STS-104 took place from July 12–24, 2001. This was the 10th mission to the International Space Station (ISS). During the 13-day flight, the crew conducted joint operations with the Expedition-2 crew. Gernhardt was one of two astronauts to perform three spacewalks to install the joint airlock "Quest" (including the first US spacewalk from the ISS), and to outfit it with four high-pressure gas tanks. The mission was accomplished in 200 Earth orbits, traveling 5.3 million miles in 306 hours and 35 minutes.