The RADAR Cop in Space

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."

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IMAGE is going to fast-forward magnetospheric physics and space weather prediction into the year 2000, says Green. Data returned by IMAGE will offer the first-ever simultaneous measurements of the densities, energies and masses of charged particles throughout the inner magnetosphere using 3D imaging techniques.

"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.

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"Every one of the instruments on board are innovative," says Green. "They are brand new technologies."

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.

Web Links

IMAGE home page - from NASA/GSFC.

IMAGE home page - from the Southwest Research Institute.

Instruments on IMAGE include:

The Radio Plasma Imager. The RPI will use radar echoes in the frequency range 3 kHz to 3 MHz to detect and monitor ionized gas (plasma) inside the magnetosphere.
Far Ultraviolet Imager. The FUI will take pictures and spectra of the entire Earth along with the auroral oval at ultraviolet wavelengths. The 3 instruments that combine to form the FUI instrument package (GEO, SI and WIC) will provide almost constant monitoring of auroral activity from above our planet. The Earth is surrounded by a cloud of neutral atoms and molecules that is largely invisible from the ground. The so-called 'geocorona' is an extension of Earth's atmosphere into space. It is mostly made up of hydrogen, because it's the lightest element. GEO will also be used to detect these neutral atoms, measure their energy and map their distribution.
Neutral Atom Imagers. The neutral atom cameras will detect neutral atoms created by ring current ions and escaping auroral ions that collide and exchange charge with the cold, geocoronal hydrogen gas. This will allow scientists to indirectly monitor and explore the ring current and auroral ion fountains.
Extreme Ultraviolet Imager. The EUVI will detect ultraviolet photons from the Sun that are scattered by helium ions in the plasmasphere, a torus of cold dense plasma surrounding the Earth in the inner magnetosphere. A sophisticated deconvolution technique will be used to translate the photon counts into images of the plasmasphere.

The RADAR Cop in Space

NASA's IMAGE satellite, scheduled for launch on March 25, will revolutionize our understanding of Earth's magnetosphere and improve space weather forecasting.

Instruments on IMAGE include: