BEIJING, May 8 (Reuters) - An experimental Chinese spacecraft returned to Earth on Monday after staying in orbit for 276 days, China's state media reported, completing a landmark mission to test the country's reusable space technologies.

The uncrewed spacecraft returned to the Jiuquan launch centre in northwest China on Monday as scheduled, according to state media.

No details were given on what the spacecraft was, what technologies were tested, how high it flew, and where its orbits had taken it since its launch in early August 2022. Images of the craft have also yet to be released to the public.

The test marks an "important" breakthrough in China's research into reusable spacecraft technology that will provide a more convenient and inexpensive way to mount future space missions, state media reported.

In 2021, what may have been a similar spacecraft flew to the edge of space and returned to Earth on the same day in a mission that was also kept largely under wraps. It landed on Earth "horizontally," according to China's main space contractor at the time.

Commentators on Chinese social media have speculated that Beijing has been developing a spacecraft like the U.S. Air Force's X-37B, an autonomous spaceplane that can remain in orbit for years.

The uncrewed and reusable X-37B returned to Earth in November last year in its sixth and latest mission, after more than 900 days in orbit.