Boeing’s Starliner can stay in space for more than 45 days, NASA says

Boeing’s Starliner capsule is performing well enough on its first-ever astronaut mission to remain in orbit longer than the originally planned 45 days, NASA says.

Starliner, which launched on June 5, has docked with the International Space Station (ISS) for an unspecified mission extension. The spacecraft is in good condition and capable of leaving the ISS in the event of an emergency. However, both NASA and Boeing are trying to understand why some of Starliner’s reaction control system (RCS) thrusters experienced problems leading up to its June 6 docking with the ISS, and why the capsule has developed multiple helium leaks. As such, Starliner will remain in space until at least later in the summer as testing and analysis continues. For example, a new round of thrust testing on the ground is expected to begin soon, possibly as early as today (July 2).

In-space tests on June 15 failed to identify the cause of the problems, though agency officials on Friday (June 28) stressed that progress has been made: the helium leaks have been stabilized and all but one of the failed thrusters are fit for use upon reentry. (Starliner has a total of 28 thrusters in its RCS; five were misbehaving, and of those five, only one will be taken offline during undocking.)

Because the RCS is located in Starliner’s service module, which is jettisoned for entry, descent and landing, the extra time in orbit will give teams time to figure out how to proceed. This will be crucial for any changes to the service module design that may be needed for future six-month ISS rotation missions that Starliner will fly as early as 2025. But to give ground teams time to test, NASA says Starliner will need to stay docked longer than the original 45-day limit for this mission. The good news is that the spacecraft looks good enough to last perhaps twice that long — or longer.

Related: Booster problems and helium leaks can’t stop Boeing’s Starliner astronaut test flight, but why do they happen?

“We’ve talked about a 45-day limit, limited by the crew module batteries on Starliner, and we’re in the process of adjusting that limit,” Steve Stich, manager of NASA’s Commercial Crew Program, told reporters during the conference call on Friday.

“We’ve looked at those batteries and their performance in space. They’re being charged by the station, and that risk hasn’t really changed. So the risk for the next 45 days is essentially the same as the first 45 days,” he said.

Starliner is actually rated to stay in orbit for up to 210 days once operational missions begin, he pointed out. But since this is only Starliner’s third mission into space, and its first with astronauts, NASA has been uncertain about its battery performance in orbit until now.

When asked by how long the mission might last, Stich said, “We haven’t decided yet how long we want to extend it.” Starliner has 12 different batteries, he explained. For this flight, similar batteries sat on the ground for a year and were then tested to make sure there were no failures, and none were found.

“What we’re really doing now is looking at the performance of the battery during flight. We’re not seeing any degradation in the cells that the batteries are in,” he added.

Boeing's white-and-blue Starliner spacecraft docked with the International Space Station in June 2024.

Boeing’s white-and-blue Starliner spacecraft docked with the International Space Station in June 2024.

The current Starliner mission, called Crew Flight Test (CFT), was originally scheduled to last about 10 days. It features two NASA astronauts: Butch Wilmore and Suni Williams. Both are former U.S. Navy test pilots with decades of experience in developmental missions like this spaceflight.

Wilmore told on May 1, ahead of launch, that the Navy gave the astronauts skills that are highly relevant to CFT, such as testing how systems work together. “Well, my goodness, that’s really the reason we’re here,” he said, reflecting on the duo’s thousands of hours of piloting experience. He later added that their experience has been “invaluable to the process” of working on Starliner.

CFT was designed to explore the unexpected in space, and has built-in flexibility in terms of scheduling. The additional ground tests are being conducted at the White Sands Test Facility in New Mexico to try to duplicate how the RCS thrusters were used during flight and especially during docking. (NASA waved off the first docking attempt on June 6, but authorized the second a few hours later.)


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Williams and Wilmore, meanwhile, are supporting the ISS astronauts with other tasks while they await the results of the White Sands test, which will last no less than two weeks. Recent NASA blog posts have detailed the CFT astronauts’ work on ISS maintenance: a few days of orbital plumbing, and then, more recently, staging items in the Permanent Multipurpose Module.

Williams and Wilmore also worked in the Japanese Experiment Module on Monday (July 1) “to disassemble an empty NanoRacks CubeSat Deployer in preparation for upcoming NanoRacks missions,” NASA officials wrote Monday (July 1).

Starliner’s first two space missions were unmanned. The first, in December 2019, failed to reach the ISS after computer glitches left it stranded in the wrong orbit. The second, in May 2022, reached the ISS safely after Boeing made dozens of repairs, but Starliner’s thrusters experienced a few problems; that’s another reason NASA and Boeing are taking their time with CFT’s return, to see why the spacecraft’s thrusters misbehaved in both 2022 and 2024.

Boeing is one of two suppliers for ISS astronaut missions, the other being SpaceX. Elon Musk’s company is using its Crew Dragon capsule, which is based on SpaceX’s Dragon cargo vehicle. Crew Dragon had a faster path to orbit: one uncrewed mission in 2019, followed by an astronaut flight test in 2020. Dragon has since sent 11 crews to the ISS, most of them on six-month operational crew rotation missions for NASA.

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