendezvous techniques.

Logically enough, the October plan proposed a starting date of 1 November 1961, instead of 1 September. Two months still separated each flight from the next, the first now scheduled for May 1963, the last for March 1965. Program costs, however, climbed higher than only two more flights might suggest. The new figure was $529.45 million, more than one and a half times the August estimate. Two factors accounted for the seeming discrepancy. One was the new provision for spare spacecraft and boosters: 12 spacecraft rather than 8 (the first plan had called for 2 spacecraft to be re-used in later missions; the revised version planned for 3 spacecraft to be refurbished, but only as spares); 15 Titan IIs instead of 10, the extra 3 to serve as backups; and 11 Atlas-Agenas instead of 4, 8 to fly and 3 spares. The combined effect of these changes added $140.45 million to the programs costs. Most of the remainder of the increase came from a new $29 million item, "Supporting Development," for paraglider.36

STG forwarded the revised project development plan to NASA Headquarters on 30 October 1961.37 Its approval expected as a matter of course, Chamberlin got busy setting up the program. Since McDonnell was obviously going to get the prime contract for the Mark II spacecraft, the company ought to be told to organize itself for the effort to assign key people to the new program, and to make sure that the staff would be available.38 Chamberlin proposed to amend the letter contract between NASA and McDonnell that had authorized the contractor to procure long-lead-time items for Mark II.39

Chamberlin wanted the McDonnell effort tailored to making a general-purpose spacecraft. This meant that Mark II should not only be able to perform its assigned long-duration and rendezvous missions, but also that it ought to be easy to adapt for other missions. Two other design objectives were only slightly less important, both springing from the notion of Mark II as a truly operational spacecraft (in contrast to the chiefly experimental Mercury): it should be simple to test realistically on the ground, leaving actual flights free to focus on major goals [65] that could only be achieved in space; and it should be easy to checkout, so a faulty spacecraft was less likely to cause a mission failure. To achieve these goals, Chamberlin thought McDonnell had three central tasks to tackle at once: for systems inherited mainly unchanged from Mercury, utmost refinement; for new systems, engineering analysis; and for special problems, like the integration of a paraglider system, special study groups.40

Chamberlin himself formed a Mark II rendezvous group, whose five members were, by mid-October, already talking to people in Langley's Aerospace Mechanics Division about some theoretical aspects of rendezvous.* 41 They had also approached (and been approached by) prospective contractors about what equipment might be needed, which allowed them to rough out a set of guidelines for rendezvous development by 10 November 1961.42 The group then began a series of technical coordination meetings with McDonnell spokesmen in St. Louis, 14-15 November.

McDonnell engineers themselves had been looking at rendezvous for several months, and the meetings showed that company and NASA thinking had diverged sharply. McDonnell had assumed that the target would not be maneuverable and that control of the spacecraft during maneuvers could be either automatic or manual automatic or manual (or some mixture), the choice hinging on how much fuel the spacecraft could carry. The company, in other words, thought the spacecraft it was going to build should be the active agent in rendezvous. In contrast, Chamberlin's group from Manned Spacecraft Center (MSC; Space Task Group had changed its name on 1 November 1961) had approached the rendezvous system as a whole, spacecraft and target, and assumed a highly maneuverable target, with pilot control of the spacecraft and ground control of the Agena.

McDonnell's approach, which favored a combination of automatic and semi-automatic control, required a spacecraft target-tracking radar, and a digital computer and inertial platform for guidance, as well as a high-capacity propulsion system. MSC's preference for semi-manual control for the spacecraft - automatically stabilized but steered by the pilot - combined with target control under ground command stressed changes in the Agena rather than spacecraft equipment: a restartable engine, a data communication system to link the Agena to ground controllers, an optical tracking aid of some kind, a radar transponder, and an attitude stabilization system.

McDonnell and MSC decided to combine their approaches, fitting the spacecraft with the equipment the company believed necessary and [66] altering the Agena to conform to what MSC wanted. This "would allow the most flexibility in the choice of rendezvous techniques without equipment change."43

By mid-November 1961, McDonnell had completed most of the documents that spelled out the company's view of what should be in the expected contract with NASA to build the two-man spacecraft. The most important was a detail specification of the Mark II spacecraft, issued 15 November.44 The McDonnell design was deliberately conservative, notably in retaining both the launch escape tower and the impact bag used in Mercury.

McDonnell engineers who drew up the specification could not yet be sure that safety permitted striking the escape tower from the design. Still under study was what might happen if a Titan II exploded on the launch pad while the crew was aboard the spacecraft. Whether ejection seats could in fact propel the two men away from an exploding booster fast enough to outdistance the expanding fireball remained in doubt. Speed and range of the ejection seat were both critical. As a hedge, the Mark II design included the escape tower.

The presence of a Mercury-type impact bag in the specification was another cautious note. The Mercury capsule had an inflatable bag that served to cushion the impact of landing. Although the paraglider promised greatly reduced landing stresses, the designers felt that work on the concept was not far enough advanced to allow them to rely on it entirely. No one really believed a either the tower or landing bag was going to be necessary but, faced with drawing up a specification for Mark II, McDonnell engineers chose to put on paper something they knew would work.45

Planning for the second phase of the paraglider program, a two-part system research and development effort, had already begun. In Phase II, Part A, the contractor was to spend eight months in further study of the design concept, chiefly to settle on what configuration would yield the best performance. The second part of Phase II called for the as-yet-unnamed contractor to build a prototype paraglider landing system, to conduct a series of unmanned and manned flight tests, and to complete a final design. The third and final phase of the program would see a paraglider system in production and pilots being trained to fly it.46 On 20 November, North American received official word that it had been awarded the contract and was authorized to begin work.47

The same team that had monitored the paraglider design study for STG** now joined spokesmen for North American, Langley, and Flight Research Center to discuss putting Phase-II A into motion. They soon agreed that the half-scale models and full-size vehicle for [67] this phase should be based on the Mark II design. "Power requirements, control actuation, landing gear, etc., should be compatible with the MK II spacecraft, where MK II is sufficiently firmed up for this to be practical without delaying the full-scale test program." Most wind tunnel testing would be done by Langley, while Flight Research Center, at Edwards Air Force Base, California, was to take charge of flight testing, all under the aegis of MSC. Even at this early date, the interface - that useful term for the region where two or more things share a common boundary - between paraglider and spacecraft was beginning to pose questions: how the glider and its gear were to be stowed; how it was to be deployed, sequenced, and jettisoned; what kind of cockpit controls and displays it would need; and how it would fit with the emergency escape system.48

When Gilruth and Chamberlin visited NASA Headquarters in late November 1961 to see Associate Administrator Seamans and report on the Mark II program, they had a good deal to talk about. Spacecraft design was just about settled, paraglider development was beginning, and some basic approaches to developing rendezvous techniques had been decided. Although Gilruth's and Chamberlin's meeting with Seamans did nothing to dampen their belief that project approval was only a matter of time, that time was not yet. Seamans was not quite ready to take the final step. November had been a busy month In NASA Headquarters, and the turmoil had touched the Mark II project.


* The Mark II rendezvous group comprised Jerome B. Hammack, Orton L. Duggan, James T. Rose, Jean L. Petersen, and Harry Shoaf. Among those the group talked to were Thomas J. Voglewede, Arthur Vogeley, Max Kurbjun, and Edgar C. Lineberry.

** Rodney Rose, Harry Shoaf, and Lester Stewart.


35 Memo, Purser to Gilruth, "Log for week of October 23, 1961," 30 Oct. 1961.

36 "Project Development Plan for Rendezvous Development Utilizing the Mark II Two Man Spacecraft," STG, 27 Oct. 1961.

37 Memo, Purser to Gilruth, "Log for week of October 30, 1961," 7 Nov 1961.

38 Memo, Chamberlin to Dir., "Proposed Amendment to Letter Contract No.6 to Contract NAS 5-59," 27 Oct. 1961, with enclosures, "Guidelines: MK-II Program Effort," n.d., and Glenn F. Bailey to McDonnell, "Amendment No. 2 to Letter Contract 6," NAS 5-59, 28 Oct. 1961.

39 Bailey, "Amendment No. 2."

40 "Guidelines: MK-II Program Effort."

41 Mark II note, Jerome B. Hammack, "Meeting with Aerospace Mechanics Representatives," 19 Oct. 1961.

42 Mark II note, "Interim Report of Proposed Rendezvous Technique, Guidance and Lunar Lander," 10 Nov. 1961, annotated to show deletion of lunar lander.

43 Memo, Raymond D. Hill, Jr., to E. M. Flesh, "Model 133N Coordination Meeting 1415 November 1961," PM-1467, 24 Nov. 1961.

44 "Mercury Mark II Detail Specification," McDonnell Rept. 8356, 15 Nov. 1961, p. 8.

45 Ibid.; Fred J. Sanders, telephone interview, 24 Feb. 1969.

46 "Statement of Work for Phase II, Part A, System Research and Development of a Paraglider Development Program," STG, 15 Sept. 1961.

47 Memo, Lester A. Stewart et al. to Dir., "Paraglider Development Program; Evaluation of Design Studies; Contract NAS 9-135, Ryan Aeronautical Company; Contract NAS 9-136, North American Aviation, Inc.; Contract NAS 9-137, Goodyear Aircraft Corporation," 22 Sept. 1961; TWX, Bailey to Neil C. Dopheide, 20 Nov. 1961; Bailey, "Letter Contract [NAS 9-167] between National Aeronautics and Space Administration and North American Aviation, Inc. (Contractor)," 21 Nov. 1961; TWX, Norbert F. Witte to MSC, Attn: Purser and Chamberlin, "Contract NAS 9-167, Paraglider Development Program Phase IIA: Full Scale Test Vehicle," MA14859, 13 Dec. 1961.

48 Stewart, "Paraglider Development Program (Phase II-A): Minutes of . . . North American Aviation, Incorporated (Contract NAS 9-135 [sic]), Program Review Meeting, November 28-29, 1961," 5 Dec. 1961; Kenneth W. Christopher, telephone interview, 18 Oct. 1972.


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