Already more than a month late getting back, two NASA astronauts will remain at the International Space Station until engineers finish working on problems plaguing their Boeing capsule, officials said Thursday.
Test pilots Butch Wilmore and Suni Williams were supposed to visit the orbiting lab for about a week and return in mid-June, but thruster failures and helium leaks on Boeing's new Starliner capsule prompted NASA and Boeing to keep them up longer.
NASA’s commercial crew program manager Steve Stich said mission managers are not ready to announce a return date. The goal is to bring Wilmore and Williams back aboard Starliner, he added.
“We'll come home when we're ready,” Stich said.
Stich acknowledged that backup options are under review. SpaceX's Dragon capsule is another means of getting NASA astronauts to and from the space station.
“NASA always has contingency options," he said.
Engineers last week completed testing on a spare thruster in the New Mexico desert and will rip it apart to try to understand what went wrong ahead of the Starliner's docking. Five thrusters failed as the capsule approached the space station on June 6, a day after liftoff. Four have since been reactivated.
It appears degraded seals are to blame for the helium leaks and thruster problems — entirely separate issues — but more analysis is needed. The team will test-fire the capsule's thrusters this weekend while docked to the space station to gather more data, said Boeing’s Mark Nappi.
Each of the 28 maneuvering thrusters can fit in a hand and weighs 2 pounds (1 kilogram). The capsule is also outfitted with bigger engines for dropping out of orbit at flight's end. All these are part of a segment that is discarded before landing, which means nothing to study for future flights.