SpaceX will launch astronauts to the International Space Station in late 2017 under a Commercial Crew order NASA announced Nov. 20.

SpaceX netted its first order some six months after Boeing, NASA’s other provider of astronaut transportation services under Commercial Crew Transportation Capability (CCtCap) contracts awarded in September 2014. SpaceX’s umbrella contract is worth $2.6 billion, while Boeing’s deal is worth $4.2 billion.

Under the CCtCap contracts, NASA pledged to order at least two missions from each company. Assuming Congress funds the program at the levels the White House has requested — which Congress never has — both companies would start launching in late 2017.

It remains to be seen which company will launch first. Whichever does will be the first to launch astronauts from U.S. soil since the Space Shuttle program ended in 2011.

“Determination of which company will fly its mission to the station first will be made at a later time,” NASA wrote in its press release.

A NASA spokeswoman declined to provide the terms of the agency’s order from SpaceX, or say why the agency waited nearly half a year to order a flight from SpaceX after ordering one from Boeing.

“NASA cannot release the award value of the post-certification mission task orders due to potential future competitions for missions,” spokeswoman Tabatha Thompson said in a Nov. 20 email. “The authority to proceed on the post-certification missions for each provider was consistent with the criteria and milestone dates pre-negotiated in their Commercial Crew Transportation Capability (CCTCap) contracts.”

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.