[meteorite-list] Cooking On A Comet...? (Rosetta)
From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Aug 19 13:46:41 2004
Cooking on a comet...?
European Space Agency
19 August 2004
One of the ingenious instruments on board Rosetta is designed to "smell"
the comet for different substances, analysing samples that have been
"cooked" in a set of miniature ovens.
ESA's Rosetta will be the first space mission ever to land on a comet.
After its lander reaches Comet 67P/Churyumov-Gerasimenko, the main
spacecraft will follow the comet for many months as it heads towards the
Rosetta's task is to study comets, which are considered the primitive
building blocks of the Solar System. This will help us to understand if
life on Earth began with the help of 'comet seeding'.
The Ptolemy instrument is an "Evolved Gas Analyser", the first example
of a new concept in space instruments, devised to tackle the challenge
of analysing substances "on location" on bodies in our Solar System.
Weighing just 4.5 kilograms and about the size of a shoe box, it was
produced by a collaboration of the UK's Rutherford Appleton Laboratory
and Open University.
The analysis of these samples from the surface of the comet will
establish what the cometary nucleus is made from, providing valuable
information about these most primitive objects.
After the lander touches down on the comet, the Ptolemy instrument will
collect comet nucleus material, believed to be a frozen mixture of ices,
dust and tar, using the Sampling, Drilling and Distribution system (SD2)
supplied by Tecnospazio Milano of Italy. SD2 will drill for small cores
of ice and dust from depths of down to 250 millimetres.
Samples collected in this way will be delivered to one of four tiny
"ovens" dedicated to Ptolemy, which are mounted on a circular, rotatable
carousel. The German-supplied carousel has 32 of these ovens, with the
remainder being used by other Rosetta instruments.
Of the four Ptolemy ovens, three are for solid samples collected and
delivered by SD2 while the fourth will be used to collect volatile
materials from the near-surface cometary atmosphere.
By heating the solid samples to 800 ?C, the oven converts them into
gases which then pass along a pipe into Ptolemy. The gas will then be
separated into its constituent chemical species using a gas chromatograph.
Ptolemy can then determine which chemicals are present in the comet
sample, and hence help to build up a detailed picture of what the comet
is made from.
It does this using the world's smallest "ion-trap mass spectrometer", a
small, low-power device built with the latest miniature technology. This
device will find out what gases are present in any particular sample and
measure stable isotope ratios.
Received on Thu 19 Aug 2004 01:45:50 PM PDT