Different types are currently being used in various projects, which
roughly break down into groups as: pure Ion drives, Plasma thruster, and
Arc-jet thruster. They vary in Isp and thrust between 600-3500 Isp and
.0001 lb up to 5 lb of thrust. These two vary inversely, so you can go
for "high" thrust, or high efficiency, but not both. The Air Force's
Phillips Labs is developing an interorbital tug that uses a thermal
solar electric generator and an Arc-Jet propulsion system. They hope to
have it up and operating by late 1998-99. This will allow 100 day
transfer times between LEO and Geosynch orbits at 1/10th of the cost of
a current chemical propelled upper stage. Each tug will have enough fuel
to do 10 missions before needing refueling. Current transfer costs range
from $10-20 million for a 10,000 lb payload.
-- TANSTAAFL!!! Michael Lorrey ------------------------------------------------------------ mailto:retroman@tpk.net Inventor of the Lorrey Drive Agent Lorrey@ThePentagon.com Silo_1013@ThePentagon.com http://www.tpk.net/~retroman/Mikey's Animatronic Factory My Own Nuclear Espionage Agency (MONEA) MIKEYMAS(tm): The New Internet Holiday Transhumans of New Hampshire (>HNH) ------------------------------------------------------------ #!/usr/local/bin/perl-0777---export-a-crypto-system-sig-RC4-3-lines-PERL @k=unpack('C*',pack('H*',shift));for(@t=@s=0..255){$y=($k[$_%@k]+$s[$x=$_ ]+$y)%256;&S}$x=$y=0;for(unpack('C*',<>)){$x++;$y=($s[$x%=256]+$y)%256; &S;print pack(C,$_^=$s[($s[$x]+$s[$y])%256])}sub S{@s[$x,$y]=@s[$y,$x]}