The RADAR Cop in Space
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March 24, 2000 --
NASA is about to launch the first spacecraft dedicated to imaging
the Earth's magnetosphere -- an invisible magnetic shield that
protects our planet from the solar wind. The "Imager for
Magnetopause-to-Aurora Global Exploration," or IMAGE, will
blast off on a Delta II 7326 rocket during an eight-minute launch
window that opens at 3:35 p.m. EST (12:35 p.m. PST) on March
25.
Right: IMAGE and its Delta rocket
are picture here inside the Mobile Service Tower at Vandenberg
AFB on March 17, 2000
"This spacecraft is going to revolutionize magnetospheric
physics and space weather forecasting," says Jim Green,
an IMAGE co-investigator at the NASA/Goddard Space Flight Center.
"Right now we don't even know what our magnetosphere really
looks like. We've created models based on point-like in situ
measurements by various spacecraft. The problem is that these
models are cartoons! They're put together from 30 years worth
of observations taken at different spots and times."
"In terms of understanding the magnetosphere, we're where
the National Weather Service was in the 50's with all their scattered
ground stations. Did they have data collection problems? Yes.
Did they have global satellite pictures? No. Predictive weather
models? No. If there was a storm in Alabama today, no one knew
if it was going to hit Maryland tomorrow."
"IMAGE brings to space weather studies what geosynchronous weather satellites have brought to surface meteorology," said Thomas Moore, IMAGE Project Scientist at NASA's Goddard Space Flight Center, Greenbelt, MD. "We may soon be treated to evening news images of plasma clouds engulfing those weather satellites."
This new view of our invisible magnetosphere will be made possible by six state-of-the-art science instruments.
Green will be working closely with data from one of the instruments that he expects to produce some of the most eye-catching pictures and movies -- the Radio Plasma Imager (RPI).
"This is gonna' be the radar cop in space," he explained. "RPI will be firing off electromagnetic waves and recording reflections. The waves bounce off ionized gas just like a police officer's radar gun pings a speeding car. [By processing this radar data] we'll get a picture of the whole magnetopause every 1 or 2 minutes!"
"Imagine you're a scientist observing the magnetosphere for 30 years and you create a mental picture of what's going on. Now I'm going to give you a picture that's worth your whole career in just 1 or 2 minutes! We're going to be imaging the magnetosphere like never before."
Right: Click
the image for a 3D simulation of the magnetosphere's shape.
The Sun is off screen to the left. The animation begins showing
the Earth, which recedes as the shape and size of the magnetosphere
comes into view. The solar wind deforms the magnetosphere into
its characteristic shape. Where the magnetosphere and the solar
wind meet is the "bow shock," represented in the animation
by a faint, translucent bullet shape. Credit: Digital
Radiance
All the data transmitted to Earth by IMAGE will be freely available
on the world wide web.
"The data are going to be handled as totally non-proprietary,"
says Dennis Gallagher, an IMAGE co-investigator at the Marshall
Space Flight Center. "At Marshall we're developing an inexpensive
ground station to capture the data stream from IMAGE. We are
in the process of buying components that should total less than
$10,000. There will be 4 helical antennas in a small phased array
tuned to 2.27 GHz. The cost could end up being as little as $5000.
We're going to take this blueprint and make it widely available.
Any ham radio operator could build one."
The University of California at Berkeley, the Air Force Academy,
and researchers in Japan also have plans to receive the IMAGE
transmissions, says Gallagher. The NOAA Space Environment Center
(SEC) will try to use the real-time down link from IMAGE for
space weather forecasting.
"Like the rest of us, the SEC forecasters will try to understand
how to use these data to predict space weather," he continued.
"We may develop new indices, new early warning indicators
for space weather. We simply don't know yet. IMAGE is opening
up a whole new frontier."
Stay tuned to NASA Scienced News for science updates from the
IMAGE mission. For more information, please see our earlier article
"Space Weather Mission Nears Launch."
| Parents and Educators: Please visit Thursday's Classroom for lesson plans and activities related to this story. |
Southwest Research Institute manages the IMAGE project
and leads the IMAGE science investigation. The IMAGE Principal
Investigator is James L. Burch.
IMAGE is the first of two Medium-class Explorer missions NASA
has scheduled for launch. The total cost of the mission, including
spacecraft, launch vehicle and mission operations for the first
two years is about $154 million. The IMAGE Project Office at
Goddard will manage the mission for NASA's Office of Space Science
in Washington, DC, while the principal investigator at SwRI has
overall responsibility for the science, instrumentation, spacecraft
and data analyses.
Lockheed Martin Missiles and Space of Sunnyvale, Calif. built
the IMAGE spacecraft -- which measures 7.38 feet in diameter
and 4.99 feet high -- under contract with SwRI. On orbit, the
RPI antennas aboard IMAGE will extend 33 feet parallel to the
spin axis and 820 feet in four directions perpendicular to the
spin axis, making IMAGE the longest spacecraft currently on orbit.
IMAGE home page - from NASA/GSFC.
IMAGE home page - from the Southwest Research Institute.