- Project Diana
Project Diana, named for the Roman
moon goddess Diana, was a project of theUS Army Signal Corps to bounce radio signals off themoon and receive the reflected signals. Today called EME (Earth-Moon-Earth), this was the first attempt to "touch" anothercelestial body . From a laboratory atCamp Evans (part ofFort Monmouth ), near Wall Township,New Jersey , a largetransmitter ,receiver andantenna array were constructed for this purpose. The transmitter, a highly modified SCR-271radar set fromWorld War II , provided 3,000watt s at 111.5MHz in 1/4 second pulses, and the antenna (a "bedspring"dipole array) provided 24 dB of gain. Reflected signals were received about 2.5 seconds later, with the receiver compensating forDoppler modulation of the reflected signal. The antenna could be rotated inazimuth only, so the attempt could be made only as the moon passed through the 15 degree wide beam at moonrise and moonset, as the antenna'selevation angle was horizontal. About 40 minutes of observation was available on each pass as the moon transited the various lobes of theantenna pattern . The first successful transmission was made on10 January 1946 at 11:58am local time.Project Diana marked the birth of the
US space program , as well as that ofradar astronomy . It was the first demonstration that artificially-created signals could penetrate theionosphere , opening the possibility of radio communications beyond the earth forspace probes and human explorers. It also established the practice of naming space projects after Roman gods, e.g., Mercury andApollo .Today, the Project Diana site is maintained by the Ocean-Monmouth Amateur Radio Club, where they sometimes operate an
amateur radio station as a special event.References
* Radar Echoes From the Moon, January 1946, By Jack Mofenson, Evans Signal Laboratory, Belmar N.J. [http://www.infoage.org/diamof.html]
* IEEE Virtual Museum [http://www.ieee-virtual-museum.org/collection/event.php?id=3456980&lid=1]
* Butrica, Andrew J. To See the Unseen: A History of Planetary Radar Astronomy. (NASA SP4218, 1996) [http://history.nasa.gov/SP-4218/ch1.htm]
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