Gemini was created to learn the techniques NASA believed were necessary to make a successful flight to the Moon. They wanted to prove that two spacecraft could rendezvous in space and fly together like two jets in formation. And they needed to prove that two spacecraft could dock with each other in flight.
The early theoretical work by people like Tsiolkovsky and Oberth indicated that journeys beyond Earth orbit would need to start from a space station, built in stages. The concept was refined further with British researchers suggested in 1949 that the space station itself wasn’t necessary. Over the course of the 50s, scientists continued to develop the idea of orbital mechanics. But thinking about it wasn’t enough. The ideas had to be tested.
The early spacecraft, Mercury, Vostok, and Voskhod weren’t maneuverable enough to test the theories to any real degree. The engineers and researchers who had come to NASA from NACA were very talented, but they’d never been asked to plan for operations outside the atmosphere. Project Mercury NASA reasoned did not need “any major technological breakthroughs.”
NASA had started the planning for Apollo with the idea of simply launching a mission directly to the Moon using the proposed Nova rocket booster. This was known as Direct Ascent, or what NASA liked to call the “all-the-way” approach. In 1959, NASA made a lunar mission its priority over a space station.
But by 1960, differing opinions started being heard from NASA leaders at the Marshall Space Flight Center in Huntsville, Alabama and the Langley Research Center in Hampton, Virginia. Von Braun had been arguing for an orbital approach since 1958. He and his team determined that while a direct ascent could lead to a flight circumnavigating the Moon, anything more than that would require orbital rendezvous. They suggested four different ideas. Two of them would require rendezvous in Earth orbit, two suggesting rendezvous in lunar orbit. His team had been working on the design of a booster they know as Juno V. The fact that it had no military application was the justification for moving control of von Braun’s team to NASA. The Juno V would eventually become the Saturn V.
Meanwhile, at Langley, the idea of orbital rendezvous was also being studied. They realized that using a small lander while leaving the return spacecraft in orbit would simplify things and save lots of weight in the process. But that would require rendezvous in lunar orbit.
The Air Force had also been studying rendezvous and orbital operations. Robert Seamans had been part of that project and brought those ideas with him when he became NASA’s Associate Administrator in September of 1960.
There were a number of plans for what to do after Mercury and before Apollo. Many of them considered ways to modify Mercury spacecraft for longer duration flights. Some called for developing a space laboratory. In November of 1959, the Space Task Group had rejected the idea of upgrading Mercury in favor of a new spacecraft. And in May of 1960, NASA administrators turned down their request for funding to study an advanced Mercury.
It was becoming clear that NASA needed to learn how to rendezvous two or more spacecraft. But the political climate in Washington wasn’t supportive. President Eisenhower believed Mercury was the only program necessary. And he rejected NASA’s request for funding for the Apollo program in the 1961 budget.
Things changed rather quickly after President Kennedy took office. NASA was now leaning more to the idea of a lunar landing than just a simple fly-by mission. George Low, the Chief of Manned Space Flight, had led a committee to consider NASA’s options and had determined in a February report that bigger, more powerful boosters were going to be necessary. The report also determined that “orbital operation techniques must be developed.”
The President hadn’t shown much interest in spaceflight to that point, but that changed in the weeks after Yuri Gagarin reached orbit. In May of 1961, the President laid out his challenge to land an American on the Moon before the end of the decade. Within NASA, the argument over direct ascent versus orbital rendezvous for a lunar mission continued. But it was clear than orbital rendezvous was something that would be necessary for the future.
Jim Chamberlain, the Space Task Group’s chief engineer, had been given the job of developing the next spacecraft in February of 1961. He knew from the start an upgraded Mercury wouldn’t do. It had been designed and built to reach space as quickly as possible. Even before its first successful flight, it was clear it couldn’t achieve the goals necessary for a lunar mission. Chamberlin presented a design for a new two-man spacecraft, Mercury Mark II, to the Space Task Group in June of 1961. It was first known as Mercury Mark II, but when NASA approved the design, the name was changed to Gemini. NASA chose McDonnell to build it and announced the project publicly on January 2nd, 1962.
The early designs also considered using a paraglider to bring the spacecraft down safely to a landing on the ground, instead of the ocean. But development delays meant it couldn’t be used until later in the program. And the fact that it was almost 800 pounds more than a conventional parachute system began to weigh heavily against it. And many of the tests that were conducted at failed. By the spring of 1964, NASA gave up. The idea was finally abandoned for good, and publicly, in August of that year.
Problems in the development of the Titan II, as well as trouble with the development of a fuel cell to be used for power instead of batteries, and the thrusters necessary for maneuvering the spacecraft, led to delays in NASA’s schedule.
The name Gemini created a mild controversy over the years, as NASA and the astronauts pronounced the word to rhyme with ‘nee,’ instead of the ‘eye’ more familiar to fans of astrology.