Two NASA astronauts who traveled to the International Space Station in early June were originally scheduled to return home a couple of weeks ago, completing a test flight of Boeing’s Starliner spacecraft.
Instead, astronauts Butch Wilmore and Suni Williams will remain on the station for several more weeks as NASA and Boeing engineers continue to study the malfunctioning vehicle’s thrusters.
But don’t call for trapped or stranded astronauts, officials said Friday. And there’s no talk of a rescue mission.
“We are not stranded on the International Space Station,” Mark Nappi, Starliner program manager at Boeing, said during a news conference on Friday. “The crew is not in any danger.”
Steve Stich, director of NASA’s commercial crew program, also attempted to allay concerns.
“The vehicle on station is in good condition,” he said. “I want to make it very clear that Butch and Suni are not stranded in space. Our plan is to continue to bring Starliner back and return them home at the appropriate time.”
Stich later added that the right time would be after additional analysis into why five of Starliner’s 28 maneuvering planes behaved strangely as the spacecraft approached the space station. Starliner’s computers, which guided the ship autonomously, were able to compensate with the remaining thrusters.
Four of the five thrusters now appear to be working correctly; the other thruster will not be used during the trip home. Mission officials hope that Starliner can undock from the space station and take Mr. Wilmore and Ms. Williams on their return trip from space, but they don’t fully understand what caused the problem.
Fatal disasters in NASA history, such as the loss of the space shuttles Challenger and Columbia, have taught mission managers to be cautious and curious when something isn’t quite right.
“I think they’re doing their job,” Wayne Hale, a retired NASA flight director, said in an interview. “Since they are in no rush to get home, it makes perfect sense to take the time to gather as much information as possible to make sure all issues are resolved. It makes a lot of sense to take the time.”
Mr. Nappi offered a similar assessment during Friday’s news conference, saying it was prudent to use the time for further analysis.
“It would be irresponsible of us, if we have time and want to do more, not to do so,” he said.
Starting next week, engineers will conduct ground tests at NASA’s White Sands Test Facility in California using a booster identical to those on the Starliner. The shots will reproduce those made by Starliner in space.
That will likely take a couple of weeks, Stich said. “Then we’ll give engineers a chance to examine that booster,” he said. “This will be the real opportunity to examine a booster, just like we’ve done in space.”
Engineers will not be able to directly examine the problematic thrusters on the spacecraft currently in orbit because they are located in what is known as the service module. That part will be discarded during the flight home and burned up in the atmosphere.
“The test will help us understand the performance of the booster and can give us 100 percent confidence that everything we’ve seen in orbit is OK,” Stich said. “It’s just one more piece of data we can have before we actually deorbit the vehicle.”
Former NASA officials like Hale said mission managers’ dismissal of engineers’ concerns contributed to previous fatal accidents.
During the launch of the space shuttle Columbia in January 2003, a piece of foam insulation from the external fuel tank broke off and struck the shuttle’s left wing. Mr. Hale, who was about to begin a new position as launch integration manager for the shuttle program, called Defense Department contacts to ask if they had the capability to visually inspect the shuttle for damage.
But managers higher up NASA’s chain of command were not curious and told Hale to retract the request for help. He obeyed.
What no one knew at the time was that the impact of the foam had punctured a wing. Upon returning to Earth, Columbia disintegrated and all seven astronauts on board died.
“In retrospect, in the Columbia case, not enough questions were asked,” Hale said. “Not enough time was spent. And the lesson that has been clearly learned is that you have to take the time available to get to the most complete answer and answer all the questions that the experts may have.”
While NASA and Boeing study the spacecraft, NASA’s Stich said, Wilmore and Williams could hop aboard Starliner to return home in the event of an emergency at the space station. In fact, when a crippled Russian satellite unexpectedly disintegrated in orbit Thursday, they briefly took refuge in the vehicle and would have used it if the space station had been hit by a large piece of debris.
The capsule is currently certified to spend 45 days docked with the space station, due to limitations of the current Starliner battery design. But so far the batteries have worked well and the stay can last more than 45 days, Stich said.
Starliner isn’t the only problem NASA has to solve right now. On Monday, a spacewalk was cut short when water leaked from the umbilical cord connecting the spacesuit while astronauts were in the airlock. Engineers still don’t understand what happened.
“We have to think about it a little more,” said Bill Spetch, NASA operations integration manager for the International Space Station program.
The next spacewalk, which was scheduled for Tuesday, won’t happen until at least late July, Specht said.
