Boeing’s Starliner capsule performed well enough on its first astronaut mission that it could likely stay in orbit beyond its originally planned 45-day limit, NASA said.
Starliner, launched on June 5, is docked with the International Space Station (ISS) for an indefinite period. The spacecraft is in good condition and is scheduled to depart the ISS in the event of an emergency. But NASA and Boeing are trying to figure out why some of Starliner’s reaction control system (RCS) thrusters developed problems before it docked with the ISS on June 6, and why several helium leaks appeared in the capsule. Starliner will remain in space at least through the end of the summer, while testing and analysis continue. For example, a new round of ground thruster tests will begin soon, possibly as early as today (July 2).
Tests conducted on June 15 in orbit failed to find the root cause of the problems, though agency officials stressed Friday (June 28) that progress had been made: The helium leaks have stabilized and all but one of the faulty thrusters are fit to return to Earth. (Starliner has 28 thrusters in total in its propulsion system; five of them were misbehaving, and of those five, only one will be disabled during undocking.)
With the RCS integrated into Starliner’s service module, which will be jettisoned before the spacecraft enters, descends, and lands, the extra time in orbit will allow teams to take their time figuring out how to do it. That will be crucial for any changes to the service module design that will 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 needs to stay docked for more than the 45 days that was the original limit for this mission. The good news is that the spacecraft appears ready to be used for perhaps double that time, if not longer.
Related: Propellant Problems, Helium Leaks Can’t Stop Boeing’s Starliner Astronaut Test Flight — But Why Are They Happening?
“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 on Friday’s teleconference.
“We’ve looked at these batteries and how they perform in orbit. They’re recharged by 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.
In fact, Starliner is expected to stay in orbit for up to 210 days once operational missions begin, he noted. But because this is only Starliner’s third mission to space, and the first with astronauts, NASA wasn’t sure until now how the battery would perform in orbit.
When Space.com asked how long the mission might last, Stich said, “We haven’t decided how long the extension will be.” Starliner has 12 different batteries, he said. Before this flight, similar batteries were on the ground for a year and then tested for defects, and none were found.
“What we’re actually doing now is looking at the battery performance in flight. We’re not seeing 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 scheduled to last about 10 days. It features two NASA astronauts: Butch Wilmore and Suni Williams. Both are former U.S. Navy test pilots and have decades of experience on development missions like this spaceflight.
On May 1, before the launch, Wilmore told Space.com that the Navy had given the astronauts skills that would be very useful for the CFT, such as testing how systems work together. “Well, that’s really why we’re here,” he said, referring to the duo’s thousands of hours of piloting experience. He later added that their experience had been “invaluable to the process” of working on Starliner.
The CFT was designed to address contingencies in space and provides some flexibility in terms of planning. Additional ground tests will be conducted at the White Sands Test Facility in New Mexico to try to replicate how the RCS thrusters were used during flight and especially during docking. (NASA canceled the first docking attempt on June 6 but authorized the second a few hours later.)
Williams and Wilmore, meanwhile, are assisting the ISS astronauts with other tasks while they await the results of the White Sands tests, which will take as long as two weeks. Recent NASA blog posts have detailed the work of the CFT astronauts on ISS maintenance: orbital plumbing for a few days, and more recently organizing the elements of 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 uncrewed. The first, in December 2019, failed to reach the ISS because of computer glitches that left it stuck in the wrong orbit. The second, in May 2022, reached the ISS safely after Boeing made dozens of repairs, but Starliner’s thrusters have had some issues; another reason NASA and Boeing are taking their time with the CFT return, to figure out why the spacecraft’s thrusters misbehaved in 2022 and 2024.
Boeing is one of two providers of astronaut missions to the ISS, the other being SpaceX. Elon Musk’s company is using its Crew Dragon capsule, based on SpaceX’s Dragon cargo vehicle. Crew Dragon took a faster path to orbit: an uncrewed mission in 2019, followed by an astronaut flight test in 2020. Dragon has sent 11 crews to the ISS since then, most of them on six-month operational crew rotation missions for NASA.