It consisted of the V-300 missile and the B-200 radar system. Both the British and the Americans became interested in the Soviet tech when random roads began appearing outside of Moscow, which were speculated to be missile sites.
However, an eyewitness sketch of unusual piece of tech piqued the interests of western intelligence even more. The sketch was of a large unit comprised of two flat, oddly-shaped discs that appeared to have rotated when in use.
Not exactly sure what the unit was for, the CIA dubbed it YO-YO. However, intelligence believed early on it was related to surface-to-air missile systems.
Though suspected, intelligence was not really sure what the YO-YO really could do. According to the CIA:
“Beginning in January 1955, the Yo-Yo was brought up at each meeting of the MEWG for many months. For the present, however, there was little that the electronics analyst could do but speculate as to what the observers had really seen and request more detailed information, especially photographs.” (1)
The analysts got their wish in August of 1955 when they received highly detailed photographs. The details of the photos proved the sketches and descriptions of the witnesses were fairly close, but the analysts were still in the dark on what the unit was.
Triangular Shaped Discs
The photographs depicted two large triangular shaped discs that were positioned across from each other in a pattern reminiscent of the Star of David. These large panels counter-rotated at about 40 rotations per minute.
The discs were mounted on straight structures that were about 20 feet high and eight inches wide. The units began appearing on the newly built roads that ran parallel to Moscow.
Though the units were not like anything the analysts had ever seen, the size of the units and the positioning on the roads further led the analysts to believe that they were used for missile guidance. However, at that point, the units were never photographed near any missiles.
The theory was that the device was still used to control surface-to-air missiles, but (at that time) no one knew how.
With the missile guidance theory in hand, the intelligence analysts had to work backwards in trying to figure out how the design in the photos could be used to guide missiles. The analysts used the basic theory of how missile guidance system worked at the time, which was that an antenna array tracked both the missile and the target through the use of direct beams of radio waves.
However, what was different was that leading up to 1955 these antenna arrays were parabolic shaped not flat triangular discs.
Analysts speculated that the edges of the triangular discs emitted a beam up and away from Moscow in attempts to detect enemy aircraft and guide the missiles to them. While the straight portion of the unit emitted a straight beam of radio waves.
According to the CIA:
“Both sets could provide range data on any target or missile in the volume of space scanned. With the whole volume covered, the antennas would not need, like a searchlight or parabolic radar, to stop scanning in order to follow a target or the defense missile, but would provide position data on these in the course of continued scanning.” (2)
With this information in hand, it appeared the Russians successfully deployed a track–while-scan system.
Though it was just a theory at the time, the analysts would eventually prove their theory right with further research and analysis.
It seemed that at the time of deployment the strange antenna array was the first use of the track-while-scan surface-to-air missile guidance system. Though the system was dubbed a silly name by American intelligence analysts, it was leaps and bounds ahead of what they had at the time.