NASA and Boeing Co said on Tuesday they were delaying the return of a planned two-member crew from the International Space Station (ISS) to conduct additional tests on their CST-100 Starliner spacecraft, aiming to resolve thruster malfunctions and helium leaks.
NASA's commercial crew program manager, Steve Stich, emphasized that astronauts Butch Wilmore and Suni Williams were not “stranded in space,” despite the extended mission duration. “Our plan is to continue to return them on Starliner and return them home at the right time,” Stich said at a briefing.
The additional tests, scheduled to begin no earlier than July 2 at NASA's White Sands Test Facility, will focus on replicating issues that caused thruster malfunctions during the spacecraft's approach to the ISS. “This will be the real opportunity to examine the thruster just like we had in space on the ground, with detailed inspections,” Stich added.
Boeing's vice president and commercial crew program manager, Mark Nappi, acknowledged the challenges in fully understanding and resolving the thruster and helium leak problems. “We understand these issues for a safe return, but we don't understand these issues enough yet for us to fix them permanently,” Nappi said.
Originally scheduled for an eight-day stay at the ISS, the CST-100 Starliner will now remain docked for an extended period to gather crucial data, including from the service module section that is jettisoned at mission's end. “We have the luxury of time,” said Ken Bowersox, NASA associate administrator for space operations.
NASA had initially set a 45-day limit for the mission based on battery life, which can now be extended due to battery performance thus far, according to Stich. However, the extended mission and technical challenges pose obstacles to certifying the spacecraft for future crew rotations, initially targeted for November.
“We understand it's going to take a little bit longer,” Stich said of the certification process, which could affect the timeline for subsequent crew missions.
During the briefing, Nappi expressed frustration with what he described as negative media coverage of the mission. “We've gotten a really good test flight that's been accomplished so far and it's being viewed rather negatively,” Nappi said.
In addition to updates on the CST-100 Starliner mission, NASA officials discussed the recent postponement of a spacewalk at the ISS due to a water leak in the airlock, as well as the agency's contract award to SpaceX for the U.S. Deorbit Vehicle (USDV).