The Boeing Starliner capsule is doing well enough on its first-ever astronaut mission that it will likely be able to stay in orbit beyond the originally projected 45-day limit, NASA says.
The Starliner, which launched on June 5, is docked at the International Space Station (ISS) indefinitely. The spacecraft is in good condition and is intended to leave the ISS in the event of an emergency. But both NASA and Boeing are trying to understand why some of the Starliner’s Reaction Control System (RCS) thrusters experienced problems before docking with the ISS on June 6, and why the capsule experienced several helium leaks. As such, the Starliner will remain in space until at least the end of the summer as testing and analysis continues. For example, a new round of ground tests of the jets will begin soon, possibly as early as today (July 2).
On-orbit testing on June 15 failed to find the root cause of the problems, although agency officials stressed on Friday (June 28) that progress had been made: helium leaks have stabilized and all but one of the faulty thrusters are rated as usable for return to Earth. (The Starliner has a total of 28 thrusters in its RCS; five misbehaved, and of those five, only one will be disengaged during disengagement.)
Since the RCS is in the Starliner’s service module, which will be jettisoned before entry, descent and landing, the extra time in orbit will allow the teams to understand how to proceed. This will be key to any service module design changes needed for future six-month ISS spin missions that Starliner will undertake as early as 2025. But to give ground teams time to test, NASA says Starliner must remain docked for more than 45 days , which was the initial outer limit for this mission. The good news is that the spacecraft looks good enough to last maybe twice that time – or more.
Related: Thruster malfunctions and helium leaks can’t stop Boeing Starliner astronauts’ test flight — but why do they happen?
“We’ve talked about a 45-day limit, limited by the crew module batteries on the Starliner, and we’re working to update that limit,” Steve Stich, NASA’s commercial crew program manager, told reporters during a teleconference Friday.
“We looked at those batteries and their performance in orbit. The stations are recharging and that risk hasn’t really changed. So the risk for the next 45 days is pretty much the same as the first 45 days.” ” he said.
He pointed out that the Starliner is actually supposed to stay in orbit for 210 days once operational missions begin. But since this is only the Starliner’s third mission in space and the first with astronauts, NASA was not yet sure of the battery’s performance in orbit.
When asked by Space.com how long the mission could continue, Stich said, “We haven’t decided how long to extend it yet.” The Starliner has 12 different batteries, he explained. Before this flight, similar batteries sat on the ground for a year and were then tested to make sure they showed no defects, and none were found.
“What we’re really doing now is monitoring battery performance in flight. We don’t see any degradation in any of the cells where the batteries are,” he added.
The Starliner’s current mission, called the Crew Flight Test (CFT), was originally supposed to last about 10 days. It features two NASA astronauts: Butch Wilmore and Suni Williams. Both are former US Navy test pilots with decades of experience working on development missions like this space flight.
Wilmore told Space.com on May 1 before launch that the Navy provided the astronauts with skills highly relevant to CFT, such as testing how systems work together. “Well, gosh, that’s really why we’re here,” he said, reflecting on the pair’s thousands of hours of piloting experience. He later added that their experience was “invaluable to the process” while working on the Starliner.
CFT was meant to explore the unexpected in space and has built-in flexibility when it comes to planning. Additional ground tests will be conducted at the White Sands Test Facility in New Mexico to try to mimic how the RCS thrusters were used in flight and especially during docking. (NASA waved off the first docking attempt on June 6, but allowed the second a few hours later.)
Meanwhile, Williams and Wilmore are supporting the ISS astronauts on other missions while they await the results of the White Sands test, which will take no less than two weeks. Recent posts on the NASA blog have detailed the work of CFT astronauts on ISS maintenance: an orbital installation for several days, then organizing items in the Permanent Multipurpose Module.
Williams and Wilmore also worked Monday (July 1) at the Japanese Experiment Module “to dismantle the empty NanoRacks CubeSat Deployer in preparation for upcoming NanoRacks missions,” NASA officials wrote Monday (July 1).
The first two Starliner space missions were shut down. The first, in December 2019, failed to reach the ISS due to computer glitches that stuck it in the wrong orbit. The second, in May 2022, reached the ISS safely after Boeing made dozens of repairs, but the Starliner’s thrusters experienced several problems; this is another reason NASA and Boeing are taking their time with the CFT return to find out why the spacecraft’s thrusters misbehaved in both 2022 and 2024.
Boeing is one of two suppliers for astronaut missions to the ISS, the other being SpaceX. Elon Musk’s company uses 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. Since then, Dragon has sent 11 crews to the ISS, most of them on six-month operational crew rotation missions for NASA.