not yet been successfully recovered. Checks of the navigation system and camera were yet to be made.
The test missions were flown out of Groom Lake, with the actual launches over the Pacific. The first D-21B to be flown was Article 501, the prototype.
The first attempt was made on September 28, 1967, and ended in complete failure. As the B-52 was flying toward the launch point, the D-21B fell off the pylon. The B-52H gave a sharp lurch as the drone fell free. The booster fired and was 'quite a sight from the ground.' The failure was traced to a stripped nut on the forward right attachment point on the pylon. Johnson wrote it was 'very embarrassing.'[322]
The first actual D-21B/B-52 test launch was made on November 6, 1967.
It was also a failure — Article 507 was boosted to altitude, but nosed over into a dive after flying only 134 nautical miles. A second launch on December 2 flew a total distance of 1,430 nautical miles before Article 509 was lost. The third attempt, with Article 508 on January 19, 1968, flew only 280
nautical miles. Several other attempts had to be aborted before launch due to technical problems. Johnson felt another D-21B failure would result in the program being canceled, so he organized a review panel to look at the problems.[323]
The resumptions of D-21 tests took place against a changing reconnaissance background. The A-12 had finally been allowed to deploy, and the SR-71 was soon to replace it. The Model 147 drone program was in full swing, with both the high- and low-altitude drones being flown. Finally, the Nationalist Chinese U-2 program was being ended. The latter was the most important — the 147 drones could not cover targets deep inside mainland China. With a 3,000-nautical-mile range, the D-21Bs could act as a replacement.
At the same time, new developments in reconnaissance satellite technology were nearing operation. Up to this point, the limited number of satellites available restricted coverage to the Soviet Union. A new generation of reconnaissance satellites could soon cover targets anywhere in the world. The satellites' resolution would be comparable to that of aircraft, but without the slightest political risk. Time was running out for the Tagboard.
It was not until April 30, 1968, that the next D-21B launch was made.
Article 511 suffered the same fate as the earlier missions, flying only 150 nautical miles.
The next mission, by Article 512 on June 16, was everything Johnson had hoped for. It flew 2,850 nautical miles — the design range — and also reached an altitude of 90,000 feet. During turns, the ramjet blew out, but it reignited each time. This confirmed the wind-tunnel results. At the end of the mission, the hatch was successfully recovered. Although it had carried no camera, Article 512 had demonstrated the complete mission profile.
Events, however, would show there was still much work to be done.
The next two missions ended in failure. Article 514 traveled only 80 nautical miles before it failed, followed by an even less successful flight of 78 nautical miles by Article 516. All these failures put Lockheed in a bind — the D- 21B was overrunning costs, and Lockheed had to put its own money into the program. Although Johnson still felt the project had a great deal of promise, he knew there were still very difficult technical challenges ahead.
The final flight of the year gave some optimism. On December 15, 1968, Article 515 flew 2,953 nautical miles. This mission carried a camera; when developed, the photos proved to be fair.
The mission of February 11, 1969, was the first attempt to fly a 'Captain Hook' mission profile. This involved a launch near Hawaii, a flight path taking the D-21 over Christmas Island or Midway, then back to Hawaii and the recovery zone. It simulated an operational mission. The D-21B was lost after flying 161 nautical miles. Lockheed believed the cause was water in Article 518's guidance system, but this could not be proven.
This was the final disappointment of the test program. Two fully successful flights followed — Article 519 on May 10, 1969, and Article 520 on July 10, 1969. Both missions were in excess of 2,900 nautical miles, and both hatches were recovered. The photos from the first mission were fair, while the second were considered good.
The twin successes demonstrated the D-21B's design performance, and the air force now considered it ready for operational flights. The air force and CIA proposed to President Nixon that the D-21B be used on 'hot' missions over Communist China. Kelly Johnson felt the probability was high that approval would be given. If the D-21B was successful, he felt it had a great future. In anticipation of the approval, the remaining D-21Bs were brought up to the configuration of Articles 519 and 520. Johnson also began looking at ways to recover the complete airframe. The initial recovery studies looked promising.[324]
In the early fall, Nixon gave the go-ahead.
With the approval to start operational missions, activities shifted to Beale Air Force Base. The two B-52Hs were moved to the base. It was home of the 465th Bomb Wing, so the two modified aircraft would not be noticed.
The D-21B overflight missions were code-named 'Senior Bowl.'
The first China overflight by a D-21B was made on November 9, 1969.
The B-52H, loaded with two D-21Bs, took off from Beale in the predawn hours and flew west. After twelve hours in the air, it was refueled by a tanker. The B-52H reached the launch point after fourteen hours. This was outside the Chinese early-warning radar network. Article 517 was successfully launched and headed toward China. Its target was the nuclear test site at Lop Nor. The guidance system had all the checkpoints programmed into it.
Once the target was reached, the D-21 was to repeat the maneuvers in reverse order to return to the recovery area. After the telemetry was shut off, however, Article 517 just disappeared. The Chinese never detected it, but Article 517 never reached the recovery zone.[325]
Following the loss, Johnson had the guidance system reprogrammed. This allowed the D-21B to miss a checkpoint and still be able to go on to the next. Inability to do this was the suspected cause of 517's disappearance.[326]
In the wake of the loss, it was decided to fly another test mission. This was made on February 20, 1970, with Article 521. It flew a Captain Hook mission with a total distance of 2,969 nautical miles. It reached an altitude of over 95,000 feet. It followed the programmed flight path within two or three miles. The hatch was recovered, and the photos were good. Lockheed was told to be ready for a second operational mission in March 1970. As events turned out, political considerations caused the program to be idle for nearly a year. It was not until late 1970 that a second 'hot' mission was authorized.
The launch was made on December 16, 1970. Article 523 flew the mission to Lop Nor successfully. Over the recovery zone, the hatch separated, but the parachute failed to open and it was destroyed on impact. Several more months went by before authorization was given for additional flights.
The third operational flight was launched on March 4, 1971. The flight of Article 526 was successful, but the attempt to recover the hatch ran into problems. The midair recovery was unsuccessful, and the parachute was damaged. The hatch splashed down, and a U.S. Navy destroyer headed toward the floating payload. During the recovery, the ship 'keelhauled' the hatch and it sank. Another ship spotted the floating Article 526 airframe, but was unable to get a cable around it before the D-21B sank.
The fourth, and what proved to be the last, D-21B overflight was made on March 20, 1971. Article 527 flew 1,900 miles into Chinese airspace, but was lost on the final segment of the route, over a very heavily defended area. Published accounts do not indicate if it was lost to Chinese air defenses or due to a malfunction.[327]
On July 15, 1971, Kelly Johnson received a wire canceling the D-21B
program. The remaining drones were transferred from Beale Air Force Base by a C-5A and placed in dead storage. The tooling used to build the D-21Bs was ordered destroyed. On July 23, Johnson went to Beale to hold a final farewell to mark the disbanding of the 4200th Test Wing. He concluded by saying, 'The remarkable part of the program was not that we lost a few birds due to insufficient launches to develop reliability, but rather that we were able to obtain such a high degree of performance with such low cost compared to any other system.'[328]
In all, thirty-eight D-21s had been built between 1964 and 1969 (Articles 501 to 538). Of these, twenty-one were flown — four in the M-21 launches, thirteen in B-52H test missions, and four in the overflights. Although two operational D-21Bs were able to reach the recovery zone, no photos were recovered.
Like the A-12 Oxcart, the D-21B Tagboard drones remained a Black airplane, even in retirement. Their existence was not suspected until August 1976, when the first group was placed in storage at the Davis-Monthan
