Boeing’s Starliner capsule is performing well enough on its first astronaut mission that it will likely be able to stay in orbit beyond the original 45-day limit, NASA says.
Starliner, which launched on June 5, is docked at the International Space Station (ISS) for an indefinite mission extension. The spacecraft is in good condition and is designed to leave the ISS in the event of an emergency. But both NASA and Boeing are trying to figure out why some of the Starliner’s Reaction Control System (RCS) thrusters had problems in the run-up to 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 later this summer while testing and analysis continues. For example, a new round of ground thruster tests will begin soon, perhaps as early as today (July 2).
On-orbit tests 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: the helium leaks had been stabilized and all but one of the faulty thrusters were rated safe. use to return to Earth. (The 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.)
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 take time to figure out how to proceed. That will be critical for any service module design changes that will be needed for future, six-month rotation missions to the ISS that Starliner will fly as soon as 2025. But to give ground crews time to test, NASA says , that the Starliner must remain docked for more than 45 days, which was the original outer limit for this mission. The good news is that the spacecraft looks good enough to be able to travel for perhaps double that time — or more.
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“We’ve talked about a 45-day limit limited by the Starliner crew module batteries, and we’re in the process of updating that limit,” Steve Stich, NASA’s commercial crew program manager, told reporters during a Friday teleconference.
“We were looking at these batteries and their performance in orbit. They recharge from a 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 expected to remain in orbit for up to 210 days after operational missions begin, he said. But since this is only the Starliner’s third mission in space and its first mission with astronauts, NASA wasn’t sure about the battery’s performance in orbit until now.
When Space.com asked how long the mission could last, Stitch 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 there were 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 current Starliner mission, called the Crew Flight Test (CFT), was originally supposed to last about 10 days. It stars two NASA astronauts: Butch Wilmore and Sunny Williams. Both are former US Navy test pilots with decades of experience in development missions like this space flight.
Wilmore told Space.com on May 1, before launch, that the Navy has given the astronauts skills that are highly relevant to CFT, such as testing how systems work together. “Well, for God’s sake, that’s really why we’re here,” he said, reflecting on the duo’s thousands of hours of piloting experience. He later added that their experience was “invaluable to the process” of working on the Starliner.
CFT is designed to explore the unexpected in space and has built-in planning flexibility. Additional ground tests will be performed at the White Sands Test Facility in New Mexico to try to duplicate the way the RCS thrusters were used during flight and especially during docking. (NASA rejected the first docking attempt on June 6, but cleared the second a few hours later.)
Meanwhile, Williams and Wilmore are supporting the ISS astronauts on other tasks while they await the results of the White Sands tests, which will take at least two weeks. Recent NASA blog posts detail the work of CFT astronauts maintaining the ISS: orbital plumbing for several days, then more recently organizing items into the permanent multipurpose module.
Williams and Wilmore also worked at the Japan 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).
The first two Starliner space missions were aborted. The first, in December 2019, failed to reach the ISS due to computer problems that stuck it in the wrong orbit. The second, in May 2022, reached the ISS safely after Boeing made dozens of fixes, but the Starliner’s engines had several problems; this is another reason NASA and Boeing are not rushing the CFT return to see 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.
