China’s Shijian-21 spacecraft, a satellite tv for pc with the said function of cleansing up area junk, has an orbital companion, however we’re not completely certain what it’s.

The Shijian-21 satellite tv for pc was launched to area by a Long March-3B rocket on October 23. Chinese state-run Xinhua information company said the spacecraft “entered the planned orbit successfully” and that it “will be mainly used to test and verify space debris mitigation technologies.”

That’s just about all we find out about Shijian-21, as China tends to be tight-lipped in relation to its affairs in area. But on November 3, the U.S. navy detected a companion object in orbit alongside Shijian-21, as SpaceNews reports. Space Force’s 18th Space Control Squadron catalogued it as an “apogee kick motor” and assigned it the designation 2021-094C.

Apogee kick motors are used to place payloads into their goal orbits, a very good instance being satellites moved from their switch orbits to geostationary orbits, also referred to as GEO. Satellites will generally eject their apogee kick motors after use, however as astrophysicist Jonathan McDowell from the Harvard-Smithsonian Center for Astrophysics defined in an electronic mail, that is “pretty rare” and “almost always done by launching to the GEO graveyard, ejecting the motor, and then lowering the payload into GEO proper.”

Graveyard orbits, or junk orbits, are the place satellites are positioned as soon as they’ve been retired. It’s executed to reduce in-space collisions and the amount of harmful area particles floating round up there. GEO, in case you’re questioning, is that particular orbit wherein satellites seem to hold immobile above a hard and fast level on Earth (an excellent configuration for telecommunications and climate satellites). But to eject an object inside GEO itself “is a bad idea and very rare,” McDowell mentioned, given the added danger of a collision on this practical orbital band.

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But this line of speculation assumes the companion object is actually an apogee kick motor. It’s “currently unknown whether the object is an [apogee kick motor], an object possibly related to space debris mitigation tests, or part of potential counterspace operations tests,” according to Space News. “The object could be used to test rendezvous and proximity operations, refueling experiments or manipulation using a robotic arm or other means.”

McDowell is likewise uncertain about the companion object being an apogee kick motor. Currently, both Shijian-21 and 2021-094C are in orbit some 50 miles (80 km) above pure GEO, “which is well within the band” used by relocating GEO satellites, he said. The two objects are 37 miles (60 km) apart, which “appears to be a deliberate synchronization,” said McDowell, to which he added: “If you just ejected and said bye-bye, you’d expect a steadily increasing separation.”

McDowell suspects Shijian-21 and 2021-094C are active payloads working in tandem, possibly monitoring radio signals from other GEO satellites, but he said we’ll have to wait a few months and see if either object makes some kind of maneuver to be sure.

Importantly, China’s Tongxin Jishu Shiyan-3 satellite, or TJS-3, did something similar back in 2018, producing a companion object, or “sub-satellite.” The “pair maneuvered in concert and carried operations including spoofing, which involves coordinated maneuvers at certain times in an attempt to confuse rivals’ space tracking networks,” according to SpaceNews. As in the current situation, Space Force classified that companion object as an apogee kick motor.

“I don’t know why Space Force thinks these second objects are apogee kick motors—is it just an (incorrect) guess on their part or do they have classified sensor data that is leading them to this conclusion?” said McDowell. That said, he believes the two missions, Tongxin Jishu Shiyan-3 and Shijian-21, “are related in some way.”

Hopefully we’ll know extra in a number of weeks or months, however for now we’re pressured to take a position.