The Ukraine war is showing US soldiers they need to be hard to find in the electromagnetic spectrum in a high-end fight

• The US Army conducted a joint-force, multinational training in Hawaii earlier this month.
• Troops focused on how to be "small and undetectable" in the electromagnetic spectrum, a commander said.

The US Army is taking lessons from the war in Ukraine, where the battlefield has often been described as transparent. There's still room for surprises, but some system or sensor is often watching.

During US Army Pacific's recent war games in Hawaii, those lessons were put to the test as soldiers focused on how to be "small and undetectable" in the electromagnetic spectrum, an airborne commander said.

USARPAC hosted its large-scale Joint Pacific Multinational Readiness Center training in Hawaii earlier this month, with a focus on preparing soldiers to fight in the tropical island environments found in much of the Indo-Pacific region.

The JPMRC, which also completes a rotation in Alaska in the winter to test soldiers' combat readiness in the Arctic, brings the Army together with other branches of the military as well as international allies and partners; this year involved over 10,000 troops and the most joint military participation the relatively new exercise has seen.

During the drills, which saw US soldiers practice fighting an adversary in humid jungle and archipelago conditions, participating troops focused on hiding from the enemy in the electromagnetic spectrum.

Maj. Gen. Marcus Evans, commander of the 25th Infantry Division out of Hawaii, told Business Insider that "certainly one of our greatest lessons learned over the past several years of watching what is occurring in Ukraine is we have to ensure that we are protecting ourselves. We have to ensure that we are seeing ourselves the same way opposing forces would see us."

The US military is coming to terms with the growing importance and challenges of electronic warfare, such as GPS spoofing, signal jamming, and surveillance, in modern combat. It is also grappling with the expanding sensor threat and the realization that individual soldier, vehicle, and device emissions can be detected in the electromagnetic spectrum.

And if you can be seen, you can be hit.

When he was chairman of the Joint Chiefs of Staff, US Army Gen. Mark Milley said that "being nearly invisible will be fundamental to survival on a future battlefield."

Other officers and war analysts have argued similar points and stressed the need for next-level camouflage. Shortened kill chains in which the time between detection and destruction has been dramatically reduced make that more important.

US Army Brig. Gen. Ed Barker, the Program Executive Officer for Intelligence, Electronic Warfare and Sensors, said back in June that the electromagnetic spectrum was another "terrain" of battle in which soldiers need to be able to hold, maneuver, and fight. The general, together with a US Air Force officer, stressed the need to dominate this space.

"The spectrum is a bad place to be second, and if we lose in the spectrum, or are unable to affect the spectrum, the joint force will lose, and we're going to lose very quickly," Col. Josh Koslov, commander of the 350th Spectrum Warfare Wing, said.

Remaining hidden in the electromagnetic spectrum is a challenge, though, and completely invisible isn't an option. "We understand that the ability to be small and undetectable in the electromagnetic spectrum is a task that we have to train more fulsomely on," Evans said, "and that our ability to move and shoot and protect has got to be integrated into everything that we do."

To be "small and undetectable" on the spectrum, soldiers have to learn what they, their weapons, and other assets look like to the enemy's systems and sensors and how to cloak their signatures or disrupt the enemy's ability to find them.

Masking signatures of troops and assets to decrease detectability is especially difficult considering the range of sensors out there, but it's that threat that increases the need for militaries such as the US to think about what they look like across the spectrum.

Evans explained that soldiers understand they are always a target, and that "informs how quickly we have to move," their training, and how they pursue agility and survivability in a potential combat scenario.

Much of the Army's recent focus on electronic warfare and the electromagnetic spectrum has come from closely observing the war in Ukraine. Over two years into the conflict, unmanned systems, electronic warfare technologies, and constant intelligence, surveillance, and reconnaissance have heavily shaped the battlespace.

While the Pentagon understands some of the challenges the US military may face in future warfighting, the Ukraine war offers the opportunity for the US to observe and solve problems now as it prepares for the possibility of high-end great-power conflict.

The US military is increasingly looking into countering detection in the electromagnetic spectrum, defeating drones, and stepping up its electronic warfare capabilities amid developments in Ukraine.

In August 2023, Doug Bush, the Army's acquisition chief, said that the Army was "fundamentally reinvesting in rebuilding our tactical electronic warfare capability after that largely left the force over the last 20 years," noting that the fight in Ukraine had added "urgency" to those efforts.

Top Ukraine war watchers and warfare experts have identified electronic warfare as an important element of future combat, arguing that top militaries around the world will need to adapt to these challenges. But war and conflict are evolving, and the Ukraine war has also shown that both sides will continue to develop countermeasures in a "cat and mouse" game, meaning any innovative solution likely won't last long before another is needed.