Saturday, May 14, 2011

OXCART and ELINT Research

The National Security Archive published a paper from Gene Poteat about electronic intelligence on Soviet air defence 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.

To Spy and Deny

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 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 serial 60-6932 (source: DVIC)

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.

Know Your Enemy and His Radar

Soviet P-14 VHF Radar "TALL KING"
source: wiki commons
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.

In the end, it turned out that OXCART could never be stealthy enough to evade Soviet radar. Fortunately, the A-12 OXCART could outfly any surface-to-air missile with its incredible speed of 3.35 Mach (2,550 mph, 4.103 km/h) and was even faster than its successor SR-71.

Building a Fast Family
Only eighteen A-12's and variants were ever build:
  • Thirteen A-12 reconnaissance aircraft for the CIA with a first flight in 1962. The program was terminated in 1968.
  • Three prototype KEDLOCK YF-12A interceptors for the USAF (see video below) had their maiden flight in 1963 and continued to fly for many years, but a planned USAF order under de name F-12B was cancelled due to high costs.
  • Two TAGBOARD M-21 drone carriers with D-21 ramjet reconnaissance drone had their first flight in 1964. USAF took over the M-21 project, which was cancelled in 1966 after a fatal collision between the D-21 drone and its M-21 airplane.
The US Air Force SR-71 Blackbird strategic reconnaissance aircraft was developed from the A-12 and had its maiden flight in 1964. Thirty SR-71 were build. The SR-71 retired from USAF in 1998 and the last two SR-71's retired in 1999 from NASA. CIA published an excellent timeline of the OXCART planes.

Lockheed M-21 TAGBOARD with D-21 drone (source: CIA)

An interesting sidenote. 92% of the A-12 and SR-71 is titanium (Ti) but the U.S. had not enough titanium to produce these airplanes. The Soviet Union was the main supplier of rutile ore, containing the required titanium dioxide (TiO2). They of course would never sell their titanium to produce U.S. spy planes, so the CIA ran an operation with front companies, pretending to be third world companies, to buy the Soviet titanium under a false flag. Below are videos about the production and machining of titanium for the A-12 and SR-71.

Although not achieving a small enough radar cross section on the A-12's for full stealth, 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.

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 probably 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.

Going Full Stealth

Already in 1964, Soviet mathematician Pyotr Ufimtsev showed that the radar cross section of an airplane could be reduced by specific configuration of its edges, but such design would make the aircraft aerodynamically unstable and impossible to fly. However, by the 1970s, flight computers had become advanced enough to keep such weird shaped aircraft stable and DARPA initiated a research program.

Lockheed requested to participate in the program. In 1977, Skunk Works' Have Blue project finally succeeded to build two prototype Have Blue stealth fighters, invisible to radar. The Lockheed YF-117A stealth fighter made its maiden flight on 18 June 1981 and became the first aircraft to remain invisible to Russian air defence. The production of the Lockheed F-117 Nighthawk stealth aircraft started in 1982.

Lockheed F-117 Nighthawk (source: SSgt Aaron Allmon)

The IWP has an interesting alumnus interview with Gene Poteat about his CIA career and work, and Poteat's bio.

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).

Archangel: CIA's Supersonic A-12 Reconnaissance Aircraft is available at CIA's Center for the Study of Intelligence. They also have a page explaining the difference between CIA's A-12 OXCART and the US Air Force SR-71 Blackbird.

Flying spy missions with the A-12 or SR-71 was not a walk in the park and had its risks. The A-12 serial 60-6932 from the photo at the top was lost at sea, killing CIA pilot Jack Weeks. SR-71 pilots are a special breed, as you can read in SR-71 – Not Average Plane for Not Average Brian Shul. Below also a video of an SR-71 that lost one engine.

In 2013, Lockheed Martin revealed plans for a successor of the SR-71. Their CEO announced in 2016 the development of the SR-72, an unmanned hypersonic drone, capable of reaching Mach 6. No further news about the project has been released since.

More about flying ELINT missions on my Silent Warriors and ELINT at NSA posts. See also DARPA's advanced research projects. An example of a high-power over-the-horizon radars is found on Mysterious Cold War Signals.

There are two excellent documentaries. Blackbird Stealth is about the SR-71 missions. Blackbird SR-71 explains its origins and development by Skunk Works. See also Kelly Johnson and Lockheed Story.

Below also the presentation of the prototype KEDLOCK YF-12A interceptor. Next, two excellent videos about the ingeneering of the A-12 and SR-71, and the titanium they were made of. Finally, the story of an SR-71 saved by the Swedish Air Force


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.

como en los dias de noe said...

Helloo mate great blog