The (very) secret history of Area 51 Just how covert is the infamous US air base? New files show that even Presidents don't always 'need to know' its activities

No one on the ground or in Pakistan's air defence spotted Area 51's latest toy as it kept watch on Osama bin Laden's compound in Abbottabad, Pakistan, on the night of the US raid that killed the Taliban leader.

Rather than one of the UFOs that the wilder fringes of the internet believe the military has stashed away at America's top-secret military site in Nevada, this "toy" was actually the latest Star Wars-type drone, or unmanned aerial vehicle (UAV), developed at the base whose existence Uncle Sam only barely admits.

Named the "Beast of Kandahar" after it was snapped at Kandahar air base in Afghanistan back in 2009, this stealthy grey batwing-shaped long-distance reconnaissance drone, officially known as the RQ-170 Sentinel, was a throwback to Area 51's golden age before the advent of the spy satellite put the spy plane out of business.

While for the post-X-Files generation Area 51 will always be associated with conspiracy theories from aliens to time machines, for journalists such as Annie Jacobsen its purpose was – and, indeed, is – to develop and test the latest kit from the military industrial complex that helps to maintain America's superpower status.

"Area 51 was the single most important Cold War facility as it was set up to push science faster and further than the Soviet Union," says Jacobsen, author of Area 51: An Uncensored History. "On one side of the road the Nevada test site was preparing for the Third World War, and on the Area 51 side they were trying to prevent it by developing air-surveillance technology.

"Today, it is doing the same job competing with whoever America sees as its enemy, whether North Korea, Iran or China."

Yet for Jacobsen one of the strangest things about Area 51 is that even in the age of WikiLeaks and Google Earth, she has "not seen anything ever leak out of Area 51", almost as if "the base is in a permanent state of lockdown".

Sitting on the edge of a dried-up lake bed cradled by mountains, only 90 miles or so from the fantasy world of downtown Las Vegas, it is perhaps not surprising that it is hard to separate the myth from the fact of Area 51, or Groom Lake, as old-timers have traditionally called it. Even "Area 51" sounds like an exercise in branding, as do its other names of Dreamland, Paradise Ranch or Homey Airport. And there is something sinisterly not-quite-real about the "use of deadly force authorised" signs that stand guard on the base's perimeter. Which can be found just inside the 4,687 square miles of the Nevada Test and Training Range and right next to the 1,350 square miles of the Nevada Test Site, where hundreds of nuclear weapons were exploded above and below ground until the test ban treaties of 1963 and 1996.

However, recent declassified documents have helped to shed light on the facts behind the myths of Area 51, from the U-2 spy plane missions that helped to unlock the secrets of the Soviet Union in the 1950s to the groundbreaking stealthy A12 that was obsolete before it even first served its country, and the record-breakingly fast recon plane the SR-71 Blackbird, which helped to spot North Vietnamese missile bases in the late 1960s and 1970s; and from the beginnings of stealth technology to the development of the F-117 stealth fighter itself, which was one of the few allied aircraft able to penetrate the air defences around downtown Baghdad and then bomb accurately. Also brought to light was the test flying of "acquired" Soviet MIG fighters in mock combat situations, which led to the founding of the Top Gun pilot programme made famous by the 1980s film of the same name.