Return of the Boeing Starliner to Earth is suspended indefinitely NASA announced Friday that they are awaiting test results of the new thrusters and an ongoing analysis of the helium leaks that occurred during the spacecraft’s encounter with the International Space Station.
But agency officials insisted that Starliner commander Barry “Butch” Wilmore and co-pilot Sunita Williams were not “stuck” in space.
NASA
“We don’t have a target (landing) date today,” Steve Stich, NASA’s commercial crew program manager, told reporters during a teleconference. “We will not target a specific date until we have completed testing.
“So basically it’s to finish the testing, finish the fault tree, take that analysis to the (mission management team) and then do an agency-level review. And then we’ll lay out the rest of the plan from disengagement to landing. I think we’re on the right track.”
The a problem for NASA and Boeing is that the Starliner’s service module, which houses the helium lines, thrusters and other critical systems, is ejected and burns up in the atmosphere before re-entry.
The engineers won’t be able to study the hardware after that, so they want to collect as much data as possible before Wilmore and Williams head home.
But the crew’s repeated extended stays on the space station as this analysis continued prompted some observers to say that Wilmore and Williams were stuck in orbit, a perception that appears to have taken root due to the absence of updates from NASA, as the target date the landing was determined. repeatedly pushed back.
Stich and Mark Nappi, Boeing’s Starliner program manager, said the description is a mischaracterization.
“It’s pretty painful to read the stuff that’s out there,” Nappi said. “We’ve had a really good test flight…and it’s being viewed rather negatively. We’re not stuck on the ISS. There’s no danger to the crew and no increased risk if we decide to bring Suni and Butch back.” to the ground.”
Stich added that he “wants to make it very clear that Butch and Suni are not stuck in space. Our plan is to continue to get them back on the Starliner and bring them home at the right time. We’ll have a little more work to do.” do to get there for the final return, but they are safe on the space station, their spacecraft is working well, and they are enjoying their time on the space station.”
Starliner launched on June 5 in the program’s first manned test flight with one known helium leak. The other four developed during the ship’s rendezvous with the space station, when the thrusters were rapidly pulsed to fine-tune the Starliner’s approach.
United Launch Alliance
When docking with the station, the valves are closed to isolate the helium system, eliminating further leaks. But once Wilmore and Williams leave and head home, the valves open again to repressurize the line or pipes.
Stich said that despite 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 repressurized.
The five rear thrusters in 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 jets were successfully tested and, despite slightly lower than expected performance levels, are considered fit for disengagement and re-entry. The fifth funnel was not “hot fired” because its earlier performance indicated that it had indeed 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 as the ones in orbit were fired during Starliner rendezvous and docking.
“We’re going to recreate that profile,” Stich said. “Then we put a pretty aggressive profile in the nozzle for the (disengagement and re-entry) phase.
NASA
It is possible that the rear thruster malfunctions were caused by higher-than-normal temperatures due to the Starliner’s orientation relative to the sun, or sequences of rapid, repetitive shots dictated by the flight software. Or both.
Ground tests, which are expected to last “a few weeks,” may provide evidence one way or the other.
“It’s going to be a real opportunity to examine the jet like we’ve had in space on the ground, a detailed inspection,” Stich said. “Once the testing is done, we’ll look at the landing plan.
As for the impression that the crew is stuck in space, both Stich and Nappi pointed out that on Wednesday, a defunct Russian satellite in a slightly lower and more inclined orbit than the space station suffered a catastrophic “event” that produced more than 100 pieces of trackable debris .
While flight controllers evaluated the trajectory of the debris, the space station’s nine-person crew was instructed to “shelter in place” aboard the appropriate spacecraft, ready to immediately depart and return to Earth in the event of a damaging impact.
Two Russian cosmonauts and NASA’s Tracy Dyson boarded their Soyuz shuttle, while three NASA astronauts and another cosmonaut boarded their SpaceX Crew Dragon. Wilmore and Williams exited the safe haven inside the Starliner and were cleared to fly home if warranted.
After about an hour, the crew was given the all clear to return to normal work. Had the Starliner been deemed unsafe, Wilmore and Williams would likely have been told to seek refuge in the Crew Dragon. But it wasn’t like that.
“We have permission to be a lifeboat in an emergency on the ISS,” Nappi said. “That means we can come back with the Starliner at any time, and that was confirmed this week.