It’s all systems go for the second attempt to launch the often-delayed Boeing Starliner crew on Saturday for a long-awaited test flight to the International Space Station, the first capsule with astronauts aboard, NASA executives said Friday.
“From the standpoint of the station, our crew, our ground teams, we’re ready to fly this mission,” said Dana Weigel, NASA’s space station program manager. “We are thrilled to be on the cusp of this historic mission.”
United Launch Alliance
The Starliner liftoff atop a United Launch Alliance Atlas 5 rocket is targeted for Saturday at 12:25 p.m. EDT, about the time Earth’s rotation will bring pad 41 at the Cape Canaveral Space Force Station into alignment with the station’s orbit.
ULA engineers are expected to begin fueling the rocket around 6:30 a.m. Veteran NASA astronauts Barry “Butch” Wilmore and Sunita Williams, acting as commander and co-pilot, plan to strap in three hours later to await liftoff.
It will take Atlas 5 about 12 minutes to lift the Starliner into orbit and begin its 25-hour rendezvous with the space station. Docking is expected at 13:50 on Sunday. If all goes well, Wilmore and Williams will detach and return to Earth on June 10, landing in the morning at a desert site in Arizona or New Mexico, depending on the weather.
“I’ve talked to them and they have full confidence in our rocket, they have full confidence in our spacecraft, our operations teams and our management teams,” said astronaut Mike Fincke, who is training to command the Starliner mission next year. “They are definitely ready to go.
Speaking of ready to “go,” the Starliner will carry a Urine Processor Pump Module that was added at the last minute to replace one that failed aboard the station earlier this week. To make room for the 150-pound component, some of the crew’s clothing and other personal items have been removed from the ship, but generic clothing is stored aboard the lab and no problems are expected.
“The two particular trunks that came out contained clothing for both Butch and Sonny as well as some … their own unique hygiene materials,” Weigel said. “Of course we have generic shampoos, soaps, etc. on board that they can only use from generic stock. Same with clothes, so they’ll do it.”
NASA
The long-awaited Starliner flight marks a major milestone in NASA’s commercial crew program, which has funded the development of SpaceX’s Crew Dragon and Boeing’s Starliner shuttles to provide shuttle transport to and from the space station without relying on Russia for onboard rides. the Soyuz spacecraft.
From the beginning, NASA wanted spacecraft from a variety of vendors to provide continuous access to the space station, although problems grounded one shuttle for an extended period.
SpaceX began flying astronauts aboard Crew Dragon ships in 2020 and has now launched 50 astronauts, cosmonauts and civilians into orbit in 13 flights. Boeing’s Starliner, by contrast, has suffered a steady stream of problems that delayed the first manned flight by four years and cost the company more than $1 billion to fix.
Wilmore and Williams were finally cleared to start on May 6. They were preparing for liftoff when ULA engineers reported problems with the relief valve used to maintain proper pressure in the oxygen tank inside the Centaur rocket’s upper stage. Not pleasant with valve performance, mission managers ordered a scrub.
Atlas 5 was taken back to ULA’s Vertical Integration Facility where a replacement valve was installed, tested and cleared for flight. Meanwhile, Boeing engineers were evaluating data collected after the cleanup that indicated a small helium leak in the piping used to pressurize the Starliner’s propulsion system.
The leak was eventually traced to a pipe leading to a specific reaction control system nozzle, one of 28 such nozzles mounted around the Starliner’s Drum Service Module. After extensive testing and analysis, mission managers he concluded that the spacecraft could safely fly as is without a credible threat to flight safety.
If the leak worsened drastically in flight, the helium line in question would isolate itself and shut down its nozzles. This would prevent normal reentry using the more powerful thrusters at the end of the mission, but there are backup plans to perform a de-orbit “burn” using two long blasts of unaffected RCS thrusters.