I've always
been interested in science. The SETI Institute hosts summer interns in their
Research Experiences for Undergraduates (REU) program, which is very similar to
one I attended 12 years ago where I had my first experience working with
spacecraft. Who would have dreamed what was to come....
In March
2008, I was selected by NASA to join the Lunar Reconnaissance Orbiter Camera
Science Team as a Participating Scientist. What is that, you may ask? The Lunar
Reconnaissance Orbiter (LRO, http://lunar.gsfc.nasa.gov/)
is a spacecraft scheduled for launch in 2009. It represents the first in a
series of lunar spacecraft, and a return to lunar exploration by NASA.
LRO carries
a suite of modern instruments for surveying the Moon for two primary purposes:
(1) to measure and characterize the lunar surface and environment for future
landed exploration missions, both robotic and crewed by humans, and (2) to
explore the lunar surface for basic scientific purposes. Of course, these two
themes are closely intertwined, one working off the other. Our spacecraft will
carry instruments for characterizing the global lunar radiation environment
(CRaTER), measuring the thermal characteristics of the lunar surface (DIVINER),
identifying water-ice deposits via spectroscopy (LAMP) and neutron detection
(LEND), accurately measuring the topographic and geodetic shape of the Moon
(LOLA), and imaging the surface of the Moon for landing site certification and
polar illumination (LROC).'
That's what
the spacecraft is; what's a Participating Scientist? There are several ways for
scientists to get involved with NASA spacecraft missions. One way is to be
part of the team that proposed, and then won, the selection for a particular
instrument on board a spacecraft. Those scientists form the core group of that
instrument's science team. NASA recognizes this selection process often
results in minimum science teams. In order to fill out the ranks of spacecraft
science teams to include extra fields of expertise or provide for
interdisciplinary studies, NASA puts out a call for Participating Scientists
for the mission.
I and many
others wrote proposals outlining how we could help the mission in various
ways. The idea behind these proposals is to show how you can not only provide
additional scientific expertise that the science team might need in their
analysis of the data, but also how you can contribute to the operations of the
instrument, and increase the scientific return of the mission. These proposals
are carefully evaluated by a review panel of scientists, and the best proposals
are selected.
One of my
areas of interest in planetary sciences can be summarized as "what is the
surface like?" I use a technique called photoclinometry or shape-from-shading
to help determine what the pixel-scale roughness of a surface is from a single
image. Understanding the roughness characteristics of a surface can be applied
to a number of scientific applications, but is also distinctly useful in the
early stages of a landing site selection process to quickly evaluate sites and
reject those that are too rough for a particular landing system. I applied this
technique for the Mars Exploration Rovers (MERs) launched in 2003, and am
working on applying it to potential landing sites for the Mars Science
Laboratory (MSL) rover to be launched next year. The narrow-angle LROC camera
will have a resolution on the surface of 50 cm/pixel. Applying my technique to
these images will result in roughness information on length scales of a meter
or less, which is about the size that robotic and human landers and rovers care
about.
There are
also techniques for doing more than just obtaining surface roughness
statistics. We can take two or more images of a location on the surface and
use those images to build a digital terrain model (similar to the way that your
eyes create a 3D model of the area around you in your head by observing the
same scene from two different angles). We'll be able to build digital terrain
models with mesh resolutions similar to the camera resolutions, and will be
able to create virtual models of places on the Moon at person-sized scales.
These kinds of data products have use for exploration applications, but are
also a way to start doing the kinds of geology work that terrestrial geologists
do on the Earth with only our high-resolution orbital imagery of the Moon.
I, and
other members of the LROC science team, will use these techniques to test
various scientific hypotheses about cratering processes, lunar volcanism and
teconism, and a whole lot of other things.
However,
that is after we launch. In the meantime I'm involved in helping the team as
the cameras are built, tested, and calibrated. We've got a lot of operations
software that needs to be tested and ready, and we've got to populate our
target database so that once we're in orbit, we're taking pictures of areas
that are relevant to LRO's scientific and exploration goals. We're also
working on the processes for how we'll archive the data and make it available
to the public as soon as we can after having taken it. We've got a lot of
preparation to do before we launch later this year, and that is exactly why the
Participating Scientists were chosen -- to add our expertise and experience to
the process of getting our instruments delivered to the launch pad and then
operational once we're in orbit, as well as contributing to the great science
that is sure to result from our return to the Moon.
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