After weeks of debate, NASA has ruled out returning two astronauts to Earth aboard Boeing’s Starliner capsule because of lingering concerns about multiple helium leaks and degraded propellants, both critical to a successful reentry, officials said Saturday. .
Despite successful tests of Starliner’s maneuvering thrusters, detailed analysis and confirmation that the known propulsion system helium leaks are stable and have not worsened, NASA has concluded that there is no way to prove that the systems continue to operate normally, ensuring a safe de-orbit, re-entry and landing.
The decision means two of four “Crew 9” astronauts scheduled to launch to the International Space Station aboard a SpaceX Crew Dragon on September 24 will give up their seats so that Starliner commander Barry “Butch” Wilmore and co-pilot Sunita Williams can return home. in his place next February.
“NASA has decided that Butch and Suni will return with Crew 9 next February, and that Starliner will return without a crew,” NASA Administrator Bill Nelson said at a post-readiness press conference. “We want to further understand the root causes (of previous problems) and understand the design improvements so that the Boeing Starliner serves as an important part of our safe crew access to the ISS.”
Nelson said new Boeing CEO Kelly Ortberg has assured the company remains committed to the Starliner program, which NASA is relying on to provide independent access to the space station alongside SpaceX.
“I told him how well Boeing worked with our team to come to this decision, and he expressed to me the intention that they will continue to work on the problems once the Starliner is back safely, and that we have our ( secured) access to the space station,” Nelson said.
Launched on June 5, Wilmore and Williams initially expected to spend a little more than a week in space on the Starliner’s first manned test flight. They will now spend at least 262 days in orbit – nearly nine months – before returning to Earth around February 22 with the two Crew 9 flyers after completing a normal six-month tour of duty.
In the process, Wilmore and Williams will become the first astronauts in history to fly into space aboard four different spacecraft: NASA’s Space Shuttle, Russia’s Soyuz, Boeing’s Starliner and SpaceX’s Crew Dragon.
The Starliner, meanwhile, will be ordered off the space station’s forward port until September 6 to perform an unmanned reentry and touchdown at White Sands, New Mexico, to deliver the long-awaited test flight to a disappointing one. conclusions.
With the departure of the Starliner, only the four-seat Crew 8 capsule, which arrived at the laboratory last March, will be available to serve as a rescue boat if an emergency forces its four-member crew, along with Wilmore and Williams, to evacuate before the boat Crew 9 arrives.
While the probability of an evacuation is remote, SpaceX will work with NASA and the crew of the station to replace the improvised seats in the Crew 8 Dragon before the shutdown of the Starliner to accommodate Wilmore and Williams in an emergency.
Once the Crew 9 capsule docks, the four outgoing Crew 8 flyers, wrapping up their own six-month expedition, will set up their ship for a normal deployment and return to Earth around October 1 as planned . Wilmore and Williams will remain behind the station with the two Crew 9 flyers launching on September 24.
The decision that ruled out a manned return of the Starliner was a fatal blow to Boeing following earlier problems that delayed the first manned flight of the Starliner by nearly four years, required a second unmanned test flight and cost the company more than $1.5 billion above and beyond its own. NASA Fixed Price Contract.
The Starliner woes come on top of Boeing’s ongoing struggle to reassure the public after two crashes of the 737 Max 8 airliner, a close call with an Alaska Airlines 737 flight earlier this year and more recent problems with an upgraded version of the company’s long-haul 777 aircraft that have shaken confidence in the aerospace giant.
But from NASA’s perspective, Nelson said he had confidence in Boeing, the prime contractor for the International Space Station and the agency’s Space Launch System lunar rocket, calling the contractor “a great partner for NASA over the years.”
When the Starliner was launched on June 5, a small helium leak in the Starliner’s propulsion system was known but not considered a safety threat. During the rendezvous with the space station the day after launch, four more developed escapes and five of the ship’s stern thrusters did not operate as planned.
These two problems triggered two months of extensive testing and analysis, adding another $125 million to the price of the mission, according to a Boeing financial update.
Boeing has strongly argued that tests and analysis of helium leaks and initial problems with the maneuvering thrusters show the spacecraft has more than enough margin to bring Wilmore and Williams safely to Earth.
Boeing said that the helium leaks have not worsened and more of the pressurized gas is on board to push the propellants to the thrusters needed to maneuver and stabilize the spacecraft through the critical de-orbit brake burn to remove . orbit for reentry and landing.
Similarly, Boeing engineers believe they understand what caused a handful of aft-facing maneuvering jets to overheat and fire at lower-than-expected thrust during rendezvous with the space station, making that the Starliner’s flight computer shuts them down during the approach.
Ground tests of a new Starliner thruster, fired hundreds of times under conditions that mimicked what those aboard the spacecraft experienced, replicated the overheating signature, which was likely caused by multiple firings during the tests of the manual capsule control system during extended exposure to direct sunlight.
The higher-than-expected heating likely caused small seals in the propellant valve “poppets” to deform and expand, the analysis indicates, which reduced propellant flow. The thrusters aboard the Starliner were tested in space under more normal conditions and all operated properly, indicating that the seals had returned to a less intrusive form.
But there was no way to guarantee that the seals would not deform further during thruster firings after disengagement or during de-orbit “burn-in” when the larger rocket engines generate high temperatures in pods housing the larger thrusters. small, which are necessary to maintain the stability of the spacecraft. for a precisely targeted landing.
“We’re all committed to the mission, which is to get Butch and Suni back,” said Steve Stich, NASA’s commercial program manager. “But as we got more and more data over the summer and realized the uncertainty of that data, it became very clear to us that the best course of action was to return Starliner without a crew.
“If we had a way to accurately predict what the thrusters would do all the way through the deorbit burn and through the separation sequence, I think we would have taken a different course of action. But when we looked at the data and he looked at the potential for thruster failures with a crew on board… it was too much of a risk.”
Boeing did not participate in Saturday’s briefing. In a statement after the announcement, Boeing said that the company “continues to focus, first and foremost, on the safety of the crew and the spacecraft. We are executing the mission as determined by NASA, and we are preparing the spacecraft for a safe and successful unmanned return.”
Following the retirement of the space shuttle, NASA awarded two commercial equipment program contracts in 2014, one to SpaceX valued at $2.6 billion and the other to Boeing for $4.2 billion.
The goal was to end NASA’s post-shuttle reliance on Russia’s Soyuz and resume launching American astronauts from US soil aboard American rockets and spacecraft. Equally important for NASA: having two independent spacecraft for crew flights to the ISS in case one company’s ship runs into problems that could put it on the ground for an extended period.
“We’re a launch anomaly from losing our ability to support this amazing thing we’re doing on the International Space Station,” said Nick Hague, one of the four Crew 9 astronauts. “We’re trying to develop Starliner to be that redundant system “. A recent Falcon 9 upper stage failure “underscores why we need redundancy more than anything I can think of.”
The original target date for the initial commercial pilot crew flights was 2017. A lack of funding in Congress and technical snags delayed development, including an explosion during a ground test that destroyed a SpaceX Crew Dragon.
But the California-based rocket maker also managed to launch manned flights in May 2020, successfully launching two NASA astronauts on a Crew Dragon test flight to the space station.
Since then, SpaceX has launched eight operational crew rotation flights to the station, three research missions to the lab funded by Houston-based Axiom Space, and a purely commercial, two-man, two-woman trip to the low earth orbit paid for by a billionaire. Pilot and businessman Jared Isaacman.
Isaacman and three crew members are expected Tuesday on another commercial SpaceX flight – Polaris Dawn – to set a new altitude record in Earth orbit and to perform the first commercial spacewalks.
Going on that flight, 50 people flew into orbit on 13 Crew Dragon flights. Boeing has now launched two astronauts – Wilmore and Williams – but it is not yet known when the craft will be ready to fly again or even if another test flight will be ordered.
During an initial unmanned test flight in December 2019, unforeseen software and communication glitches prevented a planned rendezvous with the space station. Boeing corrected these problems and chose to conduct a second unmanned test flight, at its own expense.
But during the second countdown, engineers ran into problems with the propulsion system valves stuck in the Starliner’s service module. Engineers eventually traced the problem to moisture intrusion and corrosion, causing another lengthy delay.
The second Starliner test flight in May 2022 was a success, docking with the space station as planned and returning to Earth with a timely landing. But after the flight, engineers discovered new problems: possible problems with the parachute harness connectors and concern about the protective tape wrapped around the wiring that could catch fire in a short circuit.
Work to correct these problems pushed the first manned flight to this year. When all was said and done, Boeing spent more than $1.5 billion of its own money to pay for the additional test flight and corrective actions.