Mercury was an engineering project. Its major goal was "to achieve at the earliest practicable date orbital flight and successful recovery of a manned satellite."68 This dictated utmost reliance on the best-known techniques: a ballistic reentry capsule - blunt, cone-shaped, with almost no aerodynamic lift, recovered by parachute after it returned to the atmosphere.69 But it also excluded some promising alternatives, two of which took tentative shape in NASA's 1960 budget. One was the so-called environmental satellite, a kind of small temporary space station able to sustain one or more men in orbit for several weeks or even months. The other was a maneuverable spacecraft, one equipped with rocket motors to change its path in orbit and endowed with enough aerodynamic lift to alter its flight-path in the atmosphere.
NASA asked for $300,000 to study design changes that might turn Mercury into an orbiting laboratory and for $1 million to study a Mercury refined to make it maneuverable and flyable. Looking toward a real space station, NASA also asked for $3 million to study space rendezvous techniques.70 These modest sums signalled no great commitment. When NASA ran into budget problems, this effort was simply shelved and the money diverted to more pressing needs.71
The view from Space Task Group, the Mercury team, was different. Even during the first hectic months, while Mercury was still moving from the drawing boards into the laboratories, some people in STG were turning their thoughts to what might come next. Although a ballistic capsule might get the job done quickly, it also had patent shortcomings, not the least of which was "that it will be very difficult to control the landing point within a distance of perhaps the order of a hundred miles each way."72 The ballistic capsule had been only one of three basic types under study in 1958 for a manned satellite program. The others were a winged glider and a lifting body, so shaped that even without wings it still had enough lift to allow the pilot some control.73 For later missions, either offered a clear edge over Mercury. The winged glider, which could be flown much like an airplane once it was back in the atmosphere, had been preempted by the Air Force in its Dyna-Soar program.
Dyna-Soar was a development project of the Air Research and Development Command (ARDC). The project received its name in October 1957 and Air Force Headquarters approval in November, some four years after study had begun on vehicles boosted into orbit  by rocket and gliding back to Earth under pilot control. Much of the work had been done under contract by Bell Aircraft Company. NACA joined the project in May 1958 to provide technical advice and help to the Air Force-directed and -funded program, an arrangement reaffirmed by NASA in November 1958. ARDC's consolidated Dyna-Soar development plan in October 1958 aimed the project specifically at developing a winged glider for return from orbit. Later X-20 replaced Dyna-Soar as the project's name.74 Leaving gliders to the Air Force was no hardship since many in NASA, especially in the research centers, preferred the lifting-body approach.75 As early as June 1959, STG could report promising results from studies of building some lift into a Mercury capsule.76
STG was also looking into a more radical approach to controlled spacecraft landing. Between 1945 and 1958, a Langley engineer named Francis M. Rogallo had been working at home on a flexible kite, its lifting surface draped from an inflated fabric frame.  In contrast to other flexible aerial devices like parachutes, a load-bearing Rogallo wing produced more lift than drag, though not as much as a conventional wing. But rigid wings could not be folded neatly away when not in use, and they were inherently far heavier. Rogallo first realized what this might mean in 1952, when he chanced across an article on space travel
with beautiful illustrations depicting rigid-winged gliders mounted on top of huge rockets. I thought that the rigid-winged gliders might better be replaced by vehicles with flexible wings that could be folded into small packages during the launching.77Rogallo's efforts to promote his insight met scant success until late 1958, when the new American commitment to explore space furnished him a willing audience. In December, the Langley Committee on General Aerodynamics heard him describe his flexible wing and how it might be used in "space ship landing."78 The group responded warmly, and work on the concept moved from Rogallo's home to laboratories at Langley.
A few months later, STG asked Rogallo for an informal meeting to discuss his research. Some of STG's top people, Manager Gilruth among them, showed up on 30 March 1959 to hear what Rogallo had to say.79 Gilruth was impressed enough to suggest at a staff meeting two months later that some study go into a follow-on Mercury using maneuverable capsules for land landing.80
In the meantime, STG was spreading the news about its "preliminary thinking about Project Mercury follow-ups." H. Kurt Strass of STG's Flight Systems Division reported to the Goett Committee on some ideas for a larger, longer-lived Mercury capsule. STG's thinking ranged from an enlarged capsule to carry two men in orbit for three days, through adding a three-meter cylinder behind the capsule to support a two-week mission, to cabling the combined capsule and cylinder to a booster's final stage and rotating them to provide artificial gravity. This was modest compared to the more sophisticated "environmental satellite" favored by Langley, "a true orbiting space laboratory with crew and equipment exchangeable" via ferry.81
The Goett Committee divided on just how large the next step ought to be but agreed that some such step belonged between Mercury and a lunar mission.82 So did the NASA planners, who, during 1959, were drawing up a long-range-plan for manned space flight. Although NASA's future program was "directed heavily toward manned lunar exploration" there was still a place in it for developing maneuverability and a long-life capsule, both based on modifying Mercury.83
In seeking to explore the possibilities of improving Mercury to fit it for more advanced missions, STG was moving beyond the limits of its charter. It had been formed for only one purpose:  to manage Project Mercury. By mid-1959, the initial group of 45 had grown eight-fold, and Gilruth's title had changed from Manager to Director of Project Mercury. Despite this rapid expansion, STG felt understaffed. An STG study in June 1959 concluded that 223 people should be added to the 388 authorized, just "to maintain the schedule set for PROJECT MERCURY." But simply keeping pace was not enough.
In addition, . . . some attention should be given to advanced or follow-on systems to MERCURY. It is estimated that a staff of approximately 20 additional professional personnel should be built up during the next year in order that a year or more gap will not occur in NASA manned space flight operations at the conclusion of the presently planned MERCURY Program.* 84 Gilruth foresaw a total strength of some 900 by 1 July 1960, less than half of them working directly on Project Mercury. The rest would be divided among three other projects - a maneuverable manned satellite, a manned orbiting laboratory, and a manned lunar expedition - and a supporting program in biotechnology and human factors. The maneuverable manned satellite project accounted for 302 of the 485 new positions, showing which goal STG though should he pursued immediately after Mercury.85
During the same month, June 1959, Kurt Strass argued that the time had come to stop just thinking about these projects and to start actually designing one. He proposed forming a group to work out the preliminary design of "a relatively sophisticated space laboratory providing living accommodations for two men for two weeks," ready to fly by late 1962.86 Strass found a sympathetic ear in the chief of the Flight Systems Division (FSD), Maxime A. Faget, who appointed him to head a New Projects Panel within the Division.** It met for the first time on 12 August 1959, and Strass told his fellow Panelists they were there to plan a manned lunar landing through a series of graded steps, the first of which was to define "an intermediate practical goal to focus attention on problems to be solved, and thus serve to guide new technological developments."87
The panel floundered a bit, not quite certain of the direction it should take, but soon zeroed in on the design of an advanced spacecraft suited to the lunar mission, the first step on the road that led to the Apollo spacecraft. That still left a sizable gap in the manned space flight program, which a new engineering report by McDonnell Aircraft Corporation, prime contractor for the Mercury capsule, suggested some ways to fill. The panel decided to take a close look.88
The McDonnell report of September 1959, "Follow On Experiments, Project Mercury Capsules," was the result of a summer's work by a small advanced project group.*** 89 It proposed six experiments that might be conducted with practical modifications of the Mercury capsule, to explore some problems of space flight beyond those to be attacked in Project Mercury.90 The New Projects Panel found none of the McDonnell ideas wholly satisfactory but agreed that parts of the  first three "could be combined into a new proposal which could offer increased performance and an opportunity to evaluate some advanced mission concepts at the earliest opportunity."91
All three experiments dealt with spacecraft maneuverability and guidance. The first sought to achieve some control of landing by adding an external trim-flap device to the capsule, coupled with a simple radar guidance technique or, alternatively, with a more sophisticated inertial guidance system to reduce the capsule's dependence on ground facilities. The second aimed at maneuvering in orbit by adding to the capsule a special adapter to carry a propulsion system, with guidance provided by either a Mercury system or an inertial guidance system. The third experiment was designed to test the inertial guidance system that might be used with either of the first two experiments. The system - inertial platform, computer, and star tracker - would allow the capsule to guide itself toward an orbital rendezvous, to control its touchdown point more precisely, and to navigate on lunar and interplanetary missions. All three experiments used a modified one-man Mercury launched by an Atlas, with minimum changes.92
NASA's planners in 1960 and early 1961 aimed higher than just an improved Mercury spacecraft. In St. Louis, McDonnell proposed a 14-day space laboratory.
The time, however, was not yet ripe. The attractive possibilities of experimenting with a modified Mercury capsule paled in comparison with the far more exciting prospect of designing an advanced spacecraft for a trip to the Moon. When STG's top management met a month later, on 2 November 1959, it was the advanced spacecraft rather than the modified Mercury that they decided to pursue.# 94
 That was the story of STG planning for better than a year. Although engineers were still thinking about an improved Mercury, that thought took second place to work on a new lunar spacecraft.95 Lifting reentry was still seen as an important objective, a point stressed by NASA witnesses in budget hearings early in 1960, but not necessarily as part of the Mercury program.96 By April 1960, the central aim of advanced vehicle development had become "lunar reconnaissance." The possibility of a lifting Mercury received only passing mention, as advanced planning focused on a spacecraft able to orbit the Moon, "a logical intermediate step toward future goals of landing men on the moon and other planets."97 This was the program that officially became "Apollo" in July 1960. As then conceived, it did not go beyond circumlunar flight, although lunar landing was the ultimate goal.98
What was becoming clear was that any advanced Mercury program, such as lifting reentry, was likely to become a major undertaking in its own right.99 In March 1960, STG's summary of projected funding needs for manned space flight programs put the cost of a lifting Mercury project at over $34 million during fiscal years 1960 through 1962.100 STG did go on with its lifting Mercury plans into April 1960, getting as far as a preliminary specification for the reentry control system and plans to solicit contractor proposals for the system.101
Lifting reentry, in principle, had NASA Headquarters approval. Still lacking was a firm commitment based on a specific proposal with clearly defined costs.102 That commitment failed to materialize. In May 1960, Administrator Glennan's budget analysis team turned down STG's request for funds to pursue advanced technical development of Mercury-type capsules. Glennan conceded the probability of Mercury flights beyond the three-orbit mission then authorized, to avoid a break in manned space flights, if nothing else. But thinking about somewhat longer missions was one thing; approving a lifting capsule was something else.103
That decision put a temporary halt to STG efforts to improve Mercury. Mounting problems in the project itself, especially during the last quarter of 1960, kept STG busy, and such advanced work as time allowed was limited to Apollo.
* In 1959, STC comprised three divisions: Flight Systems under Max Faget; Operations, Charles W. Mathews; and Engineering and Contract Administration, Charles H. Zimmerman (replaced in August by James A. Chamberlin).
** Besides H. Kurt Strass, the panel included Alan B. Kehlet. Head, Aerodynamics Section, Performance Branch; Jack Funk, Head, Space Mechanics Section, Dynamics Branch; Harry H. Ricker, Jr., Head, On Board Systems Branch; Robert G. Chilton, Head, Dynamics Branch; Stanley C. White, Head, Life Systems Branch; William S. Augerson, Life Systems Branch; and Caldwell C. Johnson, Head, Engineering Branch, Engineering and Contract Administration Division (the only non-FSD member of the panel). The meetings of the panel were attended by nonmembers, as well, again largely from FSD.
*** The group, headed by E. M. Flesh, McDonnell engineering manager for Mercury, included Fred J. Sanders, William J. Blatz, Darrell B. Parke, and Walter D. Pittman.
**** The panel ignored the sixth McDonnell experiment, which differed radically from the other five. It projected the use of a heavily instrumented unmanned Mercury capsule to study the problems of stability and heating during reentry from lunar orbit, simulated by launching the capsule into a highly elliptical orbit with the Atlas-Centaur.
# At the meeting were Robert R. Gilruth, his special assistant Paul E. Purser, Kurt Strass, Robert O. Piland, John D. Hodge, Caldwell Johnson, Charles J. Donlan, Max Faget, Charles W. Mathews, and James A. Chamberlin.
68 Warren J. North, secretary, "Minutes of Meetings, Panel for Manned Space Flight, September 24, 30, October 1, 1960," and Appendix A, "Objectives and Basic Plan for the Manned Satellite Project."
69 Maxime A. Faget, Benjamine J. Garland, and James J. Buglia, "Preliminary Studies of Manned Satellites - wingless Configurations: Nonlifting," in "NACA Conference on High-Speed Aerodynamics, Ames Aeronautical Laboratory, Moffett Field, Calif., 18, 19 and 20 March 1958: A Compilation of Papers Presented," pp. 19-33; Swenson, Grimwood, and Alexander, This New Ocean, pp. 86-90.
70 National Aeronautics and Space Administration Appropriations, pp. 156-58, 166-67, 186-87.
71 NASA Authorization for Fiscal Year 1961, pp. 377-78.
72 Testimony of Hugh L. Dryden in NASA Supplemental Authorization for Fiscal Year 1959, p. 50.
73 Thomas J. Wong et al., "Preliminary Studies of Manned Satellites," in "NACA Conference on High-Speed Aerodynamics," pp. 35-44; John V. Becker, "Preliminary Studies of Manned Satellites - Winged Configurations," ibid., pp. 45-47.
74 Letter, Max Rosenberg to NASA Historian, "Comments on Draft Chapter I-V and XIII-XV, Gemini History," 26 June 1970, with enclosure.
75 "Manned Space Flight Long Range Plans," pp. 15-16; memo, May to Emme, "Draft Chapters 3 and 4 of the History of Project Gemini," 29 May 1969.
76 May, "Minutes, June 25-26, 1959," p. 8.
77 Francis M. Rogallo, "Parawings for Astronautics," in Norman V. Petersen, ed., Advances in the Astronautical Sciences 16, Part 2 (1963), presented at the American Astronautical Society Symposium on Space Rendezvous, Rescue, and Recovery, Edwards AFB, Calif., 10-12 Sept. 1963, pp. 3-7; see "Man Will Conquer Space Soon," Collier's, 22 March 1952, p. 27, for the illustration.
78 Francis M. Rogallo, "Paraglider Recovery Systems," presented at the International Astronautics Society Meeting on Mans Progress in the Conquest of Space, St. Louis, Mo., 30 April, 1-2 May 1962, fig. 1 - "Flexible-wing concept as presented to Langley Committee on General Aerodynamics, December 19, 1958."
79 Langley, "Briefing given Space Task Group personnel concerning Rogallo's flexible lifting surface vehicle," 9 April 1959. Memo, Delwin R. Croom to Assoc. Dir.,
80 Memo, Purser to Gilruth, "Log for week of June 1, 1959," 8 June 1959, p. 2.
81 May, "Minutes, May 25-26, 1959," pp. 6, 9.
82 Goett memo, 17 July 1959, pp. 1-2, 4; May, "Minutes, May 25-26, 1959," pp. 6-8.
83 "Manned Space Flight Long Range Plans," pp. 3, 13-20; testimony of Low in U.S. Congress, Senate, NASA Authorization Subcommittee of the Committee on Aeronautical and Space Sciences, NASA Authorization for Fiscal Year 1960: Hearings on S. 1582, 86th Cong., 1st sess., 1959, pp. 333, 336; Douglas L. Worf, ibid., pp. 377, 383; Abe Silverstein in 1960 NASA Authorization, pp. 368, 379; "The Ten Year Plan of the NASA," pp. 25-26.
84 Purser, "Space Task Group Complement Analysis," 8 June 1959, pp. 1, 10; memo, Gilruth for all concerned, "Organization of Space Task Group," 26 Jan.1959; memos, Gilruth for staff, "Organization of Space Task Group," 3 and 10 Aug. 1959; Purser, notes, "Summary of STG Organization and Mercury Management," n.d. (through 15 Jan. 1962).
85 Memo, Gilruth to Bernard Sisco, Goddard, "Langley Space Task Group FY 1961 personnel distribution," 12 June 1959, with attached chart, "Proposed FY 1961 Personnel Distribution by Division and Project."
86 Memo, H. Kurt Strass to Chief, Flight Systems Div. (FSD), "Activation of Study Program Pertaining to Advanced Manned Space Projects," 22 June 1959.
87 Memo, Strass to Chief, FSD, "First meeting of New Projects Panel, Wednesday, Aug. 12, 1959," 17 Aug. 1959.
88 Memo, Strass to Chief, FSD, "Second meeting of New Projects Panel, Tuesday, August 18, 1959," 26 Aug. 1959, and attached chart, "Proposed Sequence of Events for Manned Lunar Mission System Analysis"; memo, Strass to Chief, FSD, "Third Meeting of New Projects Panel, Monday, September 28, 1959 (Information)," 1 Oct. 1959.
89 "Follow On Experiments, Project Mercury Capsules," McDonnell Aircraft Corporation Engineering Report No. 6919, 1 Sept. 1959 (rev. 5 Oct. 1959); memo, Newell D. Sanders to Asst. Din for Propulsion, "Booster Information Requested by McDonnell Aircraft Corporation," 6 July 1959; memo, Charles H. McLellan to Assoc. Dir., Langley, "Visit of McDonnell Aircraft personnel to Aero-Physics Division," 13 Aug.1959; Fred J. Sanders, interview, St. Louis, 14 April 1966.
90 "Follow On Experiments, Project Mercury Capsules," p. vii.
91 Memo, Strass to Chief, FSD, "Fourth meeting of New Projects Panel, Monday, October 5, 1959 (Action requested)," 7 Oct. 1959.
92 "Follow On Experiments, Project Mercury Capsules," pp. 1.1-1, 2.1-1, 3.1-1, 3.2-0.
93 Strass memo, 7 Oct. 1959; "Follow On Experiments, Project Mercury Capsules," pp. 4.1-1, 4.2-1, 5.1-1, 6.0-1, 6.1-1; Strass memo, 7 Oct. 1959.
94 Memo, Purser to Gilruth, "Log for week of November 2, 1959," 10 Nov. 1959, p. 1.
95 Memo, Dennis F. Hasson to Chief, FSD, "Meeting of January 7, 1960 to discuss future wind- tunnel tests for advanced Mercury projects (Information)," 11 Jan. 1960.
96 U.S. Congress, Senate, Committee on Appropriations, Supplemental National Aeronautics and Space Administration Appropriations, 1960: Hearings on H.J. Res. 621, 86th Cong., 2nd sess., 1960, pp. 15-16; Review of the Space Program, pp. 300, 674-75; U.S. Congress, House, Subcommittee on Independent Offices of the Committee on Appropriations, Independent Offices Appropriations for 1961: Hearings, 86th Cong., 2nd sess., 1960, pp. 276-77; NASA Authorization for Fiscal Year 1961, pp. 143- 45, 745.
97 "Guidelines for Advanced Manned Space Vehicle Program," STG, June 1960, pp. ii, 1, 4, 6, 12, 39, 47-48. This was a compilation of papers presented to NASA Headquarters between 15 April and 3 May 1960, by STG personnel. Memo, John H. Disher to Dir., Space Flight Programs, "NASA Center Briefings on Advanced Manned Space Flight Program," 10 May 1960; Robert O. Piland, "Missions, Propulsion and Flight Time," in "Guidelines for Advanced Manned Space Vehicle Program," p. 6.
98 Hugh L. Dryden, "NASA Mission and Long-Range Plan," in NASA-Industry Program Plans Conference, July 28-29, 1960 (Washington, 1960), p. 8; Low, interview, Houston, 7 Feb. 1967.
99 Charles J. Donlan, "Summary and Scheduling," in "Guidelines for Advanced Manned Space Vehicle Program," pp. 49-50.
100 "Program Funding Requirements, Manned Space Flight Programs, March 18, 1960," STG, p. 5-1.
|Lifting Mercury Program||1960||1961||1962|
|A. System Development & Evaluation||0.140||0.850||0.650|
|B. Little Joe Flight Test Hardware||0.990||1.230|
|C. Lifting Capsule Contracts||4.000||16.950|
|D. Flight Operations||0.100||0.740|
|E. Supporting C & E||0.250||1.130||7.100|
102 Goett, remarks on "Highlights of GSFC Program," in "Third Semi-Annual NASA Staff Conference," pp. 18-19; comments by Richard E. Horner and Dryden, ibid., pp. 20-21.
103 Memo, Disher to Long Range Plan & Budget File, "Meeting with Dr. Glennan on 7/9/60 to discuss long range plans for Saturn utilization by OSFP," 11 July 1960, with attached chart by Low, "Flight Program, Manned Flight - Adv. Tech. Dev.," 7 July 1960; "Chronology of Budget Preparation for Fiscal Year 1962," in NASA Authorization for Fiscal Year 1962, p. 170.