April
10, 2007
UNIVERSITY OF COLORADO
INSTRUMENTS TO LAUNCH ON NASA CLOUD MISSION
APRIL 25
A
satellite
carrying two University
of Colorado
at Boulder
instruments to study silvery-blue clouds that mysteriously form 50
miles above
Earth's polar regions every year is slated to launch from Vandenberg
Air Force
Base in California
on April 25.
The spectacular
clouds, known as
noctilucent clouds, will be probed by NASA's Aeronomy of Ice in the
Mesosphere
mission, or AIM, to determine why they form and how they change. First
spotted
in Earth's atmosphere in 1885, the clouds have been increasing in
frequency in
recent decades and may be related to increases in carbon dioxide and
methane
emissions tied to human activity on Earth, said Senior Research
Scientist Dave
Rusch of CU-Boulder's Laboratory for Atmospheric and Space Physics.
The NASA mission,
which consists
of two CU-Boulder instruments and an instrument from Utah
State University,
is being managed by CU-Boulder's LASP and will be controlled from the Space
Technology Building
at the CU
Research Park. The mission's principal investigator is Jim Russell of Hampton University
in Virginia.
"We have seen a
definite
increase in the brightness of these clouds in the past 25 years, which
gives us
cause for concern," said Rusch, principal investigator for one of the
three AIM instruments. "This mission will give us an unprecedented look
at
how the mesosphere, which is a very sensitive region of Earth's
atmosphere, is
changing."
Also known as polar
mesospheric
clouds, noctilucent clouds have become more common and have been moving
into
Earth's lower latitudes in recent decades, he said. They now are
visible in the
summer months from the United States-Canada border to the Arctic Circle and comparable
latitudes in the Southern Hemisphere. In
1999 they were spotted as far south as Coal
Creek Canyon
near Boulder, Colo.,
and Logan,
Utah.
About the size of a
small piano,
the 430-pound AIM spacecraft will be launched from a Pegasus
expendable-launch
vehicle built by Orbital Sciences Corp., of Dulles, Va.
The rocket will be carried to an altitude of 40,000 feet by a jet
aircraft over
the Pacific Ocean
and dropped in a five-second
free-fall. It will then ignite horizontally and accelerate in front of
the jet,
then climb and place the AIM satellite in a polar orbit about 370 miles
above
Earth, Rusch said.
The clouds are made
up of tiny
ice crystals the size of smoke particles in the coldest region of
Earth's
atmosphere, but exactly how and why they form is still unknown, said
Rusch.
Some scientists suspect large amounts of methane move from Earth's
lower
atmosphere into the mesosphere, or middle atmosphere, where it reacts
chemically to form water vapor. The water molecules likely adhere to
tiny dust
particles in the region to form ice crystals, the basis of the clouds,
he said.
Ironically,
greenhouse gases like
CO2 that warm Earth's lower atmosphere also cool the upper atmosphere,
possibly
enhancing conditions for ice crystal formation, said Rusch, lead
scientist for
the Cloud Imaging and Particle Size experiment, or CIPS. Consisting of
four
cameras positioned at different angles for a two-dimensional look at
the clouds
from above, CIPS will allow scientists multiple, panoramic views of the
cloud
banks and help them better determine the size and nature of the ice
particles.
A second LASP
instrument, the
Cosmic Dust Experiment, or CDE, headed by LASP Research Associate
Mihaly
Horanyi, will chart space dust raining down in the mesosphere from the
cosmos,
which scientists believe plays a key part in noctilucent cloud
formation. The
instrument is nearly identical to the Student Dust Counter, a LASP
student
instrument launched on NASA's New Horizons spacecraft in early 2006 for
Pluto
and the outer reaches of the solar system.
A third instrument
known as the
Solar Occultation For Ice, or SOFIE, built by Utah State University
researchers, will measure
cloud particles as well as temperatures and atmospheric gases thought
to be
involved in noctilucent cloud formation. The instrument will be able to
identify
"recipes" of chemicals that may trigger the formation of the bizarre,
night-shining clouds, said Rusch.
Other science team
members from
LASP on the AIM team include Gary Thomas, Cora Randall, William
McClintock and
Aimee Merkel, as well as an engineering and science support group of
faculty,
staff and students. LASP's Michael McGrath is the AIM project manager.
LASP, which has
controlled NASA
satellites since the 1980s and is now operating nine different
instruments from
campus for various space missions, will upload commands to the AIM
spacecraft
and download data twice a day by connecting to several ground stations
around
the world, said Rusch. "We've done these kinds of missions before, so
it's
pretty much a slam dunk for us now," he said.
CU-Boulder students
will be
involved in all aspects of the mission. Each pass of the satellite will
be
controlled by one professional and one student, and a number of
undergraduates
and graduate students will be involved in day-to-day science and data
analysis.
"We love to involve students in our research," he said. "I'm
getting a lot of phone calls lately from students wanting to
participate."
CU-Boulder received
about $20
million from NASA for the design and construction of CIPS and CDE and
will
receive additional funding for the management of the mission over the
next
several years, said Rusch. The AIM mission is part of NASA's Small
Explorer
Program, designed to provide frequent, low-cost access to space for
physics and
astronomy missions with relatively small spacecraft.
In addition to
CU-Boulder, Hampton
University
and Utah State,
other institutions include Virginia Tech, the U.S. Naval Research
Laboratory, George
Mason
University,
the British Antarctic
Survey and GATS Inc., an aerospace company in Newport News, Va.
AIM Deputy Principal Investigator Scott Bailey of Virginia Tech
received his
master's degree and doctorate from CU-Boulder and previously worked at
LASP.
Noctilucent clouds
first were
sighted in northern Europe in 1885, two years after a huge volcanic
eruption on
the island
of Krakatoa
in Indonesia
injected millions of tons of water vapor into the air, said Rusch. But
the
clouds have persisted long after the effects of the volcano should have
dissipated. Scientists hope the AIM mission will resolve unanswered
questions
about the beautiful but unsettling clouds.
##
Contact:
Dave
Rusch
University
of
Colorado at Boulder
303-579-1162
Rusch@lasp.colorado.edu
This
text derived from:
http://www.colorado.edu/
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