Area 51 is the common name of a highly classified United States Air Force  facility located within the Nevada Test and Training Range. Officially, the facility is called Homey Airport  or Groom Lake, named after the salt flat situated next to its airfield. Although details of the facility's operations are not publicly known it is a USAF open training range, and it most likely supports the development and testing of experimental aircraft and weapons systems based on historical evidence.
. The USAF acquired the site in 1955, primarily for flight testing the Lockheed U-2 aircraft.
The intense secrecy surrounding the base has made it the frequent subject of conspiracy theories and a central component to unidentified flying object  folklore. The CIA publicly acknowledged the existence of the base for the first time on 25 June 2013, following a Freedom of Information Act  request filed in 2005, and they declassified documents detailing the history and purpose of Area 51. south of Rachel.
Area 51 shares a border with the Yucca Flat region of the Nevada Test Site, the location of 739 of the 928 nuclear tests conducted by the United States Department of Energy at NTS. The Yucca Mountain nuclear waste repository is southwest of Groom Lake.
Groom Lake
Groom Lake is a salt flat in Nevada used for runways of the Nellis Bombing Range Test Site airport  on the north of the Area 51 USAF military installation. The lake at elevation is approximately from north to south and from east to west at its widest point. Located within the namesake Groom Lake Valley portion of the Tonopah Basin, the lake is south of Rachel, Nevada.
History
The origin of the name "Area 51" is unclear. It is believed to be from an Atomic Energy Commission  numbering grid, although Area 51 is not part of this system; it is adjacent to Area 15. Another explanation is that 51 was used because it was unlikely that the AEC would use the number. According to the Central Intelligence Agency, the correct names for the facility are Homey Airport  and Groom Lake, though the name Area 51 was used in a CIA document from the Vietnam War. The facility has also been referred to as Dreamland and Paradise Ranch, among other nicknames. The USAF public relations has referred to the facility as "an operating location near Groom Dry Lake". The special use airspace around the field is referred to as Restricted Area 4808 North .
Lead and silver were discovered in the southern part of the Groom Range in 1864, and the English company Groome Lead Mines Limited financed the Conception Mines in the 1870s, giving the district its name . J. B. Osborne and partners acquired the interests in Groom in 1876, and his son acquired the interests in the 1890s. and consisted of two unpaved 5,000-foot runways at .
U-2 program
The Central Intelligence Agency  established the Groom Lake test facility in April 1955 for Project AQUATONE, the development of the Lockheed U-2 strategic reconnaissance aircraft. Project director Richard M. Bissell, Jr. understood that the flight test and pilot training programs could not be conducted at Edwards Air Force Base or Lockheed's Palmdale facility, given the extreme secrecy surrounding the project. He conducted a search for a suitable testing site for the U-2 under the same extreme security as the rest of the project. He notified Lockheed, who sent an inspection team out to Groom Lake. According to Lockheed's U-2 designer Kelly Johnson: The CIA asked the AEC to acquire the land, designated "Area 51" on the map, and to add it to the Nevada Test Site.
Johnson named the area "Paradise Ranch" to encourage workers to move to "the new facility in the middle of nowhere", as the CIA later described it, and the name became shortened to "the Ranch". On 4 May 1955, a survey team arrived at Groom Lake and laid out a north-south runway on the southwest corner of the lakebed and designated a site for a base support facility. The Ranch initially consisted of little more than a few shelters, workshops, and trailer homes in which to house its small team. This included testing at Groom Lake, which had inadequate facilities consisting of buildings for only 150 people, a asphalt runway, and limited fuel, hangar, and shop space.
Reynolds Electrical and Engineering Company  began construction of "Project 51" on 1 October 1960 with double-shift construction schedules. The contractor upgraded base facilities and built a new runway  diagonally across the southwest corner of the lakebed. They marked an Archimedean spiral on the dry lake approximately two miles across so that an A-12 pilot approaching the end of the overrun could abort instead of plunging into the sagebrush. Area 51 pilots called it "The Hook". For crosswind landings, they marked two unpaved airstrips  on the dry lakebed.
By August 1961, construction was completed of the essential facilities; three surplus Navy hangars were erected on the base's north side—hangars, while hangar 7 was new construction. The original U-2 hangars were converted to maintenance and machine shops. Facilities in the main cantonment area included workshops and buildings for storage and administration, a commissary, control tower, fire station, and housing. The Navy also contributed more than 130 surplus Babbitt duplex housing units for long-term occupancy facilities. Older buildings were repaired, and additional facilities were constructed as necessary. A reservoir pond surrounded by trees served as a recreational area one mile north of the base. Other recreational facilities included a gymnasium, a movie theater, and a baseball diamond. It made its first flight 26 April 1962 when the base had over 1,000 personnel. Initially, all who were not connected with a test were herded into the mess hall before each takeoff. This was soon dropped, as it disrupted activities and was impractical with the large number of flights.
D-21 Tagboard
Following the loss of Gary Powers' U-2 over the Soviet Union, there were several discussions about using the A-12 OXCART as an unpiloted drone aircraft. Although Kelly Johnson had come to support the idea of drone reconnaissance, he opposed the development of an A-12 drone, contending that the aircraft was too large and complex for such a conversion. However, the Air Force agreed to fund the study of a high-speed, high-altitude drone aircraft in October 1962. The Air Force interest seems to have moved the CIA to take action, the project designated "Q-12". By October 1963, the drone's design had been finalized. At the same time, the Q-12 underwent a name change. To separate it from the other A-12-based projects, it was renamed the "D-21". . "Tagboard" was the project's code name.
This was not a new mission, as testing of foreign technology by the USAF began during World War II. After the war, testing of acquired foreign technology was performed by the Air Technical Intelligence Center, under the direct command of the Air Materiel Control Department. In 1961 ATIC became the Foreign Technology Division, and was reassigned to Air Force Systems Command. ATIC personnel were sent anywhere where foreign aircraft could be found.
The focus of Air Force Systems Command limited the use of the fighter as a tool with which to train the front line tactical fighter pilots.
In 1978, the Air Force awarded a full-scale development contract for the F-117 to Lockheed Corporation's Advanced Development Projects. On 17 January 1981 the Lockheed test team at Area 51 accepted delivery of the first full Scale Development  prototype 79–780, designated YF-117A. At 6:05 am on 18 June 1981 Lockheed Skunk Works test pilot Hal Farley lifted the nose of YF-117A 79–780 off the runway of Area 51.
Meanwhile, Tactical Air Command  decided to set up a group-level organization to guide the F-117A to an initial operating capability. That organization became the 4450th Tactical Group, which officially activated on 15 October 1979 at Nellis AFB, Nevada, although the group was physically located at Area 51. The 4450th TG also operated the A-7D Corsair II as a surrogate trainer for the F-117A, and these operations continued until 15 October 1982 under the guise of an avionics test mission.
Tonopah Test Range Airport was selected for operations of the first USAF F-117 unit, the 4450th Tactical Group . From October 1979, the Tonopah Airport base was reconstructed and expanded. The 6,000 ft runway was lengthened to 10,000 ft. Taxiways, a concrete apron, a large maintenance hangar, and a propane storage tank were added.
By early 1982, four more YF-117As were operating at the southern end of the base, known as the "Southend" or "Baja Groom Lake". After finding a large scorpion in their offices, the testing team  adopted it as their mascot and dubbed themselves the "Baja Scorpions". Testing of a series of ultra-secret prototypes continued at Area 51 until mid-1981, when testing transitioned to the initial production of F-117 stealth fighters. The F-117s were moved to and from Area 51 by C-5 during darkness to maintain security. The aircraft were defueled, disassembled, cradled, and then loaded aboard the C-5 at night, flown to Lockheed, and unloaded at night before reassembly and flight testing. Groom performed radar profiling, F-117 weapons testing, and training of the first group of frontline USAF F-117 pilots.
While the "Baja Scorpions" were working on the F-117, there was also another group at work in secrecy, known as "the Whalers" working on Tacit Blue. A fly-by-wire technology demonstration aircraft with curved surfaces and composite material, to evade radar, it was a prototype, and never went into production. Nevertheless, this strange-looking aircraft was responsible for many of the stealth technology advances that were used on several other aircraft designs, and had a direct influence on the B-2; with first flight of Tacit Blue being performed on 5 February 1982, by Northrop Grumman test pilot, Richard G. Thomas.
Production FSD airframes from Lockdown