During the latter part of World War II leaders of the National Advisory Committee for Aeronautics (NACA), the predecessor to NASA, had become interested in the possibilities of high-speed guided missiles and the future of spaceflight. It created at the end of World War II the Pilotless Aircraft Research Division (PARD), under the leadership of a young and promising engineer at the Langley Memorial Aeronautical Laboratory, Robert R. Gilruth.
Gilruth, as much as anyone, served as the godfather of human spaceflight in the United States. After his central role in PARD, he went on to lead the Space Task Group for NASA that accomplished Project Mercury, and then served as director of the Manned Spacecraft Center—renamed the Johnson Space Center in 1973—which had suzerainty over Gemini and Apollo. His organization recruited, trained, and oversaw the astronauts and the human spaceflight program throughout the heroic age of spaceflight. Yet, his name is much less well known than many others associated with these projects. He was a contemporary on a par with Wernher von Braun and a host of other NASA officials, and he certainly contributed as much to human spaceflight as any of them.
Gilruth was a representative of the engineering entrepreneur, a developer and manager of complex technological and organizational systems, accomplishing remarkably difficult tasks through excellent oversight of the technical, fiscal, cultural, and social reins of the effort. Johnson Space Center director George W.S. Abbey appropriately commented at the time of Gilruth’s death in 2000: “Robert Gilruth was a true pioneer in every sense of the word and the father of human space flight. His vision, energy and dedication helped define the American space program. His leadership turned the fledgling Manned Spacecraft Center into what it is today, the leader in humanity’s exploration of outer space.”
Gilruth established Wallops Island on the Eastern Shore as a test-launching facility under the control of Langley on July 4, 1945. From this site they launched between 1947 and 1949 at least 386 models, leading to the publication of the NACA’s first technical report on rocketry, “Aerodynamic Problems of Guided Missiles,” in 1947. From this, Gilruth and the PARD filled in the gaps in the knowledge of space flight. As historian James R. Hansen writes: “the early years of the rocket-model program at Wallops (1945-1951) showed that Langley was able to tackle an enormously difficult new field of research with innovation and imagination.”
Gilruth served as an active promoter of the idea of human spaceflight within the NACA and helped to engineer the creation of an interagency board to review “research on space flight and associated problems” toward that end. “When you think about putting a man up there, that’s a different thing,” he recalled. “There are a lot of things you can do with men up in orbit.” This led to concerted efforts to develop the technology necessary to make it a reality. In 1952, for example, PARD started the development of multistage, hypersonic, solid-fuel, rocket vehicles. These vehicles were used primarily in aerodynamic heating tests at first and were then directed toward a reentry physics research program. On October 14, 1954, the first American four-stage rocket was launched by the PARD, and in August 1956 it launched a five-stage, solid-fuel rocket test vehicle, the world’s first, that reached a speed of Mach 15.
These strides in the development of rocket technology positioned the NACA as a quintessential agency in the quest for space becoming important in the 1950s. And it enjoyed renewed attention and funding once the Soviet Union launched the world’s first satellite, Sputnik 1, on October 4, 1957. “I can recall watching the sunlight reflect off of Sputnik as it passed over my home on the Chesapeake Bay in Virginia,” Gilruth commented in 1972. “It put a new sense of value and urgency on things we had been doing. When one month later the dog Laika was placed in orbit in Sputnik II, I was sure that the Russians were planning for man-in-space.”
In the aftermath of the Sputnik crisis Gilruth and other NACA engineers ramped up efforts to advance human spaceflight:
Proposals fell into two rough categories: (a) a blunt‑nose cone or near‑spherical zero‑lift high‑drag vehicle of a ton to a ton‑and-a‑half weight, and (b) a hypersonic glider of the ROBO or Dyna‑Soar type. The first category of vehicles used existing ICBM vehicles as boosters; the second used more complex and arbitrary multiplex arrangements of existing large-thrust rocket engines. A number of contractors looked at the zero‑lift high‑drag minimum weight vehicle as the obvious expedient for beating the Russians and the Army into space. Others, notably Bell, Northrup, and Republic Aviation, set this idea aside as a stunt and consequently these contractors stressed the more elaborate recoverable hypersonic glider vehicle as the practical approach to the problems of flight in space.
By April 1958, they had concluded that the first of these options should become the basis for NACA planning for an initial human space flight.
It soon became obvious to all that an early opportunity to launch human spacecraft into orbit would require the development of blunt-body capsules launched on modified multistage ICBMs. Robert Gilruth recalled of these decisions:
Because of its great simplicity, the non-lifting, ballistic-type of vehicle was the front runner of all proposed manned satellites, in my judgment. There were many variations of this and other concepts under study by both government and industry groups at that time. The choice involved considerations of weight, launch vehicle, reentry body design, and to be honest, gut feelings. Some people felt that man-in-space was only a stunt. The ballistic approach, in particular, was under fire since it was such a radical departure from the airplane. It was called by its opponents “the man in the can,” and the pilot was termed only a “medical specimen.” Others thought it was just too undignified a way to fly.
While initially criticized as an inelegant, impractical solution to the challenge of human spaceflight, the ballistic concept gained momentum as NACA engineers, led by Gilruth lieutenant Maxime A. Faget, championed this approach. At a meeting on human spaceflight held at Ames on March 18, 1958, the ballistic approach gained official support. By April 1958 the NACA had completed several studies “on the general problems of manned‑satellite vehicles,” finding that they could build in the near term “a basic drag‑reentry capsule” of approximately 2,000 pounds and sufficient volume for a passenger.
In August 1958 the NACA developed preliminary specifications that then went to industry, especially the McDonnell Aircraft Corporation, for a ballistic capsule. Gilruth emphasized the simplicity if not the elegance of a ballistic capsule for the effort:
The ballistic reentry vehicle also has certain attractive operational aspects which should be mentioned. Since it follows a ballistic path there is a minimum requirement for autopilot, guidance, or control equipment. This condition not only results in a weight saving but also eliminates the hazard of malfunction. In order to return to the earth from orbit, the ballistic reentry vehicle must properly perform only one maneuver. This maneuver is the initiation of reentry by firing the retrograde rocket. Once this maneuver is completed (and from a safety standpoint alone it need not be done with a great deal of precision), the vehicle will enter the earth’s atmosphere. The success of the reentry is then dependent only upon the inherent stability and structural integrity of the vehicle. These are things of a passive nature and should be thoroughly checked out prior to the first man-carrying flight. Against these advantages the disadvantage of large area landing by parachute with no corrective control during the reentry must be considered.
The Mercury spacecraft that flew in 1961-1963 emerged from these early conceptual studies by Gilruth’s team at the NACA.