Uncrewed Starliner Undocks from Station for Return to Earth

The uncrewed Starliner spacecraft backs away from the International Space Station shortly undocking from the Harmony module. Credit: NASA+
The uncrewed Starliner spacecraft backs away from the International Space Station shortly undocking from the Harmony module. Credit: NASA+

At 6:04 p.m. EDT, Boeing’s uncrewed Starliner spacecraft undocked from the International Space Station. Starliner is headed for a deorbit burn at 11:17 p.m. and a targeted landing at 12 a.m. Saturday, Sept. 7, at White Sands Space Harbor in New Mexico.

NASA’s coverage will begin at 10:50 p.m. for deorbit burn, entry, and landing on NASA+, the NASA app, YouTube, and the agency’s website.


Learn more about the mission by following the commercial crew blog, @commercial_crew on X, and @NASACommercialCrew on Facebook.

Learn more about station activities by following the space station blog, @space_station and @ISS_Research on X, as well as the ISS Facebook and ISS Instagram accounts.

Get weekly updates from NASA Johnson Space Center at: https://roundupreads.jsc.nasa.gov/

Get the latest from NASA delivered every week. Subscribe here: www.nasa.gov/subscribe

Starliner Nears Departure, Crew Focuses on Space Research

Boeing's Starliner spacecraft is pictured from a window on the SpaceX Dragon Endeavour spacecraft docked to the Harmony module's forward port.
Boeing’s Starliner spacecraft is pictured from a window on the SpaceX Dragon Endeavour spacecraft docked to the Harmony module’s forward port.

Mission managers have given the first “go” for the Boeing Starliner spacecraft to undock from the International Space Station at 6:04 p.m. EDT on Friday and land in New Mexico about six hours later. NASA astronauts Butch Wilmore and Suni Williams have finished packing Starliner with cargo and configuring its cabin for return. The duo closed Starliner’s hatch for the final time Thursday afternoon readying the spacecraft for its uncrewed departure.

Wilmore and Williams will remain aboard the orbital outpost until February when they are scheduled to return to Earth aboard the SpaceX Dragon spacecraft with the Crew-9 mission. Starliner’s departure coverage begins at 5:45 p.m. Friday on NASA+, the NASA appYouTube, and the agency’s website.

In the meantime, a multitude of science occurred aboard the orbital outpost on Thursday with the crew exploring microgravity’s effect on the heart and breathing, space botany, fire safety, and Earth observations. Scientists on the ground analyze the research data for unique insights on improving human health on and off the planet as well as promoting Earth and space industries.

Expedition 71 Flight Engineer Tracy C. Dyson kicked off her day wearing a sensor-packed headband and vest while pedaling on an exercise cycle inside the Destiny laboratory module. Her cardio-respiratory data was recorded to a computer helping scientists understand how weightlessness affects a crew member’s blood pressure and breathing.

NASA astronaut Mike Barratt photographed and watered plants growing for the C4 Photosynthesis in Space experiment inside the Columbus laboratory module’s Veggie space botany facility. The investigation observes space-caused photosynthesis and plant metabolism changes in two types of grasses growing inside the EXPRESS Rack’s Veggie research device. Results may inform bioregenerative life support systems on future spacecraft and boost fundamental knowledge of botanical processes on Earth.

Fire safety on spacecraft is just as critical and important as fire safety on Earth. However, flames and materials burn differently in the weightless environment requiring a different approach to fire protection. Researchers are using the space station’s Combustion Integrated Rack (CIR) to safely study flames in space to learn how to protect spacecraft and space habitats. NASA Flight Engineer Jeanette Epps swapped components and removed burnt samples inside the CIR for a series of experiments exploring space flammability and fire suppression in microgravity.

Pointing his camera out a window in the cupola and toward the Moon, NASA Flight Engineer Matthew Dominick photographed light reflecting off the lunar surface illuminated from Earth, also called earthshine. Measuring changes in Earth’s light reflected from the Moon may help scientists update their climate models and inform the design of future atmosphere observing satellites.

Roscosmos Commander Oleg Kononenko spent his day preparing for upcoming Soyuz spacecraft operations. The five-time station resident is collecting cargo that will soon be packed in the Soyuz MS-25 spacecraft for its departure in late September. Afterward, the veteran cosmonaut readied the Rassvet module for the Sept. 11 docking of the Soyuz MS-26 crew ship bringing to the orbital lab NASA astronaut Don Pettit and Roscosmos cosmonauts Alexey Ovchinin and Ivan Wagner. Flight Engineers Nikolai Chub and Alexander Grebenkin split their day conducting a variety of Roscosmos research and lab maintenance tasks. Chub and Kononenko also participated in eye checks at the end of the day on Thursday.

The ISS Progress 89 cargo craft docked to the Zvezda service module’s rear port fired its thrusters at 3:45 p.m. for 13 minutes today raising the space station’s altitude. The orbital reboost is the third and final maneuver setting up the proper phasing for the arrival of the Soyuz MS-26 next week and Starliner’s undocking opportunity on Friday.


Learn more about station activities by following the space station blog@space_station and @ISS_Research on X, as well as the ISS Facebook and ISS Instagram accounts.

Get weekly video highlights at: https://roundupreads.jsc.nasa.gov/videoupdate/

Get the latest from NASA delivered every week. Subscribe here: www.nasa.gov/subscribe

NASA, Boeing Discuss Ground Testing, Forward Work for Starliner Return

Boeing's Starliner spacecraft as it approaches the International Space Station. Also in view is the Earth below it.
Boeing’s Starliner spacecraft, with NASA astronauts Butch Wilmore and Suni Williams aboard, approaches the International Space Station for an autonomous docking as it orbited 257 miles above the South Pacific Ocean on June 6, 2024. Photo credit: NASA Television

NASA and Boeing leadership provided an update on Starliner’s Crew Flight Test during a news conference Thursday. The integrated Starliner team continues to assess the spacecraft’s propulsion system performance and complete other tasks before scheduling its undocking from the International Space Station and return to Earth. Watch the full replay of the news conference.

Engineering teams from NASA and Boeing recently wrapped up ground hot fire testing of a Starliner reaction control system thruster at the agency’s White Sands Test Facility in New Mexico. The test series involved firing the engine under conditions like those the spacecraft experienced during its approach to the space station. The tests also included various stress-case scenarios to simulate the conditions expected during Starliner’s undocking and deorbit burn, which will position the spacecraft for landing in the southwestern United States. Teams are in the process of taking apart this thruster to conduct physical inspections. Initial findings show degraded thruster performance, which aligns with what has been observed in orbit.

Additionally, NASA and Boeing will conduct a second docked hot fire test over the weekend to demonstrate the spacecraft’s thruster performance. The first docked hot fire test occurred on June 15. The upcoming test will allow checks of the helium leaks while also verifying the thrusters are operating as expected.

NASA plans to hold an agency-level readiness review no earlier than next week. Following the review, mission leadership will finalize the plan for a normal return to Earth and select a targeted undocking date for Starliner. NASA also plans to host a televised briefing with agency and Boeing leadership following the review. More news conference details will be shared when available.

NASA astronauts Butch Wilmore and Suni Williams continue to provide additional crew time and valuable contributions aboard the space station, assisting with science investigations and helping ground teams collect critical data for post-certification, long-duration Starliner flights to the orbiting complex.

Follow the commercial crew blog, @commercial_crew on X, and commercial crew on Facebook for the latest mission updates.

UPDATE: NASA, Boeing to Stream Flight Test Mission Briefing on NASA+

Image shows Boeing's Starliner spacecraft that launched NASA's Crew Flight Test astronauts Butch Wilmore and Suni Williams to the International Space Station is pictured docked to the Harmony module's forward port. This long-duration photograph was taken at night from the orbital complex as it soared 258 miles above western China.
Boeing’s Starliner spacecraft that launched NASA’s Crew Flight Test astronauts Butch Wilmore and Suni Williams to the International Space Station is pictured docked to the Harmony module’s forward port. This long-duration photograph was taken at night from the orbital complex as it soared 258 miles above western China. Photo credit: NASA

NASA and Boeing will host a news conference with mission leadership at 11:30 a.m. EDT Thursday, July 25, to provide the latest status of the agency’s Boeing Crew Flight Test aboard the International Space Station. NASA previously planned an audio-only media teleconference to host the discussion.

The agency will provide live coverage on NASA+, NASA Television, the NASA appYouTube, and the agency’s website. Learn how to stream NASA content through a variety of platforms, including social media.

Participants include:

  • Steve Stich, manager, NASA’s Commercial Crew Program
  • Mark Nappi, vice president and program manager, Commercial Crew Program, Boeing

United States-based media seeking to attend in person must contact the newsroom at NASA’s Johnson Space Center in Houston no later than 9:30 a.m. EDT Thursday, July 25, at 281-483-5111 or jsccommu@mail.nasa.gov. U.S. and international media interested in participating by phone must contact NASA Johnson or NASA’s Kennedy Space Center in Florida at ksc-newsroom@mail.nasa.gov by 10:30 a.m. the day of the event. A copy of NASA’s media accreditation policy is online.

Read the full advisory here.

NASA, Boeing to Discuss Crew Flight Test Mission, Ground Testing

Looking down at Boeing's Starliner spacecraft attached to the International Space Station.
The Starliner spacecraft on NASA’s Boeing Crew Flight Test is pictured docked to the Harmony module’s forward port as the International Space Station orbited 263 miles above the Mediterranean Sea. Photo credit: NASA

Leadership from NASA and Boeing will participate in a media teleconference at 11:30 a.m. EDT Thursday, July 25, to provide the latest status of the agency’s Boeing Crew Flight Test mission aboard the International Space Station.

Audio of the media teleconference will stream live on the agency’s website. Participants include:

  • Steve Stich, manager, NASA’s Commercial Crew Program
  • Mark Nappi, vice president and program manager, Commercial Crew Program, Boeing

Engineering teams with NASA and Boeing recently completed ground hot fire testing of a Starliner reaction control system thruster at White Sands Test Facility in New Mexico. The test series involved firing the engine through similar in-flight conditions the spacecraft experienced during its approach to the space station, as well as various stress-case firings for what is expected during Starliner’s undocking and the deorbit burn that will position the spacecraft for a landing in the southwestern United States. Teams are analyzing the data from these tests, and leadership plans to discuss initial findings during the call.

Read the full advisory here.

NASA, Boeing Complete Starliner Engine Testing, Continue Analysis

Boeing's Starliner spacecraft that launched NASA's Crew Flight Test astronauts Butch Wilmore and Suni Williams to the International Space Station is pictured docked to the Harmony module's forward port. This long-duration photograph was taken at night from the orbital complex as it soared 256 miles above the Arabian Sea off the coast of Mumbai, India.
Boeing’s Starliner spacecraft that launched NASA’s Crew Flight Test astronauts Butch Wilmore and Suni Williams to the International Space Station is pictured docked to the Harmony module’s forward port. This long-duration photograph was taken at night from the orbital complex as it soared 256 miles above the Arabian Sea off the coast of Mumbai, India. Photo credit: NASA

NASA and Boeing engineers are evaluating results from last week’s engine tests at NASA’s White Sands Test Facility in New Mexico as the team works through plans to return the agency’s Boeing Crew Flight Test from the International Space Station in the coming weeks.

Teams completed ground hot fire testing at White Sands and are working to evaluate the test data and inspect the test engine. The ongoing ground analysis is expected to continue throughout the week. Working with a reaction control system thruster built for a future Starliner spacecraft, ground teams fired the engine through similar inflight conditions the spacecraft experienced on the way to the space station. The ground tests also included stress-case firings, and replicated conditions Starliner’s thrusters will experience from undocking to deorbit burn, where the thrusters will fire to slow Starliner’s speed to bring it out of orbit for landing in the southwestern United States. For a detailed overview of the test plans, listen to a replay of a recent media teleconference with NASA and Boeing leadership.

“I am extremely proud of the NASA, Boeing team for their hard work in executing a very complex test series,” said Steve Stich, manager, NASA’s Commercial Crew Program. “We collected an incredible amount of data on the thruster that could help us better understand what is going on in flight. Next, our team has moved into engine tear downs and inspections which will provide additional insight as we analyze the results and evaluate next steps.”

Integrated ground teams also are preparing for an in-depth Agency Flight Test Readiness Review, which will evaluate data related to the spacecraft’s propulsion system performance before its return to Earth. The date of the agency review has not yet been solidified.

NASA and Boeing leadership plan to discuss the testing and analysis work in detail during a media briefing next week. More information on the briefing will be made available soon.

While testing and analysis are happening on Earth, NASA astronauts Butch Wilmore, Starliner mission commander, and Suni Williams, mission pilot, are working alongside the Expedition 71 crew. The two participated in vein scans using the Ultrasound 2 device on Monday. Doctors on the ground monitored in real-time as the pair took turns imaging each other’s neck, shoulder, and leg veins. Afterward, Wilmore scanned the veins of fellow NASA astronaut Matthew Dominick, helping researchers understand how microgravity affects the human body.

Wilmore and Dominick also spent a portion of the day taking inventory of the food stored aboard the space station. Williams worked on a pair of studies, first exploring the use of microgravity to manufacture higher-quality optical fibers than on Earth. Williams also investigated using fluid physics, such as surface tension, to overcome the lack of gravity when watering and nourishing plants grown in space.

Follow the commercial crew blog, @commercial_crew on X, and commercial crew on Facebook for the latest mission updates.

Crew Flight Test Astronauts Contribute to Station Science, Research

NASA's Boeing Crew Flight Test astronauts Suni Williams and Butch Wilmore prepare orbital plumbing hardware for installation inside the International Space Station’s bathroom
NASA’s Boeing Crew Flight Test astronauts Suni Williams and Butch Wilmore prepare orbital plumbing hardware for installation inside the International Space Station’s bathroom, also known as the waste and hygiene compartment, located in the Tranquility module. Photo credit: NASA

NASA astronauts Butch Wilmore, commander, and Suni Williams, pilot, of NASA’s Boeing Crew Flight Test, continue contributing to International Space Station research and activities since their arrival on June 6 to the orbiting laboratory. Wilmore and Williams have completed half of all hands-on research time conducted aboard the station as the expedition crew prepares for the departure of Northrop Grumman’s Cygnus. As packing takes most of the crew’s time, the extra help from Wilmore and Williams allows packing and research to happen simultaneously. To learn more about what other crew members are doing aboard the International Space Station, visit: blogs.nasa.gov/spacestation.

Media are invited to hear Wilmore and Williams discuss their mission during an Earth-to-space call at 11 a.m. EDT Wednesday, July 10. Read the agency’s coverage advisory for more information.

On July 1, Wilmore and Williams spent the morning in the Permanent Multipurpose Module, organizing stowage and tidying up. Wilmore then moved into the Japanese Experiment Module to disassemble an empty NanoRacks CubeSat Deployer in preparation for upcoming NanoRacks missions.

Later, Wilmore prepped and viewed samples for the Moon Microscope, a demonstration that allows flight surgeons on Earth to diagnose illnesses and could provide diagnostic capabilities for crews on future missions to the Moon and Mars. Meanwhile, Williams conducted some routine orbital pluming, then audited U.S. stowage items housed inside the Zarya module.

On July 2, Wilmore joined NASA astronaut Tracy Dyson to load trash and discarded gear inside Northrop Grumman’s Cygnus spacecraft. Cygnus is scheduled to be released from the Unity module later this month for disposal over the South Pacific Ocean, ending its five-and-a-half-month stay at the orbiting lab.

Williams spent most of Tuesday on Starliner operations and then assessed the air flow of the pump filter attached to the Advanced Plant Habitat. At the end of the day, Williams and all eight of her crewmates held a conference with ground teams.

Also, on July 2, teams brought the Starliner spacecraft out of quiescent mode to conduct mission data loads, or MDLs. These are files for the spacecraft’s computer to understand current inertial and relative navigation states, Earth rotation, thermal conditioning, and more. The spacecraft was commanded back to a docked quiescent mode after MDL loading was complete.

For more information on NASA’s Commercial Crew Program, visit:

https://www.nasa.gov/commercialcrew

NASA, Boeing Discuss Ground Testing, Starliner Timeline

The Starliner spacecraft on NASA's Boeing Crew Flight Test is pictured docked to the Harmony module's forward port as the International Space Station orbited 262 miles above Egypt's Mediterranean coast.
The Starliner spacecraft on NASA’s Boeing Crew Flight Test is pictured docked to the Harmony module’s forward port as the International Space Station orbited 262 miles above Egypt’s Mediterranean coast. Photo credit: NASA

During a media teleconference Friday, leaders from NASA and Boeing provided an update about Starliner’s Crew Flight Test. The integrated Starliner team continues to evaluate the spacecraft’s propulsion system performance and complete other forward work before scheduling undocking from the International Space Station. Listen to a full replay of the teleconference.

“Our goal is to bring Butch and Suni home aboard Boeing’s spacecraft, and we are working to confirm Starliner will perform as designed to return them safely to Earth,” said Ken Bowersox, associate administrator, NASA’s Space Operations Mission Directorate, NASA Headquarters in Washington. “Space station gives us the luxury of time, allowing us to look at data we gathered on the way uphill and conduct some additional testing. We’re still in the middle of a test mission, and we want to spend more time with the data before we make the final call to put the crew aboard the spacecraft for return.”

NASA and Boeing will conduct additional ground testing at White Sands Test Facility in New Mexico to better understand the spacecraft’s thruster performance. This testing will expose Starliner’s thrusters to flight-like pulse counts and thermal conditions for ground teams to inspect and analyze. The data collected also will help determine system improvements for future post-certification missions to station.

“We spent a lot of time working to determine whether we could get meaningful data from a ground hot fire to better inform our decision making in flight, and I am extremely proud of our integrated NASA and Boeing teams for coming up with some innovative options and leveraging testing plans that were already in place for future missions,” said Steve Stich, manager of NASA’s Commercial Crew Program. “Based on the continued performance of Starliner while docked, we are working with station to extend the certification of several components beyond a 45-day mission duration, if needed, so our engineering teams can take the time they need while Butch and Suni support various in-orbit activities that are critical for sustaining station operations and research.”

Engineering teams are working to finalize testing plans and a timeline for the additional ground testing, which should occur over the next two weeks. They are taking advantage of the extra time by gathering as much data as possible while docked to station, considering the service module will not be recovered at the end of the mission.

Since Starliner’s arrival on June 6 with NASA astronauts Butch Wilmore and Suni Williams aboard, mission teams have been working to complete open work related to managing five small leaks in the spacecraft’s service module helium manifolds while reaffirming the health of the spacecraft’s reaction control system thrusters. Starliner remains available in case of an emergency on the space station that would require the crew to leave orbit immediately and return to Earth.

In addition to monitoring the hardware in orbit, which is operating normally in a docked state, NASA and Boeing continue testing and analysis on the ground by exploring potential causes for the helium system leaks and analyzing instrumentation data on Starliner’s thrusters. Engineers are working to gauge potential helium leak rates that may occur after undocking, validate operational mitigations for use in flight as needed, and explore fault tree considerations beyond what the teams have already gathered from the flight data.

They also are evaluating recent ground test results that showed better than expected performance of Starliner’s thruster instrumentation. Based upon these results, engineering teams have confidence that Starliner’s thruster pressure transducers are not overheating in flight and causing premature deselects of the thrusters in orbit, which was initially considered to be a possibility. Meanwhile, simulated propulsion system contingency scenarios continue to be worked in the lab to ensure expected performance of Starliner’s backup systems and thruster combinations for use during the return if needed.

Once all the necessary ground testing and associated data analysis is complete, leaders from NASA’s Commercial Crew and International Space Station Programs and Boeing will conduct an agency-level review. During the review, senior agency leaders and mission managers will discuss their findings and options with the broader NASA community, including international partners, to formally document the agency’s acceptance of Starliner’s flight plan and evaluate future return opportunities.

NASA plans to host a televised media briefing following the agency review to discuss the next steps ahead of Starliner’s return. The agency will share details on that briefing once it is finalized.

Wilmore and Williams continue to provide additional crew time and valuable contributions aboard the space station, assisting with spacewalks and science investigations while helping ground teams collect critical data for post-certification, long-duration Starliner flights to the orbiting complex.

Follow the commercial crew blog, @commercial_crew on X, and commercial crew on Facebook for the latest mission updates.

NASA, Boeing Target June 22 for Flight Crew Test Return

This view from a window on the cupola overlooks a portion of the International Space and shows the partially obscured Starliner spacecraft from Boeing docked to the Harmony module's forward port.
This view from a window on the cupola overlooks a portion of the International Space and shows the partially obscured Starliner spacecraft from Boeing docked to the Harmony module’s forward port. Photo credit: NASA

NASA and Boeing now are targeting no earlier than Saturday, June 22, to return the agency’s Boeing Crew Flight Test mission from the International Space Station. The extra time allows the team to finalize departure planning and operations while the spacecraft remains cleared for crew emergency return scenarios within the flight rules.

NASA and Boeing leadership will discuss the details of the new return target, flight status, and weather considerations for landing during a pre-departure media teleconference at 12 p.m. EDT Tuesday, June 18. NASA will provide additional media teleconference details soon.

“We are continuing to understand the capabilities of Starliner to prepare for the long-term goal of having it perform a six-month docked mission at the space station,” said Steve Stich, manager of NASA’s Commercial Crew Program. “The crew will perform additional hatch operations to better understand its handling, repeat some ‘safe haven’ testing and assess piloting using the forward window.”

NASA and Boeing teams also prepared plans for Starliner to fire seven of its eight aft-facing thrusters while docked to the station to evaluate thruster performance for the remainder of the mission. Known as a “hot fire test,” the process will see two bursts of the thrusters, totaling about a second, as part of a pathfinder process to evaluate how the spacecraft will perform during future operational missions after being docked to the space station for six months. The crew also will investigate cabin air temperature readings across the cabin to correlate to the life support system temperature measurements.

“We have an incredible opportunity to spend more time at station and perform more tests which provides invaluable data unique to our position,” said Mark Nappi, vice president and program manager, Commercial Crew Program, Boeing. “As the integrated NASA and Boeing teams have said each step of the way, we have plenty of margin and time on station to maximize the opportunity for all partners to learn – including our crew.”

NASA astronauts Butch Wilmore and Suni Williams, who are serving as Starliner’s crew for the mission, arrived at the International Space Station on June 6. They’ve completed numerous flight objectives required for NASA certification of Boeing’s transportation system for flights to the orbiting laboratory under the agency’s Commercial Crew Program.

Over the past three days, Wilmore and Williams have performed tasks as part of the space station team, including installing research equipment, maintaining the lab’s hardware, and helping station crewmembers Matt Dominick and Tracy Dyson prepare for a spacewalk. After NASA called off Thursday’s spacewalk, Williams worked to help the crew out of their spacesuits.

Engineering teams continue to increase their understanding of previous observations from Starliner propulsion systems on the spacecraft’s service module.

Pending spacecraft return readiness and acceptable weather conditions, Starliner will undock from the space station for a parachute and airbag-assisted landing in the southwestern United States. Get the latest mission updates by following the commercial crew blog, @commercial_crew on X, and commercial crew on Facebook.

NASA, Boeing Progress on Testing Starliner with Crew at Space Station

The Starliner spacecraft on NASA's Boeing Crew Flight Test approaches the International Space Station.
The Starliner spacecraft on NASA’s Boeing Crew Flight Test approaches the International Space Station while orbiting 263 miles above Quebec, Canada. NASA astronauts Butch Wilmore and Suni Williams aboard Starliner docked to the orbital outpost’s forward port on the Harmony module at 1:34 p.m. EDT on Thursday, June 6. Photo credit: NASA

Orbiting Earth as part of the nine-person crew of the International Space Station, NASA astronauts Butch Wilmore and Suni Williams continue testing Boeing’s Starliner spacecraft as part of its first flight with astronauts. The testing is part of the data collection on the Starliner system for certification by NASA for regular crewed mission to the orbital complex.

As part of NASA’s Boeing Crew Flight Test, Wilmore and Williams, along with teams on the ground, are stepping through numerous flight objectives following arrival of Starliner to the space station on June 6, including:

  • Powering the spacecraft down into a minimal power mode, which it will enter during operational missions while the crew works aboard station, and then powering it up again;
  • Conducting “safe haven” checks to show the spacecraft can support a crew with its own air and consumables during in an emergency on the station;
  • Performing a habitability study, along with astronauts Tracy Dyson and Matthew Dominick, to evaluate seating positions and other factors, such as air circulation for a four-person crew;
  • Evaluating spacesuit and seat-fits, as well as checkouts of the service module’s batteries.

Meanwhile, ground teams continue to assess and monitor Starliner’s performance and planning for return of the mission no earlier than Tuesday, June 18, pending weather and spacecraft readiness. Starliner is cleared for crew emergency return scenarios from space station, if needed, in accordance with the flight rules.

While Starliner remains docked to station, ground teams are continuing to evaluate propulsion system in-flight observations.

“Butch and Suni are doing great aboard station as ground teams continue digging into the details of Starliner’s on-orbit, rendezvous, and docked performance,” said Steve Stich, manager, NASA’s Commercial Crew Program. “We expected to do a lot of valuable learning on this test flight, and I am extremely proud of how the NASA and Boeing teams are working together to ensure we can safely execute the return portion of the mission.”

One of Starliner’s aft-facing reaction control system (RCS) thrusters, capable of about 85 pounds of thrust, remains de-selected as teams continue to evaluate its performance. Ground teams plan to fire all 28 RCS thrusters after undocking to collect additional data signatures on the service module thrusters before the hardware is expended. As part of normal operations, the service module separates from crew module on return, so NASA and Boeing will gather as much data as possible to aid in system assessments.

Teams currently are assessing what impacts, if any, five small leaks in the service module helium manifolds would have on the remainder of the mission. Engineers evaluated the helium supply based on current leak rates and determined that Starliner has plenty of margin to support the return trip from station. Only seven hours of free-flight time is needed to perform a normal end of mission, and Starliner currently has enough helium left in its tanks to support 70 hours of free flight activity following undocking. While Starliner is docked, all the manifolds are closed per normal mission operations preventing helium loss from the tanks.

Engineers also are evaluating an RCS oxidizer isolation valve in the service module that is not properly closed. Ground teams performed a successful propulsion system valve checkout on Sunday. All other oxidizer and fuel valves within the service module were cycled normally. The suspect oxidizer isolation valve was not cycled in the recent checkout. It will remain commanded closed for the remainder of the mission while ground teams continue to evaluate its data signatures. The crew module propulsion valves, which are part of an independent system that steers the capsule in the last phase of flight before landing, also were successfully cycled, and all those valves are performing as designed.

Mission managers are continuing to work through the return plan, which includes assessments of flight rationale, fault tolerance, and potential operational mitigations for the remainder of the flight. NASA and Boeing will hold a pre-departure media teleconference to provide additional updates before Starliner undocks from station.

With launch and docking already completed, the last remaining dynamic phase of the mission will come at the end of the flight test when Starliner will undock from the orbiting laboratory and then adjust its orbit to move away from the space station. The spacecraft, with Wilmore and Williams aboard, will perform a deorbit burn before entering the atmosphere and landing in the southwestern United States under parachutes and landing airbags to complete the flight.

As part of the agency’s Commercial Crew Program, the mission is the first crewed flight for the Starliner spacecraft. Learn more about the mission by following the commercial crew blog,@commercial_crew on X, and commercial crew on Facebook.