The launch of the private Polaris Dawn mission was postponed until Wednesday night at the last minute due to a helium leak. It was scheduled to take place shortly before dawn in Florida.
Polaris Dawn will result in the first private spacewalk.
“Teams are closely investigating a helium leak on the ground,” SpaceX, which provides the Falcon 9 rocket and Polaris Dawn’s Crew Dragon capsule, said on X. “Falcon and Dragon are healthy and the crew is ready for the multi-day mission to Earth orbit.”
Polaris Dawn is funded by tech billionaire Jared Isaacman. He has already paid for a first private mission, Inspiration4, in 2021. Mr. Isaacman paid with SpaceX for the adaptation of the Crew Dragon capsule to allow spacewalks, as well as the modification of SpaceX’s spacesuit.
The mission includes a former U.S. military pilot and two SpaceX engineers, one of whom, Sarah Gillis, will spacewalk with Mr. Isaacman midway through the five-day mission.
The mission will reach an altitude of 1,400 kilometers, the highest of any manned orbital mission. Only the Apollo lunar program has sent humans farther from Earth. The four Polaris Dawn astronauts will face radiation from the “van Allen belt,” which is more harmful because it is no longer intercepted by the Earth’s magnetic field.
Two more Polaris Dawn missions are planned, including the first crewed mission of SpaceX’s Starship moon rocket, after 100 cargo launches to Earth orbit.