News, NASA: The US space agency, NASA announced on late Friday that it was ordering the second “post-certification mission” from Elon Musk’s space transport services company SpaceX to take astronauts to the International Space Station (ISS).

SpaceX will transport two crews to the International Space Station. The private spacecraft and rocket company has won a second post-certification mission from NASA to deliver as many as four crewmembers and 220 pounds of pressurized cargo from Kennedy Space Center in Florida to the space station.

The mission marks the fourth and final guaranteed order NASA will make under its Commercial Crew Transportation Capability Contracts. SpaceX received a previous order in November 2015. Boeing also received two orders last year.

“The order of a second crew rotation mission from SpaceX, paired with the two ordered from Boeing, will help ensure reliable access to the station on American spacecraft and rockets,” Kathy Lueders, manager of NASA’s Commercial Crew Program, said in a statement. “These systems will ensure reliable U.S. crew rotation services to the station, and will serve as a lifeboat for the space station for up to seven months.”

Both companies are now planning, building and testing the hardware and related assets to carry out their first flight tests and ultimately missions for NASA. SpaceX is building four Crew Dragon spacecraft at its Hawthorne, California, facility — two for qualification testing and two for flight tests next year. The company is also modifying Launch Pad 39A at Kennedy Space Center for the future launches of crewed missions to space.

“We’re making great progress with Crew Dragon, with the qualification of our docking adapter and initial acceptance testing of the pressure vessel qualification unit completed,” added SpaceX president and COO Gwynne Shotwell. “We appreciate the trust NASA has placed in SpaceX with the order of another crew mission and look forward to flying astronauts from American soil next year.”