Gemini 10 (officially Gemini X) was a 1966 crewed spaceflight in NASA's Gemini program. It was the 8th crewed Gemini flight, the 16th crewed American flight, and the 24th spaceflight of all time (includes X-15 flights over 100 kilometers (54 nautical miles)). During the mission, flown by future STS-1 Commander John Young and future Apollo 11 Command Module Pilot Michael Collins, Collins became the first person to perform two extravehicular activities.