The Space Force discovers a mysterious object orbiting a Chinese satellite

The Chinese spacecraft Shijian-21, a satellite with the stated purpose of cleaning up space debris, has an orbiting companion, but we’re not entirely sure what it is.

The Shijian-21 satellite was launched into space by a Long March-3B rocket on October 23. Chinese state news agency Xinhua He said the spacecraft had “successfully entered its planned orbit” and that it would “primarily be used to test and verify space debris mitigation technologies.”

That’s pretty much all we know about Shijian-21, as China tends to be low-key when it comes to its affairs in space. But on November 3, the US military detected a companion object rotating in tandem with the Shijian-21, it was reported. space news. The Space Force’s 18th Space Control Squadron has listed it as an “Ogee Thrust Engine” and assigned it to designation 2021-094C.

Apogee-boosting engines are used to place payloads into their target orbits. A good example is the transition of satellites from their transfer orbits to geostationary orbits, also known as GEO. Satellites sometimes eject their apogeetic engines after they’ve been used, but as astrophysicist Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics explained in an email, this is “very rare” and “almost always done by launching a satellite into a cemetery.” Geo, take out the engine, then lower the payload to the appropriate geo orbit.”

Graveyard orbits, or scrap orbits, are where satellites are placed after they have been removed. It’s made to reduce collisions in space and the volume of dangerous space debris floating there. GEO, in the case of You ask yourself, it’s that special orbit in which satellites seem to hang motionless over a fixed point on Earth (a perfect configuration for meteorological and telecommunications satellites). But McDowell said ejecting an object into geosynchronous orbit is “a very rare and bad idea,” given the added risk of a collision at this functional orbital range.

However, this line of speculation assumes that the companion object is in fact the driver of peak momentum. “It is currently unknown whether the object is an augmented impulse motor or an object Related to space debris mitigation tests or part of tests of potential counterspace operations,” according to Space News. “The object could be used to test rendezvous and proximity operations, refueling experiments, robotic arm manipulation or other means.”

McDowell is also unsure that the companion object is an auger impulse drive. Currently, Shijian-21 and 2021-094C are in an orbit of about 80 km above pure GEO, “which is Within range’ used for Geo satellite transmission. The distance between the two objects is 60 kilometres, which “seems to be a deliberate coincidence,” McDowell said, adding: “If I just pulled it out and said goodbye, I would expect an increased separation.”

McDowell suspects Shijian 21 and 2021-094C are active payloads working in tandem, possibly monitoring radio signals from other Jio satellites, but said we’ll have to wait a few months and see if any of the objects make any kind of maneuvering from Yes, make sure.

Importantly, China’s Tongxin Jishu Shiyan-3 satellite, or TJS-3, did something similar in 2018, producing a companion object, or “sub-satellite.” “The pair maneuvered together and carried out operations, including impersonation, which include coordinated maneuvers at certain times in an attempt to confuse competitors’ space-tracking networks,” according to SpaceNews. As in the current situation, the Space Force has classified this companion object as an Ogi impulse engine.

“I don’t know why the Space Force thinks these second objects are auger impulse motors, is this just an (incorrect) assumption on their part or did they classify the sensor data that led to that conclusion?” McDowell said. However, McDowell believes that the two missions, Tongxin Jishu Shiyan-3 and Shijian-21, are “related in some way.”