Newsgroups: sci.space.shuttle
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Shuttle-ground communication and payloadprices
Message-ID: <1989Mar24.231954.17877@utzoo.uucp>
Organization: U of Toronto Zoology
References: <2099@botter.cs.vu.nl> <1989Mar20.191412.23335@utzoo.uucp> <1194@ncrcce.StPaul.NCR.COM> <1989Mar22.175026.1247@utzoo.uucp> <2102@botter.cs.vu.nl>
Date: Fri, 24 Mar 89 23:19:54 GMT

In article <2102@botter.cs.vu.nl> wallagh@cs.vu.nl () writes:
>I still don't understand why you need 3 satelites to cover all the 
>communication with the Shuttle.
>Aren't there enough tracking stations on the ground? 

Tracking stations are expensive, and NASA would like to close them down
in favor of satellite relaying.

>There is (at least) a couple in the US, some in Europe and in Australia.
>That should be enough , I think. But it isn't. Why?

Remember that tracking stations can talk to the shuttle only when it is
above their horizon.  It is at a fairly low altitude, so the circle of
coverage of a ground station isn't all that large.  You need a *lot* of
stations for continuous coverage.

>What are the costs for 1 Kg payload in the space shuttle, ariane and
>(if it's known) with the Russian satelites.

Depending on exactly which set of numbers you believe (there are several
possibilities for government-run launchers), shortly after Challenger
essentially all viable launchers in the West cost about $11000/kg for
government launches to low orbit.  This includes the shuttle; the NRC
study of the shuttle program found that (contrary to certain partisan
propaganda) the shuttle was not significantly more expensive in practice
than expendables, although it wasn't any cheaper either.  Expendable
prices have come down somewhat since, for those launchers that have
commercial competition.  The lowest number I've seen was about $4500/kg,
and I suspect that was based on very optimistic assumptions.  These
are numbers for fairly large launchers; the small ones are pricier.

I'm afraid I don't remember the current price for commercial launches
on Soviet boosters, but it's safe to assume that they're a factor of
several less.  The Soviet launchers are less sophisticated and are built
in much larger numbers on stable, well-established production lines.
-- 
Welcome to Mars!  Your         |     Henry Spencer at U of Toronto Zoology
passport and visa, comrade?    | uunet!attcan!utzoo!henry henry@zoo.toronto.edu