Imagine this: It’s June 5th, and you’re an astronaut aboard a test flight with astronauts Butch Wilmore and Suni Williams. The flight is headed for the International Space Station (ISS). Everything runs smoothly from liftoff to space, but things go awry with the thrusters and helium just before docking. The spacecraft is too hazardous to return to Earth, leaving you stranded. What was originally intended to be an eight-day stay will surely become much longer.
This is the reality of Barry “Butch” Wilmore and Sunita “Suni” Williams. Boeing’s Starliner capsule brought astronauts into space, yet could not return with them. The capsule successfully landed on Earth on September 6, 2024, but the mission was not a complete success. Instead, the astronauts will come home on a SpaceX Crew Dragon Capsule. The change of plans means the astronauts will remain at the space station until February, extending the anticipated stay from eight days to eight months. Dana Weigel, a member of the International Space Station, announced that the astronauts are adapting well to their lengthened mission. Both of them have completed long-duration stays in space in the past. Weigel added that they now have all the supplies needed for their extended eight-month stay. However, NASA is now investigating what exactly went wrong with the spacecraft’s docking.
Starliner’s issues began a day after takeoff from Cape Canaveral in Florida on June 5, 2024. One problem Starliner experienced was malfunctioning thrusters, which, even on its own, could have hindered a safe journey home. When Starliner approached the ISS, five of its 28 reaction control system thrusters malfunctioned, impeding its docking for nearly an hour. These thrusters move the capsule around in orbit, adjusting its position while it docks and undocks with the space station.
Four of the five thrusters were restored so that the astronauts could arrive at the space station, but NASA needed to investigate the malfunction regardless. NASA and Boeing engineers used a test engine to examine the thrusters’ performance. The engine and its thrusters were put under conditions similar to those the capsule experienced while traveling to the ISS. Mission members conducted a “hot fire test” as well, firing the Starliner’s thrusters in short bursts while it was docked at the ISS. The preliminary results showed that 27 of the 28 thrusters performed well. Still, according to NASA, tests had revealed that a tiny Teflon seal appeared to swell under high temperatures, which could potentially block propellant flow into the thrusters. NASA said that the expanding seals may cause thruster issues during docking. However, NASA Commercial Crew Program Manager Steve Stich said that the team “can’t totally prove with certainty what we’re seeing on orbit is exactly what’s been replicated on the ground.”
Unfortunately, the thrusters were not the only problematic aspect of Starliner’s flight. Leaks of helium also plagued it. Helium is vital to the capsule as it pushes fuel into the propulsion system. Before Starliner launched, mission members were already aware of one helium leak. Nonetheless, they claimed at the time that it was manageable and unlikely to hamper the mission or the crew’s safety. However, shortly after takeoff, officials found two more helium leaks. Despite this, at the end of July, NASA announced that testing confirmed that Starliner’s propulsion system was stable and helium leak rates hadn’t increased in a way that could prevent returning to Earth.
NASA’s decision to bring the astronauts back to Earth with SpaceX will delay their return until 2025. Although SpaceX plans to launch its next vehicle at the end of September, the original mission bringing four astronauts up was modified so that only two are now available. By doing so, Wilmore and Williams can join the pair on their return flight in February.
Starliner’s issues have undoubtedly wounded Boeing, which is striving to improve its reputation after recent incidents and fatal accidents. Stich said that there will be post-flight examinations and that “there are teams starting to look at what we do to get the vehicle fully certified in the future.”
SpaceX has thus far sent nine crewed flights to space for NASA and some commercial flights, but this was Boeing’s first attempt at a crewed flight. Starliner has been delayed for years due to setbacks in its development, and two previous uncrewed flights in the past few years have also experienced technical issues. Starliner’s first uncrewed test flight in 2019 failed to make it to the station, and the next test flight in 2022 was considered successful. However, engineers later discovered problems, including the use of flammable adhesive tape. Fixing these problems held off the first flight with astronauts aboard.
Boeing and SpaceX both have contracts with NASA as part of the Commercial Crew Program, which provides regular flights to the ISS so NASA can focus on going to the moon and beyond. As of now, Wilmore and Williams remain in space, but SpaceX’s Crew Dragon is scheduled to bring them home in February.
