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From: DIETZ@slb-test.CSNET ("Paul F. Dietz")
Newsgroups: sci.space
Subject: Comsat fuel saving maneuver invented
Message-ID: <8610180704.AA03474@s1-b.arpa>
Date: Fri, 17-Oct-86 17:48:00 EDT
Article-I.D.: s1-b.8610180704.AA03474
Posted: Fri Oct 17 17:48:00 1986
Date-Received: Tue, 21-Oct-86 08:39:06 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 18

The NY Times reported today (10/16) that engineers at Comsat Corp.
have developed a technique for reducing the fuel consumption
of comsats by up to 90%.  The technique can be applied remotely to
satellite already in orbit.

Currently, on-board thrusters on comsats in GSO are used to counter
perturbations induced by the moon.  These perturbations cause the
orbit to become nonequatorial, moving the satellite's footprint
north or south.  The new technique uses the thrusters to tilt the
satellite so the footprint remains fixed.  The new technique will
require changing the pointing hardware on some ground dishes, since
a satellite in a geosynchronous but nonequatorial orbit will bob
up and down once a day.

This technique has not been used before because electronic failure had
been thought to limit satellite lifetime.  Experience has shown,
however, that the electronics is more reliable than was first thought.
It is estimated that this change will double satellite lifetime.