Gemini 10

Gemini 10 carried John Young and Michael Collins from July 18 to 21, 1966, combining docking, powered orbital maneuvers, and visits to two separate Agena targets. The first rendezvous consumed more propellant than planned, so the crew cancelled docking practice and relied on their docked Agena's propulsion for major maneuvers. This raised the joined spacecraft's orbit and positioned Gemini to approach the Agena left from Gemini 8. Collins performed a stand-up EVA for ultraviolet photography and a separate excursion to the older Agena, retrieving its micrometeoroid experiment hardware despite limited handholds. Eye irritation curtailed the photography session, while fuel limits constrained the later spacewalk and some equipment was lost. The astronauts returned safely to the Atlantic after nearly three days. Gemini 10 demonstrated both the usefulness of a docked propulsion vehicle and an astronaut's ability to move to another orbiting spacecraft, while revealing practical limits in fuel planning and EVA worksite design.