'There was some tension in the room', NASA says of decision to bring Boeing's Starliner spacecraft home without astronauts

The decision to return Starliner home without astronauts on Friday (Sept. 7) was not without controversy, NASA said of discussions with Boeing.

The original plan had been to fly NASA astronauts Butch Wilmore and Suni Williams up to and down from the International Space Station on Starliner. Ongoing propulsion problems with Starliner, however, could not be resolved to a degree satisfying NASA's risk requirements. Astronauts Butch Wilmore and Suni Williams will remain on ISS for a long-duration space station stay and return home with the SpaceX Crew-9 mission in February 2025.

"I would say, anytime [...] where there's this kind of decision, there is some tension in the room," NASA's Steve Stich, program manager for the commercial crew program, said of the decision meeting to return Starliner without astronauts. Stich was speaking during a teleconference on Wednesday (Sept. 4). 

Boeing Starliner docked at the International Space Station during Crew Flight Test in 2024. (Image credit: NASA)

"Boeing believed in the model that they had created to predict thruster degradation for the rest of the flight," Stich added. "The NASA team looked at the model and saw some limitation. It really had to do with, do we have confidence in the thrusters, and how much we could predict their degradation from undock through the deorbit burn?"

The spacecraft is set to depart the ISS without its crew on Sept. 6 for a return to Earth on Sept. 7, to conclude a mission odyssey that began June 5 after launching its first astronauts to space. It was supposed to be only a 10-day mission, although there was flexibility given the mission was developmental.

Starliner's historic first test mission with astronauts had issues docking with the ISS on June 6 after five thrusters (out of 28) in its reaction control system misbehaved. Months of space testing, ground testing and modeling followed, but the possible root cause — overheating of the thrusters, which may lead to insulation shedding that blocks propulsion lines — could not be firmly confirmed. 

NASA ultimately determined it was too much of a risk to put the two NASA astronauts back on board Starliner, and changed its ISS manifest to bring the astronauts home in another way. 

Related: Boeing's 1st crewed Starliner to return to Earth without astronauts on Sept. 6

NASA astronauts Butch Wilmore (left) and Suni Williams during their Crew Flight Test mission on the International Space Station in 2024. (Image credit: NASA)

"From a Boeing standpoint, they certainly know their spacecraft, and they're analyzing risks and what they think the capability is with the one vehicle," Stich said. But he noted "Boeing is not in a position" to make the same risk trades that NASA does, which he said is an unfair position to put them in given the decision involved bringing in other spacecraft (SpaceX's Crew Dragon.)

"You also have to recognize that the agency is in a bit of a different position in terms of our understanding about the risks, and what's available to us without Starliner, so that's also a difference in the opinions," Stich acknowledged.

Boeing's commercial crew manager, Mark Nappi, was on the call but did not comment on the meeting Stich was speaking about. Boeing's statement on the flight readiness review last week noted that the teams at Boeing "continue to focus, first and foremost, on the safety of the crew and spacecraft."

"We are executing the mission as determined by NASA, and we are preparing the spacecraft for a safe and successful uncrewed return," Boeing officials added on X, formerly Twitter, on Aug. 24.

To make room for Starliner's two astronauts, Crew-9 was tasked to launch only two astronauts on Crew Dragon instead of the planned four. 

NASA astronaut and Space Force Guardian Nick Hague was promoted from Crew-9 pilot to commander, flying to space alongside Roscosmos cosmonaut and mission specialist Aleksandr Gorbunov; Gorbunov's seat is part of a larger set of interagency seat swaps that are difficult to reschedule. The two other Crew-9 members, NASA astronauts Zena Cardman and Stephanie Williams, will sit out this mission and be eligible for assignment to a future one.

As for Starliner, after it undocks from the ISS solo, it will likely be tasked with doing a few "hot fires" as it performs a rapid retreat from the orbiting complex, as part of ongoing testing of the propulsion system to see what engineers can learn. (This is especially important as the service module, which houses the affected thrusters and fuel, is separate from the spacecraft and will burn up in Earth's atmosphere.)

"We'll do a slightly modified departure after the undocking," ISS program manager Dana Weigel said during the teleconference. "Shortly after, the command will be sent to do a breakout burn that will take Starliner up, over and back behind the station. This alternate approach — or this breakout burn — is something that we have planned for, and it's something that the vehicle is capable and certified of doing. It just helps us to get Starliner away from ISS more quickly."

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Elizabeth Howell
Former Staff Writer, Spaceflight (July 2022-November 2024)

Elizabeth Howell (she/her), Ph.D., was a staff writer in the spaceflight channel between 2022 and 2024 specializing in Canadian space news. She was contributing writer for Space.com for 10 years from 2012 to 2024. Elizabeth's reporting includes multiple exclusives with the White House, leading world coverage about a lost-and-found space tomato on the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?" (ECW Press, 2022) is co-written with astronaut Dave Williams. 

  • Viking
    Admin said:
    Boeing's Starliner spacecraft will fly back to Earth for a landing on Sept. 7, but without its crew. Its two astronauts will ride home on SpaceX Crew Dragon in February 2025.

    There was some tension in the room', NASA says of decision to bring Boeing's Starliner spacecraft home without astronauts : Read more
    Send two Boeing execs up on the Dragon and let them bring the Starliner home.
    Reply
  • trailrider
    If it weren't for the fact that Starliner will have to depart the station, freeing up the docking port, I'd be inclined to agree. However, I think it ought to be the engineers who designed the thruster section, or maybe the managers who insisted on the design, and whoever designed the thruster system and the "doghouses" that contain them. The idea of reusability is to get all the parts back that are critical so if there are problems you can look at them directly, and not guess about what is wrong!
    Reply
  • DrRaviSharma
    Jokes apart,

    It is prudent when there are choices, as we had if Columbia situation was as openly explained as Starliner's? I had suggested five options for Columbia on the eve after disaster and several were adapted for future missions. Even then Columbia Crew could have stayed on ISS.

    Anyway, we will hopefully get deeper analysis of service module thruster firings and firing frequency or sequence as well as performance of thrusters onboard the Command Module Starliner upon landing at California after Friday.

    Yes it is a costly business but we all know risks of test fights with humans as more are to come in Artemis moon revisits as many segments have to be yet proven.
    Finally I would like us (US) to have Boeing as an option if they can correct and demonstrate through future robotic and human space flights that Starliner is an option to fly humans in addition to crewed Dragon and falcon combination.

    It is necessary when genius like Elon Musk SpaceX control might one day be out of NASA's hands, and options must be kept to avoid Shuttle gap like periods.
    Regards.
    Thanks.
    Ravi
    Reply
  • edfran
    DrRaviSharma said:
    Jokes apart,

    It is prudent when there are choices, as we had if Columbia situation was as openly explained as Starliner's? I had suggested five options for Columbia on the eve after disaster and several were adapted for future missions. Even then Columbia Crew could have stayed on ISS.

    Anyway, we will hopefully get deeper analysis of service module thruster firings and firing frequency or sequence as well as performance of thrusters onboard the Command Module Starliner upon landing at California after Friday.

    Yes it is a costly business but we all know risks of test fights with humans as more are to come in Artemis moon revisits as many segments have to be yet proven.
    Finally I would like us (US) to have Boeing as an option if they can correct and demonstrate through future robotic and human space flights that Starliner is an option to fly humans in addition to crewed Dragon and falcon combination.

    It is necessary when genius like Elon Musk SpaceX control might one day be out of NASA's hands, and options must be kept to avoid Shuttle gap like periods.
    Regards.
    Thanks.
    Ravi
    The only option for Columbia was for another Shuttle to be sent up to bring the Columbia crew home. Columbia had no means to reach the ISS and no means of repair on orbit. If concern had been high enough, the crew could have found a way to inspect the wing integrity visually. BUT......even if they had seen the wing damage, there was nothing that could have done to save the crew. Some realized that, I believe.
    Reply
  • Jan Steinman
    DrRaviSharma said:
    Jokes apart…

    It is necessary when genius like Elon Musk…
    Oh, I thought we were still on the "jokes" part.

    Musk is a capitalist, not a genius. Unless by "genius", you mean someone who took a thriving and dominant social media platform and turned it to crap. Looks like Tesla is next.

    I can imagine Musk doing the same thing to space flight. The people under him have done some amazing things, but the banks are already clamouring for the money he wasted on "X", and someday he could decide to bleed his space business dry. Then, it will be rush things out for income, and and things like faulty thrusters.
    Reply
  • Unclear Engineer
    From https://en.wikipedia.org/wiki/Space_Shuttle_Columbia_disaster :

    "Possible emergency procedures
    In its report, the CAIB discussed potential options that could have saved Columbia's crew. They determined that the mission could have originally been extended for up to 30 days, after which the lithium hydroxide canisters that were used to remove carbon dioxide would have run out.: 173  On STS-107, Columbia was carrying the Extended Duration Orbiter, which increased its supply of oxygen and hydrogen.: 398  To maximize the mission duration, non-essential systems would have been powered down,: 399  and animals in the Spacehab module would have been euthanized.: 397

    "When STS-107 launched, Atlantis was undergoing preparation for the STS-114 launch on March 1, 2003. Had NASA management decided to launch a rescue mission, an expedited process could have begun to launch it as a rescue vehicle. Some pre-launch tests would have been eliminated to allow it to launch on time. Atlantis would have launched with additional equipment for EVAs, and launched with a minimum required crew. It would have rendezvoused with Columbia, and the STS-107 crew would have conducted EVAs to transfer to Atlantis. Columbia would have been remotely deorbited; as Mission Control would have been unable to remotely land it, it would have been disposed of in the Pacific Ocean.: 400–404

    "The CAIB also investigated the possibility of on-orbit repair of the left wing. Although there were no materials or adhesives onboard Columbia that could have survived reentry, the board researched the effectiveness of stuffing materials from the orbiter, crew cabin, or water into the RCC hole. They determined that the best option would have been to harvest tiles from other places on the orbiter, shape them, and then stuff them into the RCC hole. Given the difficulty of on-orbit repair and the risk of further damaging the RCC tiles, the CAIB determined that the likelihood of a successful on-orbit repair would have been low.: 405–406"
    Reply
  • Unclear Engineer
    Regarding Jan's post:

    I do agree that Musk's behavior is a vulnerability for SpaceX. That is just an additional reason for NASA and Space Force to continue to work to create options for launch, orbiters, etc.

    But we also need to be realistic about the likelihood that Boeing will provide a viable option in the near future. Recently, Boeing has been failing in a lot of ways, and it also could just decide to no longer even attempt to support NASA because it is losing money doing so.

    Regarding "capitalists" building space systems. we really don't have an option. The U.S. government does not have enough control to marshal all of the people and resources needed just with government employees.

    Even "totalitarian" states such as the Soviet Union and China found it necessary to have "industrial leaders" who could effectively produce the technological products desired by the political leaders. And, those "industrial leaders" became personally wealthy and powerful enough politically that the politicians themselves began to feel threatened by them.

    So, let's put aside the political system sniping comments and focus on the realities of the available options. The U.S. is not going to change its political system in order to reach the Moon again or Mars, either. Nor should it, considering that it is not necessary nor even the least desirable available option. Any strategy that involves all people being perfect and behaving selflessly simply is not a realistic option available to us.
    Reply
  • COLGeek
    Political discussions are off the table gents. Please remember that. Thank you.
    Reply
  • DrRaviSharma
    My comments were not about a person, it was on redundancy and fearless sharing of such events on space missions. My two incidents were Apollo 13 where I was personally able to make mission sequence changes. Another but sad opportunity was for Columbia which I suggested 5 options could have been used. Your details amplified the solutions similar to what 5 suggestions I made and 3 of those were followed till Shuttle was retired (prematurely in my opinion).
    Also whatever be our system, Falcon, Starship when operational provide us independence from Russian dependence, and we are still hoping that Starliner could be an alternative for not depending on single source.
    Thanks.
    Ravi
    Reply
  • starman2
    I believe the decision was correct. From the report which states the thrusters "went offline" it indicates the problem is with the electronics that control the thrusters. What probably occurred was a Single Event Upset (SEU) which is due to radiation. If the electronics are weak and lack shielding, it is left open to a SEU.

    More info: https://www.rlassoc.org/Space%20News/Weather%20in%20Space/space_weather.htm
    Reply