Milestone-Proposal:Detection of Radar Signals Reflected From the Moon, 1946

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Docket #:2016-02

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? No

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:

1945-1946

Title of the proposed milestone:

Detection of Radar Signals Reflected from the Moon, 1946

Plaque citation summarizing the achievement and its significance:

Project Diana was the first contact with the moon using radar signals. On 10 January 1946, Lt. Colonel John DeWitt used an SCR-270 radar to send radar signals to the moon and detect their reflection

In what IEEE section(s) does it reside?

IEEE North Jersey Coast

IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):


IEEE Organizational Unit(s) arranging the dedication ceremony:


IEEE section(s) monitoring the plaque(s):


Milestone proposer(s):


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):


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.


Are the original buildings extant?

The base of the radar installation exists.

Details of the plaque mounting:


How is the site protected/secured, and in what ways is it accessible to the public?


Who is the present owner of the site(s)?

Info-Age Learning Center

What is the historical significance of the work (its technological, scientific, or social importance)?

Proof of Concept of Communicate through the Ionosphere with EM signals

Today it is difficult to imagine an Earth without manmade satellites in orbit, but prior to 1946, experts were unsure if such a concept was possible. On January 10, Lieutenant Colonel John H. Dewitt’s experiment to communicate outside the earth’s atmosphere was a success as the first radar pulses were sent to and received by the moon. These results crushed any doubt that EM waves suitable for long-range communication could penetrate the Earth’s ionosphere, kick starting a series of ideas ranging from worldwide wireless communication to mapping out the universe.

Worldwide communication

Prior to the success of the experiment, wireless communication up to about 400 km was performed using “skywave” communication where signals were bounced off the atmosphere which was not limited by the curvature of the earth to a larger extent than line-of-sight communication. However, this method was restricted in the possible 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 pursued 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. This success was then followed by another on November 20, 1955, where 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.

Between 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, the same way that Project Diana had done to 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 an astronomical unit and the scale of the solar system itself.

Space Age

Almost more importantly that any other benefit, the success of the project represented a symbol that lead to the beginning of the Space Age for the United States. 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 potentially 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. Project Vanguard.

(TODO: Finish section)

Detect and Control Guided Missiles

Boosted US Morale

Study the EM properties of the Earth's Atmosphere

What obstacles (technical, political, geographic) needed to be overcome?

Bandwidth Requirements

Col. DeWitt and his team 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 precision of almost 0.000009%, meaning a very stable system. This stability requirement far exceeded the usual requirements on most radars, so the team had to modify their receiver by replacing the three local oscillators with a single crystal that controlled the frequency of the signal.

The potential stability issues were magnified due to the relative motion of the moon and Earth, which would have caused a Doppler shift in the frequency calculated to be 327 Hz, putting the receiving signal outside the band of a fixed tuner. Thus, they had to modify the last stage of the receiver to be able to tune the frequency and properly analyze it.

Limitation on Antenna movement

Due to the limitations in hardware that DeWitt had access to, the antenna could only move in the azimuth, or with the horizon, and could not be elevated. Because of this limitation, the team only had approximately 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 increased the amount of time to properly conduct the experiment.

System components were being pushed

At the facility, DeWitt and his team only had access to old or insufficient hardware. There were frequent reports of parts failing due to the stress the setup was putting on them. (TODO: Article has more info on this)

Political - Some weren't convinced of its usefulness

What features set this work apart from similar achievements?


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.


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 ieee-history@ieee.org. Please see the Milestone Program Guidelines for more information.


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 ieee-history@ieee.org 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).