AMM will study the interaction between Earth's atmosphere and its nearby space environment. The mission would involve the placing of a closely-spaced formation of four identical satellites into a near-polar orbit, enabling more accurate measurements of electric currents, auroral features, and other aspects of the interaction.

"Our goal is to achieve comprehensive understanding of how the Earth's space environment -- the magnetosphere -- interacts electrically with the Earth's upper atmosphere and ionosphere to generate the beautifully complex northern and southern auroral lights," explains Dr. Barry H. Mauk, the project leader at APL and a magnetospheric physicist.

"Our multiple-satellite, formation-flying approach would provide, for the first time, the tools needed to understand how the magnetosphere generates the electrical currents, how those currents are modified and channeled to the polar regions of the Earth's upper atmosphere, and what the consequences are to the atmosphere and space.

"These processes are fundamental to many planetary and astrophysical environments, and have practical consequences for large-scale ground and space-based engineering infrastructures on Earth, such as those concerned with power distribution, communications, and navigation," added Dr Mauk

After its review of the feasibility studies, NASA will select two of the five mission proposals for full development as the third and fourth MIDEX flights. The selection is expected in September.

The Applied Physics Laboratory is a not-for-profit laboratory and independent division of The Johns Hopkins University. APL conducts research and development primarily for national security and for nondefense projects of national and global significance. APL is located midway between Baltimore and Washington, D.C., in Laurel, Md.