Rani Gran
Goddard Space Flight Center, Greenbelt, Md. April 30, 2008
301-286-2483

RELEASE: 080-37

"4D" IONOSPHERE MAP HELPS FLYERS, SOLDIERS, HAM RADIO OPERATORS

GREENBELT, Md. -- Today, at the Space Weather Workshop in Boulder,
Colo.,
NASA-funded researchers released to the general public a new "4D" live
model of Earth's ionosphere. Without leaving home, anyone can fly
through the dynamic layer of ionized gases that encircles Earth at the
edge of space itself. All that's required is a connection to the
Internet. Airline flight controllers can use this tool to plan
long-distance business flights over the poles, saving money and time
for
flyers.

"This is an exciting development," says solar physicist Lika
Guhathakurta of NASA headquarters in Washington, DC. "The ionosphere
is
important to pilots, ham radio operators, earth scientists and even
soldiers. Using this new 4D tool, they can monitor and study the
ionosphere as if they're actually inside it."

The ionosphere is, in a sense, our planet's "final frontier." It is
the
last wisp of Earth's atmosphere that astronauts leave behind when they
enter space. The realm of the ionosphere stretches from 50 to 500
miles
above Earth's surface where the atmosphere thins to near-vacuum and
exposes itself to the fury of the sun. Solar ultraviolet radiation
breaks apart molecules and atoms creating a globe-straddling haze of
electrons and ions.

Ham radio operators know the ionosphere well. They can communicate
over
the horizon by bouncing their signals off of the ionosphere -- or
communicate not at all when a solar flare blasts the ionosphere with
X-rays and triggers a radio blackout. The ionosphere also has a big
impact on Global Positioning System (GPS) reception. Before a GPS
satellite signal reaches the ground, it must first pass through
ionospheric gases that bend, reflect and attenuate radio waves. Solar
and geomagnetic storms that unsettle the ionosphere can cause position
errors as large as 100 meters. Imagine a pilot flying on instruments
descending toward a landing strip only to discover it is a football
field to the right.

"Understanding the ionosphere is clearly important. That's why NASA's
Living with a Star (LWS) program funded this work," says Guhathakurta.
Space Environment Technologies, Inc. of California received the LWS
grant and they partnered with Space Environment Corp. of Utah and the
US
Air Force to develop the 4D ionosphere.

"The best way to appreciate the 4D ionosphere is to try it," says W.
Kent Tobiska, president of Space Environment Technologies and chief
scientist of its Space Weather Division. Instructions may be found at
http://terra1.spacenvironment.net/~i...ES4Dintro.html

Within minutes of downloading the files, Google Earth will appear on
your computer screen, the globe wrapped in an atmosphere of vivid
color.
"Colors represent electron content," Tobiska explains. "Bright red is
high density; that's where radio communications are restricted to few
or
no frequencies. Blue is low density; no problem there."

Using the intuitive Google Earth interface, users can fly above,
around
and through these regions getting a true 3D view of the situation.
Make
that 4D. "The fourth dimension is time. This is a real-time system
updated every 10 minutes."

The 4D model can be fun and even a little addictive, warns Tobiska,
who
likes to use it to pilot an imaginary plane over the Arctic. "A
growing
number of commercial business flights are crossing the Arctic Circle,"
he says. "It's the shortest distance between, say, Chicago and Beijing
and many other major cities."

The ionosphere is particularly important to these lucrative flights.
While they are over the Arctic, planes lose contact with most
geosynchronous satellites and must rely on "old-fashioned" radio
communications-a link that could be severed during a radio blackout.
Using the 4D model, a flight controller could examine the ionosphere
from the flyer's point of view and use that information to anticipate
problems that could cause a flight to be delayed or diverted.

The proper name of the system is CAPS, short for Communication Alert
and
Prediction System. Earth-orbiting satellites feed the system
up-to-the-minute information on solar activity; the measurements are
then converted to electron densities by physics-based computer codes.
It
is important to note, says Tobiska, that CAPS reveals the ionosphere
not
only as it is now, but also as it is going to be the near future.
"Forecasting is a key aspect of CAPS available to our customers from,
e.g., the Department of Defense and the airline industry."

Contributing partners to the development of CAPS include the Space
Environment Corporation of Utah, Air Force Research Laboratory of
Massachusetts, and IPS MeteoStar of Colorado.

Start your own flight at
http://terra1.spacenvironment.net/~i...ES4Dintro.html