(CNN)– A SpaceX Crew Dragon capsule will bring home two NASA astronauts who have remained aboard the International Space Station for more than 80 days due to problems affecting the Boeing Starliner spacecraft, marking a surprising turn. for the troubled aerospace giant.
The news comes after the US space agency conducted a formal review this Saturday to determine whether it would deem Boeing’s Starliner vehicle safe enough to return home with its crew, or whether SpaceX’s Crew Dragon spacecraft would have to intervene. to save the situation.
The Starliner vehicle, which carried astronauts Suni Williams and Butch Wilmore to the space station in early June, suffered setbacks with helium leaks and thrusters that abruptly stopped working on the initial leg of its first crewed test flight. Engineers spent weeks trying to better understand the issues, and Boeing said Aug. 2 that its “confidence remains high” that the spacecraft would be able to return Williams and Wilmore to Earth.
However, NASA revealed during a briefing on August 7 that discussions within the space agency over the safety of the Starliner capsule had evolved, leading the federal agency to more seriously consider bringing the astronauts home in a SpaceX Crew Dragon vehicle, which has flown a dozen crewed missions to space since 2020.
On Saturday, Nelson said NASA considered its extensive experience with spaceflight, both successful and unsuccessful, in making the decision.
“We have made mistakes in the past: we lost two space shuttles as a result of there not being a culture in which information could be presented,” Nelson said. “Space flight is risky, even at its safest and even at its most routine. And a test flight, by its nature, is neither safe nor routine.”
SpaceX was already scheduled to execute a routine mission to the International Space Station, carrying four astronauts as part of standard crew rotations aboard the orbital laboratory. But the mission, called Crew-9, could now be reconfigured to carry two astronauts instead of four.
That adjustment would leave two empty seats for Williams and Wilmore to fill on the Crew-9 flight home. The astronauts would also officially join the Crew-9 team, becoming part of the official expedition. With that transition, Williams and Wilmore would remain in situ for six more months, the duration of a routine mission to the space station.
The reassignment to Crew-9 could delay the duo’s return until February 2025 at the earliest.
In that case, the Starliner would return home empty. And NASA would have to decide whether the data Starliner collected on its mission is enough to give the space agency the confidence to officially certify Starliner for human spaceflight, a step that would prepare the vehicle for routine trips to orbit.
Five of the Starliner’s 28 “reaction control thrusters” stopped working during the first leg of Boeing’s test mission. In the end all but one recovered.
And although Williams and Wilmore expected to spend only eight days in space, their stay aboard the orbital laboratory has already been extended by about two months, as engineers on the ground have worked to better understand the problems with the thrusters.
Those responsible have explained that they have been able to recreate with tests on the ground how the propellants deteriorated in space during the flight. According to Boeing, the possible cause is heat buildup inside the propellants, which may be causing the insulating gaskets to bulge and restrict propellant flow.
Alternatively, problems with helium leaks may be because seals have degraded due to exposure to propellant vapor, Mark Nappi, Boeing’s Commercial Crew program manager, said on July 25.
However, NASA has struggled to reach a consensus on how these issues could affect astronauts’ return to space and what level of risk they would pose.
Uncertainty around the level of risk is why the agency could turn to SpaceX and its Crew Dragon spacecraft to intervene.
NASA has repeatedly said that SpaceX’s potential to intervene highlights how the space agency intentionally designed its Commercial Crew Program – under which both Starliner and Crew Dragon were developed – to allow each spacecraft to serve as backup. the other.
“We are in kind of a new situation here and we have multiple options,” Ken Bowersox, associate administrator of NASA’s Space Operations Mission Directorate, said on August 7. “It’s something we’ll have to deal with in the future: we could find ourselves in a situation where we need to bring a (SpaceX) Dragon crew or a (Russian) Soyuz crew back on a Starliner.”
“That’s why we want multiple vehicles, to have that option,” Bowersox added.
Still, the federal agency funded SpaceX’s Crew Dragon and Boeing’s Starliner at the same time in 2014. Crew Dragon has now been in operation for four years, while the Starliner program is hundreds of millions of dollars over budget and years in the making. delay.
Boeing’s development process has also been plagued by errors.
For example, the first Starliner test mission, carried out in 2019 without a crew, failed in orbit and cut the flight short much earlier than expected. The vehicle ultimately did not dock with the space station as planned, and the result was revealed to be a symptom of a myriad of software problems, including a coding error that set an internal clock back 11 hours.
A second uncrewed flight test in May 2022 uncovered additional software issues, and mission teams addressed issues with some of the vehicle’s thrusters. However, the root cause of the thruster problem that affected this manned mission was overlooked two years ago.
The question of whether the Starliner vehicle finally obtains certification after its return to Earth is likely to become a controversial issue, which is considered the most dangerous stage of the mission. The autonomous vehicle will have to use its thrusters to orient itself precisely as it plunges back into Earth’s thick atmosphere. The pressure and friction are expected to heat the exterior of the vehicle to approximately 1,650°C.
Starliner’s parachutes must deploy smoothly and slow the spacecraft before activating the airbags to expand and cushion the landing.
If the Starliner capsule is eventually certified, it could join SpaceX’s Crew Dragon on routine trips to the space station to rotate personnel. Currently, those trips take place approximately every six months.
And if the spacecraft is denied certification, it would mark yet another blow to Boeing’s already badly damaged reputation. Missing the goal could cost the company many additional millions of dollars, on top of the roughly $1.5 billion the company has already recorded in losses on the Starliner program.
