After nine months in orbit, China’s mysterious space plane has landed for the second time, making the nation one of the few entities to successfully launch and recover a reusable spacecraft.

“The complete success of this experiment marks a significant breakthrough in our country’s research on reusable spacecraft technology,” Xinhua, a Chinese state media agency, reported earlier this month.

However, the Chinese government has released very little additional information about the craft; the details of its design, capabilities and performance remain hazy.

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Experts think the Chinese plane is likely similar to the Boeing X-37B, a U.S. space plane that debuted in 2010. Kevin Pollpeter, a research scientist at the Center for Naval Analyses, told Nature.com that the reveal of X-37B sparked concern within the Chinese government over the craft’s military potential. It’s possible that this spurred the country’s space program, which is closely tied to its military, to start developing its own version, Pollpeter said.

Read more: Live Science