The All Terrain Scout Transport was a descendent of two-legged walkers that saw service during the Clone Wars and the early days of the Empire. Used primarily for recon by clone troopers, the Republic’s AT-RT lacked the armor of later scout-walker models. A later model, the AT-DP, served as a bridge between the open-cockpit AT-RT and the larger, more powerful AT-ST.

AT-STs accompanied General Veers’ AT-AT walkers across the snow-covered plains of Hoth during the Empire’s attack on Echo Base. Far more nimble and maneuverable than AT-ATs, the AT-STs tested rebel defenses and protected their bigger cousins against attacks by rebel infantry.

On Endor, the Empire made extensive use of AT-STs as patrol vehicles. Endor’s vast forests and tangled undergrowth hampered the effectiveness of AT-ATs for combat operations, but the smaller AT-STs were able to operate well beneath the forest canopy, and had the firepower to deal with any threat to the shield generator protecting the Death Star.

Like most Imperial personnel on Endor, scout-walker pilots doubted the forest moon’s native Ewoks posed any threat. For them, the Ewoks were primitive tree-dwellers occasionally glimpsed during a patrol – if the Empire faced any real danger on Endor, it would come from rebel insurgents sent to sabotage the Death Star’s construction.

The Empire was wrong to take the Ewoks so lightly. The furry warriors knew their home forest and used the terrain to neutralize the Empire’s technological advantages. The Ewoks saw the paths followed by AT-STs on patrol and set up log traps on either side of that route, staving in the scout walkers’ armored heads with wooden battering rams.

The Ewoks also scattered logs across the AT-STs’ paths. The scout walkers tried to keep their footing on this shifting surface, but crashed to the forest floor, where their crews were easy prey for marauding Ewoks.

More direct assaults also proved effective against scout walkers – Chewbacca and a pair of Ewok warriors swung down from the trees to land atop an AT-ST, taking over the vehicle after a brief tussle with its crew.

Chewie then drove the scout walker to the Empire’s bunker, where Han Solo thought of the idea of using the vehicle in a ruse to bring the Imperials out of hiding and blow up the shield generator.