Nasa has asked the private sector to design new spacesuits that can be used on the Moon.
The SpaceX founder said that their work had seen them spending significant amounts of time apart.
The four amateur astronauts landed safely in the Atlantic Ocean after three days orbiting Earth.
Another mission to showcase the new astronaut vehicle is on hold as engineers check the propulsion system.
This was the first night-time landing for Nasa astronauts since Apollo 8's return 53 years ago.
SpaceX's Dragon Endeavour spacecraft has docked with the International Space Station.
As crew 2 is being sent to the International Space Station, the BBC explains what SpaceX actually does.
