Sep. 17, 1998 For nearly three decades, scientists have known that Earth is surrounded by the massive Van Allen radiation belts, which wreak havoc on spacecraft and satellite communications but also play a role in generating spectacularly beautiful auroras. Now, as one of only two universities selected by NASA's new University-class Explorers (UNEX) program, the University of Minnesota will send a spacecraft into the heart of the Van Allen belts to study the forces at work there. The researchers hope that by better understanding these forces--which also operate in virtually every other corner of the universe--they will gain a deeper understanding of how electrical and magnetic forces shape the universe and come closer to predicting hazards to communications--and astronauts. Launch is planned for mid-2001 aboard an Air Force Titan IV rocket.
The university project, along with one from the University of California, Berkeley, was chosen for UNEX from 44 proposals nationwide. UNEX is designed to provide frequent flight opportunities for specific and relatively inexpensive science missions involving students. With only three years to launch, the project will allow many students to be involved in the projects from start to finish.
"This is part of NASA's effort to do more science for less money," said project principal investigator John Wygant, an assistant professor of physics at the University of Minnesota. "It presents us with a tremendous challenge to put this program together on time and on budget."
"We've been building space experiments here since the 1950s," said project manager Keith Goetz, a physicist at the university. "But this is the first time we've been responsible for all aspects of a satellite project from beginning to end."
The five-year, $13 million project, named the Inner Magnetosphere Explorer (IMEX), will record the forces that spin, accelerate and otherwise control the fates of electrically charged particles that stream from the sun and head earthward at speeds nearing a million miles per hour. Known as the solar wind, these particles--mostly protons and electrons--run into rough sledding when they hit Earth's magnetic field. The field sends the particles spiraling along its magnetic force lines and boosts their energy by hundreds of thousands-fold. Eventually some particles are guided into the Van Allen belts, which circle Earth at altitudes between about 200 and 20,000 miles. Those altitudes define the inner- and outermost points of IMEX's highly elliptical orbit.
Because very fast, energetic particles in the Van Allen belts have caused spacecraft to fail, Wygant and Goetz expect IMEX to suffer some damage. However, the 350-pound spacecraft provides more shielding than most, so the team expects to get two years of data from it. Its launch date will place it in the Van Allen belts during the height of the 11-year solar cycle, a time when activity is expected to be strongest.
The University of Minnesota is heading a team of investigators from several institutions working on different parts of the project. Minnesota scientists are building IMEX's central instrument, which will measure electrical fields, and also a computer to control all the scientific instruments aboard. The University of Colorado is building the spacecraft. The University of California, Berkeley is providing an instrument, as are NASA's Goddard Space Flight Center in Greenbelt, Md., and the Aerospace Corp. UNEX is managed by NASA's Goddard Space Flight Center in Greenbelt, Md., for the Office of Space Science in Washington.
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