[FPSPACE] Firefly? (was Re: Italiamir)

[JamesOberg@aol.com]

In a message dated 10/22/00 8:50:31 AM Central Daylight Time, 
wayneday@gwis2.circ.gwu.edu writes:

<< Is there a point at which tethers are no longer viable?  If an object gets
 too low in the atmosphere, is the drag too great for a low-thrust system
 like a tether to overcome? >>

Two things happen as you get lower: the constant thrust of the tether can get 
overwhelmed by higher drag, and second, the drag itself can affect the 
hang-angle of the tether. And a third, good thing -- the lower you are, the 
less orbital debris there is, so the odds of the tether getting cut go way 
down. At current Mir altitude, the expected "mean-time-between-tether-loss" 
is less than a year.