From: vince@offshore.ai (Vincent Cate)
Newsgroups: sci.space.tech
Subject: Prices on Ion Drives or Hall Thrusters?
NNTP-Posting-Host: 207.42.133.230
Message-ID: <9186edb5.0307071106.12b9975d@posting.google.com>

Space Tethers can give up some momentum to a payload but they then need 
to get it back somehow.  This could be a payload going the other way,
or an electrodynamic tether, or some sort of Ion Drive or Hall Thruster.

One interesting thruster is the Russian made SPT-290.  This has thrust of
up to 1.5 newtons, weighs 23 Kg, and uses 5 to 30 kw of power.  It is rated 
at 27,000 hours. I am not sure what the ISP is, but probably between 1500 
and 2500 seconds.  See:

   http://www.videocosmos.com/magazine/nk0799.html

I am trying to find out what the SPT-290 costs, but have not yet.  
Does anyone here know what this or a similar thruster would cost?

Better yet, if I wanted 200 of them, what do you think they would 
cost?  What if we really wanted them cheap and did not want the usual
testing to get "space rating"?  When you are spending $6,000/lb to get
to GEO it makes sense to pay a lot for really reliable hardware, but
I expect tethers could get prices to LEO to under $100, so I would not
want to pay as much for thruster testing.

How hard would it be to build Hall Thrusters?  How expensive 
is the stuff to used in making Hall Thrusters?

How do prices on Ion Drives compare to prices for Hall Thrusters?  

   -- Vince