Electromagnetic Formation Flight

An exciting new idea for space exploration.

Between 1966 and 1969, the Dick Tracy comic strip proclaimed 31 times that "The nation that controls magnetism will control the universe." That prediction hasn't come true, but there may be something to it. Researchers at MIT's Space Systems Laboratory hope to use magnetism, not to control the universe, but to explore it.

Magnetism may be better than jet propulsion for coordinating the movements of vehicles in space, says Raymond Sedwick, associate director of MIT's Space Systems Laboratory.

"There are a lot of applications where the relative position of the vehicles is the most important thing," says Sedwick, "such as space construction missions or formation flight."

Sedwick is the principal research scientist on the lab's Electromagnetic Formation Flight (EMFF) project. His goal is to use superconducting magnets -- powered by solar panels and rechargeable batteries -- to extend mission life and allow more aggressive maneuvers, "without the fear of using up all of your available propellant."

One mission that might use EMFF is NASA's proposed Terrestrial Planet Finder. The goal of the mission would be to search for planets similar to Earth using interferometry -- in which an array of smaller telescopes mimics one large telescope -- to take high-resolution photographs. The technique could yield photographs 100 times more detailed than the best that the Hubble Telescope can produce. But arranging orbiting telescopes into an array would require highly accurate formation flight.

The concept guiding Sedwick's work is simple: magnets either attract or repel. Each vehicle will have three concentric superconducting magnetic rings that outline a sphere, producing three orthogonal fields. Through variation of the magnetic fields, the vehicles can be made to not only attract and repel but also move sideways, or obliquely, with respect to each other, and to rotate. In other words, the researchers can control the vehicles' relative movement in any direction.

The lab demonstrated the technology last spring. At this stage, the maneuverability of the prototype ve-hicles is rudimentary.

"There's a lot of development that needs to occur before we can really do anything even remotely complex in space," says Sedwick, "but we've demonstrated the concepts."

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Sedwick's group is also working on the other key element of the design: the thermal system. The superconducting magnets, which function only at extremely low temperatures, need proper insulation. The system being used in the lab works fine -- on Earth. Now, Sedwick and his team are focused on making that system viable for space. If all goes according to plan, they will begin working on the complete blueprints of all the hardware and software by next year and could have a flight demo ready by 2010.

EMFF is not associated with any mission, but NASA has shown interest in the idea. The research is funded by the U.S. Defense Advanced Research Projects Agency and has received additional funding from the National Reconnaissance Office and branches of NASA, including the NASA Institute for Advanced Concepts.