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NMSU research to help satellites "phone home"

As a result of New Mexico State University research, a cluster of university satellites to be launched in 2001 may use cellular phone technology to "phone home." The "3 Corners Satellite" cluster is a joint project of NMSU, the University of Colorado at Boulder and Arizona State University, funded by the U.S. Air Force, Defense Advanced Research Projects Agency (DARPA) and NASA under their University Nanosatellite program.

The "3 Corners Satellite" is a cluster of three nanosatellites, satellites weighing less than 10 kilograms (about 22 pounds), operating together in low-earth orbit. Each university will be responsible for the operation of one of the satellites, but the three will cooperate on the scientific experiments of the program.

"The satellites will measure stereo images of clouds from space," said Stephen Horan, an NMSU electrical and computer engineering professor who directs NMSU's participation in the project. "When you look at things like weather maps, it's hard to tell how high the clouds are."

This project is meant to prove the technology and concept will work, he said. "We want to show that you can receive images from space and you can process them fairly quickly." But more importantly, the project will help the researchers prove they can build and run the satellites.

Together, the Air Force Office of Scientific Research and DARPA will provide $100,000 to each of the three universities, who must then create the satellites. "We have to buy the parts, make sure they work, test the craft and get it approved," Horan said. The Air Force will coordinate the launch details, he said.

Each university will play a different role in developing, building and monitoring the satellites, Horan said. ASU will develop the basic architecture and build the satellites. As the second generation of ASU's satellite model, the effort will help the university's students learn how to build a better spacecraft, he said. CU-Boulder will oversee the on-board computer control systems to keep the satellites working and working together. NMSU will develop and test new communication techniques for the cluster.

"Most spacecraft use a dedicated radio link," Horan said. "This will be the first set of satellites to use cellular phone technology to communicate from space."

When using a dedicated radio link, he said, "you're the only one using that frequency while the satellite is over your spot of the Earth. However, you can only communicate with the satellite for five to 10 minutes about four times each day for the same reason."

Cellular phone technology uses satellites to transfer signals, and can transmit at any time to any area covered by a service provider, he said. "There's no guarantee you won't get a busy signal, but we can make the satellites lighter and less complicated by relying on the phone company to provide the infrastructure and the service."

He also wants to use existing commercial communication methods like the Internet to communicate with the satellites. It is all technology in which NASA, the Air Force, federal agencies, private industries and the space community in general are interested, he said.

Until now, the technology has existed only on paper and in labs, Horan said. He is excited about the chance to test it out. "It's aggressive, but many of the pieces already exist. This is a technology demonstration program," he said. "We'll find out what we don't really know, what unknowns we still need to worry about."

In the meantime, researchers are still working out the details, including how to get all the hardware and software they will need. They must work quickly, though, because project officials anticipate launching the satellites in about two years. "That is a very quick turn-around in the space community," Horan said.

Depending on the launch details, the expected life of the satellites will be from three months to a year and a half before the equipment wears out and the satellites begin to decay and fall back to earth. Because they are expected to be in space for such a short time, they won't need to purchase special, space-rated parts for the communication systems, Horan said, which will help defray costs. He also anticipates having some parts donated.

"One of the goals of the project, from the Air Force's point of view, is to demonstrate that universities can quickly do neat, innovative things on a shoestring budget," Horan said.

Students will benefit from the program through involvement in all aspects of the project, he said. NMSU students, for example, may gain experience in areas like dealing with regulatory bureaucracy, filing paperwork for launch certifications, verifying safety procedures and managing costs. "Students don't normally run into these things in classes or textbooks," Horan said.

Rachel Kendall