US Army Bounced 3,000-Watt Radio Signal Off Moon in 1946, Proving 2.5-Second Echo
Updated
Updated · spacedaily.com · Aug 22
US Army Bounced 3,000-Watt Radio Signal Off Moon in 1946, Proving 2.5-Second Echo
3 articles · Updated · spacedaily.com · Aug 22
Summary
At 11:48 a.m. on Jan. 10, 1946, Signal Corps engineers at Camp Evans, New Jersey, sent a radar pulse to the Moon and detected its return 2.5 seconds later—the first confirmed human contact with another world.
The test, called Project Diana, was built to answer a military question: whether radio could penetrate the ionosphere for future communication, tracking and missile-related operations beyond Earth’s atmosphere.
John DeWitt’s team achieved it with modified wartime radar—about 3,000 watts of power, quarter-second pulses and constant Doppler retuning—after weeks of failed attempts and a repaired receiver.
The echo showed radio could pass through the ionosphere and back with detectable strength, laying groundwork for satellite communications, deep-space telemetry and radar astronomy.
How did a repurposed WWII military radar bouncing a signal off the Moon trigger the modern hunt for lunar water ice?
If Project Diana proved radio waves can escape Earth, what unseen cosmic echoes might our daily modern signals be creating right now?
Project Diana and the Birth of the Space Age: The First 2.5-Second Moonbounce, Cold War Espionage, and the Legacy of Radar Astronomy
Overview
Project Diana began in 1946 when scientists successfully bounced a radar signal off the Moon, proving that radio waves could penetrate the Earth's ionosphere and shattering long-held scientific skepticism. This breakthrough led to the birth of radar astronomy, enabling active mapping of the solar system. The experiment was driven by a military need to track ballistic missiles, requiring major technical innovations like modifying transmitters and antennas, and precise mathematical calculations. Over time, these advances inspired both military moonbounce communications and modern amateur radio, while also laying the foundation for today’s global satellite networks and planetary radar observatories.