Body from Boeing Starliner spacecraft said Wednesday they are confident the capsule will bring them safely back to Earth at the end of a full stay in the International Space Station, despite helium leaks in the ship’s propulsion system and problems with maneuvering thrusters.
Launched June 5, commander Barry “Butch” Wilmore and co-pilot Sunita Williams originally expected to spend about eight days in space, putting the Starliner through its paces in the ship’s first piloted test flight.
But problems with helium and thruster leaks have prompted NASA to extend its stay on the space station indefinitely — Wednesday marked its 35th day in orbit — while engineers conduct tests and analyzes to better understand what’s causing the problem and to ensure the spacecraft is safe. so Wilmore and Williams home.
In the meantime, NASA insists the crew is not “stranded” in space, and Wilmore and Williams, speaking to reporters for the first time since the launch, appeared to agree with that assessment.
“I think where we are now, and what we know now, and how the spacecraft flies when we want to do the docking, I believe that we should, if there is a problem with the International Space Station. , we can enter the spacecraft and we can cancel, talk to the team, and figure out the best way to get home,” Williams said.
“I have a very good feeling that this spacecraft will take us home, no matter what,” he added. “Now we learn to make the most of certain situations and make sure we know everything about it.”
Asked about his faith in the Starliner, Wilmore said “we have absolute faith.”
“We actually did a thruster test when we spoke in White Sands, New Mexico, trying to replicate the (problems) we saw when we met,” he said. “And we’ll learn from that. And we’ll incorporate new processes, new procedures that we’ll use if necessary.”
But just to be on the safe side, Steve Stich, manager of NASA’s Commercial Crew Program, said the team had “destroyed” the originally developed plan when the Russian Soyuz spacecraft carrying NASA astronaut Frank Rubio to the station developed a coolant leak.
In that case, initial plans were made to be able to bring Rubio down in the SpaceX Crew Dragon capsule if worse came to worst. As it turned out, Russia launched a replacement for Soyuz and the plan was not needed.
“In that case, we decided to use the Dragon as a contingency return option for Frank … to use as a lifeboat,” Stich said. “We have the configuration of Frank in the middeck of the Dragon. I mean, of course we have dusted some of it to look relative to the Starliner, just to be prepared.
“But again, our main option is to return Butch on Suni in the Starliner. … We’re pretty far from where we are with the Soyuz. break out and come back.”
“Having a good time” in orbit after some delay
In the meantime, Williams said he and Wilmore are enjoying the extra time on board.
“We’re having fun here on the ISS,” he said. “You know, Butch and I have been up here before, and it feels like … back home. It feels good to be floating around. It feels good to be in space and to be up here with the International Space Station team.
“So, yeah, it’s great to be up here,” he said. “So I’m not complaining, Butch isn’t complaining that we’re here for a few extra weeks.”
Running four years behind schedule, Starliner launched on June 5, a month later than planned due to minor problems with the crew’s Atlas 5 booster, problems with the countdown computer and due to a small helium leak in the capsule’s rear service module. Helium is used to pressurize the Starliner’s propulsion system so that the jet can fire if necessary.
After extensive analysis, NASA and Boeing managers decided the leak was not a safety threat and the Starliner was cleared for launch.
Once in orbit and on the way to the space station, there were four more helium leaks. In addition, the Starliner’s flight computer took some of the jet’s back-to-back maneuvering off line when the telemetry did not match the set operating parameters.
One thruster was deemed unusable going forward, but the other was successfully retested. The “hot fire” test gave engineers confidence the jets needed for post-undocking maneuvers, and to keep the Starliner stable during critical de-orbit rocket firings, would be used to adjust the craft for re-entry.
The thrusters in question were facing the sun for a long time about the Starliner approach to the station and the engineers suspected that the problem experienced before was related to the high temperature and rapid firing during the final approach. They tried to duplicate these conditions in soil tests.
As for the helium leak, the propulsion system was not used when docking to the space station. The system was pressurized for the hot fire test, but otherwise the valve had been closed as planned to isolate the helium tank, eliminating additional leaks.
The system will be repressurized for undocking to enable the maneuvers required to return home. But engineers have said there is 10 times more helium in the tanks than needed for the return trip, providing a comfortable margin even if there is a leak known to be worse.
“I imagine we’re still going to do a test before canceling, so open the helium valve and the second time we open it to make sure everything is working properly, because it was planned from what we found during the thruster test,” Williams said. . “So I have confidence, Butch has confidence.”
All of the hardware in question was in the Starliner service module, which was ejected before entering the atmosphere. So, engineers won’t be able to check the equipment by hand first. Williams said they could only extend their mission to conduct as many tests as possible before returning home.
“If we just go home, we’ll lose the SM (service module) and then we won’t be able to go through all these tests and find out about our spacecraft,” he said.
Stich did not say whether the crew could be released to cancel. The next Crew Dragon crew rotation flight is scheduled to launch in mid-August and “a few days before that launch opportunity, we got to bring Butch and Suni on the Starliner.”
“So it’s kind of back-to-back,” he said. “We’re really trying to follow the data and see when is the earliest that we can target to undock and land. just follow the data (and) figure out when the opportunity to undock is right.