Nasa officials announced that astronauts Sunita Williams and Butch Wilmore, currently aboard the International Space Station (ISS), might return to Earth on SpaceX's Crew Dragon in February 2025 instead of Boeing's Starliner.
This decision hinges on the outcome of ongoing safety evaluations of the Starliner spacecraft, which has encountered multiple technical issues.
The two astronauts were delivered to the ISS in June by Boeing's Starliner capsule, marking its first crewed mission.
Initially, their mission was expected to last about eight days, but it has been extended due to propulsion system problems on Starliner. These issues have increasingly raised concerns about the spacecraft's ability to safely return them to Earth as planned.
Boeing has been conducting a rigorous testing campaign to address these problems, which include thruster failures and helium leaks.
The latest test data have revealed that overheating thrusters cause Teflon seals to warp, restricting propellant flow and weakening thrust. This has led to internal disagreements within Nasa about whether to accept the risk of a Starliner return or opt for the safer alternative of using Crew Dragon.
If Nasa decides to change Starliner's mission, Boeing will configure the spacecraft for an uncrewed return. This would be a significant setback for Boeing, which has faced numerous challenges in developing the Starliner, including management issues and engineering problems. The development of Starliner has cost Boeing $1.6 billion since 2016, including $125 million for the current test mission.
Nasa has been discussing potential plans with SpaceX to leave two seats empty on an upcoming Crew Dragon launch for Wilmore and Williams. This contingency plan involves using SpaceX's Crew-9 mission, scheduled for launch in September 2024, to bring the astronauts back to Earth in early 2025. The Crew Dragon spacecraft would be configured to carry only two passengers to the ISS, leaving space for Wilmore and Williams to return with the Crew-9 team.
The Starliner capsule has been docked to the ISS for 63 of the maximum 90 days it can stay, occupying the same port that Crew Dragon will need to use for the upcoming mission. Nasa has already delayed SpaceX's Crew-9 mission by more than a month to accommodate these plans.
Nasa's Commercial Crew Program, which oversees Starliner, has been buying Boeing more time to conduct additional testing and gather more data. A decision on whether to use Starliner or Crew Dragon is expected sometime next week.
This extended stay has integrated Wilmore and Williams into ongoing ISS missions, but it has also led to the consumption of supplies intended for other crew members.
Despite these challenges, Nasa remains committed to ensuring the safe return of the astronauts, whether on Starliner or Crew Dragon.
