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Wednesday January 23 2:35 PM ET

Inexpensive Satellite Does the Job

By TOM STUCKEY, Associated Press Writer

ANNAPOLIS, Md. (AP) – Once every 100 minutes, a bargain basement satellite loops around the earth, sending and receiving digital messages over antennae made from a metal tape measure.

A sailor on a solo crossing of the Atlantic bounces signals off the satellite to stay in touch with his family. New Zealanders on a cross-country hike use it to communicate with friends back home.

Any ham radio user with the proper digital packet-transmitting equipment who is within 2,000 miles of the 25-pound satellite can use it to send single-line text messages to a public channel.

After four months in space, the U.S. Naval Academy’s “bird” is proving surprisingly resilient, to the delight of the midshipmen and faculty advisers who designed and built it.

The so-called Prototype Communications Satellite (PCSat) was the 44th amateur satellite put in orbit. It is one of more than a dozen built by university students around the world.

At a cost of just $50,000 – including plane tickets to the Alaska launch site – it was constructed using off-the-shelf parts not designed to withstand the rigors of space. Its life span was only expected to be a few months.

Six students put together the satellite last year after a three-year research and design project made possible with a grant from Boeing Co. The Department of Defense Space Test Program approved the project and put it on a launch list.

A tape measure from Home Depot provided the antenna. Power comes from two dozen AA batteries that are recharged by the solar panels, which are in sunlight an average of 75 minutes per orbit.

Midshipmen designed circuit boards, ordering them from an Internet supplier. Parts rated for use in space, which are built to withstand the effects of radiation from the sun, would have been too expensive, so the students went with regular circuit boards.

Sept. 29 was Launch Day, and there were anxious moments at the academy as the cube-shaped satellite hitched a ride aboard an Athena rocket that blasted into space from Kodiak, Alaska.

Save for the failure of one of the six solar panels, damaged when the satellite separated from the rocket, there have been no problems.

On Launch Day, it was nine hours before PCSat made its first pass over Annapolis and the midshipmen and faculty advisers could see for themselves that their satellite was working.

“I was thrilled. It was one of the most fulfilling experiences of my life,” said Steven Lawrence, who helped build the satellite before he graduated in May.

In the following weeks, people in remote areas began to use the satellite as word about it spread through an international organization of ham radio operators.

Just how long PCSat works depends on how much solar radiation bombards the satellite and how long the batteries, solar panels and thousands of transistors withstand the sun’s damaging effects.

“If we get lucky with radiation, it could last three years,” said Darrell Boden, a professor in the aerospace engineering department.

On the Net:

http://www.ew.usna.edu/pcsat

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