2008 Annual Report - NASA Airborne Science Program

Figure 20
One stratospheric particle (upper right), captured following
the Earth’s passage through the dust trail left by Comet
Grigg-Skjellerup, was embedded into epoxy, microtomed into
many 80 nm-thick slices (golden sections arcing from right to
left), and examined using a transmission electron microscope
to reveal successively higher magnification views of pre-solar
matter (bottom two views).
the nature of bacteria that hitch rides across
oceans on stratospheric dust grains, revealing
how biota spread across the planet. Because
of targeted flights during a shower of grains
from Comet Grigg-Skjellerup, we have now
identified possible samples from a second
comet, which appear so far to have the most
primitive mineralogy of any known sample.
For example, these particles contain the
highest concentration of pre-solar stardust
grains ever observed (see Figure 20), which
means that they preserve the best record of
the interstellar cloud of dust and gas from
which out solar system formed.
There are plans for future astromaterial
collection campaigns in FY09 and beyond,
including more potential comet target dates
in the next couple of years.
URL: http://curator.jsc.nasa.gov
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