Because there is no airlock in the SpaceX Crew Dragon spacecraft used for the flight, the only way to perform a spacewalk is to let all the air out of the spacecraft, and then open one of the hatches. That requires all four crew members to wear spacesuits.
NASA and Soviet astronauts conducted spacewalks in a similar manner in the 1960s.<p>As the Crew Dragon swings around Earth in an elliptical orbit that swings as close as 120 miles to the surface and as high as 460 miles, Mr. Isaacman and Sarah Gillis, a SpaceX engineer, will exit the capsule for about 15 to 20 minutes each.<p>They will pass through the hatch at the top of the Crew Dragon with the help of a handrail that SpaceX has named Skywalker, moving around carefully and deliberately. The two will not be outside the spacecraft at the same time.<p>The other two crew members, Scott Poteet, a retired Air Force pilot and the mission’s pilot, and Anna Menon, another SpaceX engineer, will remain in the capsule to manage the umbilical cords that will feed the spacewalkers oxygen and power, and monitor the readings to make sure everything is proceeding properly.<p>After Mr. Isaacman and Ms. Gillis return inside and close the hatch, the inside of the capsule will be repressurized with oxygen and nitrogen.
The entire spacewalk, from letting out all the air to refilling a breathable atmosphere, is expected to take about two hours.