Date: 3 Jul 91 16:55:33 GMT
From: ssc-vax!bcsaic!hsvaic!eder@beaver.cs.washington.edu  (Dani Eder)
Organization: Boeing AI Center, Huntsville, AL
Subject: Re: Shuttling to the Cape

The space Shuttle Orbiter is covered with heat-dissipating insulation
of several types: carbon, refractory tiles, and refractory cloth.  The
tiles are very brittle, being made of silicate fibers sintered together
(sintering is heating a material consisting of particles or fibers
until they just begin to melt and stick at the contact points.  It is
short of bulk melting).  The strength of the tiles to mechanical
damage has been compared to Styrofoam and balsa wood.

The Shuttle, being a brick aerodynamically, moves very fast (~300mph)
in the lower atmosphere.  At these speeds rain drops act like small
bullets and would do severe damage to the tiles.  Commercial aircraft
have metal skins and fly slower at the altitudes where rain is encountered,
so they are able to stand rain drops.



-- 
Dani Eder/Boeing/Advanced Civil Space/(205)464-2697(w)/461-7801(h)/#905, 1075
Dockside Dr.,Huntsville,AL35824/Member: Space Studies Institute
Physical Location: 34deg 37' N 86deg 43' W +100m alt.
***THE ABOVE IS NOT THE OPINION OF THE BOEING COMPANY OR ITS MANAGEMENT.***