Boeing will launch its Starliner capsule to the International Space Station as part of a test flight on Thursday.
The company will try to dock the spacecraft onto the orbiting lab, and then bring it back to Earth safely, before it can launch astronauts on board the CST-100 Starliner.
Nasa has contracted Boeing to send its astronauts to the space station, in a deal similar to the US space agency's arrangement with Elon Musk's SpaceX.
However, Boeing is yet to complete a test flight successfully. Its first attempt in 2019 failed, when the capsule was unable to dock on the ISS due to software glitches.
The spacecraft will launch on a United Launch Alliance Atlas V rocket from the Cape Canaveral Space Force Station in Florida. It is scheduled to dock on the ISS on Friday, May 20. The operation will be streamed live by Nasa.
“OFT-2 [Boeing Orbital Flight Test-2] will demonstrate the end-to-end capabilities of the Starliner spacecraft and Atlas V rocket, from launch to docking to a return to Earth in the desert of the western United States,” said Nasa on its website.
“The uncrewed flight test will provide valuable data towards Nasa certifying Boeing’s crew transportation system for regular flights with astronauts to and from the space station.”
If Boeing starts sending astronauts to the ISS, it would mean increased access to space for Nasa and its partners.
The space agency's Commercial Crew Programme has helped it to launch astronauts from US soil once again, after 11 years of relying on Russia's Soyuz rockets.
SpaceX has sent four crewed flights to the station for Nasa, including its latest Crew-4 mission that was launched on April 27.
A UAE astronaut will be part of the Nasa-SpaceX Crew-6 mission, which is scheduled for launch next spring.
It will be the first time an Arab astronaut will travel on board a SpaceX rocket, and will be the first long-duration space mission by an Arab country.