Return to Earth of Boeing’s Starliner capsule is on hold indefinitely Pending the results of new thruster tests and ongoing analysis of helium leaks that appeared during the shuttle’s rendezvous with the International Space Station, NASA announced Friday.
But agency officials insisted that Starliner commander Barry “Butch” Wilmore and co-pilot Sunita Williams are not “trapped” in space.
NASA
“We don’t have a target (landing) date today,” Steve Stich, manager of NASA’s Commercial Crew Program, told reporters during a teleconference. “We’re not going to target a specific date until we complete that testing.
“So basically, it’s complete the testing, complete the fault tree, bring that analysis to the (mission management team) and then we have an agency-wide review. And then we’ll lay out the rest of the plan from landing unlock I think we’re on a good track.”
of problem for NASA and Boeing is that the Starliner’s service module, which houses the helium lines, thrusters and other critical systems, ejects before re-entry and burns up in the atmosphere.
Engineers won’t be able to study the hardware after the fact, and as a result, they want to collect as much data as possible before Wilmore and Williams go home.
But the crew’s repeatedly extended stay on the space station while that analysis has continued has led some observers to say that Wilmore and Williams are stuck in orbit, an impression that appears to have taken root in the absence of updates from NASA. as the intended landing date had been repeatedly pushed back.
Stich and Mark Nappi, Boeing’s Starliner program manager, said the description is a mischaracterization.
“It’s very painful to read the things that are there,” Nappi said. “We’ve had a really good test flight…and it’s being viewed quite negatively. We’re not stuck on the ISS. The crew is in no danger and there’s no added danger when we decide to bring Suni and Butch. back to Earth.”
Stich added that he wants to “make it very clear that Butch and Suni are not stranded in space. Our plan is to continue to get them back to the Starliner and get them home in due time. We’ll have some more work to do to get there for the final return, but they are safe on the space station.
Starliner launched on June 5 on the program’s first test flight with a now-familiar helium leak. The other four took place during the shuttle’s rendezvous with the space station when the jets flashed rapidly to fine-tune the Starliner’s approach.
United Launch Alliance
While docked to the station, the valves are closed to isolate the helium system, eliminating any additional leakage. But once Wilmore and Williams leave and head home, the valves will reopen to pressurize the lines or manifolds.
Stich said that even with the known leaks, the spacecraft will have 10 times the amount of helium it needs to get home, but engineers want to make sure the leaks don’t get worse once the system is pressurized again.
The five aft-facing thrusters on the Starliner’s service module also failed to function as expected during the June 6 approach to the space station.
After docking, four of the five aircraft were successfully tested, and despite slightly lower than expected power levels, they are considered good for disengagement and reentry. The fifth impeller was not “running hot” because previous performance indicated that it had actually failed.
But managers want to find out what caused the unexpected behavior in the other four. Starting next week, a new thruster identical to the ones aboard Starliner will be tested at a government facility in White Sands, New Mexico, just like the ones in orbit that were launched during Starliner’s rendezvous and docking.
“We’re going to recreate that profile,” Stich said. “Then we’ll put a pretty aggressive profile on the propellant for the (re-entry unlock) phase.”
NASA
It is possible that the failures with the front thrusters were caused by higher than normal temperatures due to the orientation of the Starliner with respect to the sun, or the sequence of rapid and repeated firings commanded by the flight software. Or both.
Ground tests, expected to last “two weeks”, could provide evidence one way or the other.
“This will be a real opportunity to examine a propellant like we’ve had in space on Earth, a detailed inspection,” Stich said. “Once that testing is done, then we’ll look at the landing plan.”
As for the impression that the crew is stranded in space, Stich and Nappi noted that on Wednesday, a missing Russian satellite in a slightly lower and more inclined orbit than the space station suffered a catastrophic “event” that produced more than 100 pieces. traceable waste.
As flight controllers assessed the trajectories of the debris, the space station’s nine-member crew were told to “shelter in place” in their respective spacecraft, ready to immediately launch and return to Earth in the event of an impact. harmful.
Two Russian cosmonauts and NASA’s Tracy Dyson boarded their Soyuz shuttle, while three NASA astronauts and another cosmonaut floated aboard the SpaceX Crew Dragon. Wilmore and Williams emerged from a safe haven inside the Starliner and were allowed to fly home if necessary.
After about an hour, the crew was given the go-ahead to return to normal work. If the Starliner had been deemed unsafe, Wilmore and Williams likely would have been told to seek refuge on Crew Dragon. But it wasn’t like that.
“We have an approval to be an emergency lifeboat on the ISS,” Nappi said. “That means we can get back on the Starliner at any time, and that was proven this week.”