Telemetry, << tuh LEHM uh tree, >> means measuring at a distance. Scientists and engineers use telemetry in many ways. Scientists send instruments called radiosondes high into the atmosphere to measure such things as the air temperature, pressure, and humidity above the earth. Radios attached to the balloons relay this information back to the earth.
Telemetry also helps people explore outer space. Rockets and spacecraft send information about their own performance and conditions in outer space to scientists and engineers on the earth. On human space flights, telemetry systems provide data on astronauts’ physical condition by reporting their pulse rate, blood pressure, and temperature. To save space and weight, special miniature equipment is used in spacecraft.
A telemetry system consists of a measuring instrument, a transmitter, and a receiving station. For example, a telemetry system that records temperatures at remote locations uses an electrical thermometer as the measuring instrument. Signals produced by the thermometer are transmitted by radio or by wire to a receiving station. Instruments at the receiving station record the signals on magnetic tape and convert them into meter readings and graphs.
