Nasa's astronauts Butch Wilmore and Sunita Williams, currently aboard the International Space Station (ISS), may soon learn when they'll return to Earth.
However, NASA and Boeing engineers are still assessing data from ground tests of the Starliner spacecraft, leaving the astronauts' return date uncertain.
Wilmore and Williams launched to the ISS on June 5 aboard Starliner for its Crew Flight Test (CFT), initially planned to last about 10 days. The mission, which serves as the first crewed shakedown cruise of Boeing's commercial crew vehicle, might now extend up to eight months, potentially pushing their return to 2025.
The mission faced an early setback with a minor helium leak, but the spacecraft's journey to orbit proceeded without incident. However, during docking, Starliner experienced malfunctions in five of its 28 reaction control thrusters. Consequently, NASA and Boeing extended the astronauts' stay on the ISS indefinitely to investigate the issues.
A final decision on the crew's return is expected by the last week of August.
To address the thruster problems, NASA has enlisted additional propulsion experts from the Glenn Research Center, Goddard Space Flight Center, and the Jet Propulsion Laboratory.
Ken Bowersox, associate administrator for NASA's Space Operations Mission Directorate, emphasized the value of these experts' insights during a recent briefing.
Emily Nelson, Chief Flight Director for NASA's Flight Operations Directorate, highlighted the importance of diverse perspectives in analysing the spacecraft's data.
Meanwhile, NASA has prepared contingency plans for potential emergencies aboard the ISS, allowing Wilmore and Williams to use Starliner for evacuation if necessary.
Starliner's delayed departure has impacted other scheduled flights to the ISS.
SpaceX's Crew-9 launch, initially set for this month, is postponed to late September, and a SpaceX Cargo Dragon resupply mission is rescheduled for mid-October. To avoid congestion, Starliner must undock before Crew-9's arrival, possibly without its crew.
In such a scenario, Wilmore and Williams would join Expedition 71 and 72, returning to Earth aboard Crew-9's Dragon in February 2025. Bowersox stated that the decision hinges on ensuring Starliner's propulsion system functions correctly during deorbit.
As NASA prepares for a flight readiness review, Wilmore and Williams continue to assist with ISS tasks, enjoying their extended time in space. NASA's chief astronaut Joe Acaba affirmed the agency's commitment to crew safety, stating it's worth the wait to ensure minimal risk.
