Newsgroups: sci.space.shuttle
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: TDRS-C means never having to say LOS?
Message-ID: <1988Oct31.172313.12711@utzoo.uucp>
Organization: U of Toronto Zoology
References: <6732@dasys1.UUCP> <1934@kalliope.rice.edu> <233@vuecon.econ.vu.nl>
Date: Mon, 31 Oct 88 17:23:13 GMT

In article <233@vuecon.econ.vu.nl> MorsinAc@econ.vu.nl (Triple A) writes:
>That was about it for TDRS-C/D, but when checking the launch schedule,
>I discovered they planned to get some more TDRS's up there (TDRS-E/F).
>So my question is, what are they supposed to do if we already got two
>fully operational ones (and a spare) up there? ...

Well, for one thing, TDRS-A doesn't make a really great spare, it's not
in terribly good shape.  When you're relying on these things heavily,
you may want a fully-functional on-orbit spare.

Then too, the 2+1 configuration doesn't really give quite 100% coverage,
the way they've planned to set it up.

And finally, when you get really high data rates going, the capacity of
any one TDRS is limited; I think one TDRS can only hack two high-speed
customers at a time.  Between the shuttle, the Great Observatories line
(starting with Hubble), and the hypothetical space station, that's not
a trivial limitation.
-- 
The dream *IS* alive...         |    Henry Spencer at U of Toronto Zoology
but not at NASA.                |uunet!attcan!utzoo!henry henry@zoo.toronto.edu