Progress Deorbit & Misc

> In regard to "Progress is going to be deorbited. ... Mass in LEO
is
> worth, at a minimum, about $600/lb. ..." I don't disagree in
principle, but
> the ISS is retarded by a force of about 1 Newton continuously from
> collisions with air molecules in the upper atmosphere (drag), and
so has to
> be boosted up nearly every month. The altitude of the ISS is
posted on
> http://www.heavens-above.com/issheight.asp?
Session=kebgchcpnjoklmldbbogeicc
> (to get there you will have to registrar. But it is painless and
worth it
> to see where ISS is not only in altitude, but also latitude and
longitude,
> and when Iridium Flairs can be expected, etc.) The point is that
keeping
> more objects (materials) on ISS will cause more drag (unless what
is added
> goes inside something already there) and that will cost more in
fuel to
> boost it, to keep it at the assigned altitude.
> I agree an ion engine, VASIMER engine, or electro-magnetic
tether, which
> could all provide boosts, and could be solar powered, could solve
this
> problem, but none are there yet and I expect there will be many more
> Progress space craft before they are. Then, there are those
external fuel
> tanks for the Shuttle, which is scheduled to go up next Friday.
> I like the question (implied), how can we invest in this?
> Cheers, Jay Huebner

I didn't intend the question to be implied, but explicit. Orbital
mass, in (hopefully) the not-too-distant future will be worth its
weight (mass) in ... well, silver anyway. The first organization or
consortium that develops a small, remotely-controlled space tug to
gather mass in, say, a thousand km orbit, will have a bright future
(semi-pun for you SPS enthusiasts intended). Boeing (formerly
Hughes) produces the:

Boeing 601HP Thruster:

13 centimeters in diameter
2568 seconds ISP
18 mN of thrust

Boeing 702 Thruster:

25 centimeters in diameter
3800 seconds ISP
165 mN of thrust

Wonder what they cost?