The Joint Facility at Pine Gap - the spy station at the centre of fascination and consternation in the Australia-United States alliance.

It's the top secret Australian spy base almost everyone knows exists but very few people get to see.

Now, a group of determined researchers have offered an up-close look at Pine Gap, the humming military citadel in central Australia built to suck data from the skies.

By using zoom lens digital photography and plotting the position in orbit of spy satellites, the researchers have also for the first time documented what they believe to be the function of the dozens of dishes, radar domes and antennae that bristle across base.

KRISTIAN LAEMMLE-RUFF The newest radomes at Australian's Pine Gap spy base.

The findings, released in a report by the Nautilus Institute for Security and Sustainability and led by renowned Australian defence academic Des Ball, chart the expansion of Pine Gap from its Cold War origins to monitor nuclear threats to suspected key role in deadly drone warfare of today.

The report includes a series of photographs to be shown in an upcoming exhibition in Melbourne that offer a fascinating glimpse of the spy station jointly run by Australia and the United States.

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KRISTIAN LAEMMLE-RUFF A close up of a helical array, seen at left beneath the dish.

One photo of the southern end of the base shows the most recent additions to the 19 "radomes" at Pine Gap - more than twice the number found at Pine Gap 30 years ago.

RICHARD TANTER The Torrus multi-beam antenna.

The golf ball-like outer shells keep the precise direction of the satellite dish inside hidden from prying eyes, including foreign spy satellites, so as not to give away the target of the collection efforts, as well as protecting the delicate sensors against the harsh climate.

But close examination of similar photos also led researchers to identify several other smaller systems, including a pronged antenna of about four metres known as a helical array to receive ultra high frequency signals.

In total, the researchers discovered 33 antenna systems are installed at Pine Gap at present.

Another dish, resembling a skate-board half pipe, is located in a separate fenced-off compound and was first spotted a few years ago by Richard Tanter, a University of Melbourne professor and one of the Pine Gap study researchers.

Intrigued, he climbed a tall peak in the nearby MacDonnell Ranges known as "Burt's Bluff", about 6 kilometres from the base, only to suffer a dizzying spell of vertigo.

"So I stuck my bum in a rock crevice, calmed down, balanced a camera on my knee and got that photo," Professor Tanter said.

The dish was identified as a "Torus multi-beam antenna" able to receive up to 1000 channels simultaneously, but its purpose remained a mystery until a document leaked by former NSA contractor Edward Snowden hinted it was central to a massive expansion of the functions of the base for intercepting global communications.

Construction began at Pine Gap in 1967 during the Cold War nuclear standoff with the Soviet Union at a site chosen for the angle of the horizon, allowing access to satellites that could spy on every continent except the Americas and Antarctica.

The base was thought a potential target for Soviet nuclear attack - raising fears over the population at Alice Springs, around 18 kilometres away.

There was also controversy over the compromise to Australia's sovereignty, with restriction allowing only American personnel into sections of the base until changes negotiated in the 1980s by then Defence Minister Kim Beazley allowed full access.

The Defence White Paper, released last week, said the "joint facility" at Pine Gap makes a "critical contribution" to the security of Australia and the United States, including on intelligence priorities such as terrorism and weapons of mass destruction.

But Pine Gap is also believed to play a key role in gathering target data for US drone strikes and its full function remains an official secret.

The largest of the new radomes was constructed in 2013, and the researchers believed it to be linked to recently launched satellites from the "Space Based Infrared System", described by defence industry giant Lockheed Martin as one of the "highest priority space programs" for the US.

The infrared system, which includes components orbiting high above Earth, is said to alert the US president and other key commanders should any country launch a missile as well as collect intelligence.

The researchers also used images from commercial satellites taken over more than a decade as well as historical photographs to record the evolution of construction at Pine, concluding 46 separate systems have been installed, with several dismantled as they became obsolete.

The base is dominated by large radomes the researchers judge control of a series of what are known as Advanced Orion spy satellites about 36,000 kilometres above Earth.

An Orion satellite launched in 2010 a few months after Australia and the United States signed a new agreement on space security.

The researchers said electronic signals collected at Pine Gap from the three Orion satellites include missile telemetry, radar and other military emissions, radio communications, microwave transmissions, satellite and mobile phone transmissions.