A Weber State University instructor hopes to create a magnetic propulsion system for low-orbit satellites that otherwise would be dragged back to Earth within a year.
Jay L. Smith in the school's electrical engineering technology department hopes to dramatically reduce current satellite transmission costs with some help from the Earth's magnetic field.Smith said it is relatively inexpensive to put a satellite into a low orbit of 150 miles.
But that creates some problems, he said. There is almost no atmosphere that high, but just enough molecules to create a tiny amount of drag on a satellite, slowing it down and eventually causing it to drop into the denser atmosphere and burn up.
But in those low orbits, the Earth's magnetic field might be used to help out.
Scientists already use electromagnets in satellites, said Frank Redd, director of the Space Engineering Center at Utah State University. Those electromagnets help make maneuvers called attitude adjustments, or turning the satellite to make it point in the right direction.
Because identical poles of magnets repel each other, Smith believes it is possible to create a magnetic propulsion system using the force that is now used to turn a satellite.
The electromagnets in Smith's experiment, only about the size of those people use to stick messages and pictures on their refrigerators, may seem ridiculously small.
"We'll be using the Earth's magnetic field to push against the magnets," he said. Because of the size of the magnets "it will be a very, very small thrust. But it will be working over months and months."
And, in space's zero-gravity environment, he said, "it doesn't take much force to begin moving an object, even a much larger object."
If the thrust is only applied in one direction, added to the satellite's forward velocity, Smith hopes to compensate for the small loss of speed caused by drag and thus keep low-orbit satellites up longer.
Without a means of maintaining those low orbits, communications companies do not want to install expensive equipment. If the magnetic propulsion system works, then a series of low satellites could provide the same continuous communication service as the high geostationary satellites parked 25,000 miles up.
And people with inexpensive equipment, such as FM receivers or police scanners, could pick up the signals from the low satellites, doing away with the need for big receiving dishes.
Smith has built a small experiment 1 inch thick and 9 inches square to fit inside Weber State's ADSAT satellite. Four inches thick and 16 inches square, it will be the third Weber State satellite to fly if the National Aeronautics and Space Administration agrees to carry one into orbit aboard a space shuttle.
Weber State officials hope to receive word this year that ADSAT will be accepted for launch. Then it may take up to another two years to get it on a shuttle flight. It must be launched by hand by an astronaut, and NASA plans just two flights each year with a space walk.