While flying drones have grabbed the world’s attention and rewritten the rules of combat, a quieter revolution is crawling along beneath them on the battlefield in Ukraine.

Battalions of ground robots — tracked and wheeled machines that deliver supplies, haul ammunition, evacuate the wounded, lay mines and, increasingly, hold land — now conduct thousands of missions every month. That has made them an indispensable tool for Ukrainian infantrymen who spend monthslong rotations in buried bunkers hiding from flying drones.

At the cutting edge, unmanned ground vehicles are doing what once seemed a generation away: assaulting and capturing enemy trenches. In April, President Volodymyr Zelensky said Ukrainian forces had captured a Russian-held position using only land and aerial drones, without putting a single soldier on its own side in direct danger.

Ukraine is outrunning the world’s most advanced militaries, including Russia’s, in its development of ground robots. Leading the charge are not the software whizzes behind aerial drones, but welders and grease monkeys whose MacGyvered creations help with the grunt work of infantrymen.

“Drones developed faster because they were in the hands of highly creative I.T. people,” said Oleksiy Honcharuk, a former prime minister and board chairman of Uforce, a company that makes land drones. “Ground robotic systems were mostly in frontline infantry units where the work is heavier and more practical — more about figuring out how to bolt things together so they work.”

A desperate underdog, Ukraine has turned to ever more technical tricks to stay in the fight. Cheap 3-D-printed quadcopter drones now matter more than rifles at the front. Naval drones have driven Russia’s Black Sea fleet into port. Ukrainian drone interceptors proved so effective that some were sent to the Middle East to help down Iranian attackers.

Ground combat, the realm humans know best, has been the last frontier. Hampered by debris-strewed terrain and easy prey for the drones overhead, ground robots were slow to take hold. Developing them was a lower priority and drew less money than the pursuit of aerial drones, whose nimble-fingered operators dazzled the military world.

Mechanics and infantrymen who saw a dire need for robots pressed their case. One of the first was Capt. Oleksandr Kharkovets, who now commands the ground robot battalion of the 93rd Mechanized Brigade.

Before Russia’s full-scale invasion, Captain Kharkovets ran an automotive electronics workshop. In 2023, as he fought house-to-house in the ruins of Bakhmut, he crouched behind a wall with his rifle and thought: Machines can do this.

When orders came to retreat, he left behind many dead comrades. Afterward, he decided to put his mechanic’s skills to work so that other soldiers, dead or alive, would not be abandoned.

He bolted a hook and a machine gun to a remote control vehicle, to drag the fallen away while providing cover fire. Later in 2023, the vehicle was used to retrieve a body that a special forces team had been unable to reach for a week. Captain Kharkovets filmed the mission and put together a presentation to persuade his commanders to embrace the ground robot.

“And then,” he said, “it took off.”

Saving Lives

Ukraine faces a brutal math. Its military has fewer troops than Russia. Keeping soldiers alive is an existential mission.

That has become harder as the kill zone — the band along the front where any movement invites destruction by flying drones — has expanded relentlessly. In some places, it now stretches about 15 miles back. Getting to a position can be more dangerous than holding it.

“We simply cannot afford to lose personnel,” said Major Oleksandr, whose last name is being withheld for security reasons.

He commands the unmanned ground systems battalion of the K-2 Brigade, which has more than 500 soldiers and over 600 robots, and runs five or six missions a day.

The brigade had to figure out how to better protect its soldiers, Major Oleksandr said, or “we would have soon run out of pickup truck drivers” to handle logistical needs.

Ground robots changed the equation. They are smaller and slower than pickup trucks, but harder to spot from above, and they give off no body heat. When they get blown up, no one dies.

Sgt. Dmytro Ivanov, the commander of a ground robotic systems platoon in the 36th Brigade, said that once his unit had enough unmanned machines, they “covered up to 80 percent of tasks without people — all transportation and deliveries.”

His impulse to turn to robots came from his own exhaustion. A combat engineer, he had carried mines about nine miles in a backpack. His brigade received few supplies, he said, so his team built much of its equipment from scratch.

Today, he runs two workshops near the front. One handles electronics like the radios and controllers that steer the vehicles. In the other, the buggies are welded and assembled.

The machines have their limits. On the flat steppe, they are sitting ducks. A robot cannot climb a tree, jump into a trench or improvise as a soldier can. Engineers are racing to protect the vehicles by fitting them with miniaturized air defenses.

Friendly fire is another problem. One unit experimented with sewing chips of the kind used in key fobs — RFIDs — into uniforms so that a robot’s turret could tell a Ukrainian soldier from a Russian one.

Still, Ukrainian officials say they can no longer imagine a military without ground robots. The country plans to produce 50,000 in 2026, more than double last year’s output. The military is building a center devoted to the systems.

The Russian Army uses ground robots, too, often for the same tasks, but far less than Ukraine does.

For the price of one armored infantry vehicle, said Maksym Vasylenko, the head of Ukraine’s association of ground robot systems manufacturers, a brigade can buy 77 ground robots.

“That gives you 77 attempts to complete a mission without loss of life,” he said.

Many Ukrainian soldiers argue that ground robots will never be as widespread as aerial drones.

The ground vehicles cost about $24,000 on average, twice as much as a heavy-lift flying drone and far more than a small quadcopter strapped with explosives. Aerial drones can supply troops faster and make repeated trips, though they carry much less.

Still, there are things that flying machines cannot do.

Major Oleksandr’s unit recently evacuated an assault soldier who had stepped on a mine and lost a leg. A robot traveled two-and-a-half miles through enemy territory, he said, and was struck on its way by three mines. But it brought the soldier out alive.

“Without the buggy, it would have been impossible to save him,” Major Oleksandr said, “because nobody would have taken such a huge risk to their life.”

Over the Top

Logistics drove Ukraine’s infantry to build ground robots. What excites soldiers now, however, is their fighting potential.

In December 2024, the Khartiia Corps carried out what is believed to be the first all-robot assault. A coordinated drone force in the Kharkiv region overran a Russian position. Unmanned vehicles with machine guns, flamethrowers and explosives crawled through the forest while drones watched from above.

The hopes had been modest. “Our minimum goal was for one robot to reach the enemy position,” said Lt. Andrii Kopach, commander of an unmanned ground systems company with the corps, who helped plan the mission.

A year later, he laughs at the result. “All we did was destroy one dugout,” he said. Today, robots with, for example, guns or bombs are taking prisoners on their own and delivering them to Ukrainian soldiers at a distance from the front. In practice, that has meant Russian soldiers waving a white flag or putting up their hands as a robot escorts them to a Ukrainian position.

The machines hold ground, too. Near one contested village, a tracked vehicle with a mounted 50-caliber machine gun stood watch, alone, for 45 days, said Junior Lt. Mykola Zinkevych, who commanded the operation for the Third Assault Brigade.

“Every morning it would head out for combat duty and return in the evening to recharge,” he said.

His soldiers hid the robot in three positions, shifting it every other day. The Russians never learned it was a machine, he said.

“The war is a constant experiment,” Lieutenant Zinkevych added.

The latest development is automated turrets to shoot down airborne drones. Though still experimental, they have worked dozens of times. They power down and run cool between shots, so enemy thermal cameras struggle to find them.

Each kill with these turrets, Lieutenant Zinkevych estimated, could save the lives of three or four Ukrainian soldiers.

What will come next is figured out month by month.

In the 36th Brigade, Sergeant Ivanov’s crew swaps analog cameras for digital ones, bolts on Starlink satellite units for improved navigation, and armors its robots against shrapnel. His soldiers install airless tires that a blast cannot flatten and add batteries to push the robots’ range to 30 miles.

“War has no fixed tactics,” Sergeant Ivanov said. “Everything works through the ability to assess, think ahead and improvise endlessly. Every day is different.”

Adam Satariano contributed reporting from London.