The U.S. military has successfully demonstrated a new lower-cost receiver that could form part of a future over-the-horizon (OTH) radar. The testing also raises the question of whether the High Frequency Active Auroral Research Program (HAARP) research site in Alaska, which the U.S. Air Force transferred away more than a decade ago, could be repurposed for operational use in this role. A new radar of this kind would help the United States plug critical gaps in surveillance coverage over the ever-more strategic Arctic region. Canada is notably already pursuing a multi-billion-dollar OTH radar project in cooperation with Australia for this exact purpose.

The U.S. military put out a press release yesterday regarding the testing of the newly developed receiver array, which occurred between September 7 and September 11. This was the culmination of a series of “Arctic air domain awareness” experiments conducted cooperatively by U.S. and Canadian authorities over the past three years.

The final round of experimentation last month “examined whether an existing high-frequency transmitter [HAARP], paired with a newly developed, low-cost [16-element high-frequency] receiver array, could detect aircraft beyond the coverage of current long-range radar sites,” according to the release. “The effort focused on improving awareness across a region where vast distances, harsh weather and limited infrastructure present challenges for air surveillance.”

“Researchers used the University of Alaska Fairbanks’ High Frequency Active Auroral Research Program [HAARP] facility and a receiver array in Cold Bay developed by MITRE to collect data on participating aircraft over the Gulf of Alaska and Bering Sea,” the release added. “MITRE also supported the effort throughout the three-year experiment series and designed and executed the field experiment in partnership with government, scientific, and operational participants.”

The remote HAARP site was built in the 1990s as part of a joint U.S. Air Force and U.S. Navy effort. The Defense Advanced Research Projects Agency (DARPA) was also involved. The central component of the 33-acre facility is an array of 180 crossed-dipole antennas, which can transmit up to 3.6 megawatts of radio frequency energy, according to the Air Force.

The primary purpose of HAARP was to provide U.S. government and independent researchers with a state-of-the-art facility to explore ionospheric phenomena. On the U.S. military side, work was focused on improving long-range surveillance and communications capabilities, including ways to communicate with submerged submarines. Over the years, HAARP has also been the subject of several entirely unsubstantiated conspiracy theories.

In 2014, the U.S. Air Force announced that it would shutter the HAARP site and dismantle it. However, the following year, the decision was instead made to transfer it to the University of Alaska Fairbanks, which has continued to operate it as a civilian research facility.

“During an experimental air domain awareness initiative, HAARP served as a high-power illuminator, transmitting signals toward the ionosphere to support the detection of airborne targets over Alaska’s maritime approaches,” according to the captions of several pictures that accompanied the release yesterday. “The experiment evaluated bistatic over-the-horizon detection methods to explore potential improvements in long-range surveillance and air domain awareness across Alaska’s maritime approaches.”

The most common types of OTH radars are so-called ‘skywave’ or ‘backscatter’ designs. They usually consist of two large and geographically separated arrays of antennas. The ‘illuminator’ array pumps out signals that are bounced off the ionosphere, the ionized layer of Earth’s upper atmosphere, at a specific angle so that they return to the ‘receiver’ array. Objects of interest (in the air and/or on the surface depending on the specific configuration) are detected in the process. As TWZ has previously written:

“Commonly, radars are limited by line of sight due to the curvature of the Earth in relation to the altitude they are operating at. OTHRs overcome this critical limitation, but with some major drawbacks.”

…

“While they offer much lower fidelity than many of their line-of-sight counterparts in most cases, they make up for it in huge range, hundreds of miles to thousands of miles (1,500 miles is common, for instance, for powerful military sky wave/backscatter OTHR systems) and a large coverage area. The sky wave type of OTHRs achieve this by bouncing their radio waves off the ionosphere to a coverage area where they hit targets and return the same way to the receiving station. The angle at which the radio waves hit the ionosphere dictates the range, and that angle is limited to a specific envelope or the waves won’t properly bounce back toward Earth. As such, placing the radar in the right place in relation to the targeted surveillance area or areas, to begin with, is key.”

In the testing last month, Air Force E-3 Sentry Airborne Warning and Control System (AWACS) radar planes, HC-130J Combat King II rescue aircraft, and KC-135 aerial refueling tankers “served as cooperative targets, providing known positions against which researchers could compare the experimental data,” according to the official release. “The team successfully completed testing, meeting or exceeding its test execution objectives. Initial results show the system was successfully able to achieve full skywave (beyond line of sight) detections of aircraft and correlation to truth flights. Thorough data analysis is ongoing.”

The release also says that the tests “explored how existing infrastructure and emerging technology could complement current surveillance capabilities.” This raises the possibility that the HAARP site, specifically, might be utilized as part of a new OTH radar. Whether or not this is actually under consideration is still unclear, and TWZ has reached out for more information.

Regardless, OTH radars have been experiencing something of a renaissance in recent years in the United States and elsewhere globally. Separate reports just in the past day or so have highlighted what appears to be significant progress on at least one part of a long-planned OTH radar in Russia’s Kaliningrad enclave.

Outside of Alaska, the U.S. military has been working to establish a Tactical Mobile Over-the-Horizon Radar (TACMOR) site in the South Pacific archipelago nation of Palau. The originally stated goal had been to finish work on this facility in 2026, but the project has faced legal challenges.

As already mentioned, OTH radars have also been part of U.S. plans to improve surveillance coverage in the Arctic. Like the recent testing in Alaska, there has been significant cooperation with Canada in this regard over the years, including through the U.S.-Canadian North American Aerospace Defense Command (NORAD).

Today, NORAD relies heavily on a network of ground-based radars called the North Warning System (NWS) to provide aerial surveillance coverage in the High North. The radars that make up the NWS are also all pointed northward, and none of them provide the kind of wide-area long-range coverage that an OTH design would offer.

The NWS reflects a long-standing focus on monitoring for aerial threats heading across the North Pole toward North America, especially possible nuclear strikes from Russia (and the Soviet Union before it). However, new avenues for geostrategic competition in the Arctic with Russia, as well as China, over natural resources, from oil and natural gas to fish and other sealife, as well as trade routes have emerged in recent years amid receding ice and other impacts of global climate change. This, in turn, has only prompted growing demand for surveillance coverage.

“We need a layered sensing grid, from [the] seafloor to the space layer. And we have no choice. It has to be layered and deep, a defense in depth, from a sensing point of view,” Royal Canadian Air Force (RCAF) Maj. Gen. Chris McKenna, head of 1 Canadian Air Division and the Canadian NORAD Region, also said during a panel discussion at the Air & Space Forces Association’s (AFA) annual Warfare Symposium in 2025, at which TWZ was in attendance. “And I will say I suffer from an insufficiency of ISR [intelligence, surveillance, and reconnaissance] in the Arctic on a daily basis. And I am fighting for information.”

McKenna was responding at the time to a direct question about gaps in so-called “domain awareness” in and around the Arctic and how to address them.

“I think there’s an importance here of not just air domain, but also space domain, and having a sufficiency of ISR in the Arctic to actually build you the [domain awareness] picture,” he added. “I haven’t really touched on over-the-horizon radar, but I certainly can get into it. I think that’s a really important capability given the austerity of the Arctic and the need for it to cue other things.”

For its part, Canada is now building its own new Arctic Over The Horizon Radar (A-OTHR), at an estimated cost of more than $4 billion. In an announcement last year that caught many off guard, the Canadian government announced that it would be leveraging technology originally developed for Australia’s Jindalee Operational Radar Network (JORN) to support this development. It is also important to note here that relations between Canadian authorities and the Trump administration have been and continue to be heavily strained over a variety of issues, which has prompted broad concerns about future defense and security cooperation.

Back in the United States, OTH radar plans are also now tied in with the broader Golden Dome air and missile defense initiative. Golden Dome is seeking to establish new layers of defense around the U.S. homeland against a wide array of threat types, and puts major emphasis on new space-based sensor and interceptor capabilities. Expanded defensive architectures within the Earth’s atmosphere are also part of this plan.

“Adversaries are developing and building advanced nuclear and conventional delivery capabilities,” U.S. Army Lt. Gen. Joseph Jarrard, Vice Commander of the U.S. element of NORAD and Deputy Commander of U.S. Northern Command (NORTHCOM), warned at the annual Space & Missile Defense (SMD) Symposium in August. This includes “cruise, hypersonic, and ballistic missiles, as well as fractional orbital bombardment systems, or FOBS, to threaten not only Alaska and Hawaii, but the entire continent of the United States.”

Chinese hypersonic and other developments, in particular, enable new modes of attack that “can approach North America from the south, rather than the traditional northerly vector for which our legacy early warning radars were designed,” Jarrard continued. “The Chinese have also been building a conventionally-armed ICBM [intercontinental ballistic missile] equipped with hypersonic glide vehicles that can range [sic] targets throughout Alaska, providing Chinese leaders strike options against our homeland below the nuclear threshold.”

“Russia’s advanced missiles, like the nuclear-armed Avangard hypersonic glide vehicle, are designed to circumvent the ground-based radars used by NORAD and NORTHCOM to detect and characterize an inbound threat, and challenge the ability to provide threat warning and attack assessment,” he added.

New OTH radars positioned in Alaska and elsewhere in the Pacific will not be able to address all of these threat developments alone. At the same time, the recent testing leveraging the HAARP site is another step toward meeting demands for sorely needed expanded long-range radar coverage in the Arctic.

Contact the author: joe@twz.com

The post Alaska’s HAARP Site Now Being Used To Test New Air Force Over-The-Horizon Radar Tech appeared first on TWZ.

A Russian satellite, Kosmos 2612, may have passed within approximately 85 feet (26 meters) of a U.S.-registered satellite belonging to commercial imagery provider ICEYE. This would be an extraordinarily close and potentially dangerous pass-by for two objects in space traveling at thousands of miles per hour. For weeks beforehand, ICEYE-X36, which would be of special interest to Russia, had already found itself in increasingly close orbital alignment with its pursuer. The two satellites now look to be drifting further and further apart, but the episode has been a clear sign of what is to come as the potential for conflict in space only continues to grow.

Publicly available space tracking data from the satellitemap.space and orbitalradar.com websites show that Kosmos 2612 (also written sometimes Cosmos 2612 and abbreviated K2612) and ICEYE X36 had their especially close encounter at approximately 16:07 UTC today. Private space services company LeoLabs also told TWZ today that it could not “confirm or contradict what other data sources have stated publicly,” but that it has “high-confidence that the objects came within approximately [emphasis in the original] 500 meters [1,640 feet] of each other.” Kosmos 2612 had been making progressively closer passes by ICEYE X36 in recent days.

Short time-lapse of part of this morning’s first pass of ICEYE-X36 (59103) and COSMOS 2612 (68762) over South America under partly cloudy skies. pic.twitter.com/t8RhwmKcV4

— s2a systems (@s2a_systems) October 18, 2026

6/x
Note that while ICEYE-X36 was Finnish built, it is (like other ICEYE sats who's ownership transferred) no longer Finnish. It is registered in the US but might be Ukranian owned/leased now.

— Dr Marco Langbroek (@Marco_Langbroek) October 17, 2026

“COSMOS 2612 closed from hundreds of kilometers away to extreme proximity to ICEYE-X36. It then maneuvered around ICEYE-X36,  remained nearby for an extended period, and then began moving away,” LeoLabs also stated in a report assessing the situation, which was updated today and provided to TWZ. “The latest observations show the spacecraft strongly diverging and confirm that the close-proximity activity had ended.” 

LeoLabs’ broader assessment here is supported by data from other publicly available sources, as seen below.

UPDATE: Cosmos 2612 appears to have maneuvered following a close approach with the ICEYE satellite.

The latest TLEs show 2612 in a larger orbit that will drift away with no further maneuvers.

In this animation, I fit an impulsive burn to bridge 2612’s previous TLE to its most… https://t.co/owzTZiijka pic.twitter.com/RBqGDvVH9H

— Adam Cohen (@AdamCohen8) October 18, 2026

Additional context

None of the distances stated earlier may seem especially close, let alone worrisome, by terrestrial standards. However, this is absolutely abnormal for operations in space that are not being directly coordinated by the parties involved. As a point of reference, in 2020, another Russian satellite, Kosmos 2542, came within 150 to 300 kilometers (93 to 186 miles) of USA 245, a KH-11 spy satellite, and became a major international news story.

“We are aware of the situation and tracking it closely,” a spokesperson for ICEYE’s U.S.-based division told TWZ this morning. “Our constellation architecture is designed for continuity and resilience.”

ICEYE was founded in Finland, but now has offices globally. The company specializes in providing imagery via synthetic aperture radar (SAR) from satellites like ICEYE X36, which was launched in 2024.

SAR has the benefit of being able to capture images day or night, and regardless of bad weather or other obscurants like heavy smoke. There are trade-offs in terms of the kinds of details typically visible via SAR compared to what is seen in visual spectrum imagery. Ukrainian authorities have been utilizing ICEYE imagery for years now, including for targeting purposes, as part of the ongoing conflict with Russia. There have been reports in the past that ICEYE X36 has been operating more directly under the control of the Ukrainian government, but this has not been confirmed.

Kosmos 2612 is one of six satellites (Cosmos 2609 through Cosmos 2614) the Russian military launched via a single Soyuz-2.1b rocket on April 17. The exact purpose and configuration of these satellites are unconfirmed. However, they appear to be so-called inspector types capable of rendezvousing and maneuvering close to other objects in space. We will come back to this later on.

What is clear is that Kosmos 2612 has spent the past three weeks deliberately maneuvering to extremely closely shadow ICEYE X36.

“Over two weeks beginning on September 30, 2026, Cosmos 2612 executed a series of new maneuvers that brought it back into coplanar alignment and placed it at nearly the same altitude as the commercial satellite,” Clayton Swope, Deputy Director of the Aerospace Security Project and Senior Fellow at the Center for Strategic and International Studies (CSIS) think tank in Washington, D.C., along with Research Assistant Chantal Li, wrote in an analysis of the situation just last Thursday.

“According to current orbital elements, the Russian #KOSMOS 2612 satellite is now within 1-2 km [0.6 miles to 1.2 miles] of #ICEYE-X36,” Dr. Marco Langbroek, currently a lecturer on Space Situational Awareness at the Faculty of Aerospace Engineering of Delft Technical University in the Netherlands, wrote in a thread on X on Saturday. “Based on current elements, it might come within meters of the latter within a few hours from now. This is an #RPO [rendezvous and proximity operation] without consent.”

2/x
Initially I was skeptic whether #ICEYEX36 really was an intentional target: but a series of manoeuvers by #Kosmos2612 starting on Sept 30, were clearly designed to bring the two objects very close and synchronise their orbital periods, orbital altitude and eccentricity: pic.twitter.com/BhIoi8Rtbe

— Dr Marco Langbroek (@Marco_Langbroek) October 17, 2026

“New TLEs [two-line elements] show that K2612 made a manuever [sic] on Oct 16 and is now stationkeeping within 5 km [3.1 miles] or less of ICEYE X36,” Jonathan McDowell, an astrophysicist and astronomer, who previously worked for the Harvard-Smithsonian Center for Astrophysics and has long been tracking objects of interest in orbit, also wrote in a series of posts on X on Saturday. “To my knowledge this is the first LEO [low Earth orbit] rendezvous of two active satellites where the owner of one of the sats did not give approval.”

McDowell later clarified that “close passes” of objects in orbit had certainly occurred previously, “but not I think rendezvous [sic] (matching velocity vector).”

“This is the most advanced and potentially dangerous uncooperative RPO we’ve observed,” Adam Marsh, LeoLabs vice president for technical solutions, separately told Breaking Defense.

Unprecedented orbital maneuvering

As underscored by the previous interaction of Kosmos 2542 and USA 245, close shadowing of satellites in orbit is certainly nothing new. The U.S. government, as well as Russia and others, have been observed engaging in this kind of activity in the past. At the same time, just how close Kosmos 2612 got to ICEYE X36, and how long they spent in close alignment, are, at the very least, highly unusual.

“It’s important to note that ‘red’ on ‘blue’ engagements,  such as this, are relatively uncommon in Low Earth Orbit (LEO),” LeoLabs’ report points out. At the same time, “this was not a routine conjunction or ‘fly by.’ The sequence included a controlled approach, changes in relative position, close-proximity loitering, additional small maneuvers, and a controlled departure. The behavior is consistent with sophisticated rendezvous and proximity operations (RPO).”

On top of this, there are other signs that what just happened between Kosmos 2612 and ICEYE X36 may follow a Russian playbook of sorts that could also be used in a prelude to an on-orbit anti-satellite attack.

Within weeks of their launch in April, Kosmos 2610, 2611, 2612, 2613, and 2614 had all moved orbital planes shared by multiple ICEYE satellites. Three of them subsequently made close passes by ICEYE X36, specifically, but none of them initially kept station with it. ICEYE CEO Rafal Modrzewski did say “the company later moved its ​satellite, prompting further Russian manoeuvres [sic],” according to a story Reuters published last week.

Russian satellites approaching ICEYE: a closer look at the timeline.

Tracking data via @LeoLabs_Space . Analysis via COMSPOC SSA.

On April 16, Russia launched six maneuverable satellites (Cosmos 2609-2614) from Plesetsk. Five of them — Cosmos 2610, 2611, 2612, 2613, and 2614… pic.twitter.com/ISoToOptnp

— COMSPOC_OPS (@COMSPOC_OPS) July 15, 2026

To take a step even further back, before Kosmos 2542 was caught shadowing USA 245 in 2020, there were reports that the U.S. spy satellite had shifted its orbit. This was possibly prompted by the movements of another Russian ‘inspector,’ Kosmos 2543. This does not appear to have ever been confirmed.

While in space, Kosmos 2542 had deployed Kosmos 2543 in November 2019. Then, on July 23, 2020, the U.S. military said that it had detected Kosmos 2543 itself launching a smaller object in what it described as a test of a space-based anti-satellite weapon. In a subsequent interview with Time, then-Chief of Space Operations Gen. John “Jay” Raymond, U.S. Space Force’s top uniformed officer, disclosed that American forces had first observed Russian “nesting doll” satellites – a reference to traditional Russian matryoshka dolls – similarly demonstrating the “characteristics of a weapon system” in 2017.

U.S. officials have been warning for years that Russia’s growing array of inspector-type satellites, ostensibly designed to examine other assets the country has in orbit if they break down or otherwise malfunction, are inherently dual-purpose in nature. Beyond launching projectiles, a host of other modes of attack, kinetic and non-kinetic, are enabled by the underlying ability of a spacecraft to maneuver very close to other objects in orbit and hold that position. This includes the use of grappling arms to cause damage or just tow a satellite out of orbit, spraying aerosols to harm or impair optics and solar panels, and electronic warfare jamming. A satellite could turn out to be the weapon itself, becoming a kinetic interceptor that smashes into its target on command.

One satellite shadowing another closely in orbit allows various kinds of intelligence gathering, as well. Collection of imagery and signal emissions can offer valuable details about a target’s capabilities and vulnerabilities, as well as how it is being used in a particular context.

“As observed by LeoLabs Global Radar Network and analyzed by our team, COSMOS 2612 demonstrated a sequence of capabilities that could be used to inspect, characterize, shadow, or potentially interfere with another spacecraft,” according to LeoLabs’ report. “These actions require planning, maneuverability, precise navigation, and significant fuel. They may also indicate the use of onboard sensors capable of measuring the relative position of another spacecraft.”

What has just transpired between Kosmos 2612 and ICEYE X36 highlights how just a viable threat of attack can be disruptive in its own right. Simply forcing an imagery-gathering satellite out of position could prevent it from collecting over an intended area, or at least doing so in the most effective manner.

Furthermore, satellites only have a limited amount of fuel with which to maneuver in any way after reaching orbit. Harassment in space that forces them to burn off that finite resource at a higher-than-expected rate could reduce their total operational life expectancy, as well as further limit their effectiveness and make them more vulnerable to attacks or accidents. Debris in space is a steadily growing hazard that satellites increasingly need to dodge.

The United States, among others, has been actively pursuing on-orbit refueling capabilities to help address these issues. Last month, American officials also made the bombshell admission that there are unspecified U.S. weapon systems in orbit now, ostensibly for defensive purposes amid growing threats from Russia, as well as China. Both of those countries, among others, have been actively developing and fielding various anti-satellite capabilities inside and out of the Earth’s atmosphere.

“We can only speculate about the operation’s goal, but it could have been anything from simply intimidation to outright destruction or sabotage of a U.S.-registered satellite,” CSIS’ Clayton Swope told TWZ directly today in light of the new developments regarding Kosmos 2612 and ICEYE X36. “Perhaps the operation is on hold. There are, however, several other satellites that shadowed ICEYE X36 back in May that could be brought in[to] action too.”

Attribution and broader ramifications

It is important to point out that space, as a domain, inherently creates complications when it comes to attributing any form of attack, should one occur. Satellites do suffer mishaps, sometimes with catastrophic results, the causes of which are not always clear.

Just in January, a Russian inspector satellite launched in 2014 appeared to break up unexpectedly. Sometime around the end of July, the Chinese reconnaissance satellite Yaogan 50-02, which had only been launched some four months earlier, also broke up in orbit. On Sept. 13, a similar fate befell the U.S. Cold War-era Farrah III spy satellite, also known as USA 32. At the time of writing, no firm evidence has emerged to indicate any of these incidents were the result of hostile action rather than accidents of some kind.

Update: Debris from active PRC satellite Yaogan 50-02.@S4S_SDA has now cataloged 62 pieces of debris originating from the PRC's active Yaogan 50-02 satellite (68196 / 2026-051A) on around 20 July 2026 (ref my initial analysis on Substack, link in thread).

In spite of the… pic.twitter.com/1ecF68W8VQ

— Space Domain Awareness (@shell_jim) October 12, 2026

Some recordings of USA 32 (#19460), whose fragmentation in LEO on 13 Sep 2026 at approximately 2113 UTC was confirmed by U.S. Space Forces–Space (S4S). By the time of the recordings, a large number of fragments had already dispersed over a wide section of the track. pic.twitter.com/gjRxCTPz2o

— s2a systems (@s2a_systems) September 16, 2026

“While the intention behind COSMOS 2612’s behavior remains uncertain, the deliberate nature of the activity, the fuel required to conduct this activity, and the proximity to a Western commercial imaging satellite make the event strategically important,” LeoLab’s report notes. “This event, and the capabilities demonstrated, do not establish hostile intent. It does, however, demonstrate capabilities that could support intelligence collection, on-orbit inspection, coercive signaling, interference, or preparation for future counterspace operations.”

It is very possible, if not highly probable, that Kosmos 2612’s recent activities will be indicative of a trend going forward. Aggressive and potentially dangerous maneuvering by armed forces in close proximity to each other is not uncommon within the atmosphere, especially in the air and at sea. Extending a variation of those tactics into the space domain would make sense, especially given the central role that capabilities in orbit increasingly play in modern military operations globally. Those roles extend to early warning, general intelligence gathering, weapons guidance, near-real-time communications, and beyond.

American officials have already said in the past that American assets in space are routinely the target of “reversible attacks,” meaning ones that do not cause permanent damage. That also speaks to the difficulty of attribution if there is no lasting effect or impact to draw attention to.

The U.S. government’s long-time monopoly on the space domain has also been steadily eroding in recent years, especially in light of China’s massive expansion of its intelligence-gathering and other satellite constellations. The scale and scope of what commercial satellite imagery and other space services providers, like ICEYE, offer today have led to a further democratization of space-based capabilities to countries like Ukraine that do not possess significant, if any, constellations of their own.

All of this, in turn, has increasingly driven the U.S. military, specifically, to plan for more proactive operations and potential direct conflict in orbit to ensure it retains its edge going forward. The aforementioned disclosure of U.S. on-orbit weapons is indicative of those developments and an accompanying shift in U.S. policy to be more open about counter-space capabilities.

More details may yet emerge about Kosmos 2612 and its recent rendezvous in orbit with ICEYE X36, but it already points to how space has become an increasingly likely potential zone for direct conflict going forward.

Contact the author: joe@twz.com

The post Russian Satellite’s Unprecedented Shadowing Of A Very Particular Radar Imaging Satellite Is A Big Deal appeared first on TWZ.