Successful launch of THEMIS satellites positions NASA mission toanswer key questions about Earth's auroras (Forwarded)

Media Relations
University of California-Berkeley

Media Contacts:
Robert Sanders
(510) 643-6998, (510) 642-3734

18 February 2007

Successful launch of UC Berkeley's THEMIS satellites positions NASA
mission to answer key questions about Earth's auroras

By Robert Sanders, Media Relations

BERKELEY -- After a picture-perfect launch into clear, blue skies at 6:01
p.m. EST Saturday, Feb. 17, the five THEMIS probes are healthy and in
their expected orbits, according to University of California, Berkeley,
physicist and mission principal investigator Vassilis Angelopoulos.

"Based on telemetry received by UC Berkeley's ground station, they look
really good," he said.

THEMIS, which stands for Time History of Events and Macroscale
Interactions during Substorms, is NASA's first five-satellite mission and
the first to investigate a key mystery surrounding the auroras, or
Northern and Southern lights: When, where and how are they triggered?

"The THEMIS mission will make a breakthrough in our understanding of how
Earth's magnetosphere stores and releases energy from the sun and also
will demonstrate the tremendous potential that constellation missions have
for space exploration," said Angelopoulos.

The satellites won't be in a position to answer this question until next
winter, because they must coast into the proper orbits to allow them to
detect electrical activity in space and link this to auroral outbursts via
a network of 20 ground observatories spanning Canada and Alaska. Until
then, according to David Sibeck, THEMIS project scientist from NASA
Goddard Space Flight Center, THEMIS will collect data that will help
improve our understanding of the Van Allen radiation belts surrounding
Earth and will show how energy from the sun enters the Earth's magnetic
field on the daytime side and is funneled to the nighttime side to create
auroras.

The findings from the mission may help protect commercial satellites and
humans in space from the adverse effects of particle radiation.

As of 10 p.m. EST Saturday, however, the probes were coasting in Earth
orbit as UC Berkeley's Mission Operations Center ran them through tests to
make sure they survived the launch successfully. Instrument scientists
will turn on and characterize the instruments during the next 30 days, and
the center will then assign each spacecraft a target orbit within the
THEMIS constellation based on its performance. Mission operators will
direct the spacecraft to their final orbits in mid-September so that,
during the winter, they will light up in the Earth's shadow every 4 days
to pinpoint the position of auroral substorm initiations.

The THEMIS launch, which was the responsibility of NASA's Launch Services
Program at the Kennedy Space Center, was aboard a Delta II rocket from Pad
17-B at Cape Canaveral Air Force Station, Fla. The United Launch Alliance
of Denver provided launch service

The spacecraft separated from the launch vehicle approximately 73 minutes
after liftoff. By 8:07 p.m. EST, after the five probes had flown over UC
Berkeley's ground-based radio antenna, mission operators at UC Berkeley
commanded and received signals from all five spacecraft, confirming that
they had separated properly from the carousel that Swales Aerospace had
designed to fling them into orbit.

While only two were confirmed healthy on the constellation's first flight
over the ground antenna, the other three were confirmed healthy on the
second flyover.

THEMIS is an Explorer mission, which is managed at Goddard by the Explorer
Program Office at Goddard.

"I am proud to manage the fifth medium class mission of the Explorer
Program," said NASA's Willis S. Jenkins, the THEMIS program executive. "As
we seek the answer to a compelling scientific question in geospace
physics, we are keeping up the tradition that began with Explorer I."

The Space Sciences Laboratory at the UC Berkeley is responsible for
project management, space and ground-based instruments, mission
integration, mission operations and science. Swales Aerospace of
Beltsville, Md., built the THEMIS probes. THEMIS is an international
project conducted in partnership with Germany, France, Austria and Canada.

For more information about the THEMIS mission and imagery, visit
http://www.nasa.gov/themis
or go to the THEMIS mission Web site,
http://ds9.ssl.berkeley.edu/themis/

Also see the UC Berkeley press release about the mission,
http://www.berkeley.edu/news/media/r...7_themis.shtml