Boeing's Starliner capsule is all set to launch on the uncrewed Orbital Flight Test 2 (OFT-2) mission to the International Space Station (ISS).
Following a May 11 flight readiness review, NASA and Boeing are targeting an instantaneous launch window of May 19 at 6:54 p.m. EDT (2254 GMT) for liftoff of Starliner atop a United Launch Alliance Atlas V rocket. This will be Starliner's second attempt to rendezvous and dock with the ISS, and a critical step in NASA's certification of the Boeing spacecraft for human passengers.
Starliner's first OFT mission, in December 2019, literally fell short of expectations, failing to achieve the necessary orbit to reach the International Space Station due to software glitches. Boeing readied Starliner for a do-over in early August 2021, but preflight checks hours before liftoff revealed problems in over half of the oxidizer valves in Starliner's propulsion system, and the launch was scrubbed. The capsule was unstacked from its Atlas V and returned to Boeing for repairs.
In photos: Boeing's Starliner OFT-2 mission in pictures
Now, with the valve issues finally resolved, Starliner has been declared ready to roll once more.
NASA is counting on the success of OFT-2 in order to begin sending astronauts to the space station in larger numbers. NASA's near decade-long reliance on Russian Soyuz spacecraft to taxi crews to and from the orbital laboratory was only recently eased by SpaceX's Crew Dragon, which launched its fourth operational crewed mission to the ISS last month.
In 2014, NASA, known for an abundance of cautionary redundancy, signed contracts with both SpaceX and Boeing to design and develop vehicles to launch astronauts to the space station. Starliner's eventual certification will fully realize NASA's goals for its Commercial Crew Program and allow the space agency to lessen its reliance on any single human spaceflight launch provider.
NASA says Starliner will spend between five to 10 days docked with the ISS on OFT-2 before returning to Earth for a landing in the western United States. If successful, NASA and Boeing hope to launch the capsule with its first crew before the end of 2022.
OFT-2 is scheduled to dock to the forward-facing port of the ISS's Harmony module roughly a day after launch, and it will deliver over 400 pounds (180 kilograms) of food and other provisions for the current station crews. In the event of any technical or weather issues during Thursday's countdown, NASA indicated that a backup launch window is available on May 20 at 6:32 p.m. EDT (2232 GMT).