NASA astronauts Butch Wilmore and Suni Williams are still stuck aboard the International Space Station — and plans for their return to Earth are becoming increasingly complicated.
The duo set off in June aboard Boeing’s troubled Starliner for an eight-day test mission. But the spacecraft, which had been delayed and plagued with problems before it even took off, ran into some issues during its flight, leading engineers to delay the mission to fix them.
NASA said it was not yet certain whether the Starliner could safely bring its crew back as planned. The crew may be forced to return home in February, aboard a SpaceX spacecraft.
Why are astronauts stuck?
It all comes down to whether Boeing’s Starliner can get them home safely. They were supposed to return in eight days, but safety fears have repeatedly delayed that return, and they’ve now been here for more than two months.
NASA stressed that the astronauts are not strictly grounded: in the event of an emergency on board the space station, they could, for example, return home.
What are the problems with the Starliner?
The main problem is the thruster failures that occurred when Starliner docked with the space station in June. Engineers are also concerned about leaks of helium, the element used to pressurize the thrusters.
Boeing has been testing the spacecraft remotely to try to understand the problems and find solutions, hoping to reassure NASA that it is possible to bring its astronauts home safely. But those tests have revealed more problems, leading NASA to say the return is in doubt.
How will the astronauts get home?
Boeing remains hopeful that concerns about the Starliner will be resolved. “We continue to believe in the capabilities of the Starliner and its flight logic,” the company said.
NASA has made it clear that it is still working with the company “to assess the readiness of the spacecraft, and that no decision has been made regarding Starliner’s return.” That decision may not be made until August.
If it goes in Boeing’s favor, the astronauts will return home as planned, but on a different schedule.
But if engineers can’t figure it out, the two astronauts will be able to return home on a SpaceX flight. That mission is scheduled for late September and is currently scheduled to carry four astronauts. But if necessary, two of them will be left behind and those seats will be filled by the Starliner test crew.
This team is expected to return in February, so the two test drivers will return with them early next year.
Is it a problem?
Most of the current concerns are about Starliner’s safety if it stays that long, and the fear that it will run out of resources if it is delayed too long. Starliner is scheduled for a 90-day stay and has been at the space station for 63 days, so time is of the essence.
NASA has been able to send additional supplies in the meantime to keep the astronauts comfortable. This week, a SpaceX rocket carried a resupply capsule made by Northrop Grumman that contained food and supplies, including more food and clothing for the two Starliner test pilots.
The space station is capable of serving as a home for a long time — NASA astronaut Frank Rubio holds the record, at 371 days, far longer than the Starliner crew will have to stay — and space agency officials seem confident that a longer stay will be safe.
What will happen to the Starliner if the astronauts descend by another route?
Boeing said that if astronauts were to return to Earth on another flight, it would “take the necessary steps to configure Starliner for an uncrewed return.” That would include reconfiguring the software so Starliner can return to Earth without a crew.
This will need to be done because it will free up the docking port that will be used by the incoming SpaceX ship.
This likely means that at least most of the ship will be destroyed upon entering Earth. This was always the plan, and is one of the reasons for the delay: engineers will lose most of the spacecraft as it travels through the atmosphere, and so want to keep it intact for longer to better understand what might have happened.
Did this affect other missions?
Yes, this is already the case – even if further measures will not be necessary in the future.
Another group of four astronauts were supposed to launch this month, but they will leave next month, NASA announced this week. There are only two docking ports for American capsules on the space station, and both are currently occupied, as the Starliner has been there longer than expected.
It also means that SpaceX’s four-person crew that arrived in March will be staying longer than expected.
