By Rebecca L. Grant, Ph.D., Vice President, Lexington Institute.
February 03, 2025 – The full text of this article is available below and on the 1945 website here.
Donald Trump Must Guard Spectrum for Radars to Defend the USA: No, the U.S. military cannot share a critical piece of S-band radar spectrum with commercial 5G wireless providers. Not if the new Trump administration wants to improve defenses against mystery drones and guard against threats of missiles from China and Russia.
“President Trump has talked about an Iron Dome for America,” incoming National Security Mike Waltz told CBS News, referring to Israel’s missile defense system. “That needs to include drones as well, not just adversarial actions like hypersonic missiles,” Waltz said.
The priority is clear. However, if the new Trump administration is serious about missile defense for the United States, or any improvements at all, the new team will have to engage on the priority of keeping S-band spectrum clear for military radars that track those missiles and drones.
The U.S. military relies on a slew of S-band radars to carry out critical missile tracking. During the Biden years, an idea took shape that the military might be able to share the S-band spectrum with commercial 5G wireless companies in order to meet growing consumer demand.
The demand for more wireless spectrum is beyond dispute. Social media apps and videos account for up to 80% of the demand for wireless data usage and are soaring in popularity. For example, Americans consumed 100 trillion megabytes of wireless in 2023, so the wireless industry wants Congress to “restore the FCC’s auction authority and create a pipeline of much-needed mid-band spectrum,” according to Meredith Attwell Baker, CTIA President and CEO. 5G commercial operators began eyeing the 3100–3450 MHz slice of the S-band spectrum to accommodate growth.
But the problem is that key military radars for missile defense operate in the S-band spectrum. Among the systems reliant on S-band are the Army’s Q53, the Air Force’s AWACS radar plane, the Navy’s Standard Missile 3 Block 1B, and the new SPY-7 radar, which can track satellites. The Space Force’s Long-Range Discrimination Radar in Alaska will come online later in 2025 and uses S-band to distinguish between enemy missiles and decoys.
These highly specialized radars were designed and deployed way before streaming video became a feature of daily life, and they need the full slice of S-band they were designed to use.
However, the Biden Administration reacted to the growing demand for spectrum access by pressuring the Pentagon to explore ways for commercial operators to share spectrum bands with military systems. Back in 2023, the Biden White House announced a National Spectrum Strategy aiming to “expand opportunities for spectrum access and harmonious coexistence, by whatever licensing or allocation mechanism, for all sectors,” the strategy stated. Following up, the National Spectrum Research and Development plan released in October 2024 advocated the “coexistence of radar and other spectrum-dependent systems.” Yet this research and development guide lacked a commitment to keeping S-band clear for crucial military functions.
It’s all the more astonishing, considering that the threats to the US homeland are piling up. North Korea’s dictator Kim Jong Un has overseen tests and deployment of the Hwasong-17 liquid-fueled “monster missile” with a range capable of reaching the West Coast of the United States. Experts believe the Hwasong-17 could easily be converted to carry multiple warheads.
Of course, Russia and China claim to have new maneuvering, hypersonic missiles that attack at peak speeds of a mile per second. Cruise missiles have long been a concern because they can reach supersonic speeds at very low altitudes, creating a short window for detection. Don’t forget the problem of Russian, and now Chinese bombers, in Alaskan airspace, potentially armed with conventional or nuclear missiles. Tracking an attack from any of these systems relies on S-band.
S-band is also important for countering drones. The Army’s Q-53 is an active electronically scanned radar that uses S-band and first saw combat in 2010. Imagine the moment when the military needs to move a ground-based radar like the Q-53 to a site in the USA where intrusive drones are threatening critical infrastructure. It’s hardly the moment to wait and ask wireless operators to turn their signals down.
The idea of sharing spectrum has been made alluring. However, dynamic spectrum sharing is technical and complex; it boils down to allowing commercial and defense equipment to work side by side as long as those commercial operator signals don’t create enough energy to interfere with the military radar. Sounds okay, but some of the proposals rely on complicated mechanisms, such as expecting the military to notify commercial operators when to switch off their equipment down. Other suggestions include developing AI-assisted scheduling to keep commercial use of the spectrum from impeding military systems. Deconflicting commercial and military systems in S-band has been described in some government documents as a “moonshot” project. In other words, the government is unsure whether it can be done without compromising military systems.
Senator Deb Fischer (R-Nebraska), along with bipartisan colleagues Senators Mazie Hirono (D-Hawaii) and Angus King (I-Maine) raised the alarm about allowing access for commercial operators. “We remain concerned that pursuing a policy of requiring the Department of Defense … to surrender its spectrum for non-Federal use would significantly harm DOD’s ability to carry out its missions, increase costs, and adversely affect our national security.”
The Pentagon and U.S. Northern Command will have their hands full revamping the defense of the United States. This is no time to sacrifice the effectiveness of the military’s S-band systems.
This article was originally published on the Lexington Institute: Why Donald Trump Must Protect S-Band Radar Spectrum For U.S. Defense (From 1945) | Lexington Institute