National Geographic : 1962 Feb
*-1 ~~I 1Communications from Command antenna the astronaut and all radio shoots signals to fire signals bearing informa- capsule's retrorockets tion about man and cap- and to bring space sule enter this telemetry craft back to earth. An and voice antenna. "alarm clock" in the "Slaved" to radar re- capsule also fires the ceivers, it remains focused rockets as a safety on the capsule during its measure. In an emer six-minute pass from honi- gency the astronaut zon to horizon. Telemetry scope shows multiple peaks represent- himself can trigger te ing some 90 items of information carried by radio rockets. signal from the capsule to the ground stations. s Days Reco ers t r Telltale dials, gauges, and recorders describe the space- Wavy curves on a strip-chart recorder craft's progress. Flight controllers talk to the astronaut. inscribe astronaut's heartbeat and respiration and the acceleration forces. Mercury's outposts, marvels of electronics, can locate a space craft flying five miles a second; track it; talk to the man it carries; measure the performance of the astronaut and his vehicle; and by radio signals bring man and capsule back to earth. Astronaut's heartbeat shows up as a jagged blue curve on this oscilloscope. Clocks (right) tell how long capsule has been in orbit and when it will fire its retro rockets. Upper clock shows Greenwich mean time.