D-21 Drone - 'Tagboard' / 'Senior Bowl'

D-21 in storage

The existence of the D-21 was unknown outside those closely involved with its operation until 1977, when seventeen D-21s suddenly appeared at Davis Monthan AFB for long-term storage. The 'mini-blackbird' configuration of the D-21 immediately started aviation enthusiasts speculating on their operational use and gradually the full story emerged.

The loss of Gary Powers in his U-2 over central Russia on 1 May 60 sent shock waves through the administration of President Eisenhower and he quickly decided to ban all further manned overflights of Russia and China. This decision posed something of a dilemma for Lockheed when they first flew the A-12 on 26 Apr 62, as the CIA planned to use the aircraft as a 'follow-on' aircraft for the U-2 on the USSR overflight programme. Planned from the outset as an 'overflight' rather than a 'stand-off' reconnaissance aircraft, the A-12 possessed blistering performance and was capable of sustaining Mach 3 at 90,000ft, easily beyond the capabilities of the SA-2 Guideline missile. However, the ban on manned overflights of Russia and China was unequivocal, effectively curtailing at a stroke the reason for the planes existence.

M-21/D-21 taxi

Kelly Johnson, who headed the 'Skunk Works' team responsible for the design of the A-12, had already considered the possibility of mounting an unmanned drone on the A-12, then on 10 Oct 62 the CIA finally authorised him to study just such a system. It was quickly decided that a highly modified version of the Marquardt RJ43-MA-11 ramjet engine, previously used to power the Boeing Bomarc IM-99B missile, could achieve the performance envisaged for the drone - then known as the Q-12. The basic design of the chine delta had already proved itself on the A-12, so this layout was quickly adopted for the drone. Marquardt successfully redesigned the RJ43-MA-11 ramjet engine, finally producing virtually a new engine, designated the XRJ43-MA20S-4, which proved capable of sustained performance for 1.5 hours - a previously unheard of level of performance for a ramjet. By Nov 62, although the actual specification required by the CIA had never been clearly determined, Kelly Johnson had figured out they were looking for a drone with a range of 3,000 miles and a payload of 425lbs including a camera capable of providing 6-inch resolution of targets from the operating altitude. Weighing only 17,000lbs and built of titanium and composite materials, the D-21 would have the lowest Radar Cross section (RCS) of any vehicle constructed at the Skunk Works. The D-21 was designed from the start as a 'one-way' system - after following a pre-planned route to the target and taking the photos, the drone would return to a pre-determined position over the sea, shut the ramjet down and eject its hatch, containing the exposed film, before self-destructing. The hatch would then be snatched from the air by a JC-130 as it descended on its parachute - that was the theory anyway. Only 38 D-21's were built and of those only 21 actually flew - 17 off the B-52H, including the 4 operational missions over China.

M-21/D-21 in flight

On 20 Mar 63, the CIA finally gave Lockheed a contract to build the Q-12 and attention then turned towards the A-12 aircraft that would carry and launch the drone. Whilst still in their design stage, two A-12s (60-6940 '134' and 60-6941 '135') were modified to carry the Q-21 and would be known as M-21s, to avoid confusion with standard A-12s. The two aircraft carried the drone on a top-mounted dorsal pylon located on the rear centreline between the engines and the vertical stabilisers. In addition, the 'Q' bay that normally carried the camera payload, was modified into a second cockpit for the D-21 launch control officer. The designation of the drone was also changed and it was changed from the Q-12 to the D (for daughter) 21 (adopting the numerals of the M-21 'mothership'). However, by Oct 63 Kelly Johnson was already beginning to have concerns about the difficulties that would be encountered in launching the D-21 from the M-21, involving as it did a 0.9g pushover manoeuvre at Mach 3, - considering what eventually happened, he was right to voice his concerns.

M-21/D-21

After the first M-21 / D-21 combination was fitted together successfully on 19 Jun 64 in the Skunk Works, the items were delivered separately to Groom Lake and on 22 Dec 64 Bill Park took the combination airborne for the first time. However, because of problems with some D-21 components, particularly the Minneapolis-Honeywell Kollsman star tracker guidance system, no launches were possible. Finally, on 5 Mar 66, Bill Park and Keith Beswick successfully launched a D-21 from an M-21 and, although the D-21 was lost 120 miles from the launch point over the Pacific, the basic concept had proved successful. However, Kelly Johnson continued to voice his concerns stating "This was the most dangerous manoeuvre we have ever been involved in, in any aeroplane I have ever worked on". Kelly's concerns were hardly surprising when you consider the D-21 launch sequence. After a final top up from a tanker, the A-12 would separate and start to climb and accelerate, all the time circulating the D-21's fuel back through the M-21's fuel system to ensure it was cooled, as the D-21s skin temperature rose to 600F. The D-21's ramjet was fired up once the M-21 was above 60,000ft, usually five minutes before launch, and once wound up to full power gave the M-21/D-21 combination an additional 1000lbs of thrust, quickly pushing the speed up to Mach 3.5. Then provided the LSO was happy with the indications he was receiving from the D-21, it was time for the pilot to 'bunt' the combination down and part company with the D-21, or shut the ramjet down, to prevent the M-21 from exceeding the maximum design speed for the aircraft.

D-21 mounted on an M-12

The second launch went even better with the D-21 flying 1,200 nm, reaching 90,000ft and Mach 3.3 before a hydraulic pump overheated and failed. On 16 Jun 66 the third test launch proved the most successful. The D-21 flew 1,600nm making 8 programmed turns to remain within sight of a tracking ship, but failed to eject the camera package towards the end of the flight. Still Johnson had his concerns about the safety of launching from the M-21 and proposed substituting the B-52H as a launch platform, with the D-21 propelled to its optimum height and speed by a solid rocket booster stage. Then, on 30 Jul 66, disaster struck on the fourth launch in which it was planned that M-21 '135' would launch D-21 '504'. Shortly after launch at Mach 3.3 the D-21 suffered an 'unstart' of its ramjet, rolled to the right and collided with the right wing of the M-21. This caused the M-21 to pitch-up sharply, breaking off the nose section. The two crewmembers, pilot Bill Park and LSO Ray Torick ejected successfully, but although Bill Park survived, Ray Torick suffered injuries in the high-speed ejection and drowned in the Pacific. All this was captured on film by M-21 '134' flying chase at Mach 3.3. Johnson had, as was so often the case, been proved right and insisted that the programme be abandoned - from that point on the D-21 would only be launched from a B-52H.

B-52H with two D-21Bs

With the demise of the M-21 'mothership, the name of the D-21 launch programme was changed from 'Tagboard' to 'Senior Bowl', although the D-21 was generally referred to as the 'Tag' and the remaining D-21's were modified for their new task and re-designated D-21Bs. Two B-52H aircraft (61-0021 and 60-0036) underwent extensive modifications to carry and launch the D-21B from pylons under each wing - the pylons were similar to that used for launching the X-15 from the NASA NB-52B. Further modifications included the installation of two launch panels and a variety of high-speed cameras to record the launch. All operational launches took place from the starboard pylon, the port D-21B was carried as a spare in case of a last minute malfunction. The launch sequence called for the B-52H to fly to a pre-determined launch point before dropping the D-21B from the starboard pylon. Once clear of the aircraft, the Lockheed designed 60' solid rocket would ignite, then as the combination passed through Mach 1.5, the D-21B's ramjet would ignite. After a burn of around 90 seconds the combination would reach Mach 3 and 75,000ft - at this point explosive bolts would fire to separate the D-21B which then flew off alone on its programmed sortie. A special USAF unit, the 4200th Support Squadron was formed to operate the B-52H / D-21B combination and after training at Groom Lake took up permanent residence at Beal AFB in late 1969.

B-21H with D-21Bs

The B-52H / D-21B combination was used for 4 operational sorties over China to investigate their nuclear test area at Lop Nor, some 2,000 miles inland of the China-Mongolia border. The first D-21 launched on 9 Nov 69 managed to photograph the site, but then due to a guidance malfunction, failed to execute its turn-back to the recovery area and flew straight on, eventually crashing in the former USSR. Many years later, after the end of the Cold War, Ben Rich of Lockheed visited the Russian Federation and was presented with the remains of the D-21 by the KGB. On 16 Dec 70 another D-21 reached Lop Nor, and returned to the recovery area, but after a flight of 2648mns, the hatch damaged the parachute and the camera package disappeared into the sea. On 4 Mar 71 another D-21 performed perfectly, managing to overfly Lop Nor, before returning to the recovery area after a flight of 2935nms. Once again the parachute was damaged by the hatch and dropped gently into the sea where it floated. Then, as a Navy ship tried to recover the hatch, it managed to run over it and damage it sufficiently for it to sink. Two weeks later on 20 Mar 71 another D-21 was tracked for 1,900 miles into China before it suffered some kind of malfunction and disappeared - the remains are probably still out there somewhere in the middle of the vast expanse of the Gobi desert, just waiting to be discovered. There is no evidence that the Chinese ever tracked any D-21 whilst they were hurtling over their territory.

Satellite photo of Lop Nor

Late in 1971, as President Nixon decided it was time to improve relations with China, the Defence Department ordered Kelly Johnson that not only was the D-21 programme cancelled, but all the tooling was to be destroyed. Kelly Johnson was furious at the premature cancellation of the programme and believed that allowing the USAF to hold onto the drones for nine months at Beal, where they were probably taken apart and re-assembled numerous times, probably contributed to their poor operational record. Johnson firmly believed that had the Skunk Works been responsible for maintaining the drones, they would have performed as planned. In terms of its performance in the 4 operational sorties over China, the D-21 performed well, and the inability of the supporting units to recover the exposed film can hardly be blamed on the drone, assuming the hatches was ejected in the correct location. Like every Lockheed 'black' project, the D-21 was at the cutting edge of known technology and given time and the correct support, would probably have performed as advertised. But by the early 1970's reconnaissance satellites were already providing high quality close-up photographs of China and in reality had soon completed performed the mission that sadly eluded the D-21. As a postscript to the programme, in 1986 as the Soviet Union was beginning to implode, a CIA operative showed to Ben Rich, who was by then leading the Skunk Works, a present that had been sent to him by a Soviet KGB agent. The gift was identified as a panel from the engine mount of the first D-21 mission that vanished into China in Sep 1969. The wreckage had been found by a shepherd in Siberia and was eventually acquired by the KGB, after no doubt being carefully examined by various Soviet engineers.

Despite the fact that this highly advanced drone never actually completed the mission it was desigbed for, the D-21s that survive in museums stand witness to the genius of Kelly Johnson and his 'Skunk Works' team and are the direct predecessors of todays strategic reconnaissance UAVs, such as the Global Hawk.