Frank Drake, Cornell professor and SETI pioneer, led humanity's first true METI effort with the Arecibo Message. Work began in the early 1970s as Drake organized a campaign to compose a message for broadcast via Arecibo's megawatt transmitter attached to its 305-meter antenna.
The message transmitted on November 16th, 1974, at 2380 MHz with an effective bandwidth of 10 Hz and a raw carrier power of 450 kilowatts. Arecibo's massive dish focused that energy into a narrow, directional beam.
This milestone represented a transition in METI efforts from interplanetary messaging to interstellar communication. Earlier, scientists at the Evpatoria Planetary Radar center in Crimea had transmitted a Morse Code signal toward Venus between November 19th and 24th, 1962, using the facility's RT-70 radio telescope. That message included the letters M-I-R (Russian for "peace") followed by "Lenin" and "USSR." The signals reflected off Venus and returned to Earth about four and a half minutes later. While Venus was then thought potentially habitable, the experiment aimed mainly to test the radar station's capabilities.
Later missions, including Mariner 4 in December 1962 and multiple Soviet probes, revealed Venus's true conditions: carbon dioxide atmosphere, sulfuric-acid rain, and extreme surface temperatures. This ended speculation that Venus could harbor life.
Drake's 1974 Arecibo Message represented a shift toward sending humanity's first deliberate signal to potential intelligent civilizations beyond our solar system, reflecting broader scientific motivation to communicate on behalf of all humanity rather than individual nations.