Having written about the Atlantic trash patch earlier this week, I thought I’d highlight another little known pollution problem: space debris.
In 2008 the European Space Agency released this image of the known pieces of debris orbiting the earth. Of the millions of fragments out there, about 18,000 are larger than 10cm and trackable, and that includes rocket parts, discarded equipment and over 5,000 obsolete satellites. It grows every year, as new satellites are launched and old ones are retired. Each rocket sent into orbit also leaves a trail of discarded booster sections, as this ESA graph shows. The image not shown to scale of course, but let’s zoom in a little to see just how ‘congested’ it gets.
This is the result of half a century of space technology, and it’s beginning to ring alarm bells in the space industry. The Office for Outer Space Affairs, one of the UN’s lesser known bodies, keeps a Online Index of Objects Launched into Outer Space. This year they warned that coverage of the World Cup could be disrupted as satellites could be knocked out at any time. Their warning about ensuing riots may have been a little dramatic, but it’s hard to blame them for taking any opportunity going to highlight a danger that’s so far away and invisible.
Space junk doesn’t pose any real danger to us on the surface, as any object drawn into the earth’s gravitational pull would burn up on re-entry. The big problem is our satellite systems. Last year two of them collided, instantly creating 1,500 more objects to hit. Not helping matters, China blew up a satellite with a missile in 2007, apparently to see if they could. That one act accounts for about a quarter of the debris, but before we harangue China, we might also want to remember the US Military’s ‘Needles Project‘. Conceived as a Cold War back-up communication device, scientists are still discovering little clusters of the millions of copper needles that were released into orbit in 1963.
Moving at almost five miles a second, anything larger than a speck of paint is enough to destroy a satellite, and it could become a chain reaction. As a US Defense Department review explained in May, the debris from one collision triggers a second, which causes a third, until everything in that orbit is destroyed. A worst case scenario would be a collapse in GPS systems, international communications, satellite television, and weather monitoring, and space rendered unusable for generations.
As you might expect, the people most concerned are the ones who depend most heavily on satellite technology, and the US military is a key player in finding a solution. There are solutions – debris could be knocked out of orbit from a ground-based laser or a roving robot, causing it either to burn up in the earth’s atmosphere or spin out to a higher and safer altitude. There are no cheap or easy answers.
Like the oceans, it’s easy to think of space as being vast and boundless and there for our every unthinking use, but everything has a limit. I don’t think we need to lie awake worrying about space debris, but I think it symbolises our careless attitude to the earth rather well.