The unofficial first flight of the D-21B (Article 501) occurred when one of the drones was accidentally dropped due to a mechanical failure.
November 1967 The first actual launch of a D-21B was completed successfully from a B-52H over the Pacific Ocean.
January 1968 Project HAVE DOUGHNUT, a joint USAF/Navy technical and tactical evaluation of the MiG- 21F-13 began at Area 51.
February 1968 First test flight of HAVE DOUGHNUT MiG-21.
March 1968 Project HAVE DOUGHNUT was completed.
January 1969 Project HAVE DRILL/HAVE FERRY evaluation of two MiG-17F airplanes began at Area 51 with delivery of first airplane.
February 1969 First MiG-17 test flight completed.
March 1969 Second MiG-17 delivered to Area 51.
April 1969 First flight of second MiG-17.
May 1969 Project HAVE DRILL/HAVE FERRY was completed.
July 1970 The CIA began testing a remotely piloted vehicle (RPV) At Area 51 under project AQUILINE. With a six-foot wingspan and pusher propeller, the television-guided RPV was designed to gather intelligence by intercepting electronic transmissions from inside denied territory.
November 1970 Project HAVE GLIB, evaluation of foreign radar and threat systems began. A complex of actual Soviet systems and replicas began to grow around "Slater Lake" (the pond, which had been named after the former Roadrunners commander), a mile northwest of the main base. The systems were given names such as Mary, Kay, Susan, and Kathy. They were arranged to simulate a Soviet-style air defense complex.
December 1970 BANEBERRY, a 10-kiloton blast was detonated at the bottom of a 910-foot-deep shaft on Yucca Flat. Shortly afterward, radioactive gases erupted from a surface fissure. The plume reached an altitude of 8,000 feet and moved northeast. The fallout cloud arrived at Groom Lake an hour later. Within 20 minutes, radiation levels had reached a peak exposure rate of 0.18mR/hr. (compared to a normal background reading of 0.02 mR/hr.). Within another hour the cloud had passed.
Mid-1971 The Microwave Radar/Repeater Annex (MRU-4) on a three-acre parcel at the summit of Bald Mountain was improved. Construction at the site was sponsored by the Air Force Flight Test Center (AFFTC) at Edwards AFB.