Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 exptools 1/6/84; site ihnss.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxj!ihnp4!ihnss!knudsen From: knudsen@ihnss.UUCP Newsgroups: net.space Subject: Re: Electromagnetic mass drivers Message-ID: <2298@ihnss.UUCP> Date: Thu, 8-Nov-84 19:06:35 EST Article-I.D.: ihnss.2298 Posted: Thu Nov 8 19:06:35 1984 Date-Received: Sat, 10-Nov-84 07:32:04 EST Organization: AT&T Bell Labs, Naperville, IL Lines: 21Subject: Re: Sixty Cents a Pound? References: <1062@inuxc.UUCP> The main restrictions on electromagnetic mass drivers are: (1) the object must contain quite a bit of iron (of course) (2) you really should launch above/outside/without an atmosphere. On Earth, the projectile would have to survive 3+ miles of our air, much more if not launched straight up, and EXIT our air at escape velocity, meaning a tremendous initial velocity. Aside from the ablative heat shielding required (which you have to accelerate along with the rest of the load, even tho it never leaves our planet), the G forces of DEceleration encountered after leaving the electro-gun would be almost as bad as the acceleration inside the launcher. Of course, if the object is all iron, the parts are accelerated evenly and little stress occurs during acceleration. Anyway, most advocates of mass drivers are talking about installations on the Moon, asteroids, L5 space colonies, etc. A GOOD possibility: a mass driver in low earth orbit, to shoot things up to geo-synch, to moon, Mars, .... mike k