Yet more space debris
Published on Feb 25, 2007 at 3:51 pm.
4 Comments.
Filed under space debris.
Several months ago, I posted about the increasing problem of space debris. Well, it just keeps increasing. Already this year, the number of pieces of space debris has increased by nearly 20% over what it was at the end of last year! Worse, most of that came as a result of two events.
The first was January 11. The Chinese military successfully tested an anti-satellite weapon. They did so by slamming a projectile into an old non-functioning Chinese weather satellite, smashing it to bits, and producing a cloud of space debris. There’s already been plenty said about the political implications of such a test, so I won’t go into that in this post (though I might return to the topic in a later post). Most worrisome is that the debris was hurled outward in all directions at all sorts of different velocities. This produced a cloud of debris hundreds of miles across across and thick. Much of this debris is in fairly high low Earth orbit, so it will stay there for a long time. Worse, much of it is in rather eccentric orbits, meaning that it crosses the altitudes of many satellites. Even worse, The debris was blasted into many different orbits of different semi-major axes, meaning that the different bits of debris orbit at different speeds. This means the cloud just gets bigger and bigger, until it eventually encompasses most of low Earth orbit. Fortunately, the bigger the cloud, the more diffuse it is and the less likely that an impact will occur for a satellite passing through the cloud. The bad news is that as the cloud grow, nearly all low Earth orbit satellites will pass through it. Put together, there is a substantially higher risk of impact. And, as I stated in earlier posts, the problem is that even a tiny piece of space debris is moving so fast that it would be a major impact if it were to hit something. A single nut or screw might strike with the force of a 0.50 caliber machine gun round. That would be sufficient to disable most satellites or spacecraft.
Then, less than a week ago, a Russian rocket body exploded in orbit, creating an even larger cloud of debris. At least this was an accident, but that doesn’t make the debris cloud any less worrisome. The rocket body was the Briz-M (or sometimes Breeze-M) upper rocket stage for a Proton rocket launched on February 28, 2006. A malfunction of some sort caused the rocket to shut down early, putting a satellite destined for a geosynchronous orbit into a highly elliptical useless orbit. The rocket has been orbiting Earth for the past year. But, on February 19, it was determined that it had broken up. Likely it exploded. Whatever happened, it is now a cloud of space debris rather than an intact rocket. As with the Chinese satellite debris, the rocket debris cloud is slowly expanding and spreading out. Rocket bodies exploding are a known hazard. They are supposed to use up most of their fuel, but sometimes there is fuel left over in them. In this case, the engines shut off early, and there was quite a bit of fuel and oxydizer left. As the rocket orbits, it is constantly subjected to alternating cycles of freezing cold and baking hot temperatures. Eventually something breaks or comes loose with such thermal cycling. If the oxydizer and fuel meet, then can create an explosion, blowing the rocket to bits.
Both debris clouds pose hazard to active and future satellites due to their orbits. Both have orbits that are high enough to stay out of most of the Earth’s atmosphere, and so some of this debris will likely persist for hundreds or even thousands of years. The more things that we put into space, there more debris is there. Already there have been some satellites whose loss is suspected to be due to space debris. Furthermore, the Space Shuttle Atlantis may have been struck by a very small piece of space debris. The more debris, the more this will happen. Eventually, we can expect to lose a major satellite or, worse, a manned mission due to space debris collison. So, what can we do?
Well, we can try to mitigate space debris. NASA has a policy of minimizing space debris. The Europeans, Japanese, and Russians do, too, though the Russians seem less stringent with their mitigation policies than NASA. But, even so, accidents happen. And, minimizing space debris isn’t the same as eliminating it. There is still an increasing number of objects in orbit. Eventually, about the only thing that can be done is to armour spacecraft. But, shielding is expensive to launch. It means leaving other things off. There is no good solution, I fear, especially if not all parties involved in space exploration agree.
And that is the problem. The reason that we did not test a kinetic anti-satellite weapon is mainly because of the mess that it makes. The Chinese space agency, likewise, seems to realize the danger of space debris. The anti-satellite weapon test was apparently a military decision made without even informing the space program, if reports from the Chinese office that monitors space debris are to be believed. And, that is most worrisome. If everyone doesn’t play by the rules, then you will continue to increase the amount of space debris in orbit until space becomes too dangerous to work with. And, then we all lose.
-Astroprof
A Ler…-- Rastos de Luz on February 26, 2007 at 10:40 am: 1
[…] “Yet more space debris“, no Astroprof’s Page; […]
Astroprof’s Page » Shooting down USA-193 on February 15, 2008 at 2:05 pm: 2
[…] This comes almost a year after the US and the international community publicly decried China’s test of of an anti-satellite weapon to destroy one of their defunct weather satellites, resulting in a giant cloud of space debris. That debris cloud continues to spread, endangering any satellite or spacecraft passing through it. The speed at which orbits move means that a satellite or spacecraft encountering a piece of debris in a crossing orbit would have a huge closing speed relative to the debris, making an impact from even a tiny piece of debris devastating, damaging and possibly destroying the spacecraft. […]
Jurie G on April 12, 2008 at 5:31 am: 3
I would be interested to know what is ratio of money spent on space exploration/utilisation and research into possible methods of “cleaning up” space debris?
Would it not be worthwhile for companies and governments that spend billions of our money on space programs to divert a percentage of these funds to this type of research?
It may cost money now, but think of the money, and possibly the lives it would save in the future if we could reduce instead of just minimize the amount of space junk!
This could be seen as a challenge for future pioneers!
Jurie G on April 12, 2008 at 5:35 am: 4
I would be interested to know what is ratio of money spent on space exploration/utilisation and research into possible methods of “cleaning up” space debris?
Would it not be worthwhile for companies and governments that spend billions of our money on space programs to divert a percentage of these funds to this type of research? In fact, is it not their responsibility?
It may cost money now, but think of the money, and possibly the lives it would save in the future if we could reduce instead of just minimize the amount of space junk!
This could be seen as a challenge for future pioneers!