Foreword

GEMINI was the intermediate manned space flight program between America’s first steps into space with Mercury and the amazing and unprecedented accomplishments achieved during the manned lunar expeditions of Apollo. Because of its position between these two other efforts, Gemini is probably less remembered. Still, it more than had its place in man’s progress into this new frontier.

Gemini accomplishments were manyfold. They included many firsts: first astronaut-controlled maneuvering in space; first rendezvous in space of one spacecraft with another; first docking of one spacecraft with a propulsive stage and use of that stage to transfer man to high altitude; first traverse of man into the Earth’s radiation belts; first extended manned flights of a week or more in duration; first extended stays of man outside his spacecraft; first controlled reentry and precision landing; and many more.

These achievements were significant in ways one cannot truly evaluate even today, but two things stand out: (1) it was the time when America caught up and surpassed the Soviet Union in manned space flight, and (2) these demonstrations of capability were an absolute prerequisite to the phenomenal Apollo accomplishments then yet to come.

America’s first manned space flight program, Mercury, involved a careful buildup of flight duration to slightly beyond one day with accompanying concerns about man’s physiological response to weightlessness and other aspects of his safety and well being. In the meantime, the Russian effort had achieved durations of five days, flight of a multiple crew shortly after the Mercury Program had terminated, and the first extravehicular operation by a cosmonaut shortly before the first manned Gemini flight. The question at that time was who would perform the first rendezvous, seen as a very complex operation but absolutely needed for future space endeavors.

About the time Gemini started, the Russian effort slowed down as they attempted to develop and flight qualify their second-generation manned spacecraft, Soyuz. In the meantime, Gemini, America’s second-generation spacecraft, reeled off ten manned flights in less than twenty months - a flight rate yet to be surpassed in any space program. The last five manned launches were accompanied by nearly simultaneous and precisely timed launches of rendezvous target vehicles. During this period, rendezvous demonstrations and many other activities took place which were not to be matched by corresponding Soviet accomplishments for years to come, and more than five years passed before the two-week long mission of Gemini VII was exceeded by the Russians with their Salyut spacecraft.

However, these Gemini mission spectaculars were not aimed at “beating the Russians"; rather, their purpose was to support and demonstrate needed mission capability for the upcoming Apollo flights to the Moon. Apollo needed a reliable rendezvous and docking operation if the astronauts were to get back from the Moon. Could this be done? Gemini demonstrated such a capability with great success six straight times and with many different techniques. The Apollo missions required a duration of a week or two. Could this be done? Gemini demonstrated mission durations of one and two weeks with no major untoward effects on the astronauts. The Apollo astronauts would spend hours outside their spacecraft exploring the lunar surface. Could this be done? Of the five EVA missions conducted in Gemini, four of them lasted from two to four hours. Tired astronauts returning from the Moon would want to land as close as possible to the recovery aircraft carrier. Could this be done? Indeed, it was accomplished seven straight times during the last two-thirds of the Gemini Program. Apollo needed to develop advanced reliable systems. Could this be done? Their names probably still sound strange to many, but fuel cells, cryogenic storage of hydrogen and oxygen, ablative thrusters using hypergolic propellants, an onboard digital computer, an inertial guidance system, and a rendezvous radar were developed and demonstrated in Gemini. One must admit to considerable difficulty in these developments, but, in the end, they provided a high degree of confidence that systems embodying high reliability could be obtained.

Equally important to Apollo was the training provided by the Gemini missions to the flight and ground crews. The mission control center techniques and the flight control team procedures were largely implemented during Gemini. Of the astronaut complement assigned to the first four flights to the Moon, ten of the twelve had prior Gemini flight experience and the other two had been members of Gemini backup crews. In all, over half of the Apollo crew members had direct Gemini flight experience.

Gemini also carried forward a major experiment program in space science and applications. Over 50 such experiments were carried out involving astronomy, biology, atmospheric sciences, medicine, radiation effects, micrometeoroid investigations, space environmental effects, and others. Technical and operational experimentation involved such things as low light level TV observations, special photography, special communications tests, tethering of two vehicles, and gravity gradient stabilization. The hundreds of synoptic weather and Earth terrain color photographs taken contributed greatly to the development of the meteorological and Earth resources programs which are now bringing important benefits from rapid global observations of the Earth to people here on the surface.

Lest one think that the Gemini flights were carried forward with great smoothness, be assured that most of them encountered real cliff-hanging incidents. On Gemini IV, the astronauts had great difficulty in closing the hatch after their EVA which was accomplished only after great physical exertion and almost complete exhaustion. Needless to say, corrections were made before the next flight. Gemini V, which was planned to fly for eight days, was almost called back after a few hours because of loss of pressure in the cryogenic tanks supplying fuel for the new electrical power devices called fuel cells. But the crew and flight controllers nursed the spacecraft along for the full mission duration by powering down the spacecraft and using just a few watts of electrical power. Their problems were compounded when some of the attitude stabilization rockets failed late in the mission.

After loss of the first rendezvous target vehicle, caused by an explosion during launch, Gemini VI and VII were reconfigured so that Gemini VII served as the rendezvous target for Gemini VI in the “Spirit of 76” mission just before Christmas in 1965, after which Gemini VII continued to struggle along with balky fuel cells for a record duration of 14 days in space. Gemini VIII spun out of control just after accomplishing the first docking in space. The crew was able to correct this condition in spite of rotating nearly one revolution every second. But the spacecraft had to be returned to Earth rapidly and landed in the western Pacific Ocean. Astronauts became exhausted from EVA exertions on Gemini IX and XI. Only the last mission, Gemini XII, (and perhaps Gemini X) could be called really smooth, carried out pretty much as planned.

In spite of all these exciting mission events, problems, and accomplishments, the thing that stands out in my own mind is the way in which the effort and dedication of many individuals and groups coalesced into an extremely effective team. This cliche is often voiced whenever an activity is successful, but, in Gemini, the observed capacity for accomplishment proved to be well beyond a program manager’s most optimistic hopes. Although not so visible from a program manager’s level, this cooperation and support had to extend to the level of the NASA Administrator and his interfaces with the President, congressional leaders, heads of other agencies, industry, and the Public in general. Most certainly, this same situation occurred during the Apollo Program and, no doubt, has occurred in connection with most major achievements of man. However, Gemini - though a complex undertaking - was small enough for this to stand out very clearly. Such an experience leads one to believe that man can accomplish almost anything if sufficient dedication and cooperation exists between and within the groups involved.

In Gemini, this esprit de corps was actually enhanced by the mistakes made or the problems encountered because of the positive approach to dealing with them. A prime example of this occurred when a critical hydraulic system failed on the launch vehicle just at engine start prior to liftoff on the first full systems test of Gemini. The response of the people involved was truly outstanding. Even though recovery from this problem involved trying work over the Christmas holidays, everyone involved put forward a maximum effort, including the small job shop that built a new casting, the hydraulic valve contractor, the prime contractor, the Air Force, its support contractors, and NASA. As a result of such effort, the cause of the failure was isolated, a completely new component designed, built, tested, qualified, installed, and checked out so that a second attempt could be made only six weeks after this major difficulty occurred. There may have been evidences of parochialism and vested interests early in the programs but after an event and accomplishment such as that, the whole team concentrated on the program in the spirit of an elite group.

I believe that this is a lesson and a legacy that our space programs have left to future generations just as other eras of great accomplishment have done. Admittedly, Mercury, Gemini, and Apollo had very clear objectives. But even in more complex and confusing situations an integrated and dedicated striving to solutions of problems would seem to be an approach well worth taking. In today’s world, there seems to be an undue degree of second-guessing and lack of cooperation in many endeavors. Gemini was far from perfect, but, although its people recognized and encountered imperfections they strove as a group for perfection.

Charles W. Mathews
Associate Administrator for Applications
July 1975