NASA learned how to fly in space 47 years ago. At least, that's when it first started figuring it out. The Mercury program that launched the first American astronauts really just took them along for a ride. But the second program, Project Gemini, was different. Lofty program goals demanded the astronauts apply their piloting skills to spaceflight. This second-generation spacecraft was no fully automated capsule with the astronaut acting as systems monitor. It was the spacecraft equivalent of a fighter jet.NASA began working on its follow-up program to Mercury in 1959. Originally designated Mercury Mark II, it was intended to build on the knowledge gained form Mercury, and help the United States gain a permanent foothold in space. But the program quickly developed into something much more complicated than just putting two men in a bigger capsule in orbit.President Kennedy's 1961 promise of a manned lunar landing by the end of the decade gave NASA a goal and asked a lot of questions. Could astronauts survive in space long enough to reach the Moon then safely leave their spacecraft to walk on its surface? But, before going to the Moon, a crew would have to rendezvous and dock with their lunar module in orbit, a manoeuvre they would have to repeat once the moon-walking duo reunited with their colleague waiting in orbit. (It's actually two separate spacecraft that travel to the Moon.) If orbital rendezvous was impossible, so was the Moon. So NASA's astronauts had to learn to really fly in space.The Soviets managed orbital rendezvous in 1962 and 1963, but only sort of. On both occasions one Vostok spacecraft was followed into orbit by a second, the latter launched at such a time and speed that the two would at least momentarily orbit fairly close to one another. But it wasn't a proper rendezvous. Wally Schirra compared the Soviet feat to a man walking down a busy street catching a glimpse of a pretty girl on the other side. Neither stops walking, and the traffic prevents the man from locking eyes with the girl, let alone talking to her. Schirra likened true rendezvous to that man running across the street through all the traffic to nibble that girl's ear. That's what the Gemini astronauts were going to do. They were going to make their spacecraft proverbially nibble on the ear of a target vehicle. And they were going to do it entirely manually.All control in the Gemini spacecraft was managed by control sticks or hand controllers, including all the burns during orbital rendezvous. Without an optical sight on board like the one included on Apollo, everything was with the astronauts looking out the windows and feeling how the spacecraft was moving.The attitude hand controller, the one that controlled where the spacecraft pointed was between the commander and the pilot (there was no co-pilot standing among these men), so that each man could reach it. Moving that controller backward or forward, left or right, or by twisting it, the astronaut fired any of the eight thrusters in the spacecraft's adapter section to adjust the spacecraft's yaw, pitch, and roll, respectively.But this wasn't new. This was the extent of the control the Mercury astronauts had had. The real innovation was the two T-handle controllers, one to the commander's left and the other on the pilot's right, that gave the astronauts translational control. Pushing the handle forward fired two 100-pound thrusters at the spacecraft's rear adapter section. Pulling it back, up, or down would fire other thrusters in the center of the adapter to move the entire spacecraft backwards, up, or down.All these adjustments were made relative to the astronauts' perspective. The trick was to do this and keep in mind the intricacies of orbital mechanics. In orbit, pushing a spacecraft forward so it gains speed takes it higher relative to the Earth. So if you're trying to catch up to something orbiting at the same altitude as you but further ahead, speeding up will actually take you further away from where you're trying to go. To close the gap between you and your target, you have to slow down, get into a lower orbit, pass the target, then speed up to regain the higher orbit and close the gap.Complicated, but not for the Gemini astronauts. Gus Grissom, the commander of Gemini 3 that launched on March 23, 1965, said it was a simple matter of turning on the computer's Orbital Attitude and Manoeuvering System, pointing the spacecraft at the horizon, and pushing the thruster.So complete and precise was the was level of control the Gemini astronauts had over their spacecraft that in December 1965 Schirra was able to fly Gemini 6 in tight circles around Gemini 7, coming safely within inches of his colleagues' vehicle. The experience was like flying with the Blue Angels at 18,000 miles per hour, he said, only easier because there's no turbulence in space. Just a smooth ride.NASA learned a lot on the 10 manned Gemini missions that flew between March 1965 and November 1966. The principle unknowns surrounding the Moon shot had been answered, and the classic "astronauts vs. engineers" debate had been solved. Contrary to engineers' fears, astronauts could properly fly in space.
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