Newsgroups: sci.space.shuttle
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Launch windows on Clarke orbit satallites
Message-ID: <1988Feb25.001311.25013@utzoo.uucp>
Organization: U of Toronto Zoology
References: <379@attila.weitek.UUCP>
Date: Thu, 25 Feb 88 00:13:11 GMT

> Are there critical launch windows when a sattalite is to be placed into
> Clarke orbit?  I seem to recall mention of them but never understood
> why.  The relative positions of the launch site and the final parking
> orbit don't change. Do they?

No, but the relative position of the Sun does.  Most modern solar-powered
satellites don't unfold their solar panels fully until they are
finished with major maneuvering, because the panel structure is not built
for high accelerations.  This means that the maneuvering configuration has
only limited power available and may not be able to pivot its solar panels
the way the operational configuration can.  As a result, the maneuvering
phase has to maintain favorable sun angles.  This can mean quite narrow
launch windows.
-- 
Those who do not understand Unix are |  Henry Spencer @ U of Toronto Zoology
condemned to reinvent it, poorly.    | {allegra,ihnp4,decvax,utai}!utzoo!henry