Boeing's Starliner will remain at the International Space Station (ISS) for several more days. NASA and Boeing are now targeting no earlier than June 26 for a return to Earth.

The new date was announced by NASA during a teleconference on June 18 and is the latest in a succession of date revisions. Previously, the return had been set for June 22, but managers decided that more time was needed to check out the spacecraft ahead of lengthier stays.

The team is targeting No Earlier Than (NET) 0210 UTC June 26 (2210 EDT June 25) for undocking, followed by an 0851 UTC June 26 (0451 EDT June 26) landing at White Sands Space Harbor, New Mexico.

"We are continuing to understand the capabilities of Starliner to prepare for the long-term goal of having it perform a six-month docked mission at the space station," said Steve Stich, manager of NASA's Commercial Crew Program. "The crew will perform additional hatch operations to better understand its handling, repeat some 'safe-haven' testing, and assess piloting using the forward window."

Managers also confirmed that a "hot fire test," in which seven of the eight aft-facing thrusters were pulsed in two bursts totaling almost two seconds in duration, was successful. Although NASA described the test as "part of a pathfinder process" to evaluate spacecraft performance, the test might also smooth brows left furrowed following the loss of five thrusters during the spacecraft's rendezvous with the ISS. The problem appeared to be software-related, and four thrusters were recovered.

The fifth thruster showed what Stich described as a "strange signature" during the briefing and produced almost no thrust. As such, managers have opted not to use it during undocking and deorbit.

The original departure date was moved partly due to a planned spacewalk on June 13. The spacewalk was cancelled following a "spacesuit discomfort issue" involving Matt Dominick. Managers have rescheduled the spacewalk for June 24, switching out Dominick for Mike Barratt. A second is planned for July 2.

According to NASA, the Starliner has been cleared for "crew emergency return scenarios within the flight rules." Handy, since the vehicle has now sprung multiple leaks in the service module manifolds. Five small leaks were noted earlier in the mission, although managers reckoned that the vehicle had more than enough left to complete it. Seven hours of free-flight time is needed for a typical end-of-mission, and Starliner has enough helium left for considerably longer.

Engineers want to better understand the helium leaks and thruster issues. Starliner's service module will burn up in the Earth's atmosphere during the return to Earth, meaning that an extension to the vehicle's stay at the ISS will be a useful opportunity to gather more data.

Stich observed that dealing with the helium leaks was a prerequisite for a possible operational mission in 2025. In the June 18 teleconference, he said: "We're not going to go fly another mission like this with the helium leaks," noting that the thruster issues also needed to be better understood.

All of which suggests it might be the second half of 2025 before Boeing's Starliner is launched again. ®

https://www.theregister.com//2024/06/19/boeing_starliner_prepares_delay_iss/