Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site ssc-vax.UUCP Path: utzoo!watmath!clyde!cbosgd!ihnp4!mhuxn!mhuxr!mhuxt!houxm!vax135!cornell!uw-beaver!ssc-vax!eder From: eder@ssc-vax.UUCP (Dani Eder) Newsgroups: net.space Subject: Re: communications satellite insurance rates Message-ID: <237@ssc-vax.UUCP> Date: Wed, 25-Sep-85 13:15:19 EDT Article-I.D.: ssc-vax.237 Posted: Wed Sep 25 13:15:19 1985 Date-Received: Fri, 27-Sep-85 04:12:20 EDT References: <536@petrus.UUCP> <528@riccb.UUCP> <539@petrus.UUCP> <530@riccb.UUCP> <564@petrus.UUCP> Organization: Boeing Aerospace Co., Seattle, WA Lines: 26 In response to Phil Karns question about why the Shuttle can't deploy comsats immediately like an expendable: Communications satellites live in Geosynchronous Orbit, where they orbit the earth every 24 hours. Since the earth also rotates every 24 hours, the satellite appears to hang over a single spot on earth. To get to that specific location as quickly as possible, so as to start producing revenue for the satellite owner as soon as possible, you want a transfer orbit that intersects your destination. You start a satellite on it's way to Geosynchronous one-half orbit earlier in low earth orbit. The shuttle orbit , and hence the initial satellite orbit, remains fairly stationary in inertial space, inclined 28.5 degrees to the equator. The transfer orbit is attached to the destination in GEO, which is moving around once per 24 hours. Thus once every 24 hours there is an opportunity to deploy and inject a comsat. This is why comsats are generally launched one per day starting with the first mission day. If the satellites are spaced fairly far apart in GEO, it would be possible to launch two or more in one day. The alternative, which takes longer, is to launch the satellite as soon as possible. The satellite then arrives at the wrong place in GEO> YOU MAKE your orbit slightly un_synchronous< and drift to the correct location> this takes weeks> DANI EDER ??? boeing >> ssc_VAX!eder Brought to you by Super Global Mega Corp .com