In this image provided by NASA, SpaceX astronauts are greeted by those already aboard the International Space Station after the Dragon capsule successfully docked on Saturday. Their arrival brings the total number of astronauts on the station to a recent high of 11. NASA via AP hide caption
Astronauts (from left) Victor Glover, Michael Hopkins, Shannon Walker and Japan's Soichi Noguchi wave to family and friends as they leave for the launch site on Sunday. John Raoux/AP hide caption
SpaceX's Crew Dragon capsule approaches the International Space Station ahead of docking Sunday. NASA / NASA TV hide caption
President Trump, Vice President Pence and Karen Pence view the SpaceX flight to the International Space Station at Kennedy Space Center on Cape Canaveral, Fla., on Saturday. Alex Brandon/AP hide caption
A SpaceX Falcon 9, with NASA astronauts Doug Hurley and Bob Behnken in the Dragon crew capsule, lifts off from Pad 39A at the Kennedy Space Center in Cape Canaveral, Fla., on Saturday. David J. Phillip/AP hide caption
Clouds pass over the SpaceX Falcon 9, with the Crew Dragon spacecraft on top of the rocket on Launch Pad 39-A on Wednesday at Kennedy Space Center in Cape Canaveral, Fla. David J. Phillip/AP hide caption
NASA astronaut Doug Hurley rehearses putting on his SpaceX spacesuit last week at the Neil A. Armstrong Operations and Checkout Building at Kennedy Space Center in Florida. Kim Shiflett/NASA hide caption
A time exposure of the United Launch Alliance Atlas V rocket carrying the Boeing Starliner crew capsule on an flight test to the International Space Station lifts off in Cape Canaveral, Fla., on Friday. Terry Renna/AP hide caption
The Crew Dragon landed safely in the Atlantic Ocean on Friday morning, with a splashdown at 8:45 a.m. ET, as scheduled. The uncrewed craft had been on a test flight in which it docked with the International Space Station. NASA TV Screenshot by NPR hide caption
In this photo provided by NASA, the SpaceX Crew Dragon is pictured just beside the International Space Station. SpaceX's new crew capsule arrived at the station on Sunday in a remarkable moment for commercial space exploration. NASA via AP hide caption