Saturday, May 14, 2011

OXCART and ELINT Research

The National Security Archive contains a paper from Gene Poteat about electronic intelligence on Soviet air defenses to assisted research of stealth technology for the OXCART spy program. Gene Poteat, an electrical engineer and physicist, worked on the OXCART project.

By the end of the 1950's, the CIA's regular U-2 spy plane missions over the Soviets Union collected most valuable intelligence. The U-2's were also equipped with basic ELINT (Electronic Intelligence) and discovered a build-up of Soviet surface-to-air radars. The new radar, codenamed TALL KING by NATO, would become a serious threat to the vulnerable U-2 reconnaissance flights.

Meanwhile, CIA's top secret OXCART program was to produce a stealthy high-speed high-altitude spy plane and Kelly Johnson's legendary Skunk Works started the development of OXCART's Lockheed A-12 (the precursor to the well known SR-71 Blackbird). The first shootdown of a U-2 plane in 1960, over Soviet airspace, only urged the CIA even more for a solution to the radar threat.

Lockheed A-12 OXCART (source: wiki commons)
In 1959, Gene Poteat was assigned to the CIA's ELINT Staff Office to assist in the development of the stealth technology to make OXCART invisible to Soviet radar. However, before devising an answer to Soviet radar, they first had to know what kind of radar the Soviets used, how it performed and where it was located. At that time, there was hardly any information on Soviet radar capabilities, let alone to make an intelligence estimate on the subject. ELINT on Soviet systems was virtually non-existing, but OXCART should be invisible to radar.

Soviet P-14 VHF Radar "TALL KING"
The CIA engineers had to find ways to intercept and analyse radar signals from very large distance. The C-97 and RB-47 airborne ELINT platforms, flying near East-German and Soviet borders, provided the first information to develop precise measurement systems and radar jamming equipment. ELINT missions with this new equipment, placed on C-97, RB-47, C-130 and RC-135 platforms, supplemented with clandestine CIA missions, provided lots of valuable information. They could finally map the locations and coverage of the TALL KING radars.

They also developed the MELODY system, a so-called bistatic interception that uses objects like the Soviet's own missiles, or even the moon, to reflect radar signals over very large distance, far beyond the horizon. This enabled tracking and analysis of remote radar locations inside Russia.

A new project, codenamed PALLADIUM, measured the sensitivity of Soviet radar and the skills of Soviet radar personnel. To do so, PALLADIUM platforms received the radar signals, manipulated the signal and sent it back to the Soviets. This way, they could create any type of ghost aircraft from any size, at any speed. CIA cooperated with NSA, whose SIGINT capabilities could intercept the Soviet military reactions, or the lack of it, to these bogus radar information. These performance tests on Soviet radar provided the engineers with a basis for the required specifications for the OXCART stealth program.

At the end, it turned out that OXCART could never be stealthy enough to evade Soviet radar. Fortunately, OXCART's A-12 could outfly any surface-to-air missile with its incredible speed of 3.35 Mach (2,550 Mph or 4.103 Km/h). Only thirteen A-12's and its variants, the two M-21 drone carriers and three YF-12A, were ever build . Nevertheless, PALLADIUM made possible the development of sophisticated radar jammers and warning systems, and assisted in the research to reduce a plane's radar cross section. The OXCART planes eventually retired to be succeeded by its notorious sister plane SR-71. The F-117 stealth fighter would be, with the help of PALLADIUM intelligence, the first to remain invisible to Russian air defense.

The CIA's ELINT Staff Office continued with various other projects, related to Soviet radar. Satellite imagery disclosed a huge radar, deep inside the Soviet Union. The HEN HOUSE, as this radar was codenamed, was a high powered over-the-horizon radar, capable of following U.S. satellites and distant missiles or aircraft. The CIA installed a receiver on a Baltic Sea island to intercept and analyse that radar. The MELODY system, with its bistatic intercepts, also provide electronic intelligence, showing that the Soviets were cheating on the 1972 ABM treaty negotiations. Many more projects will probable never be disclosed.

The small group of CIA engineers were among the first who used the aether to understand and deceive the enemy's electronic systems. This secretive and highly technical black art eventually evolved into today's indispensable Information Warfare.

Gene Poteat's paper can be downloaded from this National Security Archive link on their Science, Technology and the CIA pages, or alternatively at this link (better readable). Poteat's bio is found on WIP. More about flying ELINT platforms on my ELINT at NSA and Silent Warriors posts. An example of a high power over-the-horizon radars is found on my Mysterious Cold War Signals.

Below a nice video from the prototype YF-12A variant of the A-12 OXCART (the A-12, by the way, was even faster than its successor SR-71). There are also two documentary fragments part 1 (3 min) and part 2 (15 min) about the A-12 OXCART.

1 comment:

Nis Weihrauch said...

Hello Dirk! You ought to mention, that Sweden - by means of two DC-3 ELINT aircrafts (one of them was shot down by a MiG15-fighter in 1952 - acquired a lot of information about Soviet radar, which was on a large scale passed on to NATO via Great Britain.
Vy 73, Nis W.