Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!henry From: henry@utzoo.UUCP (Henry Spencer) Newsgroups: net.space Subject: Re: Electromagnetic mass drivers Message-ID: <4617@utzoo.UUCP> Date: Sun, 11-Nov-84 00:16:55 EST Article-I.D.: utzoo.4617 Posted: Sun Nov 11 00:16:55 1984 Date-Received: Sun, 11-Nov-84 00:16:55 EST References: <2298@ihnss.UUCP> Organization: U of Toronto Zoology Lines: 22 > The main restrictions on electromagnetic mass drivers are: > (1) the object must contain quite a bit of iron (of course) > ... You are thinking of induction motors, which are essentially obsolete as electromagnetic accelerators. Nowadays the favored accelerator technology is the linear synchronous motor, which requires magnetic coils on the accelerated object. And by the way, a "mass driver" is a specific type of accelerator in which the payload is carried by a bucket for acceleration, and the bucket is then decelerated for re-use while the payload continues on. This permits accelerating small payloads without throwing away a costly magnetic-coil system for every payload. "Mass driver" is **NOT** a generic synonym for "electromagnetic catapult". Electromagnetic catapults have been around for quite a while. The mass driver, with its recirculating buckets, was invented by a specific man: Gerard O'Neill. He could have patented it, and perhaps should have. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry