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Starliner Mission Extended, All Systems Stable

Starliner pictured on station, through the window of Crew Dragon.
Credit: NASA

Boeing’s Starliner Crew Flight Test (CFT) has once more been extended, but everything remains stable and safe for the station, spacecraft, and crew. A new return date has yet to be determined, but it will be no earlier than early July. After an Agency-level readiness review in the near future, mission managers will set an undocking date, with landing to follow one day later.

CFT is set to remain docked to the ISS until sometime after July 2nd. This is the 4th extension to the mission after docking to the International Space Station (ISS). The helium leaks identified earlier in the mission still exist, but Boeing and NASA teams have verified that there is ample margin and remaining helium to return home safely. After the thruster hot fire test conducted on June 15th, the helium manifolds were again isolated and leak rates decreased accordingly. The primary motivation for the extension is to deconflict with planned US spacewalks on June 24th and July 2nd as well as allow more time for teams to analyze propulsion system data. The agency-level review is needed as the mission duration has operated longer than initially cleared by the pre-launch Flight Readiness Review. This is not unusual,  and was done for the SpaceX Demo-2 mission, Crew Dragon’s first crewed flight, back in August 2020. NASA’s blog post announcing the extension states that “Boeing’s Starliner spacecraft remains cleared for return in case of an emergency on the space station that required the crew to leave orbit and come back to Earth.”

With the helium manifolds closed, the leaks are practically nonexistent, so there is no time pressure to go home before the CRS-31 resupply mission in August. With six crew members operating the US segment instead of the usual four, tasks aboard the ISS, such as more science experiments, can be performed with greater efficiency. In particular, EVA support is made much easier. Butch and Suni, alongside the Boeing/NASA starliner teams, are also conducting additional tests of the spacecraft to better inform post-flight certification for operational missions and future upgrades. This is also the only time extra data collection and hardware analysis of the helium manifolds and thrusters can be performed, as the Service Module is discarded before atmospheric entry. All pre-docking test objectives have been successfully completed, so teams have added additional objectives to take advantage of the extra time. This is not unprecedented, as SpaceX’s Demo-2 was extended up to a 2-month stay to perform similar additional tests and analysis of vehicle health..

If Calypso was unfit for an emergency return and the crew was effectively stuck on station, the attitude and actions being taken by NASA would be much more serious. When Soyuz MS-22 suffered a coolant leak in December 2022, actions taken included moving NASA astronaut Frank Rubio’s seat liner to the Crew Dragon Endurance, discussion of putting Safe Haven procedures into place, and Roscosmos openly considering and ultimately launching Soyuz MS-23 uncrewed to serve as a replacement. No discussions of comparable severity are taking place for Starliner CFT. While the crew is practicing Safe Haven procedures, this was already part of their mission plan, and the practice is only to demonstrate such procedures should future flights need them.

As Butch and Suni continue to assist the Expedition 71 crew, there are no safety concerns. All systems are operating well and the expanded ISS crew is proceeding with life as normal aboard the ISS. Boeing and NASA are taking the opportunity to learn as much as possible about the new crew system, both in terms of CFT’s technical issues and Starliner’s performance for longer duration missions. Rehearsals continue as ground teams prepare for the eventual landing at White Sands Space Harbor, concluding the certification mission for America’s second Commercial Crew spacecraft.

Edited by Scarlet Dominik and Nik Alexander

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