SpaceX Crew Dragon Departs, Carrying NASA Astronauts Toward Home

What have the astronauts been doing aboard the space station?

Originally, the mission was to last only up to two weeks, but Mr. Behnken and Mr. Hurley ended up with a longer and busier stay at the space station. Because of repeated delays by SpaceX and Boeing, NASA ended up short-handed, with only one astronaut, Christopher J. Cassidy, aboard the space station when the Crew Dragon and its two passengers docked.

They stayed two months, helping Mr. Cassidy with space station chores. Mr. Behnken and Mr. Cassidy performed four spacewalks to complete the installation of new batteries on the space station. Mr. Hurley helped by operating the station’s robotic arm.

The men have also been contributing to science experiments in low earth orbit. They assisted in a study of water droplet formation in the low gravity environment of the space station using a shower head, and another that used fruit punch and foam to look at how to manage fluids in space. They also helped install new equipment inside the station that will be used in future scientific research.

Mr. Cassidy will remain aboard the station with two Russian astronauts, Anatoly Ivanishin and Ivan Vagner. All three are to stay on board through October when another crew of one American and two Russian astronauts will replace them.

When are the next Crew Dragon flights, and who will they carry?

The first operational flight of the Crew Dragon will launch no earlier than late September. It will take three NASA astronauts — Michael S. Hopkins, Victor J. Glover and Shannon Walker — and one Japanese astronaut, Soichi Noguchi, to the space station.