By Mike Wall
Yunhai 1-02’s wounds are not self-inflicted.
In March, the U.S. Space Force’s 18th Space Control Squadron (18SPCS) reported the breakup of Yunhai 1-02, a Chinese military satellite that launched in September 2019. It was unclear at the time whether the spacecraft had suffered some sort of failure — an explosion in its propulsion system, perhaps — or if it had collided with something in orbit.
We now know that the latter explanation is correct, thanks to some sleuthing by astrophysicist and satellite tracker Jonathan McDowell, who’s based at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
McDowell described the incident as the first major confirmed orbital collision since February 2009, when the defunct Russian military spacecraft Kosmos-2251 slammed into Iridium 33, an operational communications satellite. That smashup generated a whopping 1,800 pieces of trackable debris by the following October.
However, we may be entering an era of increasingly frequent space collisions — especially smashups like the Yunhai incident, in which a relatively small piece of debris wounds but doesn’t kill a satellite. Humanity keeps launching more and more spacecraft, after all, at an ever-increasing pace.
“Collisions are proportional to the square of the number of things in orbit,” McDowell told Space.com. “That is to say, if you have 10 times as many satellites, you’re going to get 100 times as many collisions. So, as the traffic density goes up, collisions are going to go from being a minor constituent of the space junk problem to being the major constituent. That’s just math.”
Our current space junk problem is not that severe, but the Yunhai event could be a warning sign of sorts. It’s possible, McDowell said, that Object 48078 was knocked off the Zenit-2 rocket by a collision, so the March smashup may be part of a cascade.
“That’s all very worrying and is an additional reason why you want to remove these big objects from orbit,” McDowell told Space.com.
Read the article at: https://www.space.com/space-junk-collision-chinese-satellite-yunhai-1-02