NASA said on Wednesday that it has granted five more astronaut trips to Elon Musk's SpaceX, for a total of $1.4 billion.
NASA's Commercial Crew program, which transports people and cargo to and from the International Space Station, is responsible for the additional missions.
The agreement will cover missions Crew-10 through Crew-14, totaling about 20 spacecraft seats.
While NASA expects Boeing's Starliner capsule to fly people to space relatively soon, SpaceX is the only company certified to fly operational crewed missions for the agency for the time being.
NASA also awarded SpaceX three astronaut flights in December as part of a sole-source update to its Commercial Crew Transportation Capabilities contract, which was first awarded in 2014.
NASA officials said with today's update that SpaceX's CCtCap agreement is now worth a total of $4.9 billion.
Russia, a major space station partner, plans to leave the ISS in 2024 to build a Russian-operated space station; however, analysts believe the such station will not be completed until at least 2028.