Killer nuts and bolts from Outer Space!

NASA Debris Plot

Today, most of the newspapers and news channels around the world carried stories and pictures of astronauts on the International Space Station (ISS) completing a successful space walk. The space walk was carried out to install power and data cables between two points in preparation for a solar array deployment on the ISS.


Three Cheers for humanity - Job well done! Pictures of astronauts from outer space beamed across the world. However, only few in the media did mention a trival matter!


"Astronauts Lose Bolt During Spacewalk"!


So what's the big deal about loosing a bolt in space, right? In a report published in the journal Science by NASA Scientists J.-C. Liou and N. L. Johnson in early 2006, they estimated the pieces of space junk measuring 4 inches or more, total somewhere around a staggering 5,500 tons.


What is space junk?

Since the first satellite, Sputnik 1, was launched in 1957, thousands of space probes, satellites and telescopes have been sent into space. Just as we have created rubbish mountains on Earth, we've also accumulated a blanket of junk around the Earth.

This debris silently zooms around the globe at speeds of up to 25,000 miles per hour with altitudes ranging from hundreds to thousands of miles. NASA frequently replace windows on the space shuttle that have been damaged by objects as small as a flake of paint.

How much junk is out there?

Radar and optical monitoring can pinpoint the location of space debris only centimeters in size. The current estimate is that there are over a million bits of debris orbiting the Earth. About 70,000 objects about the size of a postage stamp have been detected between 850 - 1,000 km above the Earth. (Source: BBC)


A 2004 NASA report identified Russia as the source of the largest number of debris items, closely followed by the United States. Other sources were France, China, India, Japan and the European Space Agency.


Yes, we humans have left our trace of garbage even in outer Space. Space junk consists of jettisoned spacecraft parts, nuts and bolts, solar cells, abandoned satellites, paint chips, nuclear reactor cores, spent rocket stages, solid fuel fragments. The oldest debris still on orbit is the second US satellite, the Vanguard I, launched on 1958, March, the 17th, which worked only for 6 years. In 1965, during the first American space walk, the Gemini 4 astronaut Edward White, lost a glove. For a month, the glove stayed on orbit with a speed of 28,000 km/hour, becoming the most dangerous garment in history. More than 200 objects, most of them rubbish bags, were released by the Russian Mir space station during its first 10 years of operation.


Most of the junk re-enter the Earth's atmosphere and burn up on entry. But there is enough junk which is stuck in permanent orbit to cause concern. NASA has setup the NASA Orbital Debris Program Office which is responsible to track space junk. The Space Command's electronic eyes can spot a baseball-sized object up to about 600 miles high, officials say. But at 22,300 miles up, where geostationary satellites roam - providing weather images used by forecasters - an object has to be as big as a volleyball to be seen.

At the most rudimentary level, the U.S. Space Command keeps track of many of the objects orbiting Earth, including debris. As of June 2000, the total number of trackable space objects including 90 space probes, 2,671 satellites and 6,096 pieces of space junk was a whopping 8,927.

If any of the more than 6,000 space-junk objects gets too close for comfort to a satellite or inhabited spacecraft, the Space Command sends out a warning. Already, the ISS has had to move out of the way of an oncoming piece of space debris; in October 1999, ground controllers successfully maneuvered the ISS out of the way of a piece of debris that was headed right for the station. The space shuttle has also had to make way for a number of pieces of space junk.

What are the dangers from debris? (Source: BBC)

Although most of the debris in space is small, it's travelling extremely fast. Below altitudes of 2,000 km, the average relative impact speed is 36,000kmph (or 21,600 mph).

At this speed, collision can be dramatic:

• A 1mm metal chip could do as much damage as a .22-caliber long rifle bullet

Bits this size don't generally pose a large threat to spacecraft, but can erode more sensitive surfaces and disrupt missions.


• A pea-sized ball moving this fast is as dangerous as a 400-lb safe travelling at 60 mph

Debris this large may penetrate a spacecraft. If this happens through a critical component, such as the flight computer or propellant tank, this could be fatal.


• A metal sphere the size of a tennis ball is as lethal as 25 sticks of dynamite

This debris will penetrate and seriously damage a spacecraft.

The most space debris created was by the destruction of the upper stage of a Pegasus rocket launched in 1994. Its explosion in 1996 generated a cloud of some 300,000 fragments bigger than 4 mm and 700 among them were big enough to be catalogued. This is as good as sand blasting over a long period of time which will take off several inches off any surface. "We get hit regularly on the shuttle," said Joseph Loftus, Assistant Director of Engineering for NASA's Space and Life Science Directorate. "We've replaced more than 80 [shuttle] windows because of debris impacts."


Danger of getting hit on the head by a killer bolt or toothbrush?

Trivia has it that an American woman, Lottie Williams is on record as the first and only (as of January 2006) person ever to be hit by space debris created by humans. While walking in a park in Tulsa, Oklahoma, on January 22, 1997 at 3:30 am, she noticed a light in the sky that she said looked like a meteor. Minutes later, Williams was hit in the shoulder by a 6-inch blackened metal object 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. Ms. Williams was not injured.


So chances of being hit by space junk are one in a billion or trillion. And now with space tourism becoming a reality - they better have a garbage policy before space junk includes wafer covers, plastic bags, cola cans, disposable cameras, tissues and who knows what else. It would not only cause a stink in outer space but even future headlines which may read "Space tourist fatally wounded by mineral water bottle travelling at 36,000kmph".


No wonder Aliens have stopped visiting Earth! Must be difficult to drive a UFO safely through all that space junk.


If you are still interested in reading more, here are some links for further reading:

Space Junk: The full list
Astronauts Lose Bolt During Spacewalk - ABC News
Space Junk by Robert Roy Britt
Space Debris a Growing Problem, NASA Report Says
Orbiting Junk Continues to Threaten International Space Station
Space Junk and ISS: A Threatening Problem
Science and Nature: Space - BBC
Living Off Space Junk
NASA Orbital Debris Program Office
Space debris