“It may just be an inert piece of hardware,” McDowell said on Tuesday.
Canada-based amateur astronomer Scott Tilley, who helped Nasa find one of its long-lost satellites, said neither the object nor the plane had emitted any new signals since the release.
Often seen as a counterpart of the US military space plane X-37B, there has been very little information released about Shenlong’s size or capabilities.
After Shenlong’s third launch in December, space activity trackers suggested that it released at least five objects into low-Earth orbit, two of which were thought to be satellites since they were giving off radio signals similar to the plane’s signals. But the objects were mostly likely debris of the Long March rocket, which sent Shenlong to its initial orbit, Tilley said.
“Most, if not all, of them have probably re-entered Earth’s atmosphere,” Tilley said.
Not much is known about how this third mission has been going, except that the space plane raised its orbit from around 300km to 600km in late January – where it has remained.
Chinese space authorities have not revealed details of the Shenlong’s latest mission, or when it will return. All that has been said was contained in a brief report released by state media just after the launch.
“It’s going to operate in orbit for a period of time before returning to its intended landing site in China,” state news agency Xinhua said in the launch report.
“Reusable technology verification and space science experiments will be carried out to provide technical support for the peaceful use of space.”