Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 11/03/84 (WLS Mods); site escher.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!princeton!astrovax!escher!doug From: doug@escher.UUCP (Douglas J Freyburger) Newsgroups: net.astro Subject: Re: Launch Window. What do they mean by this? Message-ID: <72@escher.UUCP> Date: Mon, 10-Feb-86 15:46:10 EST Article-I.D.: escher.72 Posted: Mon Feb 10 15:46:10 1986 Date-Received: Wed, 12-Feb-86 06:32:54 EST References: <2170@amd.UUCP> <1073@mit-eddie.UUCP> Organization: NASA/JPL, Pasadena, CA Lines: 23 >I have been wondering what they mean when they say that the >Shuttle, or other space vehicle, has missed the launch window. >Is there a region of space that they need to travel through >in order to minimize the affects of the Van Allen belts or does >this term refer to an on ground time table? Any help on solving >this question would be appreciated. > >paulw The rockets used now can only boost so much so fast. Launch window timing is a question of what the orbits of the planets are and where they are now and will be at the end of the flight. We are so short on payload that we have to use transfer orbit very close to Hohman (sp?) Transfer Orbits. These are the optimal elipse-to-elipse (circle-to-circle) orbits, but they require close timing. -- Doug Freyburger DOUG@JPL-VLSI, JPL Mail Stop 23 escher!doug, escher!teleop!doug Pasadena, CA 91109 etc.