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Boeing Starliner
An artist’s conception shows Boeing’s CST-100 Starliner spacecraft, which is designed to carry astronauts and cargo to and from the International Space Station. (Boeing Illustration)

Last month’s problem with leaky rocket engine valves has forced Boeing to rearrange the sequence of tests for its Starliner space taxi, with the first crewed flight to the International Space Station now planned for no earlier than mid-2019.

John Mulholland, a Boeing vice president who’s program manager for the CST-100 Starliner program, laid out the revised schedule today during a teleconference with journalists.

The current plan calls for an uncrewed Starliner capsule, known as Spacecraft 3, to be launched atop a United Launch Alliance Atlas 5 rocket to the International Space Station in late 2018 or early 2019.

Another capsule, Spacecraft 1, will be put through an uncrewed pad abort test during the first few months of 2019. Assuming that test is successful, Boeing would launch the Starliner’s first crew to the space station aboard yet another Starliner, Spacecraft 2, a month later.

Boeing had planned to start with the pad abort test, which would make use of a “pusher” rocket system designed to throw the capsule clear of its launch vehicle in the event of an emergency. Then it would have done the uncrewed demonstration flight, followed by the crewed demonstration flight, perhaps by the end of 2018.

June’s problem, which cropped up during a hot-fire test of the launch abort system at White Sands Missile Range in New Mexico, forced a change of plans.

“Several of the abort engine valves failed to fully close” at the end of a 1.5-second test firing, Mulholland said. That resulted in a leak of toxic hypergolic propellant, but no damage to the hardware and no injuries to the test team, he said.

Boeing has already identified the problems, and “our team is off fixing those problems,” Mulholland said. Aviation Week quoted him as saying in an earlier interview that the problems had to do with springs that didn’t have enough force to seal off the valves. Four of the eight valves in the four-engine system failed to close, he told Aviation Week.

The fix will involve a “potential combination of operational changes and minor design changes,” Mulholland told reporters today.

The uncrewed demonstration flight was moved to the head of the line because that test doesn’t require firing the launch abort system, which was built for Boeing by Aerojet Rocketdyne. The shift will give engineers more time to ensure that the valves, the four 40,000-pound-thrust engines and the entire system works as designed.

Once Spacecraft 1’s abort system passes its test, Spacecraft 2 can then be cleared for takeoff with spacefliers on board. The crews for Boeing’s demonstration flight, and for SpaceX’s parallel demonstration flight, are to be announced amid fanfare at NASA’s Johnson Space Center on Friday.

Friday’s announcement is expected to identify Chris Ferguson, who was the commander of NASA’s last space shuttle mission and is now Boeing’s director of crew and mission operations, as a member of the first Starliner crew. Today Mulholland paid tribute to Ferguson “and all he’s meant to this nation, and to our company, and to the development of this spacecraft.”

“So we’re really looking forward to the celebration of that announcement,” Mulholland said.

It was Ferguson and his crew who left a U.S. flag behind on the space station during the last shuttle mission in 2011, to be picked up by the next space crew to be launched from U.S. soil.

In light of Boeing’s schedule adjustment, will that crew arrive on a Starliner or on SpaceX’s Dragon spaceship? SpaceX has hinted that its first crewed flight could take place by early next year, but Mulholland declined to speculate.

“I really have no visibility into SpaceX progress or the fidelity of the SpaceX schedule,” he said. “Our entire focus is grounded in making sure that we do everything we can to ensure a safe vehicle, and meeting the schedule parameters that I’ve laid out.”

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