Government's Archive of Satellite Imagery along with the remaining Skylab photographs. 2019 shooting incident On January 28, 2019, an unidentified man drove through a security checkpoint near Mercury, Nevada, in an apparent attempt to enter the base. After an vehicle pursuit by base security, the man exited his vehicle carrying a "cylindrical object" and was shot dead by NNSS security officers and sheriff's deputies after refusing to obey requests to halt. There were no other injuries reported. UFO and other conspiracy theories Area 51 has become a focus of modern conspiracy theories due to its secretive nature and connection to classified aircraft research. Theories include: The storage, examination, and reverse engineering of crashed alien spacecraft, including material supposedly recovered at Roswell, the study of their occupants, and the manufacture of aircraft based on alien technology Meetings or joint undertakings with extraterrestrials The development of exotic energy weapons for the Strategic Defense Initiative (SDI) or other weapons programs The development of weather control The development of time travel and teleportation technology The development of exotic propulsion systems related to the Aurora Program Activities related to a shadowy one-world government or the Majestic 12 organization Many of the hypotheses concern underground facilities at Groom or at Papoose Lake (also known as "S-4 location"), south, and include claims of a transcontinental underground railroad system, a disappearing airstrip nicknamed the "Cheshire Airstrip", after Lewis Carroll's Cheshire cat, which briefly appears when water is sprayed onto its camouflaged asphalt, and engineering based on alien technology. In the mid-1950s, civilian aircraft flew under 20,000 feet while military aircraft flew up to 40,000 feet. The U-2 began flying above 60,000 feet and there was an increasing number of UFO sighting reports. Sightings occurred most often during early evening hours, when airline pilots flying west saw the U-2's silver wings reflect the setting sun, giving the aircraft a "fiery" appearance. Many sighting reports came to the Air Force's Project Blue Book, which investigated UFO sightings, through air-traffic controllers and letters to the government. The project checked U-2 and later OXCART flight records to eliminate the majority of UFO reports that it received during the late 1950s and 1960s, although it could not reveal to the letter writers the truth behind what they saw. Similarly, veterans of experimental projects such as OXCART at Area 51 agree that their work inadvertently prompted many of the UFO sightings and other rumors: