The NASA/ARPA mission specification of a circular orbit to be achieved by "the most reliable available boost system . . . at an altitude sufficiently high to permit a 24-hour satellite lifetime" (before the natural decay, or degradation, of the original orbit because of slight but effective upper-atmospheric friction) had carefully avoided a commitment to either a booster or an orbital altitude. The Space Task Group proceeded on the assumption that both apogee and perigee of the manned ballistic satellite should be within the rough limits of 100±25 miles high. The Task Group chose 100 statute miles (87 nautical miles) as the nominal average altitude to ensure a full-Earth-day lifetime for the one-ton manned moonlet.
The outer limits of Earth's atmosphere, where it blends in equilibrium with the solar atmosphere or plasma, seemed around 2,000 miles, and the "edge" of the outer ionospheric shell was thought to be perhaps 4,000 miles above sea level, but these were irrelevant parameters for orbit selections. ICBM performance data at that time made it certain that the "most reliable available boost system" could not boost a 2,200-pound ballistic capsule even to the 400-or-so-mile "floor" of the Van Allen belt.19
The Atlas ICBM was still "the most reliable available boost system"; there was as yet no viable alternative booster. All preliminary hardware planning had been based on the assumption that the Atlas would prove its power and prowess very soon. The NACA nucleus of NASA was composed for the most part of aeronautical engineers, airplane men not yet expert with missiles and rockets. Few of them at first fully realized how different were the flight regimes and requirements for the technology of flight without wings.
Since World War II winged guided missiles or pilotless drone airplanes had given way to rocket-propelled ballistic projectiles; by 1958 the industrial base and engineering competence for missilery had matured separately from and tangentially to the aviation industry.20 If the manned satellite program were to become the first step for sustained manned space flight, a new synthesis between science and engineering and a new integration between the aircraft and missile industries would be necessary. "Space science" and "aerospace technology," terms already made popular by the Air Force, were now in the public domain, but their meanings were vague and ambiguous so long as they held so little operational content. Silverstein, Crowley, and Albert F. Siepert, the men who became the first executive directors of the top three "line offices" of NASA Headquarters, indubitably had their debates on programming operations for NASA and the Nation. But on the need for new syntheses and reintegrations of established disciplines and industries there could be no debate. NASA's legal mandate to coordinate and to contract  for cooperative development "of the usefulness, performance, speed, safety, and efficiency of aeronautical and space vehicles" was second only to its first objective in the Space Act, expanding "human knowledge of phenomena in the atmosphere and space."21
The complex prehistory of NASA and the manned satellite program began to impinge on NASA policy. It affected project planners as soon as they set forth their intention to put a man into orbit. Industrial and military investments in feasibility studies to this same goal had been heavy. The Space Task Group decided in mid-October to withdraw from all contacts with industrial contractors while finishing its preliminary specifications for the manned satellite capsule. STG thus avoided any accusations of favoritism, but lost about two months in time before it was able to acquire the latest classified and proprietary studies and designs by other organizations.
Three most pertinent examples of industrial research going on concurrently with government research and leading up to seminal proposals for manned satellite specifications were those studies being conducted by the Convair/Astronautics Division (CV/A) of the General Dynamics Corporation in conjunction with the Avco Manufacturing Corporation, studies by the General Electric Company in conjunction with North American Aviation, Inc., and those by McDonnell Aircraft Corporation. The CV/A-Avco proposal to the Air Force in April 1958 for a spherical drag-braked manned satellite was followed by more reports by CV/A in June and November, and these proved that the builders of the Atlas were exploring every avenue for civilian uses of their booster rocket. Convair men like Karel J. Bossart, Mortimer Rosenbaum, Charles S. Ames, Frank J. Dore, Hans R. Friedrich, Byron G. MacNabb, F. A. Ford, Krafft A. Ehricke, and H. B. Steele had a continuing interest in seeing their fledgling weapons carrier converted into a launch vehicle for manned space flight, either with or without an upper stage.
At NASA Headquarters, Abe Silverstein decided early in November to formalize his earlier approval of Faget's plan for the "bare Atlas." On that basis a formal bidders' briefing for the capsule contract was planned for November 7. Only after mid-December, when all the proposals were in, did STG learn how great had been other industrial investments in research for a manned ballistic satellite.22
Although the Atlas airframe, design, and systems integration had all grown directly out of Convair engineering development, the liquid-fueled rocket engines for the Atlas, as well as for the Redstone, Jupiter, and Thor missiles, were all products of the Rocketdyne Division of North American Aviation, Inc. Hence North American, when teamed with another corporate giant, General Electric, appeared also to be a prime contender for the manned satellite contract. The Space Task Group was only dimly aware at this time of the specifications that had emerged from North American and General Electric as proposals for the Air Force's "Man-in-Space-Soonest" studies, but it did know at least that its own ballistic capsule plan was at variance with the "high lift over drag" thinking at North American.23
 Back in May 1957, five months before Sputnik I, James S. McDonnell, Jr., the founder and president of a growing aircraft corporation bearing his name, gave an address at an engineering school commencement ceremony. He predicted a speculative timetable for astronautics that placed the achievement of the first manned Earth satellite, weighing four tons and costing one billion dollars, between the years 1990 and 2005 A.D. One year later, in a similar address, McDonnell sagaciously abandoned his timetable and said:
I think it is fortunate that the Soviets have boldly challenged us in [space science and exploration] . . . . Their space challenge is a fair challenge. We should accept this challenge and help to turn it primarily into peaceful channels.Off and on since Sputnik II, McDonnell Aircraft Corporation's Advanced Planning Group had assigned first 20, then 40, and, from April through June 1958, some 70 men to work on preliminary designs for a manned satellite capsule. Led by Raymond A. Pepping, Lawrence M. Weeks, John F. Yardley, and Albert Utsch, these men had completed a thoroughgoing prospectus 427 pages in length by mid-October 1958. People at Langley had been aware of this work in some detail, but when NACA and PARD became part of NASA, a curtain of discretion fell between them and STG. The McDonnell proposal was repolished during November before it took its turn and its chances with all the rest of the bidders.25
So, fellow pilgrims, welcome to the wondrous age of astronautics. May serendipity be yours in the years to come as man stands on the earth as a footstool and reaches out to the moon, the planets, and the stars.24
While interested aerospace companies were endeavoring to fulfill the Government's plans and specifications for a manned satellite, a number of men in the institutional setting at Langley were busily engaged in final preparations for the bidders' conference. Craftsmen like Z. B. Truitt and Scott Curran, in the Langley shops, fabricated new models of both the couch and the capsule for demonstration purposes. Engineering designers like Caldwell C. Johnson and Russell E. Clickner, Jr., reworked multiple sets of mechanical drawings until Faget and the Task Group were satisfied that they had the architectonic engineering briefing materials ready for their prospective spacecraft manufacturing contractors. Gilruth, Donlan, Mathews, and Zimmerman meanwhile approved the block diagrams of systems as they evolved. They looked over their requirements for outside support in future launching operations, flight operations, trouble-shooting research, and crew selection and training. With everything going on at once among half a hundred men at most, there was no time now in STG for second thoughts or doubts about whether the "Faget concept" would work.26
Questions of policy and personnel at the time of the organization of NASA and during the birth of this nation's manned space flight program were affected significantly by a conflict then existing between the experts on men and the experts on missiles. In the eyes of the Space Task Group, the medical fraternity, particularly some Air Force physicians, was exceedingly cautious, whereas the Space Task Group  seemed overly confident to some Air Force medical men and some of their pilots. During the deliberations of the joint NASA-ARPA Manned Satellite Panel, the contrast between the technical aspects of the Air Force's "Man-in-Space-Soonest" proposal and the Faget plan sponsored by the Langley-PARD group had been resolved in favor of the latter. Air Force planners of the Air Research and Development Command early had accepted a basic ground rule specifying 12 g as the design limit for capsule reentry loads. They had opposed the so-called "bare Atlas" approach, which would carry the risk of imposing accelerations up to 20 g in case of a mid-launch abort. As a last resort they too had turned to the standard Atlas as the most feasible launch vehicle even though, Faget believed, Air Force aeromedical experts had not accepted the significance of the physiological demonstrations by Carter C. Collins and R. Flanagan Gray on the Navy's centrifuge at Johnsville in July that man could sustain 20 g without lasting harmful effects. In calculating the risks in manned space flight, the group at Langley saw this event as having paramount importance.27
To ensure that NASA would have intelligent liaison and some expertise of its own in dealing with military aeromedical organizations, one of the early official actions of the NASA Administrator was the appointment on November 21 of a Special Committee on Life Sciences, headed by W. Randolph Lovelace II. This committee, composed of members from the Air Force, Army, Navy, Atomic Energy Commission, Department of Health, Education, and Welfare, and private life, should provide "objective" advice on the role of the human pilot and all considerations involving him. However, NASA and particularly STG would soon discover certain difficulties with this, as with other, review committees "having a certain amount of authority . . . yet no real responsibility" for seeing that the program worked properly.28
On a similar but lower plane, Gilruth asked for and received from the military services three professional consultants for an aeromedical staff. Lieutenant Colonel Stanley C. White from the Air Force and Captain William S. Augerson from the Army were physicians with considerable experience in aerospace medicine, and Lieutenant Robert B. Voas from the Navy held a Ph. D. in psychology. Thus both NASA and STG ensured the autonomy of their medical advice while at the same time they tapped, through White, the biomedical knowledge gained by the Air Force in its "Man-in-Space-Soonest" studies and, through Augerson, that gained by the Army and Navy through joint biosatellite planning.29
18 John P. Mayer, interview, Houston, Oct. 19, 1964. For an overview of scientific expectation from the IGY, see D. R. Bates, ed., The Earth and Its Atmosphere (New York, 1957; Science Editions, Inc., 1961), 97-112. The difference between "sounding" and "probe" rocket flights was generally accepted by 1958 as being a matter of altitude, with the division point at a height of one Earth radius. Sounding rockets were those ascending to about 3900 miles; instrumented rockets going higher than that were called probes. On the word "aerospace" as used by the Air Force, see David Burnham, "The Air Force Coins a Word," The Reporter, XXVIII (June 6, 1963), 32-33.
19 On the evolution of the standard atmosphere, see the works of Harry Wexler, Director of Meteorological Research of the United States Weather Bureau, and the foreword by Maurice Dubin, Norman Sissenwine, and Wexler to U.S. Standard Atmosphere, 1962 (Washington, 1962), xiv-xv. Also a 1957 course of lectures sponsored by Space Technology Laboratories and the University of California at Los Angeles provided a comprehensive topical guide to the "state-of-the-art" of aerospace technology and achieved wider circulation when printed: Howard Seifert, ed., Space Technology (New York, 1959).
20 Peck and Scherer, The Weapons Acquisition Process, 9, passim. See also article by H. Guyford Stever, "Outer Space: The Technical Prospects" in Lincoln P. Bloomfield, ed., Outer Space: Prospects for Man and Society (Englewood Cliffs, N.J., 1962). Comments by Manley J. Hood of Ames, Oct. 29, 1965, disagree with this general assessment, but the missile divisions of old aircraft corporations were more often than not semi-autonomous.
21 NASA First Semiannual Report to Congress, 36, 37, 50. On this synthesis, see Hugh L. Dryden, "Scientific Bases of Airplane, Projectile and Missile Development," paper, American Ordnance Assn., New York City, Dec. 7, 1955, 2-3. Cf. John B. Rae, "Science and Engineering in the History of Aviation," Technology and Culture, II (Fall 1961), 391-399.
22 The Convair/Astronautics-Avco Mfg. Corp. "Proposal for a Manned Satellite," No. ARL 03752, April 30, 1958, was an excellent introduction for STG to the men behind the Atlas as well as to their preliminary thinking. Cf. "Study for Manned Space Vehicle," Convair/Astronautics, June 1958; and H. S. Gault and M. R. Tyson, "Study - Increased Capability of XSM-65 for Manned Space Flight Using 'Off-the-Shelf' Upper Stages," Convair/Astronautics, A2P-059, Nov. 5, 1958. Memo, Silverstein to Assoc. Dir., Lewis Research Center, "Request for Information on Atlas LOX Pump Performance," Nov. 14, 1958; Silverstein interview.
23 Ms., R. B. Oakley, "History of North American Aviation, Inc.," undated [about June 1964], 9. For some insight into General Electric's contribution to the NAA/GE studies, see memo for files, Hugh M. Henneberry, "Briefing by General Electric Representatives on Studies Related to Man-in-Space Program," July 17, 1958.
24 James S. McDonnell, Jr., "The Conquest of Space: A Creative Substitute for War," speech, Washington University, St. Louis, June 9, 1958. Cf. McDonnell, "The Challenge of Man's Future in the Golden Age of Engineers," speech, University of Missouri School of Mines and Metallurgy, Rolla, Mo., May 26, 1957.
25 "Manned Orbital Flight," Report 6272, McDonnell Aircraft Corp., Oct. 10, 1958. Cf. "Manned Orbital Flight Planning Proposal," Report 6418, McDonnell Aircraft Corp., Oct. 15, 1958. Kendall Perkins, interview, St. Louis, Aug. 31, 1964; Raymond A. Pepping, interview, St. Louis, Sept. 1, 1964.
26 "Briefing for Prospective Bidders for Manned Satellite Capsule," STG, Nov. 7,1958; Ms., Jack A. Kinzler for Project Mercury Technical History Program, "Manufacturing by NASA for Project Mercury," Aug. 1963; E. M. Gregory, interview, Langley Field, Va., Jan. 7, 1964; Caldwell C. Johnson, "Specifications for a Manned Satellite Capsule," undated [about Oct. 20, 1958]; C. C. Johnson, interview, Houston, Feb. 13, 1964.
27 Faget, marginal notes on "Outline of History of United States Air Force Man-in-Space Research and Development Program," anon., Aug. 1962; Wood, "Comments on Draft of Congress Staff Report on Mercury," Jan. 26, 1960. See also Mae M. Link, Space Medicine in Project Mercury (NASA SP-4003, 1965), 16, 67.
28 Purser, "Project Mercury Background Material," March 23, 1959, 1; Purser, "Summary of Management, Design and Operational Philosophy," lecture, University of Houston, Spring 1963, 3. Cf. Purser, Faget, and Smith, eds., Manned Spacecraft) 492.