What makes Mir more difficult than previous space re-entries is the magnitude of the forces of nature already acting on Mir, in comparison to the stabilization and impulse capabilities of the Progress tug sent to do the job.

At 137 tonnes, the Mir space station is about 20 times heavier than the Soyuz and Progress craft which the Russians are accustomed to de-orbiting.

Like a tug maneuvering an ocean liner, the little Progress M1 craft now docked with Mir has to steer and push MIR around. Able to carry about 3.8 metric tons of fuel, much of which is needed for orientation, Progress can produce only a very limited velocity change. This means that the controllers must wait until Mir is teetering on the brink of a natural re-entry.

As many readers are aware the Drop Zone has been carefully chosen, but what exactlly is so attractive about the South Pacific?

Firstly, a craft in an orbital inclination of 52 degrees only overflies areas between 52N and 52S latitude, ruling out the polar regions.

Secondly, having a drop zone near to this latitude (as opposed to near the equator) means their are several chances to deorbit in this area, should the first attempt fail.

Thirdly, and most obviously, the "graveyard" provides an ocean area without islands and consequently people (see Figure 1).

Community Email This Article Comment On This Article Related Links SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Space Tourism, Space Transport and Space Exploration News Memory Foam Mattress Review SPACE MEDIA NETWORK PROMOTIONS Solar Energy Solutions Tempur-Pedic Mattress Comparison ... Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News SPACE TRAVEL NASA Refines Design For Crew Exploration Vehicle Washington DC (SPX) Jan 12, 2006 NASA's Constellation Program is making progress toward selecting a prime contractor to design, develop and build the Crew Exploration Vehicle (CEV), America's first new human spacecraft in 30 years.