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Re: (meteorobs) P/2000 G1 & Vgeo
----- Original Message -----
From: "Robert Gardner" <rendrag@earthlinkdot net>
To: <meteorobs@jovian.com>
Sent: Friday, June 02, 2000 12:20 AM
Subject: Re: (meteorobs) P/2000 G1 & Vgeo
> I don't know. I am only familiar with the ablation nose cones. Perhaps
someone
> out there who is familiar with heat sink nose cones can shed some light on
the
> subject of the effect of the conductivity. Heat sink nose cones were made
of
> highly thermal conductive metal as I recall. The person would have to be
fairly
> old because I think that technology was dropped in the sixties.
>
I guess I'm old enough to meet your requirements, Robert. I worked at the
CIA in the sixties when it was operating the Corona photographic satellites
(see the article in the Spring 1998 CSI Bulletin at
http://www.ciadot gov/csi/bulletin/csi8.html#rft1).
These satellites were an early application of the spacecraft technology that
blossomed after WWII (before and after Sputnik in 1957). The film exposed in
the satellite camera was returned to Earth for developing and exploitation
in a specially-designed re-entry vehicle protected (kept cool) by an
ablative heat shield. It was the first space program in which a satellite
payload was recovered without having it burn up on re-entry. This first-ever
ablative heat shield was a durable, highly heat-resistant alloy called a
cermet. The heat shields on the Mercury, Gemini, and Apollo spacecraft were
its direct descendants.
I am not familiar with what you call "heat sink nose cones". Their name
implies that they absorb and retain the re-entry heat rather than sloughing
it off by ablation. That's a hellava lot of heat for a spacecraft or a
meteor to retain with melting.
Paul O. Johnson
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