Initially HAARP was jointly funded by the U.S. Air Force, the U.S. Navy, the University of Alaska Fairbanks, and the Defense Advanced Research Projects Agency (DARPA).

Effects of the transmission and any recovery period can be examined using associated instrumentation, including VHF and UHF radars, HF receivers, and optical cameras.

This may lead, among other things, to improved methods for submarine communication or an ability to remotely sense and map the mineral content of the terrestrial subsurface, and perhaps underground complexes, of regions or countries.

The current facility lacks range to be used in regions like the oil-rich Middle East, according to one of the researchers involved, but the technology could be put on a mobile platform.

The project's specifications were developed by the universities, who continued to play a major role in the design of future research efforts.

According to HAARP's original management, the project strove for openness, and all activities were logged and publicly available, a practice which continues under the University of Alaska Fairbanks.

The profile of the ionosphere is highly variable, changing constantly on timescales of minutes, hours, days, seasons, and years.

During active ionospheric research, the signal generated by the transmitter system is delivered to the antenna array and transmitted in an upward direction.

At an altitude between 70 and 350 km (43 and 217 mi) (depending on operating frequency), the signal is partially absorbed in a small volume several tens of kilometers in diameter and a few meters thick over the IRI.

[33][34] Each part of the two section crossed dipoles is individually fed from a specially designed, custom-built transmitter that operates at very low distortion levels.

The HAARP site was constructed in three distinct phases:[36] In the United States, there have been two related ionospheric heating facilities: the HIPAS, near Fairbanks, Alaska, which was dismantled in 2009, and one at the Arecibo Observatory[38] in Puerto Rico, which collapsed in 2020.

The European Incoherent Scatter Scientific Association (EISCAT) operates an ionospheric heating facility capable of transmitting over 1 GW effective radiated power (ERP), near Tromsø, Norway.

[39] The Sura Ionospheric Heating Facility, in Vasilsursk, Russia, near Nizhniy Novgorod, is capable of transmitting 190 MW ERP.

[40] Michel Chossudovsky stated in a book published by the Committee on Monetary and Economic Reform that "recent scientific evidence suggests that HAARP is fully operational and has the capability of triggering floods, hurricanes, droughts and earthquakes.

[8][42][43] Allegations include the following: In 1995, Elisabeth Rehn, Finnish Member of the European Parliament, tabled a motion for a resolution on the potential use of military-related resources for environmental strategies.

Magda Aelvoet, Belgian MEP and President of the Green Group, becomes convinced that HAARP is a secret weapon system.

[49][50] In 1998, the two MEPs, convinced by Begich's theory that HAARP poses a threat to the environment, decided to write a report in which they interviewed only two people — Begich and Rosalie Bertell, head of a Canadian association which also supports the conspiracy theory of chemtrails — the invited representatives of the United States and NATO did not respond.

[50] It is on the basis of these two testimonies alone, in which Begich is described as a doctor without having any qualification, that a report by the European Parliament's Committee on Foreign Affairs, Security and Defense Policy relating to the environment, security and foreign policy takes up these assertions and adopts a resolution indicating that "HAARP (High Frequency Active Auroral Research Project) by virtue of its far-reaching impact on the environment to be a global concern and (the European Parliament) calls for its legal, ecological and ethical implications to be examined by an international independent body before any further research and testing.

"[51] Two Georgia men arrested on drug charges in November 2016 were reportedly plotting domestic terrorism based on conspiracy theories about HAARP.

According to police, the men wanted to destroy HAARP because they believed the facility manipulates the weather, controls minds and even traps the souls of people.

"[52][53] Stanford University professor Umran Inan told Popular Science that weather-control conspiracy theories were "completely uninformed," explaining that "there's absolutely nothing we can do to disturb the Earth's [weather] systems.

"[42] In 2016, in response to these claims, the University of Alaska Fairbanks Geophysical Institute, which manages the facility, announced that HAARP will host an annual open house in August, allowing visitors to tour the complex.

[55][needs update] This project resurfaced again during the 2022 United Nations Climate Change Conference, known as "COP 27", sparking conspiracies as well as many fantasies, and speaking also about geo-engineering.

[60] Following the widespread visibility of the aurora borealis over much of the Northern Hemisphere in May and again in October 2024, conspiracy theorists promoted HAARP as the true cause of the event.

[61] HAARP gave rise to a live album by the rock band Muse and became the theme of novels like La Route de Gakona by Jean-Paul Jody [Wikidata].