Top NASA leaders, including NASA Administrator Bill Nelson, are meeting in Houston on Saturday to decide whether Boeing’s Starliner spacecraft is safe enough to return astronauts Butch Wilmore and Suni Williams to Earth from the International Space Station.
The Flight Readiness Review (FRR) is expected to conclude with NASA’s most significant safety decision in nearly a generation. One option is to detach the Starliner spacecraft carrying Wilmore and Williams from the space station in early September as originally planned, or to return the capsule to Earth without a crew member.
As of Thursday, the two veteran astronauts had spent 77 days aboard the space station, nearly 10 times longer than the eight-day stay they had originally planned. Wilmore and Williams were the first to launch and dock with the space station aboard the Starliner spacecraft, but as they neared orbit, which they completed on June 6, multiple thrusters failed and the capsule’s propulsion system leaked helium.
That led to months of testing in space and on the ground, data reviews, and modeling by engineers trying to figure out the root cause of the thruster problems. Engineers believe the thrusters overheated, causing Teflon seals to bulge, blocking the flow of propellant to small control jets and resulting in a loss of thrust. The thrusters’ condition improved once Starliner docked with the station, which eliminated the repeated burns required when the spacecraft was flying alone.
But engineers and managers have yet to agree on whether the same problems will recur or worsen on the capsule’s journey back to Earth. In a worst-case scenario, if too many thrusters fail, the spacecraft won’t be able to properly orient itself to make the crucial braking burn that will bring the capsule back into the atmosphere for landing.
The suspect thrusters are installed in Starliner’s Service Module, which will perform the deorbit burn and then separate from the Crew Module carrying the astronauts before re-entry. Another set of smaller engines will fine-tune Starliner’s trajectory during descent.
If NASA officials decide it’s not worth the risk, Wilmore and Williams could stay on the space station until at least February of next year, returning to Earth on a Dragon spacecraft provided by SpaceX, Boeing’s rival in NASA’s Commercial Crew Program. That would eliminate any threat to the crew’s safety from thruster problems on the Starliner spacecraft on the journey to Earth, but it would come with myriad side effects.
Those impacts include disrupting space station crew operations by removing the two astronauts from SpaceX’s upcoming flight, exposing Wilmore and Williams to additional radiation while in space, and dealing a devastating blow to Boeing’s Starliner program.
If Boeing’s capsule can’t return two astronauts to Earth, NASA may not approve Starliner for operational crew missions without additional test flights, which would mean Boeing wouldn’t be able to complete all six crew missions under its $4.2 billion contract with NASA before the International Space Station is retired in 2030.
FRR-Right to Speak
The flight readiness review at NASA’s Johnson Space Center in Houston begins Saturday morning. Former astronaut and NASA Space Operations Mission Directorate director Ken Bowersox will chair the meeting. NASA Administrator Bill Nelson will also participate. If the FRR does not reach unanimous agreement, the final decision could go to NASA Deputy Administrator Jim Freeh or Nelson, who ranks above Bowersox.
“Formal objections are presented and reconciled during NASA’s flight readiness reviews,” NASA said in a statement Thursday. “Other agency leaders who regularly participate in human mission launch and return readiness reviews include NASA’s Administrator, Deputy Administrator, Under Secretary, directors of various agency centers, flight operations offices, and agency technical officials.”
NASA said it plans to hold a press conference after 1pm ET on Saturday to announce the agency’s decision and future steps.
Lower-level managers will meet Friday in what’s called a program management board to discuss their findings and positions before the FRR. At the last program management board meeting, managers were divided on whether NASA was ready to approve the Starliner spacecraft as safe enough to return astronauts to Earth.
There is one new piece of information that engineers will report to the program management committee on Friday.
“Engineering teams have been working to evaluate new models designed to represent how thrusters work and more accurately predict performance during the return phase of the flight,” NASA said. “This data may help the team better understand system redundancy from undocking through separation of the Service Module. Ongoing efforts to complete new modeling, characterize spacecraft performance data, refine the integration risk assessment, and determine community recommendations will be incorporated into the agency-level review.”
