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objects (ODOs). But, unfortunately, the network can’t track anything smaller than about four inches across. NASA estimates there could be as many as 500,000 ODOs that are big enough to wreck a spacecraft but too small to track from Earth.
THE KESSLER SYNDROME
It wasn’t until the late 1970s that the space program looked at this problem head-on, after NASA scientist Donald Kessler and his colleagues warned that LEO could become so crowded that it would no longer be safe to launch new missions. If an item as small as an old bolt or screw could destroy a spacecraft, Kessler told them, imagine what an entire defunct satellite could do.
In February 2009, scientists had the opportunity to find out: A 2,000-pound decommissioned Russian satellite crashed into a still-operational 1,200-pound American model, obliterating both crafts and turning them into a dense cloud of dangerous debris. That event—the rendering of two large objects into thousands of smaller ones, each capable of going out on its own to destroy other spacecraft—is called the Kessler syndrome . Space junk multiplies at a constantly accelerating pace: More junk equals more collisions, and more collisions mean more junk. Even if humans never launch another rocket, the number of ODOs will still continue to multiply.
Not helping matters, in 2007 the Chinese government shot down an old communications satellite, presumably just to show they could do it. The test, which was deemed a success by the Chinese, added thousands of objects to the catalogue of ODOs. The following year, the United States also shot down one of its own satellites—supposedly because it was on a course to crash back to Earth with a full tank of toxic fuel. Now it’s 1,000 toxic bits and pieces.
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In 2006 the record holder for longest stay surrounded by centipedes, Boonthawee Seangwong and the record holder for longest stay surrounded by scorpions, Kanjana Kaetkeow, got married .
----
In 2009 the danger of space junk made big news when three crew members aboard the International Space Station had to evacuate into a waiting spacecraft because a five-inch chunk of an old rocket was heading straight for them. Thankfully, it missed. Afterward, NASA acknowledged that debris comes close enough to the station to cause concern several times per month, and the station has to take evasive action to avoid a collision about once a year.
FAR OUT
Unfortunately, the technology to clean up LEO doesn’t exist yet. But there is good news: The closer an object is to Earth, the less time it will last up there. The reason: The planet’s atmosphere, thin as it is at very high altitudes, exerts drag on objects in orbit, causing them to slow down. As they decelerate, they fall and typically burn up as they enter the thicker lower atmosphere.
Moving farther away from the planet, however, that atmospheric drag decreases exponentially—just a small change in altitude translates into a large difference in how long an object can expect to remain in orbit. A piece of space junk that would last only a few months at 150 miles up could last for years at 600 miles, decades at 800 miles, and centuries at 1,000 miles.
Because of this, most new satellites are designed to fire their rockets one last time when they come to the end of their operational lives. The blast moves them either low enough that they will crash back into the atmosphere, or up into a “graveyard orbit” of more than 22,000 miles—high enough that they are thought to be out of the way (for now).
MORE DIRT ON SPACE JUNK
Along with old satellites and booster rockets, there’s a lot of other random stuff hurtling through space. For example:
• 480 million copper needles: Launched by the U.S. military in 1963, the needles, which were only the width of a hair, were meant to disperse around Earth and act as a sort of giant space antenna. It was hoped that this system would replace undersea cables for transatlantic communications, and it
THE KESSLER SYNDROME
It wasn’t until the late 1970s that the space program looked at this problem head-on, after NASA scientist Donald Kessler and his colleagues warned that LEO could become so crowded that it would no longer be safe to launch new missions. If an item as small as an old bolt or screw could destroy a spacecraft, Kessler told them, imagine what an entire defunct satellite could do.
In February 2009, scientists had the opportunity to find out: A 2,000-pound decommissioned Russian satellite crashed into a still-operational 1,200-pound American model, obliterating both crafts and turning them into a dense cloud of dangerous debris. That event—the rendering of two large objects into thousands of smaller ones, each capable of going out on its own to destroy other spacecraft—is called the Kessler syndrome . Space junk multiplies at a constantly accelerating pace: More junk equals more collisions, and more collisions mean more junk. Even if humans never launch another rocket, the number of ODOs will still continue to multiply.
Not helping matters, in 2007 the Chinese government shot down an old communications satellite, presumably just to show they could do it. The test, which was deemed a success by the Chinese, added thousands of objects to the catalogue of ODOs. The following year, the United States also shot down one of its own satellites—supposedly because it was on a course to crash back to Earth with a full tank of toxic fuel. Now it’s 1,000 toxic bits and pieces.
----
In 2006 the record holder for longest stay surrounded by centipedes, Boonthawee Seangwong and the record holder for longest stay surrounded by scorpions, Kanjana Kaetkeow, got married .
----
In 2009 the danger of space junk made big news when three crew members aboard the International Space Station had to evacuate into a waiting spacecraft because a five-inch chunk of an old rocket was heading straight for them. Thankfully, it missed. Afterward, NASA acknowledged that debris comes close enough to the station to cause concern several times per month, and the station has to take evasive action to avoid a collision about once a year.
FAR OUT
Unfortunately, the technology to clean up LEO doesn’t exist yet. But there is good news: The closer an object is to Earth, the less time it will last up there. The reason: The planet’s atmosphere, thin as it is at very high altitudes, exerts drag on objects in orbit, causing them to slow down. As they decelerate, they fall and typically burn up as they enter the thicker lower atmosphere.
Moving farther away from the planet, however, that atmospheric drag decreases exponentially—just a small change in altitude translates into a large difference in how long an object can expect to remain in orbit. A piece of space junk that would last only a few months at 150 miles up could last for years at 600 miles, decades at 800 miles, and centuries at 1,000 miles.
Because of this, most new satellites are designed to fire their rockets one last time when they come to the end of their operational lives. The blast moves them either low enough that they will crash back into the atmosphere, or up into a “graveyard orbit” of more than 22,000 miles—high enough that they are thought to be out of the way (for now).
MORE DIRT ON SPACE JUNK
Along with old satellites and booster rockets, there’s a lot of other random stuff hurtling through space. For example:
• 480 million copper needles: Launched by the U.S. military in 1963, the needles, which were only the width of a hair, were meant to disperse around Earth and act as a sort of giant space antenna. It was hoped that this system would replace undersea cables for transatlantic communications, and it
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