Forterra, a US autonomous vehicle manufacturer, revealed today that more than 100 of its autonomous all-terrain vehicles have been deployed to conflict zones in Ukraine over the past nine months, in what the company believes is the largest deployment of autonomous ground vehicles in combat by any US defense technology company.

“I think this is true for every defense technology ever created: until you get to the reality of combat, you just don’t know,” Scott Sanders, Forterra’s chief growth officer and former US Navy officer, told TechCrunch.

Funded with U.S. defense dollars, the mission is part of a growing effort to transform the U.S. military by supporting the Ukrainian resistance to Russian invaders. While aerial drones have attracted much of the attention in the fight, the dynamics they have created – extensive no-go zones where surveillance can lead to death from above – have led Ukrainian strategists to also seek ground autonomy.

“There’s nowhere to hide,” explained Master Sergeant Corey Wilkens, who heads a program developing autonomous vehicles and tactics for the US military. “You become very, very vulnerable to being attacked by [first-person view drones]other types of drones that launch ammunition, artillery, mortars and the whole range of things they have.”

Ukraine is already building its own unmanned ground vehicles (UGVs) to help move supplies and ammunition, or evacuate wounded soldiers, but they are typically battery-powered and can only carry up to 250 kilograms, according to a Ukrainian army soldier who has worked with the vehicles and whom TechCrunch will not identify for security reasons.

Forterra’s Lancer vehicles, based on Polaris ATVs and equipped with a custom sensor and computing stack, are gasoline-powered and can carry 750 kilograms of cargo, making them more versatile and useful. “The bottom line is that this UGV for logistics and simply maintaining our defense is the most important UGV in Ukraine,” the soldier said. “It’s bloody fantastic and we’re dying to get more.”

At first they didn’t feel that way. The Ukrainian Armed Forces have had mixed experiences with Western contractors bringing new technology to the battle, and Forterra’s offerings initially seemed too geared toward the U.S. Army’s high-level requirements. Modifying the vehicle for the situation, particularly by adding a Starlink satellite internet antenna, made it a big value-add.

Since arriving in Ukraine last October, the vehicles have traveled more than 2,500 miles on more than 1,100 missions, carrying 777,440 pounds of total weight and completing 52 casualty evacuations. Some have been lost in combat, especially if they become trapped in deep mud or other terrain where Russian forces can attack them at their leisure.

Forterra has learned some useful lessons: about electronic warfare, updating its software from afar, how to maneuver in difficult conditions, and how to ensure its vehicles don’t break down. The company, which has raised more than $500 million in venture funding from funds including XYZ Venture Capital and Moore Strategic Partners, is now better positioned to compete for lucrative national security contracts.

They have also seen the limits of autonomy: For now, Ukrainian soldiers have primarily been teleoperating the vehicles in combat zones, partly because they are too valuable to lose and partly because autonomous vehicles are not fully prepared for the realities of war.

While, for example, vehicles can navigate autonomously across various terrains, they are not at the point where they can identify unexpected enemy forces and react appropriately. “In fact, we need to be able to respond to enemy threats, live, while we are facing the enemy, something that the autonomy does not yet know how to do,” explained the Ukrainian soldier.

Forterra, which started working on autonomous vehicles 20 years ago, is working on how to combine the types of algorithms that gave us self-driving cars with newer generative AI software that allows machines to react to their environment in a pervasive way. As with other autonomous systems, one of the key obstacles is collecting the right data.

“There are a lot of things you have to do that aren’t available in an open source model because they’re not things humans do, whether it’s figuring out how to navigate a minefield or [operating] “A weapons system,” Sanders told TechCrunch. “You need to be able to turn the dials and a few more things of a classic robotic approach, and then leverage AI where necessary.”

Competitors in this space are solving similar challenges, such as Scout AI, which raised $100 million earlier this year to train basic models and develop a suite of autonomous platforms for the military that includes UGVs. Other startups like Field AI and Overland AI are testing UGVs with the US military.

Even with the limitations of UGVs, American military experts are convinced that it is time to invest in these tools. “Land autonomy is now achievable and we have seen it,” Wilkens said.

Scott Philips, Forterra’s chief innovation officer, visited a Ukrainian unit’s operations center to see the vehicles in action firsthand, earning the unit’s respect for visiting an area within range of Russian attacks.

“What stood out to me was seeing exactly where the seams are: which steps are still manual, where data needs to be manually re-entered or verified, and where the team has already found ways to automate or speed things up,” Philips told TechCrunch. “That’s the kind of ground truth that you can’t get from a slideshow because it shows precisely where better tools could take the pressure off the people doing this work in real time.”

A challenge posed by the Ukrainians: make it cheaper. Forterra’s Lancers are not expensive for their class, thanks to their reliance on Polaris’ commercial supply chain for the vehicle itself, but they are still too valuable to be used as freely as UAVs can be.

“Attrition is simply a fact on this battlefield, and we have lost some at this point, and it hurts, and we need more and therefore we need them cheaper,” the Ukrainian soldier told TechCrunch.