Russian Satellite and Chinese Rocket at 'Very High Risk' of Colliding, Could Make Big Mess in Space

BY ARISTOS GEORGIOU 

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Experts say there is a "very high risk" that two large pieces of space junk—a defunct satellite and on old rocket part—could collide on Thursday evening.

LeoLabs, a California-based company that tracks space debris, said their modeling suggests the satellites will miss each other by less than 82 feet, but that there is up to a 20 percent chance of a collision.

The combined mass of both objects, which are in low-Earth orbit at an altitude of around 615 miles, is roughly 2.8 metric tons, the company said.

Orbital debris is defined as any man-made object orbiting our planet that no longer serves a useful function. It can include non-functional spacecraft, abandoned launch vehicle stages and other junk produced by space missions.

These bits of space junk travel at very high speeds—up to 18,000 miles per hour, or faster than a speeding bullet. This speed means that despite their tiny size, they pose a significant risk to spacecraft and astronauts in orbit.

To date, their have been surprisingly few collisions in low-Earth orbit (LEO.) But experts are growing increasingly concerned as the number of satellites and the quantity of orbital debris grows.

In 1978, NASA scientist Donald J. Kessler proposed the idea that the density of objects in LEO could become so great, that collisions between objects would create a feedback loop of more space debris and further collisions.

The "Kessler syndrome," as this hypothesis is now known, could make it very difficult or even impossible to carry out space missions in the coming decades due to the high risk of collision with space debris.

Astronomer Jonathan McDowell from the Harvard-Smithsonian Center for Astrophysics, who monitors space activities, identified the two space objects set for a close shave on Thursday. He said one is a defunct Russian "Parus" navigation satellite launched in 1989, while the other is a spent Chinese ChangZheng-4c rocket stage that launched in 2009.

Any collision between the two objects could cause them to break apart, producing lots of smaller pieces in the process. NASA says there are millions of pieces of space debris smaller than a marble in low-Earth orbit, and tens of thousands of pieces that are larger than a softball.

Posting on Twitter, McDowell said the mess the two objects would make if they collided would be "very bad," noting that most of the debris generated would stay in low-Earth orbit "for decades."