Summary and Key Points: The A-12 Oxcart, a high-altitude reconnaissance aircraft developed by Lockheed's Skunk Works for the CIA, preceded the renowned SR-71 Blackbird. Entering service in 1967, the A-12 flew at speeds over 2,260 mph and reached altitudes of 90,000 feet. During Operation Black Shield, it conducted 29 reconnaissance missions over Vietnam and North Korea.

-Despite its speed and radar-evading features, the A-12 was not completely invulnerable, with one plane reportedly damaged by a surface-to-air missile in 1967.

-The A-12 was eventually replaced by the SR-71, which remained unscathed despite being targeted multiple times.

Nothing Could Stop The A-12 Oxcart – Not Even Vietnamese Missiles

The Lockheed SR-71 has been widely hyped for its abilities. The high-flying, super-fast aircraft continues to be the source of legend among aviation geeks.

Developed in secret in the late 1950s, the SR-71 could cruise to more than 80,000 feet above the earth, near the edge of space, and able to reach a top speed of 2,193 mph it could outfly any missile that was launched at it. It still holds the record for a cross-country flight, traveling from Los Angeles to Washington, D.C. in just 64 minutes, 20 seconds.

But First, the A-12 Oxcart

Yet, before the SR-71, there was the A-12, a high-altitude reconnaissance aircraft built for the United States Central Intelligence Agency (CIA). Developed at Lockheed's top-secret Skunk Works under Project Oxcart, it was based on designs of aviation pioneer Clarence "Kelly" Johnson. The Lockheed design was selected over Convair's FISH and Kingfish designs, and it served as the precursor to the United States Air Force YF-12 prototype interceptor and SR-71 Blackbird.

Following numerous prototypes, several lost models, and crew deaths during testing, the A-12 finally entered service in 1967. Eighteen of the aircraft were built, of which only 13 were mass-produced A-12s, while the others were pre-production units or drone carrier variants. As part of Operation Black Shield, the A-12 flew dozens of reconnaissance sorties in the latter stages of the Vietnam War. It was well suited to the missions, as it was capable of performing sensitive intelligence-gathering flights while traveling at speeds over 2,260 miles per hour, or three times the speed of sound (Mach 3).

As the Central Intelligence Agency (CIA) explains on its website, "The only A-12 reconnaissance operation, codenamed BLACK SHIELD, took place from May 1967 to May 1968.  A detachment of six pilots and three A-12s based at Kadena Air Base in Okinawa flew 29 missions over East Asia.  The panoramic stereo camera aboard each aircraft yielded considerable high-quality imagery that within hours of landing was processed and under the eyes of photointerpreters, who extracted key intelligence information in support of US military operations during the Vietnam War.

"CIA's A-12 represents a pioneering achievement in aeronautical engineering and, to this day, holds records for speed and altitude (Mach 3.29 at 90,000 feet) for an air-breathing piloted jet aircraft."

Over the course of those missions, the aircraft flew 26 over North Vietnam and three over North Korea.

Special Fuel: Plasma Stealth

While the A-12 was faster than any aircraft that hoped to catch it, it wasn't actually invisible. Yet, efforts were created to make it a whole lot harder to see on radar. It utilized several then-state-of-the-art features to reduce the radar cross-section, and that included its shape and radar-evading structures, as well as the use of composites in its construction. It also incorporated radar-absorbing materials on the outer skin.

Then there was the fuel.

As TheDrive had reported in 2019, "a key component of the Skunk Works plan to make the A-12 harder to spot on radar involved a cesium-laced fuel additive to dramatically reduce the radar signature of the plane's massive engine exhausts and afterburner plumes by creating an ionizing cloud behind the aircraft to help conceal its entire rear aspect from radar waves."

The cesium additive enabled what has been described as " plasma stealth," which essentially involves creating a cloud of plasma, or ionized gas, around some or all of an object. In this case, it helped conceal the aircraft while it traveled at Mach 3.

One Might Have Been Hit

One point not noted by the CIA is that during the 29 missions in Asia, one may have come closer to being shot down than the intelligence agency may have liked to admit.

According to a recent report from TheAviationGeekClub, an A-12 was damaged by a surface-to-air missile (SAM) on Oct. 10, 1967, while conducting a mission over North Vietnam an A-12 with pilot Dennis Sullivan at the controls. A pair of S-75/SA-2 SAM sites launched no less than six missiles at the spy plane, which was reportedly flying with a speed of Mach 3.1 at an altitude of 84,000 feet (ca 25,600m).

"A post-flight inspection revealed a piece of metal lodged against a support structure of the right-wing fuel tank which had penetrated the right wing's underside, passing through three layers of titanium," TheAviationGeekClub explained. "It appears the piece of metal was not a fragment of the warhead but rather, debris from the missile’s body. That was of secondary importance as what mattered was that the A-12 was hit. Consequently, even an aircraft flying at an altitude of about 80,000 feet (approximately 24,000m) and with a speed of Mach 3, could not consider itself to be completely safe."

The A-12 was soon replaced by the SR-71, and not a single one of those aircraft was ever shot down – but it was fired upon by North Vietnam, North Korea, and Libya on multiple occasions.

Author Experience and Expertise: Peter Suciu

Peter Suciu is a Michigan-based writer. He has contributed to more than four dozen magazines, newspapers, and websites with over 3,200 published pieces over a twenty-year career in journalism. He regularly writes about military hardware, firearms history, cybersecurity, politics, and international affairs. Peter is also a Contributing Writer for Forbes and Clearance Jobs. You can follow him on Twitter: @PeterSuciu. You can email the author: [email protected].

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