The design that
came into being was a small spinning spacecraft that would carry inflatable
plastic tubes. During the flyby the tubes would be exposed to comet dust
in the coma of Halley. The particles would penetrate the tubes, vaporize
and the comet vapor would condense on the inside of the tubes. This was
called atomized sample return and it would provide direct information on
the elemental and isotopic composition of Halley. The mission was often
called Halley Earth Return or HER.
Another JPL Halley mission studied at that time was called HIM, Halley
Intercept Mission. Neither HIM or HER ever got off the drawing board. The
US failed to be included in a spacecraft that flew past Halley in 1986.
ISEE was sent on its many Lunar encounters and in 1985 it flew by comet
Giacobini-Zinner. Although it was still the same spacecraft, it was renamed
ICEE (International Sun Earth Explorer) and it did make a distant upstream
journey near Halley. Although, it never was close enough to detect the
comet or collect samples.
The Halley
efforts did help produce the idea that a low cost sample return mission
could be done from a comet. Unlike other bodies, comets release matter
into space, and a simple spacecraft just flying by can snatch samples without
the complex landing and surface operations required for sample return missions
to the Moon, Mars and asteroids.
One of the most negative aspects of the atomized sample return concept
was that the sample was vaporized by the high speed of collection. This
process would destroy the valuable chemical, structural and mineralogical
information recorded in the particles. Information on the nature of comets
and their formation is recorded at very small scale. It is like having
the history of the world on a CD with all information recorded at very
tiny scale. If the CD is preserved its tiny dots can be read. If the CD
is damaged, melted or vaporized, the information is lost.
How do you catch comets in space?
Click on: To Catch
Comets in Space
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