Boeing’s Starliner spacecraft has successfully returned to Earth after an eight-month mission to the International Space Station (ISS), though without its intended crew of astronauts Butch Wilmore and Indian-American Sunita Williams. The uncrewed return marks a significant milestone for Boeing’s troubled Starliner program, which has been plagued by technical difficulties.

The spacecraft autonomously undocked from the ISS at 6:04 p.m. ET on Friday, embarking on a six-hour return journey to Earth. It utilized its maneuvering thrusters to lower its orbit and reentered Earth’s atmosphere, concluding with a parachute-assisted landing at the White Sands Space Harbor in New Mexico.

Originally slated to be an eight-day test flight for NASA astronauts Wilmore and Williams, their mission was prolonged due to propulsion system issues. The problems, which arose during the Starliner’s approach to the ISS in June, included the failure of five of the spacecraft’s 28 maneuvering thrusters and helium leaks in the propulsion system. Although the capsule successfully docked with the ISS on June 6, Boeing launched a months-long investigation into the failures, resulting in additional costs of $125 million for the company.

Despite the propulsion issues, Boeing engineers recently uploaded new software to Starliner, allowing it to return safely without a crew. Wilmore and Williams, who became the first astronauts to fly the Starliner in June, remain on the ISS with seven other astronauts. They will return to Earth aboard a SpaceX vehicle in February 2025.

This latest Starliner mission underscores Boeing’s ongoing challenges in space, an area where it once led before SpaceX’s emergence as a cost-effective alternative for NASA. Starliner’s problems have persisted since its failed 2019 uncrewed test flight to the ISS, with the latest mission being Boeing’s third attempt to prove the spacecraft’s reliability.