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the growing junkyard
What a difference 50 years makes. At right, two images show the number of objects in orbit around the Earth in 1963 and early 2013. The data come from catalogs compiled by
what's all this junk?
Space junk is any man-made object in orbit that no longer serves a useful purpose.
The majority of all space junk is in low Earth orbit, which is below 1,250 miles.
Objects in orbit are traveling at incredible speeds. For instance, the
sizing up the problem
The U.S. Space Surveillance Network is tracking more than 22,000 objects larger than 4 inches in diameter.
There are also about 1,000 operational spacecraft in orbit around the Earth.
The Earth is smaller than scale
breakdown of junk
42% Fragmentation debris suchas fuel, batteries and paint flakes.
22% Nonfunctional spacecraft.
19% Mission-related debris.
17% Rocket bodies.
The estimated number of objects between 0.4 inches and 4 inches is around 500,000.
The estimated number of objects smaller than 0.4 inches exceeds tens of millions.
where the junk is concentrated
The graphic below depicts a cutaway of the low Earth atmosphere from sea level to 1,250 miles in space; the atmosphere is shaded to show areas with the highest and lowest density of space debris.
2009 A defunct Russian satellite collided with a functioning U.S. commercial satellite. The collision destroyed both and added 2,000 trackable objects at this altitude.
The first man-made satellite to orbit Earth, Sputnik.
Former Soviet space station Mir
Hubble Space Telescope
A 2008 study concluded the Chinese are responsible for 42 percent of the debris in orbit; the U.S. created 27.5 percent and the Russians 25.5 percent.
Altitude above sea level
Debris in orbit below 370 miles normally falls back to Earth within several years.
The time for orbital decay at this altitude is a century or longer.
Objects from here are in medium Earth orbit. At 12,644 miles, they are considered to be in high Earth orbit.
The station can maneuver to avoid tracked objects and does an avoidance maneuver once a year on average.
what goes up ...
There are about 1,000 functioning satellites in space, fewer than one-third of all that have been launched. Each will re-enter the Earth's atmosphere at some point. The chart above shows
1989 had more than twice as much debris re-enter than 2012
Chicken Little can take a deep breath
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