NASA plans two more Boeing Starliner flights and an uncrewed test of the capsule's thruster fixes
NASA intends to exercise options for a fifth and sixth Boeing Starliner flight and to fly an uncrewed test as early as December, with crew returning by 2028. The plan would keep a second US crew capsule available beside SpaceX's Crew Dragon, if Boeing's thruster fixes hold up in flight.
The Scientist · Science desk
What happened
- On Starliner's 2024 crewed test, Butch Wilmore and Suni Williams went up for an eight-day stay and spent 286 days on the station, coming home in a SpaceX Dragon.
- NASA's investigation found the service module thrusters ran outside their engineering qualification, causing the loss of control, with heat and design features among the factors.
- Boeing has made thermal modifications to the service module, and NASA and Boeing have also agreed on an added thruster valve design change.
Why it matters
- What it limits constraint Starliner-1 can confirm the thermal fix, but the finished valve redesign, new crew module thrusters and batteries come afterwards, so astronauts on Starliner-2 would fly hardware the test did not.
- What doesn't add up contradiction NASA's release emphasizes thermal and design causes; Scientific American reports the investigation ranked lax NASA oversight first, and a test flight's data cannot show whether that has changed.
- Who's exposed exposure Each slip in the 2028 crew date lengthens NASA's dependence on Crew Dragon, a capsule SpaceX has said it wants to retire in favor of Starship.
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Starliner-1 is an experiment built around one variable. NASA describes it as an engineering evaluation mission to verify improved thermal environments, obtain performance data for system qualification and identify residual risk ahead of crewed missions [3]. The variable is heat. Ground testing and analysis traced the thruster trouble to a combination of factors, including the thermal environment and features of the design [17], and the flight is where NASA will evaluate Boeing's thermal changes to the service module [8].
Dana Weigel, manager of NASA's Low Earth Orbit Program, said NASA "will test Starliner's propulsion system through targeted demonstration objectives and disciplined operational controls" [4]. NASA Administrator Jared Isaacman described the order of work. "We are starting with an uncrewed Starliner-1 mission to the International Space Station to validate the improvements made to the spacecraft and gather the flight data we need," he said [2].
I think that sequence is sound for the question it asks: fly the thermal change without people, then finish the valve work afterwards [9]. The thing this doesn't tell you is how the crewed vehicle will behave. After the flight, NASA and Boeing will complete a valve modification aimed at poppet seal extrusion, a seal problem NASA says harms thruster performance [9]. The same post-flight list includes new crew module thrusters, new batteries and minor parachute changes [10]. Isaacman said NASA would then "complete the testing and certification required for crewed flight" [16], so evidence for those later changes has to come from that work. The release does not say which rocket will launch Starliner-1. Vulcan certification applies after the Atlas V's final flight [14], and the Atlas V is no longer in production, according to Scientific American [15].
The 2024 flight is the baseline. After a helium leak and malfunctioning thrusters, NASA decided Butch Wilmore and Suni Williams could not return aboard the capsule [11]. Their stay ran about 36 times its planned length [23]. If Starliner-2 carries crew by 2028, up to four years will separate crewed Starliner flights [24]. Scientific American reports that Woody Hoburg, the NASA astronaut on Monday's briefing panel [22], would command that mission [19].
Isaacman put the case for keeping Starliner in terms of redundancy. "NASA has been committed to having multiple crew transportation options since the beginning of the Commercial Crew Program," he said [7]. Crew Dragon is currently the only operational capsule that can carry NASA astronauts, and SpaceX has been open about wanting to retire it and the Falcon 9 in favor of Starship, Scientific American reported [6].
The two accounts of what went wrong in 2024 differ in emphasis. NASA's release describes programmatic and technical issues and 61 recommendations to the agency [21]. Scientific American reports that the February report named lax NASA oversight of Boeing, a lack of data transparency with vital personnel and poor decision making as the biggest cause [18]. A test flight returns thermal and thruster data. Whether oversight has changed will have to be shown another way; Isaacman said NASA will keep implementing the investigation team's corrective actions [16].
What to watch
- Whether Starliner-1 launches in the December to January 2027 window NASA gave, and on which rocket.
- What Starliner-1's thermal and thruster data show, and what residual risk NASA reports before finishing the valve redesign.
- The formal exercise of options for flights five and six, and progress on certifying Vulcan to carry crew.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence68
- Adoption20
- Hype gap+12
- Incentives70
- Confidence66
Perspective Coverage
3 publishers- Builder
- Builder 31%
- Operator
- Operator 47%
- Investor
- Investor 22%
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
The uncrewed Starliner-1 has the potential to fly in December of this year or January 2027.
- [2]
"We are starting with an uncrewed Starliner-1 mission to the International Space Station to validate the improvements made to the spacecraft and gather the flight data we need,"
- [3]
Starliner-1 will be an engineering evaluation mission to verify improved thermal environments, obtain necessary performance data for system qualification, and identify residual risk ahead of crewed missions.
- [4]
"With the safety of our space station crew and the public as our highest priority, we will test Starliner's propulsion system through targeted demonstration objectives and disciplined operational controls."
- [5]
"Our current plan is to return astronauts on Starliner-2 by 2028."
- [6]
SpaceX's Crew Dragon is the only operational crew capsule that can ferry NASA astronauts; SpaceX has not been shy about wanting to sunset Falcon 9 and Crew Dragon in favor of Starship.
- [7]
"NASA has been committed to having multiple crew transportation options since the beginning of the Commercial Crew Program."
- [8]
Boeing has made thermal modifications to the spacecraft's service module, which NASA will evaluate on Starliner-1; NASA and Boeing have also jointly decided to implement an additional thruster valve design modification.
- [9]
Following the flight, NASA and Boeing will complete the service module thruster valve design modification, focused on addressing poppet seal extrusion and its adverse effects on thruster performance.
- [10]
Boeing also will implement other improvements including new crew module thrusters, batteries, and minor modifications to the parachute system.
- [11]
On the 2024 crewed test, Starliner carried Butch Wilmore and Suni Williams to the ISS for a planned eight-day stay; a helium leak and malfunctioning thrusters led NASA to decide they could not return aboard the capsule.
- [12]
Wilmore and Williams, on what was supposed to be an eight-day stay, spent 286 days on the ISS before returning in a SpaceX Dragon capsule.
- [13]
NASA intends to exercise options for a fifth and sixth flight to and from the space station using Starliner.
- [14]
NASA will work with Boeing and United Launch Alliance to certify the Vulcan rocket for use after the Atlas V rocket's final flight.
- [15]
Starliner originally flew on ULA's Atlas V, which is no longer in production; NASA plans to use ULA's Vulcan Centaur for future Starliner missions.
- [16]
"From there, we will use what we learn, continue implementing the corrective actions identified by our Program Investigation Team, and complete the testing and certification required for crewed flight."
- [17]
The investigation identified Starliner's service module reaction control thrusters operating outside their engineering qualification, which resulted in the loss of control during the Crew Flight Test; ground testing and analysis found the thruster issues resulted from a combination of factors, including the thermal environment and features inherent in the design.
- [18]
The February report concluded the biggest cause of the failed mission was lax NASA oversight of Boeing, a lack of data transparency with vital personnel and poor decision making.
- [19]
A crewed Starliner mission in 2028 would be under the command of NASA astronaut Woody Hoburg (spelled Hobert by Scientific American).
- [20]
"He's an absolutely brilliant guy who's helping on a lot of our mission priorities, and I am confident his experience will serve this mission incredibly well,"
- [21]
In February NASA released Program Investigation Team findings on the programmatic and technical issues behind the uncrewed return of Starliner in 2024; the investigation identified 61 recommendations to NASA.
- [22]
The Monday, Sept. 28 news conference participants were Jared Isaacman, Dana Weigel, NASA astronaut Woody Hoburg and John Mulholland of Boeing Commercial Crew.
- [23]
The astronauts' 286-day stay was about 36 times the planned eight days.
- [24]
If Starliner-2 carries crew by 2028, up to four years separate crewed Starliner flights.
Sources
3 independent publishers whose own reporting we read for this story.
- nasa.govNASA, Boeing to Provide Update on Starliner Development
2 articles · September 28, 2026
- phys.orgNASA ramps up support to get Boeing's astronaut capsule flying after Butch and Suni fiasco
2 articles · September 29, 2026
- scientificamerican.comNASA to attempt uncrewed and crewed missions with Boeing’s troubled Starliner spacecraft
1 article · September 28, 2026
Topics and entities
Topics
- Human spaceflight safety
- Commercial Crew Program
- International Space Station operations
Entities
- Boeing
- International Space Station
- NASA
- Jared Isaacman
- Boeing Starliner
- United Launch Alliance
- SpaceX