Space junk poses real threat
International Space Station faces greatest risk
Canadian astronaut Steve MacLean is hovering on the outer truss of the International Space Station. Concentrating on the work before as the Earth lies 200 km below.
The continents whiz by at speeds greater than race cars. Add the fact there’s a gorgeous sunrise every 90 minutes and you can hardly blame him for getting distracted.
When he’s done work on one of the several ports he’s opening up, he goes to reattach its cover. But something is missing – one of the bolts that secures the corner of the cover to the truss. A quick search for it turns up no results; the bolt has floated off into space.
MacLean has unwittingly added a bolt to the thousands of pieces of space junk floating around Earth’s orbit. A seemingly harmless piece of metal, the bolt takes on a dangerous prospect when it is accelerated in orbit by Earth’s gravity. It becomes one of many pieces of metal hurtling through space at thousands of kilometers an hour. Space junk is a real threat to satellites, and even astronaut’s lives.
Space is often thought of as a vast, open void of nothingness. Yet as humans have reached out beyond our planet, we’ve brought our junk with us. In 2000, the U.S. Space Command reported almost 9,000 pieces of junk floating in Earth orbit. Since each piece is traveling at high speed, they threaten to puncture the spacecraft orbiting earth.
Aside from contributing a small piece of trash to the veritable junkyard now orbiting Earth, MacLean’s also had some close calls with debris. NASA’s Space Shuttle Atlantis returned the crew to Earth safely, but only after a day’s delay due to concerns over an unidentified object floating alongside the Shuttle. Using the Canadian-made robotic arm to investigate, astronauts realized a plastic bag had floated out of their open cargo hold.
Upon the Shuttle’s return to Earth, a small hole was discovered in a radiator panel. Luckily, the 2.5 mm hole didn’t damage the sensitive heat shield that protects the crew upon re-entry.
It was the “second-most-damaging particle that we’ve encountered in the program,” NASA spokesman James Hartsfield told the Times. But it “posed no danger to the crew and no change to the mission.”
Atlantis wasn’t the only spacecraft put at risk by random pieces of space debris. The International Space Station took a hit while MacLean was aboard, and the crew sounded the emergency alarm as a result.
A small piece of space junk had broken a gasket on the Elektron oxygen generation system. Toxic potassium hydroxide gas was leaking out as a result and astronauts acted quickly to bag up the liquid globules. The toxin was not life-threatening and the oxygen generation system has since been repaired, but the incident illustrates just how easily something as small as a bolt could jeopardize the lives of those on-board the ISS.
The two nations who make the most forays into outer space are also the two worst polluters of it. The U.S. and the Russian Space Agency had put 3,758 and 3,941 pieces of junk into orbit respectively as of June 2000. But it’s the U.S. who has the distinct honour of the oldest piece of space debris – the Vanguard I satellite was launched in March, 1958. After just six years of operation, it became the first hunk of space junk.
The U.S. is also the only nation to have space junk that was a potential threat to Earth dwellers. Space junk, just like meteors, will dip out of orbit and into Earth’s atmosphere often. Usually it burns up before hitting the surface, but sometimes it is too large to completely incinerate – as was the case with Skylab.
After six years in orbit, Skylab was in bad need of repair. But an interruption in NASA’s shuttle program meant it wasn’t going to come in time. One way or another, the scientific space lab was degrading in orbit and going to crash into Earth. Knowing it posed a risk, NASA attempted some attitude shifting to crash it into the ocean.
They succeeded just partially. Most of the debris landed in the Indian Ocean, but another portion ended up in the Australian Outback. No one was hurt and no property damaged, but town authorities fined the U.S. government $400 for littering.
Since then, the amount of space junk re-entering Earth’s atmosphere is becoming greater with each passing year. The U.S. Space Command reported over 100 pieces falling to Earth for the first time in 2000. It is just one of the many ways space junk is getting more dangerous.
Estimates put the growth of the belt of junk around Earth growing at 4 per cent per year. Most at risk as a result of this is – you guessed it – the International Space Station. The National Academy of Sciences calculated the chance of a fully assembled ISS operating for ten years has a one in five chance of getting pierced by space junk.
Who knows, maybe it will be that bolt that MacLean errantly let drift off into space while he was distracted by the majesty and beauty of empty space before him.
