Operation Hat | By Dr. Mahipal Singh Rathore | Free PDF Download

What was Operation HAT?

A covert operation by USA’s Central Intelligence Agency (CIA)and India’s Intelligence Bureau (IB)  to place a  nuclear-powered telemetry relay listening device on the summit of Nanda Devi in Uttrakhand’s Garhwal Himalayas, to keep track of further nuclear activities conducted by China.


Nanda Devi is the second highest mountain in India, and the highest located entirely within the country. Elevation – 7816 m / 25,643 ft “Bliss-Giving Goddess“ –  regarded as the patron-goddess of the Uttarakhand Himalaya **Kangchenjunga, which is higher, is on the border of India and Nepal.


Why a device on top of a mountain?

• China’s nuclear program was hard to monitor

• No precision satellite imagery

• Remote location of Xinjiang

• Ground based sensors not usable due to mountains

• Nanda devi was securely located INSIDE India

How was the operation carried out ?

• The device which was provided by US consisted of an equipment weighing around 56kg, 8 to 10ft antenna, two transceivers sets and most vital component, a SNAP (System for Nuclear Auxiliary Power) generator.

• The generator’s nuclear fuel consisted of seven Plutonium capsule, which came in special container.


• Carrying these equipments to such high altitude was not a easy job. Moreover, dealing with radioactive element like plutonium was risky.

• US agency recruited top US civilian climbers, together with four of India’s best climbers from 1962 Everest expedition.

• On 18th October 1965, a team lead by Manmohan Singh Kohli, reached Camp IV, at over 24,000 ft.

• A terrible blizzard and severe cold conditions forced Team leader Manmohan Singh Kohli to choose between men and machine: He chose to save the lives of his men.

• The nuclear generator was nicknamed as Guru Rinpoche (a Buddhist god) by the climbing sherpas.

• The generator was radiating heat and was uncontrollable, so they were unable to take the generator with them. They secured it near Camp IV and they returned to safety.

• When they returned in May 1966, all the equipment along with plutonium capsules was missing.

• The plutonium capsules have a longevity of over hundred years. Those capsules could be buried under snow.

• The southern slopes where the SNAP lay buried is a major source of headwater of Ganges.

• There were real chances of contaminating river water with plutonium. Search operation for the equipment continued for next two years, but with no success.

  • In 1967, the Americans with the help of Manmohan Singh Kohli and other Indian climbers successfully installed a second nuclear powered listening device on the peaks of Nanda Kot(elevation 22510 ft), near Nanda Devi
  • It worked for the greater part of the year before developing a snag.


  • In 1968, when a team went to retrieve the second equipment in Nanda Kot, they were shocked to see no sign of entire equipment. They dug the place were it was installed. The hot generator made the ice to melt up to 8ft in all directions, placing itself at the centre of a spherical cave. This defective equipment was carried away in a helicopter by the Americans
  • It was after a decade, in 1977 when this mission was published in Outside magazine
  • The Indian Prime Minister admitted to this mission at the time.
  • The fear was of large-scale plutonium contamination of the Rishi Ganga, the river that drains the Nanda Devi glaciers into the Ganga.
  • Water sources and rocks were tested for hints of radiation
  • The mountain and the surrounding Nanda Devi Sanctuary were closed to expeditions

Indian History | Free PDF

By Dr. Mahipal Singh Rathore

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