Thomas Henry Marshburn is an American physician and a former NASA astronaut. He is a veteran of three spaceflights to the International Space Station and holds the record for the oldest person to perform a spacewalk at 61 years old.

NASA Extreme Environment Mission Operations, or NEEMO, is a NASA analog mission that sends groups of astronauts, engineers and scientists to live in the Aquarius underwater laboratory, the world's only undersea research station, for up to three weeks at a time in preparation for future space exploration.