The Economic Times

US Army in 1946 sent radar pulse towards moon and something astonishing happened 2.5 seconds later

The year 1946 saw a remarkable feat by the US Army as they bounced radar signals off the Moon, demonstrating that radio waves can traverse the ionosphere. This innovative test, called Project Diana, utilized modified radar equipment from WWII. The successful detection of lunar echoes not only confirmed this capability but also served as a catalyst for the evolution of radar astronomy and the broader realm of space exploration.