nuclear-news

The problem of space junk

The problem of space junk The Space Fellowship 13 Feb 09 “………………………………Accumulation of space debris is also increasing radiation levels in the near-Earth environment.
 In its day, the Soviet Union launched 33 spacecraft with nuclear power units aboard. After fulfilling their missions, the units were jettisoned from the satellites and put in the so-called burial orbit (700 to 1,000 kilometers). There, their cores, consisting of fuel clusters, were jettisoned in turn.Currently, 44 radiation sources from Russia are parked in the burial orbit. They are: two satellites with unseparated nuclear power units (Cosmos-1818 and Cosmos-1867), fuel assemblies and 12 closed-down reactors with a liquid metal coolant, 15 nuclear-fuel assemblies, and 15 fuel-free units with a coolant in the secondary cooling loop. They are to spend no less than 300 to 400 passive years in the orbit. That is enough for uranium-235 fission products to decay to safe levels.

The United States is another contributor to the high levels of radiation in near-Earth space. In April 1964, its Transit-SB navigation satellite with a radio isotope generator aboard failed to enter orbit and broke into pieces. While burning up in the atmosphere, it scattered about a kilogram of plutonium-238 over the western part of the Indian Ocean north of Madagascar. The result has been a 15-fold increase in background radiation around the world. A few years later, the Nimbus-B weather satellite with a uranium-235 reactor crashed into the Indian Ocean.

Today, there are seven American radiation sources circling the Earth in orbits ranging from 800 kilometers to 1,100 kilometers, and two more in near-geostationary ones.The lurking threat of both Russian and American nuclear satellites is that, should they fall apart upon collision with space debris, vast expanses of near-Earth space would be contaminated. Additionally, if some of the fragments had a velocity after collision and destruction that was below orbital speed, they would fall out of orbit and pollute some parts of the Earth’s surface. In the worst-case scenario, the atmosphere could be heavily contaminated.

The Space Fellowship

February 14, 2009 - Posted by Christina Macpherson | 2 WORLD, wastes