First launch attempt The first attempt to launch the 6A mission (second attempt for Gemini spacecraft No. 6) was on December 12, 1965, at 9:54 a.m. EST. carrying the astronauts away from the disaster that would be the result of a fully fueled Titan II falling back onto LC-19. However, Schirra did not feel any movement and knew that the booster had not lifted, so he decided not to abort. His quick thinking probably saved the mission as the reliability of the Gemini ejector seats was questionable; the astronauts could have been badly injured from high g-forces as the seats had to launch them at least 800 feet, which was deemed a safe distance from an exploding Titan II. In addition, the cabin interior had been soaking in pure oxygen for hours. Tom Stafford, in a NASA oral history in 1997, later recalled: Even if the astronauts had not been injured or killed, ejection would ruin the spacecraft and delay the mission for months. After the Stage I engines ignited and shut down, it still took about an hour for the booster to be made safe. The delay was due to the discovery of fuel (
UDMH) leaking out of the
PSV drain valve. The fuel had been ignited by the engine start, and the resulting fire was discovered when the Pad Crew inspected the engine compartment. Water spray was initiated and a cap was installed on the drain line. After removing the propellant from the Titan II, the booster was checked out and it was found that the plug which sent the lift-off signal to the spacecraft had dropped out, causing the clock to start. Testing revealed that some plugs came out more easily than others, so they were replaced by different ones that would stay in place properly. However, the electrical plug turned out to not be the only problem with the booster. Examination of telemetry also showed that the Titan actually began experiencing thrust decay before the plug dropped out. Engine No. 1 was unaffected and nearly reached 100% thrust at shutdown, while Engine No. 2 never transitioned to in-flight performance levels. Engineers spent all night combing through the first stage, but failed to find any cause for the thrust decay. Eventually however, one technician identified the problem, which was a plastic dust cover inside the gas generator that had been carelessly left inside when the booster was assembled months earlier at the Martin-Marietta plant, blocking the flow of oxidizer. The cover was removed and the Titan II cleared for another launch attempt. Had the inadvertent electrical disconnect not occurred, the abort sensing system would have sent a shutoff command to the Titan at T+2.2 seconds due to the loss of Engine No. 2 chamber pressure. Since launcher release and liftoff would take place at T+3.2 seconds, a pad fallback still would not have occurred in this scenario and the astronauts would have been safe.
Second attempt and rendezvous The Titan's batteries were replaced and the fuel prevalves, which had opened, were removed and it was decided to launch without them. The second attempt to launch the 6A mission (third attempt for Gemini spacecraft No. 6) was successful on December 15 at 8:37:26 a.m. EST. All went well through launch and ascent; first stage cutoff occurred at T+160 seconds and second stage cutoff at T+341 seconds. Spacecraft separation occurred at T+361 seconds and the crew entered a orbit. The plan called for the rendezvous to take place on the fourth orbit of Gemini 6. Their first burn came 94 minutes after launch when they increased their speed by 5 meters (16 feet) per second. Due to their lower orbit they were gaining on Gemini 7 and were only 730 miles, (or 1,175 kilometers), behind. The next burn was at two hours and eighteen minutes when Gemini 6A made a phase adjustment to put them on the same
orbital inclination as Gemini 7. They now only trailed by . The radar on Gemini 6A first made contact with Gemini 7 at three hours and fifteen minutes when they were away. A third burn put them into a orbit. As they slowly gained, Schirra put Gemini 6A's computer in charge of the rendezvous. At five hours and four minutes, he saw a bright star that he thought was Sirius, but this was in fact Gemini 7. After several more burns, the two spacecraft were only 130 feet (40 meters) apart. The burns had only used 112 lbs. (51 kilograms) of propellant on Gemini 6A, leaving plenty for some fly-arounds. During the next 270 minutes, the crews moved as close as one foot (30 centimeters), talking over the radio. At one stage the spacecraft were stationkeeping so well that neither crew had to make any burns for 20 minutes. Schirra said that because there is no turbulence in space, "I was amazed at my ability to maneuver. I did a fly-around inspection of Gemini 7, literally flying rings around it, and I could move to within inches of it in perfect confidence". As the crew sleep periods approached, Gemini 6A made a separation burn and slowly drifted more than from Gemini 7. This ensured that there would not be any accidental collisions while the astronauts slept.
A Christmas surprise The next day, before reentry, The
Smithsonian Institution claims these were the first musical instruments played in space and keeps the instruments on display.
Reentry Gemini 6A fired its retro-rockets and landed within of the planned site in the Atlantic Ocean northeast of
Turks and Caicos. It was the first recovery to be televised live, through a transportable satellite earth station developed by
ITT on the deck of the recovery aircraft carrier
USS Wasp. The Gemini 7 and 6A missions were supported by the following U.S. Department of Defense resources: 10,125 personnel, 125 aircraft and 16 ships. ==Insignia==