The U.S. Air Force is moving ahead with its plan to build homeland-defense radars that can detect a new generation of Russian cruise missiles—including a search for sites whose total area could cover nearly half of Manhattan.

The “initial architecture” calls for the U.S. to buy four long-range radars and for Canada to buy two, said Paul Ferraro, president of air power at Raytheon Technologies, which intends to bid to supply the systems.

Each radar needs roughly 1,500 acres of land, according to 2024 budget documents, so the Air Force is looking for a total of about 6,000 acres. 

“For operational security reasons we want to limit information on the specific locations, but the plan is to locate our initial two systems in the Northwest United States,” Air Force spokesperson Ann Stefanek said. 

Stefanek’s service and the Army Corps of Engineers will conduct environmental impact analyses on the “specific locations identified prior to receiving approval for military construction,” Stefanek said. 

Meanwhile, Canada is looking at land in southern Ontario for its radars, said Jessica Lamirande, a spokesperson for Canada’s National Defence Department.

“Up to four areas” will be required for transmitters and receivers, Lamirande said. 

“As such, the department is reaching out to private landowners, indigenous communities, other federal government departments, the Province of Ontario, and local municipalities to determine their interest in selling land to DND for this project,” she said. 

Lamirande said the department will make a final decision on the locations by next spring.

That’s around the same time—early to mid-2024—that the U.S. Air Force will start talking to industry about building the sites for the Over-The-Horizon Radar program, Stefanek said.

America’s current homeland-defense radars weren’t designed to see low-flying cruise missiles of the sort that Russia has used to attack Ukraine. North American Aerospace Defense Command, the combined U.S.-Canadian command that operates the radars, has been called out for its gaps in detection after it missed Chinese surveillance balloons and other unidentified objects that have slipped into U.S. airspace. The command hopes this over-the-horizon radar program, which will integrate with existing radars, will fill some of those gaps. 

“OTHRs will assist in filling domain awareness gaps in our existing infrastructure by allowing us to better detect and track threats, and fuse that data into a globally integrated picture that provides better options to decision makers,” a NORAD spokesperson said in a statement.

The Air Force has asked for more than $400 million in its 2024 budget to design, develop, test, and field the OTHR program. 

Russia has a “threat that is very viable now that was not viable in the past—and that threat is for them to launch a cruise missile over the North Pole through Canada and either into Canada or the United States,” RTX’s Ferraro said. 

Such missiles would approach at low altitudes and have the ability to maneuver in flight, presenting a far different challenge from decades-old intercontinental ballistic missiles. 

RTX plans to offer its Next Generation Over-the-Horizon Radar, which bounces radio waves off of the ionosphere instead of looking directly at a target.

Ferraro said that RTX’s system is the only American radar that can meet the program’s expected requirements.

“We are the only U.S. domestic source of supply for expertise in over-the-horizon radars. There may be some foreign sources of supply,” he said.

Stefanek didn’t comment on RTX’s offering, but said that “multiple industry players” have shown interest in developing “components of the systems.”

The DND’s Lamirande said it’s “too soon to know” which radar system will be selected for Canada.