NASA and SpaceX have shifted the launch of the Crew-9 mission, which is supposed to transport a crew to the orbiting laboratory for a six-month science mission and return Boeing's Starliner astronauts stuck in space back to Earth.

The SpaceX Polaris mission that is supposed to feature a spacewalk by members of an all-private crew is facing delays after a Falcon 9 rocket booster from a separate, uncrewed satellite mission tipped over and exploded on a floating platform Tuesday night.

The four astronauts of the Polaris Dawn mission traveled to 870 miles above Earth on Tuesday. Ahead of them Thursday is a bold private spacewalk.