Xref: utzoo sci.space:4556 sci.space.shuttle:540
Path: utzoo!linus!husc6!ut-sally!im4u!milano!banzai-inst!wex
From: wex@banzai-inst.SW.MCC.COM (Alan Wexelblat)
Newsgroups: sci.space,sci.space.shuttle
Subject: Re: Payload of shuttle flight directly after last Challenger.
Message-ID: <139@banzai-inst.SW.MCC.COM>
Date: 10 Feb 88 20:06:10 GMT
References: <347@flatline.UUCP> <1988Feb3.133415.12432@utzoo.uucp>
Organization: MCC, Austin, TX
Lines: 26

In article <1988Feb3.133415.12432@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes:
> ...that great scare word "plutonium" without mentioning that it
> would go up in an armored canister designed to survive a launch
> failure.  (There have been some doubts expressed about whether the
> canisters are in fact tough enough for all possible cases, but they
> definitely would have survived the Challenger disaster.)  This is
> not just speculation:  such a canister went into the ocean some
> years ago after an expendable launcher failed; it was recovered
> intact, wiped clean, and re-used. 

Er, yes and no.  Yes, the canister is designed to survive an
explosion.  Specifically, it can withstand forces up to 2,000 psi.
This is (as Henry notes) clearly enough to withstand a spashdown after
failure of an unmanned.

However, NASA tests indicate that an exploding shuttle ET might
generate forces as high as 20,000 psi.  What's particularly
troublesome are detonation-on-pad scenarios, which involve these
higher pressures.  If the cannister did explode, the resulting
shower of material might contaminate the entire space center.

The point is that while the risk is relatively low, the potential
consequences of a failure are so high that alternatives should be
given more serious consideration, including the alternative of
hardening the cannister to withstand 20,000 psi.  (Could such
shielding be jettisoned after the space probe was free-flying?)