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The Question
(Submitted January 06, 1997)
I have an idea for space exploration. The idea in theory is simply to
piggy back a satellite or probe to a comet with a travel time of 10 years
or less. If there is such a comet. When the comet returns, download
any and all information gathered. I haven't quite figured out how it
would be attached.
I would like the e-mail address of someone I can correspond with on
this. I need to know if this would work, or why it would not, in layman's
terms, for I am not a scientist of any sort. Can you direct me to the right place?
The Answer
What an interesting idea! There are indeed short period comets.
Comet Enke has a period of 3.3 years, and comet Wild-2 takes
6.15 years to make one complete trip around the Sun. In fact, there is
a mission called STARDUST which is a collaboration of NASA/Jet Propulsion
Laboratory, Lockheed Martin, and University of Washington, that will
launch a low-mass probe to fly through the tail of comet Wild-2 and
collect samples of that material. You should check out the web-page
for this project, at
http://stardust.jpl.nasa.gov/.
They have a lot of detailed information about the project, both the
scientific goals and the mechanics of the orbit, as well as a good
amount of educational material related to the project.
As far as actually landing a probe on a comet, that may be
pretty tricky. The nucleus of the comet can be tumbling around, due
to the release of gases on the surface of the comet. This can make
the attempted landing very difficult. In addition, once the probe
was on the surface of the nucleus it could possibly be damaged by
the outgassing. If this outgassing is not what you were planning
to study, it could disturb the results of the experiments you were interested
in. There is an ESA mission being planned that will land a probe on the surface
of comet Wirtanen (see
http://www.esoc.esa.de/external/mso/roseta.html). This
mission is called ROSETTA.
It would be possible to place your probe into an
orbit that is similar to the comet's orbit, either in front of it
somewhat, or lagging behind the comet. By the time
you've got the probe near the comet, you've already placed the probe in the
comet's orbit and it will make its way round the inner solar system
with the comet.
Comets are important to study because they
are the oldest, most primitive bodies in our Solar System,
and are thus the earliest record of the formation of the solar system.
The material that comets are composed of is very rich in organic
material; it is for this reason that comets are thought to possibly
be involved in the origin of life on Earth. I encourage you to stay
enthusiastic about comets, and new, never-been-done-before ideas
about exploring them.
Here at Goddard's laboratory for High Energy Astrophysics,
we have experience mainly with spacecraft that are launched into
orbit around the Earth to observe stars and galaxies in the X-ray
and gamma-ray regions of the spectrum. We don't have expertise
at planning and designing comet encounter missions, so what I
say below is mainly an educated guess. The folks at JPL who are
working on the STARDUST mission will know much more, and I encourage
you to talk to them about your idea.
So for further information, try sending your question to
stardust@jpl.nasa.gov, or to the questions and comments section of the
JPL main page at: http://www.jpl.nasa.gov/.
Regards,
Padi Boyd,
for Imagine the Universe!
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