Boeing’s Starliner finally takes off, but mission control reports more helium leaks

Enlarge / Boeing’s Starliner capsule lifts off aboard United Launch Alliance’s Atlas V rocket.

After years of delays, Boeing’s Starliner spacecraft finally entered orbit from Florida on Wednesday, sending two veteran NASA astronauts on a long-delayed test cruise to the International Space Station.

The Starliner capsule lifted off at 10:52 a.m. EDT (14:52 UTC) atop a United Launch Alliance Atlas V rocket. Fifteen minutes later, after shedding two strap-on boosters and a core stage powered by a Russian RD-180 engine, the Atlas V’s Centaur upper stage launched Starliner right on target to begin a nearly 26-hour search for the station. space. Docking at the space station is scheduled for 12:15 p.m. EDT (16:15 UTC) on Thursday, where NASA astronauts Butch Wilmore and Suni Williams will spend at least a week before returning to Earth.

Speaking shortly after Wednesday’s launch, NASA Administrator Bill Nelson said Wilmore and Williams, both former U.S. Navy pilots, will “test this from gizzard to gizzard” to ensure that Boeing’s Starliner is ready for six-month operational crew rotation missions to the ISS.

long time to come

This is a big moment for NASA and Boeing. The launch of the Starliner test flight brings NASA closer to having access to two independent commercial spacecraft that carry astronauts to low-Earth orbit, the cornerstone of an initiative the agency began working on a decade and a half ago. For Boeing, the first launch of astronauts aboard Starliner comes as the once-vaunted aerospace contractor wrestles with safety concerns about its 737 workhorse.

NASA awarded Boeing a $4.2 billion contract to complete development of the Starliner spacecraft in 2014, with the goal of carrying astronauts to the capsule starting in 2017. The company first announced the spacecraft that became on Starliner, then known only as CST-100, in 2010 at the Farnborough International Airshow.

In the 2010 announcement, Boeing officials said they hoped to declare the CST-100 spacecraft operational in 2015, but Congress initially did not allocate the funds NASA said it needed to support the development of new commercial crew vehicles after the retirement. of the space shuttle. . Boeing then ran into numerous technical problems, resulting in a major fuel leak during ground testing, an aborted unpiloted test flight to the space station in 2019, and further delays caused by valve corrosion. . Another test flight in 2022 achieved all of Boeing’s major goals, setting the stage for the crewed test flight.

But last year, officials discovered that Boeing had mistakenly used flammable tape around wire bundles inside the Starliner spacecraft, causing another schedule delay. Engineers also discovered they needed to redesign a component of the capsule’s parachute system, which would extend the crew’s test flight into 2024. These delays cost Boeing nearly $1.5 billion of its own coffers. American taxpayers were freed from cost overruns because NASA’s contract with Boeing is fixed-price.

Meanwhile, SpaceX’s Crew Dragon spacecraft, which NASA supported alongside Boeing in the commercial crew program, began transporting astronauts in 2020. To date it has launched 13 crewed missions for NASA and private clients.

NASA astronauts Suni Williams and Butch Wilmore.
Enlarge / NASA astronauts Suni Williams and Butch Wilmore.

Two previous attempts to launch the Starliner crew test flight on May 6 and June 1 were interrupted by a faulty valve on the Atlas V rocket and a failure in the power supply for a ground computer on the launch pad. . In the time between those two launch attempts, engineers discovered a small but persistent helium leak in Starliner’s service module. Helium, which the spacecraft uses to power thrusters from the internal tanks to the maneuvering thrusters, is an inert, non-toxic gas, and managers ultimately determined that the leak was stable and did not add any unacceptable risk to the mission.

That led to approvals to proceed with the June 1 launch attempt, then another countdown on Wednesday that culminated in the successful launch of Starliner. Milestones reached early in the flight demonstrated that the spacecraft was performing well.

“We’re underway on the mission,” Wilmore radioed to mission control in Houston Wednesday afternoon. “And I can tell you, I wish I could have taken you all on that climb. It was pretty exciting.”

“It was kind of a shock that we actually released it,” Williams said. This was the third time the two astronauts had strapped themselves into the Starliner capsule in hopes of launching into space, following two failed launch attempts over the past month.

“It was cool to jump off the planet and then feel the Atlas V doing its job,” Williams said. “There were a few bumps here and there, a couple of G’s.”

This was also the first time a crew launched ULA’s Atlas V rocket, which flew its 100th mission on Wednesday. It is also the first time astronauts have launched a member of the historic Atlas rocket family since the final flight of NASA’s Mercury program in 1963.

A few hours after launch, Wilmore and Williams took turns at the controls of Starliner for a series of demonstrations to show that crew members could point and fly Starliner manually if its automation failed. All those payments seemed to go well.

“Suni and I have done some manual maneuvers and they are accurate, even more so than the simulator,” Wilmore said. “I mean, stopping exactly at a number you want to stop at. The precision is pretty amazing.”

One leak turns into three

When speaking to ground controllers Wednesday afternoon, Wilmore said that the Starliner test flight had “just gone swimmingly” so far. But as the crew prepared for a night’s sleep shift before Thursday’s docking at the space station, two new helium leaks appeared in the Boeing capsule.

The spacecraft’s service module houses most of Starliner’s propulsion system, including 20 larger orbital maneuvering engines and 28 less powerful reaction control system thrusters for precise targeting and smaller adjustments. Starliner has four doghouse-shaped propulsion capsules around the circumference of the service module, with lines for hydrazine fuel, nitrogen tetroxide oxidizer, and helium pressurizer routed to each propellant pack.

Two helium collectors power each doghouse. The leak discovered before the Starliner launch was attributed to a flange on a manifold in the port deckhouse, or left-hand, capsule. On Wednesday night, engineers detected two more helium leaks: one in the other manifold in the port house and another in the house on top of the service module.

Brandon Burroughs, a Boeing engineer, described the two new helium leaks as “small” in a discussion broadcast on NASA TV’s live coverage of the Starliner test flight. These leaks did not appear during troubleshooting of the known ground leak.

Boeing engineers are evaluating helium leaks in two of four "Dog house" propulsion capsules in the service module of the Starliner spacecraft.
Enlarge / Boeing engineers are evaluating helium leaks in two of the four “doghouse” propulsion capsules in the Starliner spacecraft’s service module.

With this finding, three of Starliner’s eight helium manifolds now show signs of leaking, and mission controllers told the crew they will have an update on the situation after they wake up at 4:30 a.m. EDT (08 :30 UTC) on Thursday. It was not immediately clear how significant the leaks might be, nor the immediate implications for the spacecraft’s planned arrival at the space station.

“It looks like we detected a couple more helium leaks,” said Neal Negata, an engineer who works as the spacecraft communicator, or CAPCOM, in mission control. “We’re ready to copy and figure out exactly what you mean by detecting another helium leak.” leak, so give it to us,” Wilmore radioed to the ground a few moments later.

Negata told Wilmore that they will isolate the collectors that were recently found to be leaking helium, while the collector that was known to leak before launch will remain open. “That will give the teams the ability to manage the spacecraft,” Burroughs said.

Before they were comfortable launching with the known helium leak, engineers determined that the Starliner spacecraft could handle up to four more helium leaks, even if the existing leak worsened, according to Steve Stich, commercial crew program manager for the space agency. POT.

“It’s a resilient system,” Stich told reporters last month. “This is a high-pressure system, and helium is a very small, tiny molecule, and it tends to leak.”

In its current configuration with two closed helium manifolds, six of the 28 thrusters in the spacecraft’s reaction control system will be disabled. The capsule has the ability to operate on a subset of its propellants, and Burroughs said Boeing engineers believe “the helium system remains safe for flight.”

“This was not unexpected and we are planning for cases like this,” he said. “The team will work to ensure that we are in a good configuration to complete our mission, which is docking and rendezvous with the ISS.”

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