The High Frequency Active Auroral Research Program (HAARP) project is research funded by the United States Air Force, the Navy and the University of Alaska with the official purpose of "understanding, simulating and controlling ionospheric processes that could change the operation of communications and surveillance systems."

It started in 1993 with a series of experiments over twenty years. It is similar to numerous existing ionospheric heaters around the world, and has a large number of diagnostic instruments with the aim of improving the scientific knowledge of ionospheric dynamics.

There is speculation that the HAARP project is a US weapon capable of controlling the climate by causing floods and other catastrophes. In 1999, the European Parliament issued a resolution stating that HAARP was manipulating the environment for military purposes, calling for an assessment of the project by Science and Technology Options Assessment (STOA), the European Union body responsible for studying and assessing new technologies. In 2002, the Russian Parliament presented President Vladimir Putinwith a report signed by 90 deputies from the International Relations and Defence committees, claiming that HAARP was a new "geophysical weapon" capable of manipulating the earth's lower atmosphere.

In May 2014 it was announced by the US Air Force that the project would be terminated. The project was created by US Senator Ted Stevens, when he exercised great control over the US defense budget.