16. Another record for altitude in space was set by Gemini XI
The ability to maneuver and dock with another vehicle to be used to boost the spacecraft out of low earth orbit was a critical phase of the planned Apollo missions, which was why it was stressed during the Gemini program. Failing to complete a docking maneuver would require a mission to the moon to be aborted. Gemini XI docked with an Agena and used it to boost its orbit to the Gemini record of 739 nautical miles, then disengaged and connected the two spacecraft with a tether. Spinning the connected vehicles created a small but measurable amount of gravity in one of the experiments conducted by astronauts Pete Conrad and Richard Gordon. The docking was done on the first orbit, simulating an ascent from the surface of the moon to an Apollo command module.
The many scientific experiments conducted by Gemini XI included the use of power tools, which were evaluated for their effectiveness and ease of use in zero-gravity conditions. Re-entry for the mission was the first for an American mission that was completely controlled by computers, and the spacecraft returned to earth less than two miles from its planned landing point, within sight of the recovery ship USS Guam. Gemini XI was the penultimate flight of the program, and one of the most successful missions of the entire space program to that point. One remaining Gemini mission was completed, during which Buzz Aldrin completed over five hours of EVA, demonstrating that many of the problems encountered on the Gemini missions had been resolved.