Boeing’s Starliner capsule returned to Earth late Friday after an almost three-month stay at the International Space Station marking the end of its unexpected, extended mission.
Though this capsule journeyed back alone, two test astronauts—Butch Wilmore and Suni Williams—remained aboard the ISS, where they are expected to stay for an additional five to six months.
Starliner undocked from the space station just after 6 p.m. ET, according to NASA. After spending roughly six hours free-flying in orbit, the capsule made its slow descent to Earth.
Before departing, the astronauts gave a warm farewell to the capsule they had piloted in June, which Williams had nicknamed “Calypso.”
Addressing mission control, Williams stated, “It is time to bring Calypso home… You have got this. We have your backs, and you’ve got this. Bring her back to Earth.”
Just before midnight, the capsule approached the critical stage of its return — reentry. As with any spacecraft, this phase is perilous, requiring Starliner to navigate the intense pressure and heat as it plunged through Earth’s atmosphere at speeds exceeding 17,000 miles per hour, 27,400 kilometers per hour.
This process can heat the spacecraft’s exterior to temperatures over 3,000 degrees Fahrenheit, 1,649 degrees Celsius.
During its descent, a newly redesigned set of parachutes deployed, slowing Starliner’s fall before airbags cushioned its touchdown at White Sands Space Harbor in New Mexico, a site with a rich history, once used to train NASA’s space shuttle pilots.
Starliner safely landed at 12:01 a.m. ET Saturday, a crucial success for Boeing’s efforts in the space program.
“We will review the data and determine the next steps for the program,” said Mark Nappi, vice president and program manager of Boeing’s Commercial Crew Program. Despite the safe landing, the future of the Starliner program remains uncertain. NASA’s Commercial Crew Program manager Steve Stich acknowledged that while the reentry and landing were “darn near flawless,” it’s not yet clear how or when Starliner will fly again.
“If we’d had a model that would have predicted what we saw tonight perfectly, yeah, it looks like an easy decision to go say we could have had a crewed flight,” Stich remarked, referencing the decision to bring the capsule home without the astronauts. “But we didn’t have that.”
Starliner’s uncrewed return was largely due to complications encountered on the flight to the ISS, including a series of helium leaks in June that impacted the spacecraft’s thrusters.
Helium, used to pressurize the thrusters, leaked out during the outbound flight, delaying the test mission. Additionally, five out of 28 “reaction control system” (RCS) thrusters failed during the trip to the space station, with only four eventually recovered.
NASA and Boeing spent weeks troubleshooting these problems while the spacecraft remained docked at the ISS, causing Wilmore and Williams’ stay to be extended from eight days to several months.
While officials believed they had identified the root of the issues—blaming overheating within the “doghouses” that house propulsion components and degraded Teflon seals—the thruster system could not be physically inspected until Starliner’s return.
Because Starliner’s service module, the section housing the problematic thrusters, was designed to detach and burn up during reentry, NASA was unable to analyze the hardware after the spacecraft separated from the ISS.
The uncertainty surrounding these critical systems led NASA to conclude that it was too risky to return the astronauts aboard the capsule.
“The bottom line relative to bringing Starliner back is — there was just too much uncertainty in the prediction of the thrusters,” Stich explained. “It was just too much risk with the crew, and so we decided to pursue the uncrewed path forward.”
Despite the setbacks, Starliner completed its descent using a different set of thrusters, known as the “Orbital Maneuvering and Attitude Control” (OMAC) thrusters, which are significantly more powerful than the RCS thrusters. During the capsule’s final checks on the way down, one of the onboard thrusters did malfunction, though it didn’t affect the overall success of the landing.
NASA and Boeing have had disagreements about the level of risk throughout the mission.
Boeing maintained confidence in Starliner’s ability to return with a crew, but ultimately left the decision to NASA, which chose to prioritize safety.
“It just depends on how you evaluate the risk,” Stich said, adding that NASA took a broader view than Boeing.
Boeing has already faced considerable challenges with Starliner, including a costly redo of its 2019 test mission after software problems prevented the spacecraft from reaching the ISS.
With this latest test flight complete, it remains to be seen whether NASA will require Boeing to conduct another test or if the vehicle will be certified for future crewed missions.
