For decades, space experts have worried that a speeding bit of orbital debris might one day smash a large spacecraft into hundreds of pieces and start a chain reaction, a slow cascade of collisions that would expand for centuries, spreading chaos through the heavens.
What happened yesterday is far worse than a speeding bit of orbital debris smashing a large spacecraft, as was envisioned in this NY Times article almost exactly 2 years ago. What happened yesterday was two very large spacecraft smashing into each other.
Two big communications satellites collided in the first-ever crash of its kind in orbit, shooting out a pair of massive debris clouds and posing a slight risk to the international space station. NASA said it will take weeks to determine the full magnitude of the crash, which occurred nearly 500 miles over Siberia on Tuesday.
So how bad was it? Did they just bump into each other? Was it catastrophic?
According to Discover Magazine's blog, the satellites collided at approximately 1.5km/second. That's about 3,600 MPH.
Again, if I have my numbers about right, the explosion resulting from the energy of impact would have been about the same as detonating a ton of TNT.
We should all hope his numbers are not right.
According to AP's report, as found at HuffPo, "The Iridium craft weighed 1,235 pounds, and the Russian craft nearly a ton." And, "NASA said it will take weeks to determine the full magnitude of the crash."
The full magnitude of the crash could, in the very worst case scenario, end human space exploration for centuries and even eliminate our use of communications satellites. Scientist have long warned that our space debris was becoming a major threat.
Cascade warnings began as early as 1978. Mr. Kessler and his NASA colleague, Burton G. Cour-Palais, wrote in The Journal of Geophysical Research that speeding junk that formed more junk would produce "an exponential increase in the number of objects with time, creating a belt of debris around the Earth."
This cascading effect was dubbed the Kessler Syndrome:
The Kessler Syndrome is a scenario, proposed by NASA consultant Donald J. Kessler, in which the volume of space debris in Low Earth Orbit is so high that objects in orbit are frequently struck by debris, creating even more debris and a greater risk of further impacts. The implication of this scenario is that the escalating amount of debris in orbit could eventually render space exploration, and even the use of satellites, too prone to loss to be feasible for many generations.
In a nutshell, there is a possible scenario where some space trash hits something causing it to explode. Then the debris from that hits more stuff and that stuff hits even more stuff etc. This process cascades creating a massive, impenetrable debris cloud surrounding Earth.
I am not suggesting that the sky is falling here. But this is a critical situation - at least until we have more information. These two satellites may very well create a debris cloud with enough in orbit volume to start the dreaded chain reaction. Unlikely, maybe. But not impossible.
Here's an idea of just how much stuff is orbiting the Earth:
Between the launch of Sputnik on 4 October 1957 and 1 January 2008, approximately 4600 launches have placed some 6000 satellites into orbit; about 400 are now traveling beyond Earth on interplanetary trajectories, but of the remaining 5600 only about 800 satellites are operational - roughly 45 percent of these are both in LEO and GEO. Space debris comprise the ever-increasing amount of inactive space hardware in orbit around the Earth as well as fragments of spacecraft that have broken up, exploded or otherwise become abandoned. About 50 percent of all trackable objects are due to in-orbit explosion events (about 200) or collision events (less than 10).
In pictures, compliments of the European Space Operations Centre
So, in a few weeks, when nothing much comes of this, don't look back and think Tocque was needlessly scaring the shit out of people. I am NOT claiming that anything significant will come of this. I am claiming that a possibility exist. I don't think anyone, NASA included, can gauge the probability of this turning disastrous yet. But I can tell you that a lot of scientists and astronomers are extremely worried right now. I'm pretty worried myself.
Even without the potential for a chain reaction, this is another case where human space trash threatens our reach into space. It puts at risk, among other things, the Hubble telescope and the International Space Station. On the upside, it also puts at risk Rupert Murdoch's array of propaganda delivery devices circling the planet.
But I can assure, the risk is not worth getting Sean Hannity off of our TV sets. Our remote controls are just fine for that.
Update This story was also covered well by John DE here.