Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site denelcor.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!houxm!houxz!vax135!floyd!cmcl2!seismo!hao!denelcor!lmc From: lmc@denelcor.UUCP (Lyle McElhaney) Newsgroups: net.space Subject: Re: Sterilization of space craft Message-ID: <453@denelcor.UUCP> Date: Sat, 2-Jun-84 18:03:47 EDT Article-I.D.: denelcor.453 Posted: Sat Jun 2 18:03:47 1984 Date-Received: Tue, 5-Jun-84 08:34:30 EDT References: <275@ames-lm.UUCP> Organization: Denelcor, Aurora, CO Lines: 25 Concerning sterilization of the Viking landers: Each lander was constructed in class 100,000 clean room conditions. After completion, they were encased in a bioshell through which only electrical connectors and piping for loading propellants pierced. The entire lander with shell was then baked at 450 degrees F for 40 hours, enough to ensure that the 450 degree temperature had permeated the entire structure of the lander (including all the electronics, the pyrotecnic assemblies, the batteries, and so on). After liftoff, above the atmosphere, the bioshell was jettisoned. While in Martian orbit, the lander was specially oriented toward the sun for sufficient time that the entire exposed surface received sufficient UV to kill any bacteria on the lander surface. This "Sterilization Plan" was performed in accordance with NASA contractual requirements, in turn derived from a space treaty (I think under UN auspices) that specifies a fifty year moratorium on pollution of Mars by terrestrial fauna, not to speak of allowing the biology experiment to find bonafide Martian life. I can remember debates over whether the precautions were sufficient to keep bacteria encapsulated within the cast body of the lander itself from leaking out before the fifty year limit had expired. it was, all in all, an extremely interesting project to work on. -- Lyle McElhaney (hao,brl-bmd,nbires,csu-cs,scgvaxd)!denelcor!lmc