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After weeks of troubleshooting and recent tests meant to replicate the issues plaguing Boeing’s Starliner spacecraft, NASA and Boeing officials still aren’t ready to name a return date for the two astronauts piloting the vehicle on its inaugural crewed test flight.
Engineers do finally have some possible answers about what ultimately caused some of the Starliner’s problems during the first leg of its trip, which included helium leaks and thrusters that unexpectedly quit working.
The revelations come after Boeing and NASA spent the past couple of weeks working to understand the problem on the ground.
At a site in New Mexico, engineers fired test engines more than 1,000 times, replicating how the thrusters on the space-bound Starliner would have ignited. They then fired the thruster to try out several ways the engines might fire on the way home from space, according to Boeing.
The goal of this testing was to gain a better understanding of why the spacecraft’s thrusters unexpectedly shut down, and what — if any — dangers are associated with turning those thrusters back on.
Officials said they were able to replicate how the thrusters in space deteriorated during flight with the ground tests. And the testing may have helped give engineers a better understanding of the issue’s “root cause”: Heat building up inside the thrusters may be causing Teflon seals to bulge, restricting the flow of propellant.
That testing has “given us additional confidence to undock in return,” said Mark Nappi, Boeing’s Commercial Crew Program manager.
Still, officials did not definitively say Thursday that the Starliner spacecraft that carried veteran NASA astronauts Butch Wilmore and Suni Williams to the International Space Station would be the same vehicle that brought the astronauts back home.
“There is a lot of good reasons to complete this mission and bring Butch and Suni home on Starliner,” Stich said after noting that NASA does have contingency options if Starliner is not approved to bring the astronauts home.
“We need to get through the process right,” he added. “We have another critical Starliner mission management team to review all the thruster data that we just talked about.”
“Of course, I’m very confident we have a good vehicle to bring the crew back with,” Nappi said.
As of Thursday, the astronauts have been in space for about 50 days. NASA has previously indicated that the Starliner can stay in space for a maximum of 90 days.
Additional Starliner testing
Separately, engineers may have made headway understanding helium leaks that hampered the first leg of Starliner’s journey. But Boeing and NASA will take a close look at that issue again during additional testing of the vehicle that will continue this weekend, Stich said.
“The key attributes of the flight rationale really are that we understand the helium leaks — we understand the stability of the leaks and how we can manage those, should they get bigger,” Stich said.
That testing will include firing 27 of the Starliner’s thrusters while the vehicle remains docked with the ISS in space.
NASA and Boeing also plan to carry out a review to plan for Starliner’s undocking, which “could be as early as late next week,” according to NASA’s Commercial crew program manager, Steve Stich.
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