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: sail with holes Message-ID: <5196@utzoo.UUCP> Date: Sat, 9-Mar-85 20:41:19 EST Article-I.D.: utzoo.5196 Posted: Sat Mar 9 20:41:19 1985 Date-Received: Sat, 9-Mar-85 20:41:19 EST References: <221@npois.UUCP> Organization: U of Toronto Zoology Lines: 13 > Clearly holes under a quarter wave length could work to reduce > weight and drag, while not altering reflectiveness much. I have trouble > imagining the process by which this stuff is made. How could a few square > miles of this stuff be cheap ? That's precisely the hard part. Ultrathin aluminum is not hard to make by vapor deposition in vacuum, but punching lots of submicroscopic holes in it isn't simple. Perhaps a photolithographic process like that used in ICs, using shortwave ultraviolet so the holes are small by visible-light standards? But how to make it fast and cheap...? -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry