The mysterious breakdown of the Yunhai 1-02 satellite in March has likely been solved. The discarded remnants of an old Russian rocket appear to have smashed into the Chinese satellite, in what is an ominous sign of things to come in our increasingly cluttered low Earth orbit.
On March 22, 2021, the 18th Space Control Squadron of the U.S. Space Force published a surprising tweet announcing the breakup of Yunhai 1-02 — a Chinese military satellite launched in September 2019. The breakup had occurred four days earlier, and it wasn’t immediately clear as to why this satellite, at less than two years old, should suddenly experience such a calamitous malfunction. In its tweet, the Space Force squadron said its “analysis is ongoing” and that it would track the 21 newly created pieces of debris.
#18SPCS has confirmed the breakup of YUNHAI 1-02 (#44547, 2019-063A), which occurred on March 18, 2021, at 0741 UTC. Tracking 21 associated pieces – analysis is ongoing. #spaceflightsafety #spacedebris @spacetrackorg
— 18 SPCS (@18SPCS) March 22, 2021
This sort of thing is not without precedent. Satellites do get wrecked in orbit, though it happens very rarely. Back in 2016, for example, Japan’s Hitomi satellite spun out of control owing to human errors and crummy software; the satellite spun wildly out of control, causing it to break up. Frighteningly, a similar scenario could’ve played out on the International Space Station a few weeks ago, when Russia’s Nauka module began to fire its thrusters shortly after docking.
Another possibility is that the Yunhai 1-02 satellite was deliberately shot down. China did exactly this in 2007 with an anti-satellite (ASAT) weapon, shooting down a defunct weather satellite. The incident created hundreds of pieces of debris and considerable international angst. India did a similar thing in 2019 — an incident that likewise resulted in a dangerous debris field in low Earth orbit.
A collision with space junk could explain the demise of Yunhai 1-02, and again, a precedent also exists for this sort of scenario. In 2009, the Iridium 33 communications satellite smashed into Kosmos-2251, a defunct Russian military communications satellite. NASA described the incident as being the “most severe accidental fragmentation on record,” as the collision produced more than 1,800 pieces of debris larger than 10 cm.
Some crafty sleuthing from Jonathan McDowell, a researcher at Harvard-Smithsonian Centre for Astrophysics, suggests something similar happened to Yunhai 1-02, in which a chunk of space junk slammed into the Chinese satellite. While scanning through the Space-Track.org catalogue (which contains data from the 18th Space Control Squadron), McDowell noticed an odd note about orbital debris object 1996-051Q (48078). The debris object was described as having “collided with a satellite.”
Space-Track catalog updated today with a note for object 48078, 1996-051Q: "Collided with satellite".
This is a new kind of comment entry – haven't seen such a comment for any other satellites before. Let's look a bit closer:
— Jonathan McDowell (@planet4589) August 15, 2021
“This is a new kind of comment entry — haven’t seen such a comment for any other satellites before,” wrote McDowell in a tweet published on Sunday, August 15. Diving deeper, the astrophysicist identified the debris object as being a remnant of a Russian Zenit-2 rocket, which delivered the Tselina-2 electronic intelligence satellite to orbit in 1996.
An obvious candidate for the affected satellite was Yunhai-1-02, which turned out to be the case. A quick analysis of the data showed that Yunhai 1-02 and the Russian space junk passed to within 1 km of each other on March 18, and “exactly when 18SPCS reports Yunhai broke up,” McDowell tweeted.
To which he added: “37 debris objects have been cataloged so far from the breakup — there are likely to be more.” He describes the incident as the “first major confirmed orbital collision in a decade,” referencing the aforementioned smash-up in 2009. Despite the collision, Yunhai 1-02, though no longer in use, is still making orbital adjustments, which suggests the collision wasn’t completely catastrophic, said McDowell.
I reached out to McDowell to learn more about the offending Russian space junk, the nature of the collision, and what should happen next.
The size of debris object 48078 is not known, but it’s likely somewhere from 5 to 30 centimetres wide, McDowell said. He explained that in-space collision involving a small object of this size will damage a satellite, “but not destroy it completely.” Small objects are increasingly appearing in orbit, “so we expect more incidents like this, and indeed we have been seeing about one a year.”
I’ve covered some close-calls in the last several years, including an incident involving two defunct satellites: the joint NASA-Netherlands Infrared Astronomical Satellite (IRAS) and the the U.S. Naval Research Laboratory’s GGSE-4 satellite, which launched in the late 1960s. And back in June, an errant chunk of space junk pierced a hole in Canadarm2, a robotic arm currently in service on the ISS.
The space junk problem “is real,” said McDowell, “and as the number of satellites increases we should expect many more like this as well as increasing numbers of the rarer but more serious debris events.” The Space Force will continue to monitor and catalogue the debris that came from this event, but McDowell says we may never get official confirmation of this apparent collision. As for Yunhai 1-02’s unexpected movements, “it’s possible that it is just tracking mistakes,” he said.
An uncomfortable amount of space junk circles Earth. Estimates from the European Space Agency suggest 900,000 objects from 1 to 10 cm and 34,000 objects larger than 10 cm are currently in Earth orbit.
A major concern is that debris might trigger a Kessler Syndrome, which is akin to a snowball that increasingly gets bigger as it tumbles down a maintain. Upsettingly, the debris caused by this latest collision could go on hit other objects in space, resulting in an even larger debris field. A hypothetical cascade could conceivably destroy troves of satellites, which would be very bad and make low Earth orbit inaccessible. The time has come for us to better regulate space and clean up our junk.