WASHINGTON — NASA and Boeing will further delay the first crewed launch of the company’s CST-100 Starliner, which had been scheduled for July, to address two newly discovered issues with the spacecraft.

At a briefing June 1 announced on little more than an hour’s notice, officials said they were standing down from preparations for the Crew Flight Test (CFT) of the spacecraft, with two NASA astronauts on board, which had been scheduled for as soon as July 21. They set no new date for the test flight to the International Space Station.

One issue is with components in the parachutes called soft links. Those components had a lower load limit than previously expected, decreasing the overall factor of safety in the parachute system “pretty significantly,” said Mark Nappi, vice president and program manager for CST-100 Starliner at Boeing.

The second issue is with tape used to wrap wire harnesses in the spacecraft that tests have shown is flammable. That tape, he said, is used “quite extensively” on Starliner.

Both concerns were highlighted as “emerging issues” in a May 26 NASA statement that was otherwise positive about the prospects for a July launch of the CFT mission. Nappi said subsequent studies of both the parachutes and the wiring issues, which had been found only recently during final certification work, led Boeing to conclude they should halt preparations for the launch.

That decision, he said, went to Boeing leadership all the way to Chief Executive Dave Calhoun. “Boeing unanimously decided that this is something that we needed to correct,” Nappi said. “We decided to stand down the preparations for the CFT mission in order to correct the problems.” That decision, and the notification of NASA, took place earlier in the day.

Nappi declined to say how long these issues will delay the mission. He said the company needed five to seven days to study what needs to be done and schedules for completing that work. Asked later in the call if a launch of CFT later this year was feasible, he said it was but that it was premature to consider any new launch dates for it. “I certainly don’t want to commit to any dates or timeframes until we spend the next several days understanding what we need to go do.”

Both the parachute soft links and wiring tape were used on the Orbital Flight Test (OFT) 2 uncrewed test flight in May 2022 without incident. The soft link issue, officials said, would only be a concern if one of the three main parachutes failed, putting additional loads on the other two, while the flammable tape would have required what Nappi called “multiple failures” elsewhere in the spacecraft.

NASA backed Boeing’s decision to delay CFT. “We applaud Mark for deciding to stand down and we support that decision 100%,” said Steve Stich, NASA commercial crew program manager. He added that agency leadership, up to Administrator Bill Nelson, supported the decision.

The delay is the latest in a series of setbacks for Starliner that include a flawed initial OFT test flight in December 2019 and stuck valves that delayed the OFT-2 reflight by nearly 10 months. In March, NASA and Boeing said they were delaying the CFT mission from April to July to give teams more time to complete certification work.

NASA’s Aerospace Safety Advisory Panel (ASAP), at a public meeting May 25, expressed skepticism that the agency and Boeing could complete the certification work in time for a July launch. It called on the agency to bring in an independent panel, perhaps from the NASA Engineering and Safety Center (NESC), to perform what Patricia Sanders, chair of the panel, called a “deep look” at the remaining work.

Stich said that the agency is accepting that recommendation through having NESC engineers embedded in teams throughout the Starliner program. Those engineers will brief a panel organized by NASA’s Office of the Chief Engineer. A similar process, he said, is used on other programs. “That’s what we plan to use to fulfill what the ASAP is requesting, which I think is an excellent request,” he said.

This latest delay comes two days after the third anniversary of the launch SpaceX’s equivalent to CFT, the Demo-2 mission of its Crew Dragon spacecraft. SpaceX has now launched 10 crewed missions for NASA and private customers, most recently the Ax-2 private astronaut mission in May.

Stich emphasized that NASA is still expecting Boeing to bring Starliner into service. “NASA desperately needs a second provider,” he said, providing redundancy. “We support Boeing and we’re doing everything we can during the investigation of each of these issues, and try to get to flight as soon as we can, when it’s safe to do so.”

Nappi, when asked if Boeing had considered abandoning Starliner, initially offered an ambiguous response. “We’ve been talking about the future of Starliner and how we’re going to move forward,” he said. He later clarified that was referring to long-term decisions about whether to build another Starliner vehicle to support higher flight rates and when to transition from the Atlas 5 launch vehicle that will be used for initial Starliner missions.

Asked later if there had been any discussions within the company about dropping Starliner, he said there had been “not serious discussions.”

Stich said that he had seen progress at Boeing since the earlier problems with Starliner. “I have seen a tremendous change in the Boeing culture since the first Orbital Flight Test,” he said. He said the work leading to CFT had been “very thorough and comprehensive” and that it was uncovering design issues made years ago.

“My view is that the safety culture has always been strong,” said Nappi moments later, explaining that the reason issues were just now being found was “a certain sense of optimism” in earlier phases of spacecraft design. “The process is catching these things, and we’ll continue to do these thorough reviews, catch things, talk about them and fix them.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...