Milestone-Proposal:Detection of Radar Signals Reflected From the Moon, 1946
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This Proposal has been approved, and is now a Milestone
To the proposer’s knowledge, is this achievement subject to litigation? No
Is the achievement you are proposing more than 25 years old? Yes
Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes
Did the achievement provide a meaningful benefit for humanity? Yes
Was it of at least regional importance? Yes
Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes
Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes
Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes
Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes
Year or range of years in which the achievement occurred:
Title of the proposed milestone:
Detection of Radar Signals Reflected from the Moon, 1946
Plaque citation summarizing the achievement and its significance:
On 10 January 1946, a team of military and civilian personnel at Camp Evans, Fort Monmouth, New Jersey, USA, reflected the first radar signals off the Moon using a specially modified SCR-270/1 radar. The signals took 2.5 seconds to travel to the Moon and back to the Earth. This achievement was the beginning of radar astronomy and the space age.
In what IEEE section(s) does it reside?
IEEE New Jersey Coast
IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:
IEEE Organizational Unit(s) paying for milestone plaque(s):
Unit: IEEE New Jersey Coast
Senior Officer Name: Irfan Lateef
IEEE Organizational Unit(s) arranging the dedication ceremony:
Unit: IEEE New Jersey Coast
Senior Officer Name: Irfan Lateef
IEEE section(s) monitoring the plaque(s):
IEEE Section: IEEE New Jersey Coast
IEEE Section Chair name: Irfan Lateef
Proposer name: Kit August
Proposer email: Proposer's email masked to public
Proposer name: Albert Kerecman
Proposer email: Proposer's email masked to public
Proposer name: Krishna Raghunandan
Proposer email: Proposer's email masked to public
Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.
Street address(es) and GPS coordinates of the intended milestone plaque site(s):
Building 9162, 2300 Marconi Road Wall, New Jersey 07719, 40.1848558, -74.0565185
Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.
Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. The intended site of the milestone plaque is in Building 9162, which houses electronics for the "space Sentry" parabolic dish used for detection of pulsars and for demonstrating live voice "moon bounce" reflections. It is located within the enclosed compound that transmitted the radar pulses and received the reflected signals from the Moon on 10 January 1946.
Are the original buildings extant?
The base of the radar installation exists.
Details of the plaque mounting:
The plaque is to be mounted on a wooden screen in the entrance way inside Building 9162.
How is the site protected/secured, and in what ways is it accessible to the public?
The site is surrounded by a 10’ high chain link fence topped with barbed wire, a chain link pad-locked vehicle gate, and is protected by security cameras. Building 9162 is locked and secured. The address of the plaque site is 2300 Marconi Road, Wall New Jersey 07719. The site is available to visitors from 1 PM to 5 PM on Wednesdays and Saturdays. Special group tours can be arranged by calling InfoAge Science History and Learning Center at 732-280-3000.
Who is the present owner of the site(s)?
Wall Township, NJ 07719, 2700 Allaire Road, Phone: 732-449-8444, ext. 2216; Fax: 732-449-8996; Attn: Jeff Bertrand, Administrator.
What is the historical significance of the work (its technological, scientific, or social importance)?
Proof of Concept The effort resolved doubts about whether Electromagnetic Waves suitable for long-range communication and radar could penetrate the Earth’s Ionosphere. It was the first documented experiment in radar astronomy and in actively probing another celestial body, and was the dawn of the space age, with personnel at Site Diana, Camp Evans, Fort Monmouth, New Jersey, USA, demonstrating the ability to communicate with extraterrestrial bodies beyond Earth. Measurements were made of surface roughness and mapping of shadowed regions, and provided the first crude information on the small scale topography of the moon.
These results emboldened a series of ideas ranging from worldwide wireless communication, radar astronomy, artificial satellites, and rocket launched probes to the moon and planets.
Prior to the success of the experiment, wireless communication was performed using “skywave” communication up to about 400 km, where signals were reflected or refracted off the ionosphere. While this form of communication was not limited by curvature of the earth line-of-sight, it was restricted in frequency range and data rate.
Demonstrating that signals could travel from the earth to the moon and back was proof of concept for the idea of what is known as Earth-Moon-Earth (EME), or “moonbounce” communication. Following the success of the project, the US Navy set out to explore the implications and applications of this form of communication - the idea of a reliable, secure EME scheme. The first major milestone to this Passive Moon Relay project happened on July 24, 1954, where voice was successfully transmitted from Stump Neck, Maryland to Washington, DC. Following this success, on November 20, 1955, transmissions were sent to San Diego, California and soon after to Wahiawa, Hawaii. The system in its completed state began seeing use in 1960 and was expanded to accommodate ship-to-shore transmissions. In the later 1960s the system became obsolete due to the advent of artificial satellites in orbit to serve the same purpose.
Radar Astronomy Before 1946, scientists observed the universe using large passive radio telescopes that caught and recorded radio waves emanating from the universe outside the earth’s atmosphere. This technique of passive reception was part of a field known as radio astronomy. Following the success of Project Diana, scientists had access to what is known as radar astronomy. Unlike radio astronomy, this technique is an active observation by reflecting microwaves off objects and analyzing the reflected signal, in the same manner as Project Diana had done with the moon.
Radar astronomy has many advantages over previous forms of observation. The ability to control and measure the source of the transmission allowed scientists to extract information that was difficult to obtain before, such as composition and relativistic data. Since 1946, this technique has been used to gather a wealth of data about the geological and dynamic properties of many of the planets, moons, and asteroids that orbit our sun. Additionally, it has been used to determine the length of the Astronomical Unit (AU) and the scale of the solar system itself.
Space Age The success of the project became a symbol that lead to the beginning of the Space Age for the United States. Days after the success of the project, the New York Times commented that "somehow ... the moon and all the heavenly bodies become more real ... more than a guide to navigators and an inspiration to poets ... tangible objects to which we can reach out." For the first time in its history, the US was able to “touch the stars” so to speak, where it could communicate with objects and potential beings well outside of its grasp up until that point. With this new found reach from a communications perspective, the US sought to extend that to a physical presence.
In the early 1950s, President Dwight Eisenhower was skeptical about the possibility of human spaceflight, although he did see promise in artificial satellites for commercial and military use. The stage was finally set when President John F. Kennedy set a goal of sending men to the moon by 1968.
Detect and Control Guided Missiles Following the success of the project, the War Department talked about "radio control of missiles orbiting Earth above the stratosphere." Today, Earth satellites and space probes are directed and re-positioned via this “radio control”.
Boosted US Morale This achievement brought promise of a coming golden age of science and technology arising from the aftermath of World War II. It refocused engineers and scientists to new goals centered on benefiting humanity, and created a need for developing solid state technologies capable of surviving space launch and environments.
What obstacles (technical, political, geographic) needed to be overcome?
LTC. DeWitt, E. King Stodola, Jack Mofenson, Dr. Harold Webb, Herbert P. Kauffman and a contributing team including: Edwin Armstrong, W. S. McAfee, F. Blackwell, G. Cantor, J. Corwin, A. Davis, R. Guthrie, A. Kampinsky, H. Lisman, C.G. McMullen, W.S. Pike, J. Ruze, J. Snyder, and O.C. Woodward, had calculated that they needed a narrow bandwidth of 20 Hz on a 111.5 MHz signal to properly conduct the experiment. This meant that, as a base requirement to success, they needed to have a very stable system. This stability requirement far exceeded the usual requirements on most radars, so the team replaced the SCR270/1 receiver by modifying E. H. Armstrong’s developed transmitting and receiving equipment that employed three local oscillators with a single, crystal controlled source that was multiplied to provide the first three separate local oscillator frequencies needed, and which also supplied control of the transmitter oscillator. After three fixed heterodyne stages, the final heterodyne employed an independent adjustable-frequency (tunable) crystal for the local oscillator injection, to achieve the final intermediate frequency (IF) of 180 cps (Hz) with a bandwidth of 50 cps (Hz).
The potential stability issues were magnified due to the relative motions of the moon and Earth, which caused a variable Doppler shift in frequency calculated to be a maximum of 327 Hz, putting the receiving signal outside the band of a fixed tuner, thus, requiring the last stage to be tunable.
Limitation on Antenna movement Due to the limitations in hardware, the antenna could only move in the azimuth (about the horizon), and could not be elevated. Because of this limitation, the team only had about half an hour each time the moon rose and set to conduct the experiment, as opposed to the entirety of its arc in the sky. This vastly decreased the amount of time to properly conduct the experiment.
Limitation on Antenna Gain. The SCR 270/1 radar antenna was insufficient to achieve a positive signal to noise ratio (S/N) for the project, therefore two antennas were assembled together to produce a gain of about 250 above an isotropic radiator, providing a calculated S/N margin of about 15dB above the system and path length losses.
System components were being pushed At the facility, the team had access to old or insufficient hardware following the war. There were frequent reports of parts failing due to the stress the setup was putting on them.
Political Some weren't convinced of the project’s usefulness, and thought it was a waste of time and money. Once achieved, however, the doors opened to a new era - the space age was born.
What features set this work apart from similar achievements?
There are no prior documented similar achievements. Zoltan Bay and a Hungarian team achieved a similar result on February 6, 1946. Since their receiver did not have the sensitivity required, and their antenna did not have the gain needed to directly detect the reflected signal, they used an accumulating coulometer to acquire a 30 fold increase in the signal to noise ratio, producing a signal, post processing, 4% above the noise floor. Zoltan Bay acknowledged the prior accomplishment of Project Diana and authenticated it’s findings to be, in fact, correctly presented (see, “Reflection of Microwaves from the Moon”, Z. Bay, link.springer.com, article received 18th November 1946).
Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.
1) "How Diana Touched the Moon", IEEE Spectrum, May 1980 (copy sent to advocate)
2) Front Page Lead Article, New York Times, January 25, 1946.
3) Mofensen, J., “RADAR Echoes From the Moon”, Electronics, Volume 19, April 1946, pp 92 – 98.
4) Gootee, Tom (April 1946), “RADAR reaches the moon”, Radio News, Ziff-Davis Publishing Co., 35 (4), pp. 25 – 27.
5) Dewitt, J. H., Jr.: Stodola, E. K. (March 1949), “Detection of Radio Signals Reflected from the Moon”, Proceedings of the IRE, 37 (3) pp. 229 – 242. (copy sent to advocate)
7) Butrica, Andrew J. (1996). To See the Unseen: A History of Planetary Radar Astronomy. NASA. Archived from the original on 2007-08-23.
8) Buderi, Robert, “The Invention that Changed the World”, Chapter 13 (The New Astronomers), Pub. Simon and Schuster, Copyright 1996, ISBN: 0-684-81021-2. (copy sent to advocate)
9) “Message to Moon Proves Atmosphere Penetration”, Electrical Engineering, March, 1946, pp 140-141,
Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to firstname.lastname@example.org. Please see the Milestone Program Guidelines for more information.
All reference material has been uploaded. Letter from the Jersey Coast Section Chair, attesting to sponsor this milestone, pay for and monitor the plaque, and to pay for the ceremony, is in progress and will be submitted when received.
Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to email@example.com with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).