Boeing’s Starliner spacecraft returns to Earth, wrapping up critical test mission

Boeing's new passenger spaceship, the CST-100 Starliner, returned to Earth this afternoon after less than a week aboard the International Space Station, landing safely in the New Mexico desert thanks to parachutes and airbags. The successful touchdown marks the completion of a critical test mission for Starliner, which demonstrated the vehicle's capacity to launch into orbit, dock with the station, and safely return home.

Boeing's Starliner capsule, shaped like a gumdrop, was developed in collaboration with NASA to transport humans to and from the International Space Station, or ISS. The project is part of NASA's Commercial Crew Program, which tasked commercial businesses with developing space taxis that could transport humans to low-Earth orbit. However, before allowing NASA humans to fly in Starliner, the space agency required the spacecraft to demonstrate that it could perform all of the functions of a voyage to the ISS without people on board.

With today's landing, the uncrewed test flight, known as OFT-2, has come to a close, with Starliner completing all of the main steps it was supposed to. The spacecraft safely launched into orbit on May 19th, flying atop an Atlas V rocket; it approached and docked with the International Space Station on May 20th; and it undocked from the space station today afternoon before returning to Earth. However, the flight was not without its bumps. Starliner had a variety of troubles with its numerous thrusters, which are small engines used to control and push the vessel across space, throughout the journey. However, none of these issues proved fatal to the trip, and Starliner was able to finish OFT-2 on time.

It's also been a long and winding trip to this point. The acronym OFT-2 stands for Orbital Mission Test-2, which is the designation of this test flight. This is because it's a repeat of the same test flight that Boeing attempted in 2019. Boeing flew Starliner without a crew in December of that year, launching it into orbit on another Atlas V rocket.However, once Starliner detached from the rocket, a software malfunction forced the capsule to fire its thrusters improperly, and the spacecraft ended up in the wrong orbit. Because of the problem, Starliner was unable to reach the space station, and Boeing was unable to demonstrate the spacecraft's capacity to dock with the ISS. Boeing had to return the spacecraft early and was able to land it at New Mexico's White Sands Missile Range, which is also where Starliner landed today.

Last summer, Boeing attempted a second launch of the Starliner, but the countdown was delayed only hours before departure when the firm discovered that more than a dozen propellant valves were stuck and not opening correctly. It's taken Boeing this long to solve the problems, and the firm thinks it's feasible that the valves will need to be redesigned in the future. But now, two and a half years after the first failed trip, Starliner has demonstrated that it can launch and dock with the ISS independently – a critical capability that it will need to demonstrate again once humans are on board.

Landing is also a crucial responsibility for Starliner in order to securely transport people back to their homes. The capsule undocked from the ISS at 2:36 p.m. ET today afternoon to show those capabilities for this voyage, slowly flying around the station and eventually removing itself from the orbiting lab. Starliner utilized its onboard engines to slow down and pull itself out of orbit at 6:05 p.m. ET, placing it on a collision path with Earth's surface. The vehicle crashed into the planet's atmosphere shortly after, encountering temperatures of up to 3,000 degrees Fahrenheit. The Starliner was then slowed by a sequence of parachutes before landing at White Sands, which was cushioned by airbags. It was Starliner's second successful landing, after the vehicle's initial failed test flight in 2019.

“That touchdown coming at 5:49pm Central Time, almost exactly six days into the mission,” NASA communications officer Brandi Dean remarked on a broadcast of the landing. “Just a beautiful touchdown in White Sands this evening.” 

However, there was significant anxiety about this landing because the Starliner had various thruster difficulties throughout the voyage. Two of the capsule's 12 engines that help it get into the appropriate orbit failed when it flew into space last week. The thrusters turned off early due to a decline in chamber pressure, according to Boeing. Starliner's flight control system was eventually able to redirect to a backup thruster in time, and the spacecraft was able to enter orbit on schedule. However, despite the two failed thrusters, those same thrusters were required to send Starliner out of orbit, and they appeared to perform as expected.

There were other issues during the flight as well. Due to low chamber pressure, a few of smaller thrusters intended to move Starliner during docking also failed. It did not, however, prevent the capsule from docking with the ISS. “We have a lot of redundancy that really didn’t affect the rendezvous operations at all,”stated Steve Stich, NASA's Commercial Crew Program program manager, during a news briefing following docking.Furthermore, the Boeing crew discovered that several of Starliner's thermal systems intended to cool the spacecraft were operating at abnormally low temperatures, which the engineering team had to deal with during the docking.

While docked with the ISS, Starliner nonetheless completed several of its objectives. This weekend, astronauts on the International Space Station opened Starliner's door, boarded the spacecraft, and retrieved goods that had been delivered to the station. Rosie the Rocketeer, a mannequin that went along inside Starliner to mimic what it will be like when humans go on board, was also returned down to Earth.

There's still a lot of work to be done now that Starliner has returned to Earth. NASA and Boeing will investigate the aircraft's problems in the next months to see if the Starliner is ready to transport humans to space during a test flight called CFT, or Crewed Flight Test, which might happen by the end of the year. That will be a significant achievement for Boeing, which has lagged well behind SpaceX, NASA's other Commercial Crew partner. SpaceX's Crew Dragon spacecraft, which transported its first passengers in 2020, has already performed five crewed missions to the station for NASA.

However, if Starliner is given the green light to fly humans, NASA will finally have what it has long wanted: two American businesses capable of sending astronauts into space.