Word: signal
(lookup in dictionary)
(lookup stats)
Dates: during 1950-1959
Sort By: most recent first
(reverse)
...detect cosmic rays in space and two incredibly light but powerful radio transmitters-would have to be modified in one respect. It contained a miniature tape recorder to record the cosmic-ray data during a trip around the earth and then transmit it quickly when triggered by a coded signal sent up from the ground. Designed for Vanguard, this elegant apparatus would not work in Explorer I, which would spin too fast. So it was removed, requiring Explorer I to broadcast continuously...
GETTING information from a satellite is tricky business. "If you want to measure the temperature up there," says Van Allen, "you can't put a mercury thermometer in your bird. You have to read temperature as an electrical signal." This is done with a tiny "thermistor," whose resistance to current put out by the satellite's batteries varies with temperature. The change affects the frequency of the electronic signal sent out by the satellite's transmitter, thus reporting the temperature to the ground...
When this mixed signal reaches the ground, it is recorded on magnetic tapes. In Van Allen's laboratory the tapes pass through a machine that separates each imposed audio tone from the carrier frequency and records it visually as a jiggly red line on a wide band of graph paper (see chart...
...powerful nuclear charge need only be blasted free of the earth and set in orbit around the sun. Since its speed will not be the same as the earth's, it will move steadily away. When it gets far enough, it can be exploded by a radio signal or a timing mechanism...
...launching rocket and will snap into position as soon as it is spaceborne. The array of solar batteries is expected to develop as much as 400 watts, about enough to run a small toaster. Most of the energy will be stored in nickel-cadmium batteries. When triggered by a signal from the earth, the batteries will power the satellite's radio transmitter...