Space Junk Or Debris Needs Cleaning Up But Where’s The Bin?

Did you ever walk around town, getting annoyed at all the rubbish? It’s quite easy to pick it up and put it in a bin, although you wouldn’t think so looking at the state of some areas. In space, unfortunately, there are no litter bins are no floating cleanup people with a long stick happily prodding away at the rubbish. If there was there would  need to be a very large rubbish bin in orbit around the Earth.

At the end of 2003, there were some 10 000 catalogued debris objects around Earth, comprising:

• operational spacecraft — 7%
• old spacecraft — 22%
• rocket bodies — 17%
• mission-related objects — 13%
• miscellaneous fragments — 41%

Artificial debris includes spent satellites, cast off Yo-Yo de-spinners (used to de-spin spacecraft after launch), tools dropped during spacewalks, discarded rocket upper stages and the fragmentary remains of craft that have exploded or otherwise broken up.

There are around 50 000 more uncatalogued objects larger than 1 cm floating around waiting for a satellite or spacecraft to hit. Uncatalogued objects include nuts and bolts, gloves, bits of aluminium slag from solid rocket motor propellant and droplets of Sodium-Potassium coolant that escaped from Russian nuclear-powered reconnaissance satellites when they ejected their reactor cores.

Space debris

The really dangerous bits are intermediate in size, between 1 and 10 cm. These are hard to detect yet pack a kinetic energy punch sufficient to cause catastrophic damage. One cm is also the maximum size of debris that can be defeated by modern shielding technology; Space Shuttle windscreens have been damaged by flecks of paint as small as 0.3 mm in size travelling at a mere 14 400 kph. The fastest debris, at 50 000 kph, are travelling about 17 times faster than a machine gun bullet.

Do you still fancy that joyride into orbit? Well, luckily enough, it’s not as dangerous as it sounds. Preventative measures have been taken so that being in orbit isn’t a death sentence. Paint flakes and solid rocket propellant causes erosive damage similar to sandblasting. Most of the damage can be stopped through the use of a technique originally developed to protect spacecraft from micrometeorites, by adding a thin layer of metal foil outside of the main spacecraft body.

Impacts take place at such high velocities that the debris is vaporized when it collides with the foil, and the resulting plasma spreads out quickly enough that it does not cause serious damage to the inner wall. Many satellites cannot be protected this way, the solar panels and windows for instance, and they receive constant wear by debris and micrometeorites. So don’t look at the view for too long and take some spare batteries for your CD player for when the solar panels are damaged.

Orbital debris in Saudi Arabia

The only way to stop damage from larger bits and pieces is to move the satellite or spacecraft. This means that you must be able to see the space debris. The NASA orbital debris program office observes the debris in various ways. Ground-based optical telescopes and radars provide a lot of information and to supplement this impacts are measured on spacecraft or satellites that have returned to the Earth.

The international space station can change its orbit, but if the space junk isn’t seen early enough then it is too late to move the station and the crew retreats to a safe area, in this case the Soyuz capsule. This happened quite recently in March 12th 2009.

Of course, something hitting a spacecraft, space station or satellite will cause more space junk as bits will be broken off or the whole of the satellite made into junk.

If you’re thinking that this doesn’t affect you , then you are wrong. This is not just confined to space as the debris’s orbit can decay and rain down on the Earth. One spectacular piece of space junk was the Skylab. The Skylab couldn’t maintain its orbit long enough for the space shuttle to rescue it and therefore its orbit decayed.

Orbital debris impact

There has only been one recorded incident of a person being hit by human-made space debris. In 1997 an Oklahoma woman named Lottie Williams was hit in the shoulder by a 10 x 13 centimetre piece of blackened, woven metallic material that was later confirmed to be part of the fuel tank of a Delta II rocket which had launched a U.S. Air Force satellite in 1996. She was not injured

Really, space is a great place and we marvel at its beauty. It should be treated as a national park, or the orbit of Earth anyway (to make the whole of space a national park would be a rather large undertaking). Debris produced today is being limited at the moment, and that is fine, but what about all the junk already there?

A few ideas have come up, such as junk-zapping lasers and garbage-collecting rockets. The most well-known of these projects is the Orion Project, a major study which began in the late 1970s, and which continues to undergo development with help from NASA and other government agencies. The focus of Orion has been to look at the possibility of using high-powered laser-light beams to actually deflect orbital debris out of the way of spacecraft and into the Earths atmosphere where it can burn up out of harms way.

There is probably some quite historical space junk flying around the Earth , and perhaps one day it will be captured, sorted through and put into a museum. But for now “duck” may become an astronaut’s favourite word.

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