posted on Jan, 23 2008 @ 09:17 PM
# As of april, 2005 at least 13 nuclear reactor fuel cores, 8 thermoelectric generators, and 32 nuclear reactors are known to be in Earth orbits below
# Low Earth orbit ~ 250-600 km from earth - International space station
# Geosynchronous stationary orbit ~ 35,785 km from earth - communications satellites
# ~ 20,000 km from earth - Global Positioning System (GPS) satellites
Before 1961, the entire Earth satellite population was just over 50 objects. Now earth orbit is cluttered with: ~11,000 objects bigger than 10 cm, of
which ~9,000 are catalogued and tracked (~8000 are of US or USSR origin) - including around 600 functional spacecraft; ~100,000 objects from 1-10 cm
-- too small to track, dangerous to spacecraft; and several million objects smaller than 1cm.
What are they? Jettisoned mission junk, rocket fuel, space station garbage, abandoned rocket parts, used nuclear reactors, leaked radioactive coolant
and exploded bits (~150 unplanned explosions of rockets and satellites have occured to date). Collisions between orbiting debris make even more
debris. Hundreds of close passes (less than 1 km apart) occur daily between catalogued objects. Each year around 100 objects fall out of orbit and
survive re-entry, crash landing somewhere on earth. Dozens of earth orbit satellites launched by the USSR and the USA between 1965-1988 used nuclear
power. Several have fallen out of orbit and crash landed. Nuclear power systems are being considered for projects in the next decade. About 75 - 100
new satellites are launched each year.
UN Office for Outer Space Affairs: www.oosa.unvienna.org