Paddle-Wheel Satellite

(2 of 2)

Other eyes look into subjects of more immediate importance to men on earth. A small mirror housed in a tube peers down from one side of Explorer VI and gathers impressions of the cloud layers over the earth. An electronic counter digests the mirror's impressions and turns them into radio signals, which eventually become crude photographs of the earth's weather patterns. Two magnetometers watch the earth's magnetic field, may help map the field and explain its curious storms and their effect on earth communications.

To keep the interior of the paddle-wheel satellite at an even temperature range as it passes from the cool shadow of the earth into the blazing heat of the naked sun, Explorer VI has on its outer skin a patch of black-carbon paint. A thermostat actuates a small shield that alternately covers and uncovers the patch as heat requirements dictate. Since the satellite uses electricity much faster than the paddle wheels can make it signals from the earth periodically shut of the largest of Explorer VI's three radio transmitters. A memory device called Telebit takes over, stores up what the satellite learns during its silence. When the transmitter is turned on again, Telebit spills out the stored information in the digital transmission system, a coding method so concise that data collected during a 4½-hour period can be sent in a few seconds.

Kick in Reserve. Explorer VI is expected to hold its hip-swinging orbit for at least a year. During that time it may illuminate problems of the universe from Einstein's theory on the curvature of space to the question whether man can really get past the Van Allen radiation belts by entering space above the earth's poles. At week's end a spokesman for the National Aeronautics and Space Administration reported: "The paddle wheel is doing well. It is converting solar energy into electrical energy. The signals are coming in loud and clear." If its perigee edges in too close to the earth, the paddle-wheel satellite still has a 5-lb. kick rocket that can be fired to elongate its orbit; last week's launching was such a perfect shot that the kicker was not fired.