The story of the D-21 Drone and project Senior Bowl, the Most Secret Program ever developed by the famed Lockheed Skunk Works

The story of the D-21 Drone and project Senior Bowl, the Most Secret Program ever developed by the famed Lockheed Skunk Works

By Linda Sheffield Miller
Jan 16 2022
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At Beale Air Force Base , in California, you would think that the SR-71 Blackbird program would be the biggest blackest deepest secret. You would be wrong.

At Beale Air Force Base (AFB), in California, you would think that the SR-71 Blackbird program would be the biggest blackest deepest secret.

But you would be wrong.

The biggest secret was Senior Bowl.

The top secret D-21, the high-speed, high-altitude spy drone air launched from the the back of a Mach 3 A-12 aircraft
M-21 and D-21.

According to Air Force Test Center History Office documents, all manned flights over the Soviet Union were discontinued by President Dwight Eisenhower after Francis Gary Powers’ U-2 spy plane was shot down May 1, 1960. However even if the US government was planning on using satellites for reconnaissance, the technology was still a few years away and the Central Intelligence Agency (CIA) determined unmanned drones could fill the gap until satellites became viable.

For this reason in the 1960s the famed Lockheed “Skunk Works” developed the D-21 a highly-advanced, remotely piloted aircraft (RPA) designed to carry out high-speed, high-altitude strategic reconnaissance missions over hostile territory.

The D-21 required a mothership to launch given its ramjet engine, which needed to be air-launched at a certain speed to activate. Initially, Lockheed testers used an M-21 (essentially a modified SR-71 Blackbird) to air launch the D-21 drone. The D-21 would be launched from the back of the M-21. Ideally, after conducting its reconnaissance mission it would eject a hatch with photo equipment to be recovered either mid-air or after the hatch landed.

However, on the fourth flight test, the D-21 experienced an “asymmetric unstart” as it passed through the bow wake of the M-21 causing the mothership to pitch up and collide with the D-21 at Mach 3.25. Crewmembers Bill Park and Ray Torick ejected from the M-21, but Torick’s flight suit became ripped and filled with water when he plunged into the ocean where he drowned.

Tagboard Flyers: the story of the B-52 bombers that carried the D-21 Mach 3 ramjet-powered reconnaissance drones
B-52 and D-21.

After the accident and after the death of Ray Torick, a test flight engineer, the M-21 launch program was cancelled but testers still believed the D-21 would make a valuable reconnaissance vehicle and decided to launch the drone from B-52Hs under a top secret test program named Tagboard. The new code name for the D-21 project became Senior Bowl.

It was Kelly Johnson, President of Skunk Works, who suggested to use the B-52. As a result of Johnson’s advice two B-52’s were modified: 61#0021 and 60#0036. Both B-52’s are still in the US Air Force (USAF) inventory. The ultra secret 4200 test squadron was formed at Beale.

Only a few of the men that flew the SR-71 had been read into the program: out of necessity one of the few included my father Richard “Butch” Sheffield, SR-71 RSO who had already been read into Oxcart in 1965. In his unpublished book he writes that on the flightline he was with Bob Spencer, SR-71 pilot. They were taxing out when they saw the B-52 with a drone underneath it. Spencer asked ‘What is that under that B-52?’ My Dad responded ‘I have no idea.’ He couldn’t tell Bob Spencer the truth.

These two B-52‘s were kept away at the end of the runway apart from any other operations.

D-21 drone.

The D-21s were used on four flights over communist China but none of these missions fully succeeded.

Two flights were successful, however the imagery could not be recovered from the D-21’s hatch. The other two operational flights ended with one being lost in a heavily defended area and the other D-21 simply disappeared after launch.

The main mission of the D-21 was to fly over China and take pictures of its nuclear weapons test facility in the remote west central of the country near Lop Nor.

The pictures were supposed to be dropped in the ocean and recovered by the Navy. During the Cold War this information was necessary for the defense of the US.

B-52H print
This print is available in multiple sizes from – CLICK HERE TO GET YOURS. B-52H Stratofortress 2nd BW, 20th BS, LA/60-0008 “Lucky Lady IV”.

The fourth and final mission of the D-21 drone took place on Mar. 20, 1971 and was undertaken by D-21 #527. Experts at the 4200th Support Squadron and at Skunk Works concluded that #527 must have malfunctioned. It was thought to have gone down near Lop Nor. This drone is on display in China at their national aviation museum. So we know that it got close.

Senior Bowl lasted from January 1968 until Jul. 15, 1971. Interestingly, after the fall of the Soviet Union, Ben Rich (then retired president of Lockheed’s Skunk Works) finally had an opportunity to tour Russia himself. While in Moscow, the KGB presented Rich with a gift of what they thought were the remains of a stealth fighter that had crashed in their territory. As it turned out, the wreckage was actually pieces and parts of the lost D-21 Drone!

Be sure to check out Linda Sheffield Miller (Col Richard (Butch) Sheffield’s daughter, Col. Sheffield was an SR-71 Reconnaissance Systems Officer) Facebook Page Habubrats for awesome Blackbird’s photos and stories.

Photo credit: U.S. Air Force

B-52 Model
This model is available from AirModels – CLICK HERE TO GET YOURS.

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Linda Sheffield Miller

Linda Sheffield Miller

Grew up at Beale Air Force Base, California. I am a Habubrat. Graduated from North Dakota State University. Former Public School Substitute Teacher, (all subjects all grades). Member of the DAR (Daughters of the Revolutionary War). I am interested in History, especially the history of SR-71. Married, Mother of three wonderful daughters and four extremely handsome grandsons. I live near Washington, DC.
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