Boeing Crew Flight Test
Boeing Crew Flight Test was the first crewed mission of the Boeing Starliner capsule. Launched on June 5, 2024, the mission flew a crew of two NASA astronauts, Barry E. Wilmore and Sunita Williams, from Cape Canaveral Space Force Station to the International Space Station. The mission was meant to last eight days, ending on June 14 with a landing in the American Southwest. However, Starliner's thrusters malfunctioned as it approached the ISS. After more than two months of investigation, NASA decided it was too risky to return Wilmore and Williams to Earth aboard Starliner. Instead, the Boeing spacecraft returned uncrewed on September 7, 2024, and successfully landed at the White Sands Space Harbor in New Mexico. The astronauts rode down aboard SpaceX Crew-9 on March 18, 2025.
Originally scheduled for launch in 2017, Boe-CFT experienced numerous delays. The spacecraft's two preceding uncrewed orbital flight tests, Boe‐OFT and Boe‐OFT‐2, were conducted in 2019 and 2022 respectively.
Starliner was placed atop the Atlas V launch vehicle on April 16, 2024, but the mission's launch was repeatedly postponed by technical problems. An oxygen valve problem on United Launch Alliance's Atlas V rocket scrubbed the first launch attempt on May 7. A second launch attempt on June 1 was scrubbed when a ground computer failed. Subsequent delays were caused by helium leaks in the Starliner's service module; helium leaks would continue to be a problem throughout the mission. The third launch attempt on June 5 at 14:52:15UTC was successful.
Pre-mission delays
The first uncrewed test, Boe‐OFT, originally planned for 2017, was delayed by development problems. It launched in 2019, but software errors prevented Starliner from reaching the ISS during that flight, precipitating delays to subsequent flights. Boe‐OFT‐2, the second uncrewed test flight attempt, was scrubbed in 2021 by valve problems. It finally flew in 2022 and met all flight objectives. In August 2023, Boeing announced that the third flight—the first crewed one—would be delayed at least to March 2024 due to weakness in certain joints within the parachute system and potentially combustible materials in the wiring harnesses. Boeing underwent multiple investigations before another flight test would be permitted.Capsule
Boe-CFT was the second mission for the Starliner Calypso capsule. NASA announced that Boeing prepared to reassemble the vehicle for flight, following multiple checkouts, for the CFT mission in August 2020, and that new parachutes and airbags would be fitted. The Boe-CFT capsule's docking system was modified to accommodate the new re-entry cover, which debuted on the Boe-OFT‐2 test flight.Crew
Because of the delays, crew assignments were changed several times after the initial assignments in 2018. Nicole Mann was initially assigned to this mission, which would have made her the first woman to fly on the maiden crewed flight of an orbital spacecraft, but she was subsequently re-assigned to the SpaceX Crew-5 mission, becoming the first female commander of a NASA Commercial Crew Program launch. For medical reasons, Eric Boe, who was originally assigned to the mission in August 2018 as the pilot, was replaced by Michael Fincke on January 22, 2019. Boeing astronaut Chris Ferguson was originally assigned to the flight as commander, but he was replaced by NASA astronaut Barry E. Wilmore on October 7, 2020. Ferguson cited family reasons for the replacement. Matthew Dominick replaced him on the backup crew.On April 18, 2022, NASA said that it had not finalized which of the cadre of Starliner astronauts, including Barry E. Wilmore, Michael Fincke, and Sunita Williams, would fly on this mission or the first operational Starliner mission. On June 16, 2022, NASA confirmed that this CFT mission would be a two-person flight test crewed by Wilmore and Williams; Fincke trained as the backup spacecraft test pilot and remains eligible for assignment to a future mission. Williams is the first woman to fly on a maiden crewed flight of an orbital spacecraft.
Mission
Overview
The third launch of the Atlas V N22 variant launched Starliner with a crew of two. The vehicle docked with the International Space Station and was supposed to return to Earth for a ground landing in the southwestern United States. Originally intended as an eight-day mission, Starliner encountered problems with the propulsion system prior to docking with ISS. The mission was extended several times to allow for analysis, and NASA eventually decided to leave the crew aboard ISS and return Starliner to Earth without the crew after three months in space. The crew returned on SpaceX Crew-9.Boe-CFT was the first launch of a crewed spacecraft by an Atlas V launch vehicle. It was the first launch of a crewed spacecraft utilizing a member of the Atlas family of launch vehicles since Mercury-Atlas 9 flown by Gordon Cooper in May 1963 and the first launch of a crewed spacecraft from Cape Canaveral Space Force Station since that of Apollo 7 in October 1968.
The uncrewed Starliner made a ground landing at White Sands in New Mexico.
Launch
In 2023, following the discovery of a technical problem with the spacecraft's parachute system and a flammability concern on the spacecraft's wiring, CFT was delayed to no earlier than March 2024. In November 2023, NASA announced that the mission was on track for an April 2024 launch, with most of the flammable material removed from the spacecraft and a drop-test of the redesigned parachute system planned for January 2024. This test was successful, allowing NASA and Boeing to proceed into launch preparations. In February 2024, the Atlas V rocket was moved into ULA's Vertical Integration Facility at Space Launch Complex-41, starting preparations for stacking ahead of the launch. In March 2024, the launch was rescheduled from April 22 to early May due to scheduling conflicts on the ISS, with a launch date of May 6 announced in early April. Work on the Starliner spacecraft inside Boeing's production facility was completed on April 15, and the spacecraft was moved to the launch pad and stacked on top the Atlas V rocket the following day. The crew arrived at Kennedy Space Center on April 25, and on the same day the mission concluded its Flight Test Readiness Review, officially approving the mission to proceed. On May 2, the SpaceX Crew-8 Dragon spacecraft moved from the forward port of the ISS Harmony module to the zenith port, to make room for the CFT mission, which is only approved to dock on the forward port. Following the completion of ULA's Launch Readiness Review, the Atlas V rocket rolled to its launch pad on May 4.May 6, 2024, attempt
The first attempt to launch CFT, on May 6, 2024, was scrubbed around T−2 hours before launch due to a chattering oxygen pressure relief valve on the rocket's Centaur upper stage. While this problem had been seen in previous Atlas V flights and could be resolved simply by closing and reopening the valve, flight rules prohibited doing so with crew on board, which forced the decision to scrub the launch. The next day, the launch team determined that the valve had opened so many times it would need to be replaced, delaying the launch to May 17 as the rocket had to be rolled back to its Vertical Integration Facility. Meanwhile, in an unrelated problem, NASA and Boeing discovered a small helium leak on Starliner's propulsion system, which delayed the launch further to allow the teams to assess the situation. The delay was so lengthy, Wilmore flew back to Houston to spend additional time in the Starliner flight simulator to keep his skills fresh.June 1, 2024, attempt
On May 24, following several days of analysis, NASA and Boeing announced plans to launch CFT on June 1 without repairing the helium leak, determining that the spacecraft was safe to fly even if the leak rate worsened by many times. This review also uncovered a "design vulnerability" in the propulsion system that could prevent the spacecraft from completing a deorbit burn in a very remote failure mode; engineers then devised a new reentry mode to employ should this failure mode occur. Astronauts Barry Wilmore and Sunita Williams after returning to Houston following the previous scrub, flew back to Kennedy Space Center on May 28. After a May 29 meeting, teams from NASA, Boeing, and ULA confirmed readiness for a June 1 launch.In late May, the pump in the ISS urine processor assembly malfunctioned, halting the ability to convert the crew's waste back into drinkable water. NASA made the decision to place a replacement pump on the Starliner. To maintain a consistent mass and accommodate the pump, Wilmore's and Williams' suitcases, containing personal clothes and toiletries, were removed; instead, the CFT crew was to use generic spare clothes and toiletries already aboard the ISS.
The second launch attempt, on June 1, was scrubbed 3 minutes and 50 seconds before liftoff after an automatic hold was triggered when one of three redundant ground launch sequencer computers gave slower-than-normal readings. This was found to have been caused by a faulty power supply unit connected to that computer. On June 2, a ULA team replaced the computer chassis containing this power supply and verified that the new hardware was performing normally.