7 October 2021
Space Debris
Beam me up Scotty.
By Paul Branch
As a former communications satellite specialist, I am often asked “Why is there so much junk in space, and should we be worried?” My stock answer to the second part of this very astute question runs along the lines of “No, not yet — there is a lot of other stuff you should be really worried about, but please ask someone else about climate change, the next wave of the pandemic coupled with the ‘flu, fuel shortages, sparse supermarket shelves and the chances of a decent knees-up over Christmas”. But let’s take a quick look at what’s currently floating around above us and what to do about it.
From the start of the Space Age over sixty years ago we have managed to take our propensity to pollute the environment to a new level. Around five thousand rockets have been launched resulting in the deployment of thousands of satellites, many of which are currently active but most are now dead bits of machinery orbiting the Earth. It’s estimated there are over 30,000 pieces of space junk larger than 10 cm, and 128 million pieces larger than 1 mm, all of which could collide, at pace, with operational satellites or the International Space Station (ISS). During the last 20 years the ISS has had to adjust its orbit to reduce the risk of an impact 25 times.
In many cases the orbits decay and the space borne rubbish accelerates back down from whence it came. At best this gives scientists and newspapers the opportunity to try to predict where and on whom they will land. At worst the larger chunks of metal could have a nasty impact, but the chances are that there will just be a harmless splash in some part of the oceans which make up the majority of our planet. Still, it’s not a neighbourly gesture on the part of the space operators concerned, who seem to be mainly Russian or Chinese. There are ways used by the more responsible satellite companies to mitigate the risks by reserving the last bit of fuel on a dying satellite to propel it up, rather than down, in the direction of the Sun where eventually it will be obliterated. Other methods are being developed to hoover up the larger bits of junk, including entire satellites; in particular Surrey Satellite Technology has successfully tested a very large magnetic net to grab a passing dead spacecraft. But for the smaller bits there is no solution other than to wait for them to drop back into Earth’s atmosphere, as happened with a rather chunky piece of Chinese satellite recently. There is a United Nations convention governing the disposal of used space objects which have outlived their usefulness but it has no teeth in the way of penalties for failure to comply, and outer space isn’t exactly a comfortable environment in which to employ litter traffic police or recycling enforcers.
Larger satellites do their business in geostationary orbit 23,000 miles away, orbiting above our Equator at the same speed as the Earth’s rotation, so to a observer here on the ground they’re fixed in space. The newer, smaller satellites being deployed in droves by the likes of Messrs Musk and Bezos move around in low earth orbit only a few hundred miles up. These are visible to the naked eye in the night sky, much to the annoyance of seasoned deep space astronomers who greatly resent the light pollution they produce. If all proposed plans come to fruition, there will be some 50,000 of these little airborne transmitters flitting across the horizon, and of course the probability of collisions increases drastically along with the expanded son et lumiere spectacle we will all be able to experience for free. The European Space Agency performed its first satellite manoeuvre to avoid colliding with a SpaceX constellation over two years ago, so it’s highly likely ESA’s satellite controllers are by now getting used to the idea.
There is mankind’s litter elsewhere in space, such as on the lunar surface with detritus weighing close to 200,000 kg including a number of exploratory space probes, three Moon buggies, three golf balls, a piece of Andy Warhol art and a family photo of one of the Apollo astronauts. And there are solar panels left behind from other Apollo flights (not for NASA the admonition to take your rubbish home with you) which are being used as targets to reflect earthly laser beams projected to measure the distance between the Earth and Moon. From these measurements there is some good news and something to ponder. The results confirm that the Moon’s orbital distance from us does indeed vary due to its slightly elliptical orbit. The not-so-good part is that the Moon is slowly distancing itself from the Earth to the extent that, in a few billion years’ time, the mutual gravitational attraction will no longer be sufficient to keep us together and the Moon will move away in search of a better offer elsewhere in the cosmos.
And finally, it’s heart-warming to report that scientific fact and television fiction have combined spectacularly with the news that Captain (eventually Admiral) James T Kirk, long-serving Commander of the US Starship Enterprise, is finally poised for a real Star Trek adventure. The former actor William Shatner, at the age of 90, will be part of the next four-man crew aboard Jeff Bezos’s New Shepard space tourist vehicle due to blast off on 12 October, albeit for a mere 10 minutes’ jaunt some 60 miles into space. Shatner could have gone up sooner, with Richard Branson’s Virgin Galactic in July, but declined Branson’s offer. One version of the reason for his refusal was his fear of flying …. the other was that Branson asked Shatner to pay full fare for risking his life, whereas Shatner assumed he would be offered a huge fee for his endeavour. Either way, Shatner won’t be the first Star Trek original cast member in space. That honour belongs to James Doohan, the long-suffering engineer “Scotty” whose ashes were smuggled onto the International Space Station in 2008.
Given that the Bezos craft carries a crew of four, it’s interesting to speculate who else would be best suited to accompany Captain Kirk on his voyage. The wonderful views of planet Earth afforded the intrepid travellers would doubtless include examples of terrestrial litter and pollution brought about by climate change and other manmade activity, enough you’d think to persuade anyone in their right mind that the time for prevarication and posturing is long gone, and that concerted international action and cooperation should be the only priority. Maybe a trio of likely lads comprising Xi Jinping, Jair Bolsonaro and our very own Boris Johnson would benefit from the experience. They could discuss and agree a grand plan while Kirk is at the helm, but heaven forfend that at the end of the flight when it’s time to sail back to Earth, the old fella should mistakenly press the UP rather than the DOWN button and they all float off to become just another piece of space junk.
tile photo: Jeremy Thomas on Unsplash
