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Re: (meteorobs) P/2000 G1 & Vgeo

At 02:38 PM 6/3/00 -0500, you wrote:
>----- 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

========================

In the late fifties and early sixties there was a material employed in such
a manner called "Pyroceram."  It was a very tough and high temperature
resistant ceramic developed by Corning to be used for reentry nose cones.
It did not turn out to be the panacea everyone had hoped for and was
quickly dropped from the space program and found its way into almost
everyone's dining room as Corelle china.

J.

++++++++++++++++++++++

If we were truly intelligent and adaptable, as some think,
We wouldn't be standing motionless by the rail watching
Our ship sink.

J. Richard "Dr. Doom" Jacobs

++++++++++++++++++++++
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