SpaceX won a $2.6 billion contract from NASA in 2014 to develop the capsule. Crew Dragon is an evolved version of the company’s Cargo Dragon capsule, which has completed 16 missions to the ISS. But, even when it was built to launch cargo, SpaceX’s intent was always to build a vehicle capable of launching astronauts.
There are a few key differences between Cargo Dragon and Crew Dragon. Notably, Crew Dragon is both taller and heavier than the cargo version. NASA said Crew Dragon will eventually be able to send as many as four astronauts at a time to the ISS. Additionally, Crew Dragon has eight “SuperDraco” engines that Cargo Dragon does not. Those will be used in the event of an emergency while the astronauts are on board.
Read: Step inside SpaceX’s Crew Dragon capsule, launching the next generation of US spaceflight
Safety is key for the Commercial Crew program, as it represents one of NASA’s biggest partnerships with the private industry.
“We are not going to fly until we’re ready to fly these folks safely,” SpaceX President and COO Gwynne Shotwell told reporters in August. She said the company needs “to demonstrate that this vehicle is capable of taking astronauts up from U.S. soil as often as NASA will allow us to do so.”