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From: OTA@S1-A.ARPA
Newsgroups: net.space
Subject: spool
Message-ID: <663@sri-arpa.UUCP>
Date: Fri, 3-Aug-84 04:55:00 EDT
Article-I.D.: sri-arpa.663
Posted: Fri Aug  3 04:55:00 1984
Date-Received: Sun, 5-Aug-84 08:11:39 EDT
Lines: 62

From:  Ted Anderson 

Date: 2 Aug 1984 8:49-PDT From: dietz%USC-CSE@ECLA To:
redford@shorty cc: space@MIT-MC.ARPA Subject: Re: How Does
Geostar Work?

Geostar works by triangulation.  A signal addressed to a portable
tranceiver is sent from the central ground station via one of the
satellites.  The ground unit then emits a very short
omnidirectional microwave pulse (with ID information included).
All four satellites receive this pulse, and transmit it back to
the ground station.  Time delays are used to compute position.
The position is then transmitted back to the ground unit.

The Geostar ground unit is simply a microwave tranceiver capable
of emitting high power (500 watts, I believe) short duration
pulses, along with some fast control logic to detect when the
unit is being polled and to receive and display position
information.  Average power consumption is low, because the
pulses are so short (a microsecond?).

The Navstar system uses passive ground units, since they must
operate in combat conditions where radio silence is critical.
These passive units must do the triangulation themselves, so they
are expensive.

Paul Dietz dietz%usc-cse@usc-ecl

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Date: 2 Aug 1984 14:41:29-EDT From: Hank.Walker at CMU-CS-UNH
Subject: tethered satellite stories

A recent one is "Tank-Farm Dynamo" by David Brin in the November
1983 Analog.  A space station is created out of two groups of
shuttle external tanks connected together by cables.  Shuttles
take advantage of the fact that the lower platform is moving
slower than orbital velocity by "landing" on it and transfering
their payload.  The dynamo effect of a cable moving through
magnetic fields is used to pump energy into the stations orbit to
compensate for atmospheric drag.

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Date: Thu, 2 Aug 84 10:51:41 pdt From: David Smith
 Message-Id:
<8408021751.AA01896@HP-MARS> To: space%mc@csnet-relay.arpa
Subject: Apollo 2-6 Cc: dsmith@csnet-relay.arpa Source-Info: From
(or Sender) name not authenticated.

The spacecraft which burned on the pad was known as Apollo 204
for some reason.  I think (but am not at all sure) it was also
counted as Apollo 4. One unmanned Apollo was lofted into a high
suborbital trajectory, then rammed into the atmosphere at 25000
mph to test the heat shield.

                        David Smith dsmith%hp-labs@csnet-relay
...!ucbvax!hplabs!dsmith Formerly at Cmu-cs-ius.arpa

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End of SPACE Digest *******************