The rock is an eroded volcano that lies 260 miles (418km) west of the Western Isles and is only 30m (100ft) wide and 21m (70ft) high above the sea.
The Nato documents report how the UK claimed Rockall in 1955.
The government feared that it could be used by "hostile agents" as a place to monitor the Hebrides Rocket Range.
A small team of military personnel was taken to Rockall by the Royal Navy in September 1955 to claim as UK territory.
A Union Flag was raised and a plaque installed on the rock.
In the documents, it says: "This decision of the UK government was connected with the fact that the UK government had recently decided to set up a guided missile range in South Uist, in the Outer Hebrides.
"The island of Rockall was uninhabited but this government wished to guard against the possibility of hostile agents installing themselves on the island in order to observe the effects of the tests on the South Uist range."
People have stayed on Rockall, though only temporarily, in the past, including in 1997 when three campaigners from Greenpeace managed to climb on to the rock.
They lived on Rockall for 42 days and renamed it Waveland in protest at exploration of new oil and gas reserves in the surrounding seabed.
In 2014, a Scots adventurer broke the record for occupying the remote North Atlantic rock.
Adventurer Nick Hancock survived on there for 43 days, beating the previous record held by three Greenpeace campaigners who lived there for 42 days.
The time also beat the previous solo record of 40 days set by Tom McClean in 1985.
Mr Hancock celebrated achieving the solo record by popping a small bottle of champagne while also sending a tweet with a message to veteran adventurer Mr McClean, of Morar in the west Highlands.
His message was simply: "Sorry Tom."

Six suicide attackers and an Afghan security guard were killed. At least 17 civilians were injured.
A minibus was detonated but another bomb-laden car defused, police said.
The Taliban, who have launched several high-profile raids on Kabul, said they were behind the attack.
The BBC's Bilal Sarwary in Kabul says the attacked area is often packed with civilians who come to collect passports and national identity cards at the interior ministry.
Intelligence chief Gen Zaher Zaher told the BBC the clearance operation was now over.
The area affected in central Kabul is heavily barricaded - and the NDS compound, which also houses several Western embassies, is surrounded by tall, thick cement walls designed to protect it from bomb blasts.
A senior Afghan security official told the BBC that the attackers targeted the NDS unit where suicide attackers and key Taliban commanders are interrogated.
The NDS said that one suicide attacker drove a minibus which exploded outside the NDS building.
Five others, armed with semi-automatic weapons and hand grenades, then fought the security forces for 15 minutes before being killed by guards.
According to the NDS, another vehicle packed with explosives was defused shortly afterwards.
The main explosion took place around noon local time (07:30 GMT). A plume of smoke rose from the area, and gunfire and police sirens were then heard.
One eyewitness, Mohammad Zia, told Associated Press that the vehicle with the bomb inside drove up to the gates of the barricaded NDS building and then was detonated.
A number of wrecked cars could be seen.
Shop owner Qais Ahmad told Reuters: "I was inside the shop when I heard noises and a huge bang. All the windows in my shop were destroyed and injured my head."
The attack comes shortly after the return from the US of President Hamid Karzai, who was discussing the future of his country after the Nato-led troops withdraw at the end of next year with President Barack Obama.
Wednesday's attack on the embassy area of Kabul is the first since November, when a suicide bomber killed two Afghan security guards and wounded three.
Last month, NDS chief Asadullah Khalid was wounded in a Taliban suicide bombing in the Taymeni area of central Kabul.
The Taliban said the attacker had posed as a peace messenger.
Mr Khalid has been in the job since September and has a reputation for being fiercely anti-Taliban.
Militant groups continue to mount regular attacks in Afghanistan, raising questions as to how the Afghan security forces will cope after 2014.
Declassified documents reveal concerns of the UK government 60 years ago that Rockall could become a base for spying on a missile test site.
[NEXT_CONCEPT]
Suicide bombers have attacked a building belonging to Afghanistan's National Directorate of Security (NDS) in the capital, Kabul, officials have told the BBC.