NASA’s Sunita Williams and Butch Wilmore, who have spent over a month in space, are capable of returning to Earth in case of an emergency, or on a spacecraft other than Boeing’s Starliner. But there’s catch. And what if thrusters on spacecraft malfunction on return mission?
Are NASA astronauts Sunita Williams and Butch Wilmore really “stuck” in space or is it their choice to spend more time in weightlessness than scheduled? Here’s a deep dive into two factors that may explain the idea behind Starliner astronauts’ extended stay in space.
1. Starliner could return ‘if absolutely necessary’
First, Steve Stich, manager of NASA’s Commercial Crew Program, said earlier this month, “Starliner is ‘go’ to return in an emergency.” His statement came as NASA maintained that Starliner could still return astronauts to Earth if absolutely necessary.
But in what conditions would Sunita Williams and Butch Wilmore be brought back from space? The “absolutely necessary” situation will arise if the Starliner capsule must serve as an escape pod from the ISS in an emergency or if any of Starliner’s perishable items – such as its solar panels – show signs of expiring earlier than planned, Reuters reported.
Wilmore said that on July 10, two astronauts tested a “Safe Haven procedure,” sheltering inside Starliner in the event they needed to suddenly undock from the ISS. The test went well, he said.
Meanwhile, Sunita Williams explained one of the checks for Starliner involved practicing for safe haven “to make sure that we have all the emergency equipment laid out and we need to have to get into or spacecraft and use it as a safe haven – in case something happens to the space station,” she said.
An official also spoke about how they will return to Earth if they were to do it today. On July 10, the official said that if they were to do the “undocking today”, they would just perform a nominal undocking and return. He said that the propulsion system is highly redundant on each other. “So if there was an issue in any one of the thrusters, the redundance will take over and bring us safely home,” he added.
2. Starliner is not the only option NASA has to bring back astronauts
If not Boeing’s Starliner, NASA also has the fallback option to bring back the two astronauts quickly from space using a rival company’s spacecraft, SpaceX’s Dragon spacecraft, if there were a true emergency.
The Crew Dragon ferried four astronauts to the station in March and is able to fit more people in an emergency. But the use of Crew Dragon seems unlikely. SpaceX is Boeing’s competitor.
However, NASA focuses on safely returning Williams and Wilmore to Earth, and the prime option is to return on Boeing’s Starliner capsule.
On August 2, Boeing said in a statement that it “remains confident in the Starliner spacecraft and its ability to return safely with crew”.
So, why are Starliner astronauts overstaying in space?
Earlier this month, Wilmore said that human space flight is not easy in any regime and there have been multiple issues with every spacecraft that has ever been designed, and “that’s the nature of what we do”.
“The mantra you have heard that failure is not an option, that’s why we are staying here now,” he had said.
On their extended stay in space, Wilmore added the crew faced degradation in the thrusters. “And that’s why we are staying because we are going to test it…We are going to get the data we need to help inform our decision so we make the right decision,” he said.
LIVE from the @Space_Station: @NASA_Astronauts Butch Wilmore and Suni Williams discuss their @BoeingSpace #Starliner Crew Flight Test mission. https://t.co/Tsp7CjfjU7
— NASA (@NASA) July 10, 2024
Meanwhile, Sunita Williams explained why studies on Starliner were important. She said that the service module (SM), where the thrusters are situated, will detach from the capsule and burn up in the atmosphere. This would mean the end of being able to study how they react in space.
“We have practised a lot, and I have a real good feeling that the spacecraft will bring us back home…we are learning now to optimize our specific situation to make sure that we know everything about it [the spacecraft]…,” Sunita Williams said on July 10, in her first interaction with media after Starliner launch.
NASA had earlier rescheduled the planned return three times, and now has no date set for it. As per a Reuters report, Starliner could stay docked at the ISS for up to 72 day while relying on various backup systems.
Why Starliner’s return delayed: ‘Helium leaks, thruster anomalies’
Starliner, which was supposed to return around mid-June, has now been in space for over 50 days as the crew pursues fixes mid-mission.
The team, in space and on ground, has been conducting thruster testing and working on a return flight readiness review to prepare for Starliner’s eventual undocking and landing.
Starliner launched on June 5 on Crew Flight Test (CFT), carrying Butch Wilmore and Suni Williams to the International Space Station (ISS) for a planned week-long stay. The spacecraft reached the ISS on June 6.
During the trip, Starliner experienced helium leaks and thruster anomalies – which delayed the spacecraft’s return. The capsule has had five helium leaks, five maneuvering thrusters go dead and a propellant valve fail to close completely.
Starliner’s propulsion system is part of the craft’s “service module”. The problems center on this system, which is needed to back the capsule away from the ISS and position it to dive through Earth’s atmosphere, Ruters reported.
Many of Starliner’s thrusters have overheated when fired, and the leaks of helium – used to pressurize the thrusters – appear to be connected to how frequently they are used, according to Stich.