Ukraine has put thousands of new war robots into the fight. Fall and winter will test how they handle mud and snow.

Ukraine's ground robot fleet has grown since last winter. Chris McGrath/Getty Images

Ukraine's ground robot fleet has swelled , but new tests lie ahead, specifically the thick autumn mud and the winter cold and snow that can make battlefield movement more difficult and stress certain systems.

Over the last year, the country's military and industry have prioritized fielding an army of robots to attack, gather intelligence, carry gear, and evacuate the wounded. The purpose is to replace as many human soldiers as possible in the war's most dangerous sectors.

The fleet has expanded significantly and advanced technologically since last winter. Now it faces seasonal tests.

"These ground robotic systems are constantly being improved," Oleksandr Yabchanka, head of robotic systems for Ukraine's Da Vinci Wolves Battalion, told Business Insider.…