December 10,
2008: Sixty years of humans putting objects into orbit has left a lot of junk
up there. Currently, over 300,000 dangerous objects 10 mm (.4 inch) in size are
up there. The smallest of these is capable of disabling a satellite, or
damaging a spacecraft. That's because these objects hit at very high speed (9-10
times faster than a bullet) if they, and their target, are coming from
different directions. There are nearly 18,000 objects 10 centimeters (4 inches)
or larger. These can do some catastrophic damage, to satellites or spacecraft.
There are billions of objects smaller than 10mm, and these are responsible for
many satellites failing early because of cumulative damage from getting hit by
several of these micro objects. In 2007, the number of objects that could be
tracked from the earth (using radar or telescopes) increased 20 percent.
There are
lots of people keeping an eye on this clutter. The U.S. Air Force Space
Surveillance Network, which tracks nearly 18,000 objects 10mm and larger,
stopped sharing all of its information four years ago, for national security
reasons. The Russian Space Surveillance System is known to use radar to track
over 5,000 objects in low orbit. But the Russians have never shared this data
completely, or regularly.
Filling in
the gaps are two international organizations; IADC (Inter-Agency Space Debris
Coordination Committee) and ISON (International Space Observation Network).
IADC is a government operation, whose members include the U.S. NASA, and the
equivalents in Russia, China and several other major nations. Like most
government organizations, not all data is shared.
ISON is a
non-government organization, and they come up with some of the most interesting
stuff. ISON comprises 18 scientific institutions, 18 observatories, 25
telescopes and over a hundred professionals. ISON does not, as far as anyone
knows, withhold data because of any national security concerns. This is fairly
certain because ISON work is monitored, and complemented, by the efforts of thousands
of amateur astronomers and orbital addicts who connect via the Internet, and
constantly scour the orbital space for new objects, and dangerous movements by
existing ones.
ISON already
has spotted 152 larger (over 10mm) objects that have never been reported by any
of the government organizations. The Internet based amateurs are often the
first to spot a lot of this new activity, mainly because they have more
eyeballs, and, in some cases, impressive optical equipment, searching the
skies.
