IEEE Spectrum May, 2015 - 55

a sEntinEl For spacE

of the sky to another
pass this test will be passed on to the Minor Planet Center of the
15 times an hour, collecting light for 3 minutes at
Smithsonian Astrophysical Observatory, in Cambridge, Mass., which
each spot. This same observing sequence will be
manages a huge database of all NEO observations. There astronoprecisely repeated in the next hour. Then the telemers will calculate an orbit for each object and send their results
scope's computer will compare each pair of images
to the NEO Program Office at NASA's Jet Propulsion Laboratory, in
of the same patch of sky.
Pasadena, Calif., which projects orbits forward in time to look for
An NEO won't look much different than a star on
stuff that could hit Earth. If NASA fi nds something, its office will
a given snapshot, but it will move many pixels in
issue a notice, and professional and amateur astronomers will be
that 1-hour interval. When two images taken 1 hour
able to follow up with ground-based observations to improve our
apart indicate a change, the onboard computer will
knowledge of the object's orbit and get a better fi x on the threat.
store the 5-by-5-pixel area surrounding
the change in both images. The observatory will then move to a new set of 15 areas
of the sky for the next 2 hours, and then
on to another set after that.
We expect there to be numerous spurious detections due to variable stars,
main belt asteroids, charge deposited by cosmic rays, and other noise
TRAINING & EDUCATION FOR PROFESSIONALS
sources. But the protocol we've devised
for content-driven data compression-
saving only those areas of an image
that show a change-should allow us
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SHORT PROGRAMS
send data back to Earth on anything
that could potentially be an NEO. A typRegister for a 2 - 5 day intensive course and gain critical knowledge
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the ground. NASA has agreed to let the
the needs of a global workforce.
B612 Foundation use the agency's Deep

co nti n u e d F Ro M pag e 37 |

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EXPERTISE AND KNOWLEDGE

Space Network, a global group of giant
parabolic-dish antennas that are used to
pick up spacecraft transmissions from
all over the solar system. Time is a precious commodity on the network. With
our image-processing strategy, we can
store data for a week and then download it all (about 4 gigabytes) in a relatively economical 4 hours.
Astronomers at the University of Colorado Boulder's Laboratory for Atmospheric and Space Physics will be the
first to comb through the data. They will
examine the pairs of images taken an
hour apart to hunt for moving objects.
Then they'll compare these detections
with ones taken two days later to see
if any might correspond to physically
possible orbits. Those detections that

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Table of Contents for the Digital Edition of IEEE Spectrum May, 2015