September 6, 2024

— In the end, the only thing missing from what turned out be a safe, as-planned landing for Boeing's Starliner spacecraft was its crew.

Left aboard the International Space Station due to the caution taken by NASA, astronauts Barry "Butch" Wilmore and Sunita "Suni" Wilmore could only watch by video as the capsule on which they launched three months earlier autonomously touched down under parachutes and on a cushion of air bags at the White Sands Space Harbor in New Mexico on Friday (Sept. 6).

The CST-100 Starliner spacecraft, named "Calypso," landed as planned at 10:01 p.m. MDT (12:01 a.m. EDT or 0401 GMT on Sept. 7).

"Great landing of Calyspo! I don't think that could have gone better," said Williams in an exchange with mission control soon after the capsule was back on Earth.

NASA engineers expressed concern that helium leaks and issues with thrusters overheating that were experienced during Starliner's rendezvous with the space station in June could happen again, causing problems with the spacecraft safely returning to Earth. After tests of the Starliner's reaction control system (RCS) jets both in orbit and on the ground, the agency's managers made the decision to bring Wilmore and Williams home with the next SpaceX Dragon crew, rather than risk their landing on board the Starliner.

Although Boeing supported NASA's decision, the company issued a statement saying that its engineers believed the Starliner was capable of returning safely with its crew. "Our confidence is based on this abundance of valuable testing from Boeing and NASA," the company stated on Aug. 2.

Crew Flight Test reentry and landing. Click to enlarge video in new pop-up window. (NASA)

Wilmore and Williams are now scheduled to land with SpaceX Crew-9 members Nick Hague of NASA and Aleksandr Gorbunov with Roscosmos in February 2025, eight months after the eight day stay that both NASA and Boeing said was the original plan for the Crew Flight Test (CFT) mission. Despite the extension and contrary to some media reports, the astronauts were never and are not "stranded" in space.

"They always had a way to depart the space station," said Steve Stich, NASA's manager for the commercial crew program, during a pre-landing press briefing. "To me, when somebody is stranded, that is a location where they cannot leave."

Calypso undocked from the forward-facing port of the space station's Harmony node at 6:04 p.m. EDT (2204 GMT), much like a still-to-be-named sister ship did on an uncrewed test flight in 2022. This time, though, the Starliner followed a "breakout burn" approach to more quickly separate from the station, resulting in less stress being put on the capsule's thrusters.

"Without the crew on board [being] able to take manual control if needed, there are just a lot less variables that we need to account for [by doing the breakout burn]," said Anthony Vareha, NASA's lead flight director for Starliner's return from the space station.

After Starliner was a distance from the station, flight controllers test fired several of the spacecraft's RCS thrusters. Of the 12 small jets on the crew module, one did not fire when commanded. The 12 thrusters are divided into two strings of six each, with only one string being used during normal operations, so the loss of one thruster was only "a slight loss of redundancy," according to a NASA commentator.

The flight controllers also tested 10 of the 28 RCS jets on the service module and they all performed as expected.

Starliner, absent its crew, returned to Earth loaded with cargo, including a reusable oxygen tank and the pressure suits that Wilmore and Williams wore for launch and when docking to the space station.

"It is, of course, bittersweet to be packing up Starliner and putting our [mass] simulators in our seats. But you know we want to do the best we can to make sure she's in good shape," said Williams in an exchange with mission control in Houston on Wednesday. "We want [Calypso] to have a nice landing in the desert."

Starliner successfully fired its orbital maneuvering and attitude control (OMAC) engines for just under a minute to bring it out of orbit and begins its reentry into Earth's atmosphere about 45 minutes before reaching the ground. No longer having use of its thrusters or other in-space systems, the capsule jettisoned its service module as it approached White Sands from the southwest, passing over part of the Baja Peninsula before flying over Mexico and then crossing into the United States and New Mexico.

Pilots flying aboard NASA's WB-57 high-altitude aircraft tracked the Starliner's approach, confirming the deployment of the capsule's parachutes and jettison of both the forward and base heat shields. A Boeing recovery team was positioned near the landing site and moved into place once the capsule was on the ground, securing Calypso and beginning preparations for its overland delivery back to the processing facility at the Kennedy Space Center in Florida.

Looking forward, Boeing and NASA will review the data from this flight to address the issues that arose and decide how to proceed with certifying Starliner to begin operational crewed flights to the space station no earlier than August 2025.

"On a test mission, things don't always go as you plan and so we were prepared," said Stich during a post-landing press conference, replying to a question from collectSPACE. "We're very happy to have the vehicle home. To me, that's a success. Clearly, we've got some work to do. The teams will understand that work and move forward."