NASA and Boeing said May 26 that they are still working towards launching the CST-100 Starliner in July on a crewed test flight despite “emerging issues” and concerns raised by the safety committee.
In a statement released just before work wrapped up before the weekend, the two organizations said they had completed a “checkpoint review” on May 25 of preparations for the Crew Flight Test (CFT) mission, currently scheduled for no later than July 21. NASA astronauts Butch Wilmore and Sonny Williams will fly aboard the CFT to the International Space Station for a short test flight, the spacecraft’s first crewed flight.
NASA and Boeing said they have now completed 95% of the certification work needed for the CFT. They also addressed all of the anomalies from Orbital Flight Test (OFT) 2 mission, an uncrewed Starliner test flight to the International Space Station one year earlier.
“We are taking a systematic approach to the Starliner’s first crewed flight that incorporates all the lessons learned from the various in-depth test campaigns,” Steve Stitch, NASA’s Commercial Crew Program manager, said in a statement. “In addition to finalizing work in progress, the team remains vigilant about tracking new technical issues as we complete manned flight certification.”
That statement mentioned “emerging issues that need a course of closure” before NASA and Boeing decided to fuel the spacecraft in June for a launch in July. Boeing officials said earlier this year that they decided to fuel the spacecraft only within 60 days of launch as a measure to mitigate any fuel leaks that could corrode valves, an issue that has delayed an August 2021 OFT-2 launch attempt.
Among the problems was the replacement of a valve in the spacecraft service module’s thermal control system, which was reducing flow in one of the two redundant loops that cooled the vehicle’s avionics. NASA and Boeing said replacing the valve would take about a week, and should not affect the CFT launch schedule.
Engineers are also evaluating whether the tape used for wiring could pose a flammability hazard. Although this tape is commonly used on other spacecraft, they are evaluating whether it is acceptable for manned flights. The organizations said the assessment should be done before a decision is made to fuel the spacecraft.
Another system under review is the Starliner parachutes. NASA and Boeing said they are reevaluating the margins in the parachutes, including the “overall efficiency” of the joints in this system, to ensure they achieve the safety factors required for a manned spacecraft.
The statement came a day after a public meeting of NASA’s Space Safety Advisory Committee (ASAP) in which the committee’s chair, Patricia Sanders, raised concerns about the ability to complete work, such as parachute certification, in time to meet a planned July 21 launch.
“It is imperative that NASA not succumb to pressure, even unconsciously, to release the CFT without addressing all remaining barriers to certification,” she said, recommending that NASA bring in an independent group, such as the NASA Engineering and Safety Center, “to take a deep look at items on the path to closure.”
The NASA/Boeing statement did not mention the ASAP meeting. However, it did address one issue Sanders raised about spacecraft batteries. The organizations said they approved the batteries for use in the CFT “based on additional testing and analysis” with a proposal to upgrade the batteries on future missions.
Stich said, in the statement, that the agency and company have made progress since late March, when we announced that certification work would drive the launch of CFT from April through July.
“If you look back a couple of months ago at the work that was before us, it was all done,” he said. “The joint team is flexible and resolute in its goal of having the crew fly the Starliner as soon as it is safe to do so.”
However, he did not rule out any missteps from the current July launch date. “If there is a need to adjust the schedule in the future, we will definitely do it as we did before. We will only fly when we are ready.”
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