Littering and fly tipping are the bane of many a community. But already, the human race has managed to pollute space with numerous pieces of junk. Currently, an estimated 100 million human artefacts are drifting above in perpetual orbit.
Amongst these artefacts are decommissioned satellites, batteries and parts of rockets; not to mention space suits and, for a period of time, a spatula lost during a repair on a space station.
The debris is a risk to working satellites, and there are often collisions with space junk. If the current rate of littering continues we’ll be lucky to find a path through to travel to Mars or anywhere else.
However, science is trying to come to the rescue! To combat this trend, various inventions are in the pipeline to clean up space, including ‘janitor’ satellites, laser tractor beams and anelectro-magnetic tether, to capture the rubbish. I don’t think I need to talk the enormous technical challenges these ideas face, and just not dumping things in the first place may be somewhat simpler. Or failing that, making sure the pieces left are small enough to burn up in the Earth’s atmosphere. The end of space junk doesn’t look likely to happen soon, 4500 more satellites are soon due to be launched into low Earth orbit to enable global Broadband coverage. I hope end-of-life plans are in place for these new additions!
The oldest redundant satellite orbiting currently is a weather satellite that has its own Twitter account. Fengyun has been orbiting Earth at 28,000 Kilometres per hour since 2007. Now heading towards imminent destruction by the atmosphere, Fengyun is spending its final months sending some poignant tweets on the nature of life and the universe.
You can find the satellite on twitter @FengyunAdrift
This account, as well as music recordings and a short documentary called Adrift’ ‘exploring the troubling, beautiful, dangerous and fascinating world of space junk ‘were created by a group of artists.
To find out more, visit: Project Adrift
Like a firework…
Many pieces are of space junk are made of titanium, which with its 1670 °C melting temperature, won’t burn up on re-entry to Earth.
The French space agency has proposed a solution: using thermite. Thermite is a mixture of metal powder, fuel and metal oxide, which releases heat when ignited, as with fireworks and welding processes.
Most varieties are not explosive, but can create brief bursts of high temperature in a small area. Thermite attached to the metal partswould ignite when entering the upper atmosphere creating holes in the structure and increasing the likelihood of the pieces breaking up on re-entry.
Thermites have diverse compositions. Fuels include aluminium, magnesium, titanium, zinc, silicon, and boron. Aluminium is common because of its high boiling point and low cost.
Oxidizers include bismuth(III) oxide, boron(III) oxide, silicon(IV) oxide, chromium(III) oxide, manganese(IV) oxide, iron(III) oxide, iron(II,III) oxide, copper(II) oxide, and lead(II,IV) oxide.