Produced by: Tarun Mishra Designed by: Manoj Kumar
NASA and Boeing announced that the return of the Starliner capsule from its first human mission to the ISS is delayed to June 26, due to thruster troubleshooting and a scheduled spacewalk.
Originally expected to spend about a week at the ISS, the Crew Flight Test (CFT) mission’s departure has been extended nearly three weeks past its initial timeline, with landing set for 4:51 a.m. EDT at White Sands Space Harbor in New Mexico.
The delay allows for additional evaluation of thruster issues that affected Starliner’s first docking attempt on June 6. Five of Starliner’s 28 reaction control thrusters failed during the final phase of the rendezvous, though four recovered later.
The delay also accommodates a rescheduled ISS maintenance spacewalk now set for June 24. This activity had been postponed due to a spacesuit issue during the initial suit-up.
Over the weekend, a thruster hot-fire test was conducted by Boeing and NASA ground team members, which bolstered confidence in the thruster performance. However, one thruster remains offline due to low pressure observed during docking.
Small helium leaks in the reaction control system (RCS) thrusters were first discovered on the launch pad in May. Additional leaks appeared during the mission, prompting a fault tree analysis to determine the causes.
The CFT docking was more demanding on the propulsion system compared to the uncrewed test flight in May 2022, firing thrusters more frequently. Ongoing hardware simulations aim to model and address the helium leak issues.
NASA and Boeing emphasize the developmental nature of the CFT mission, with 77 out of 87 flight test objectives already met. The remaining objectives will be assessed during the undocking and landing phases.
Starliner, along with SpaceX’s Dragon capsule, is part of NASA’s efforts to transport crews to the ISS. The successful completion of the CFT mission is essential for certifying Starliner for operational ISS rotation missions, anticipated to begin with Starliner-1 in 2025.