Rocket battle droids, also known as hunter battle droids or pod hunter droids, were modified B1-Series battle droids, equipped with rocket packs, fusioncutters and floodlights, which scouted and destroyed life pods adrift in space.
Rocket battle droids in action.
In 22 BBY, when Jedi Master Plo Koon's Star Destroyer Triumphant was attacked and destroyed by General Grievous' Malevolence, rocket battle droids were deployed in a Droch-class boarding ship to seek out and destroy all survivors/witnesses of the Triumphants destruction. Armed with cutting equipment, in addition to the standard blaster, these droids attacked the life pods that had been jettisoned from the Triumphant, breaching the windows and dooming the survivors to die in the vacuum of space. After killing all those aboard Pod 1977, they moved on to the life pod which housed Plo Koon and his men. Plo Koon, however, was waiting for them, armed with his lightsaber. He and clone troopers Sinker and Boost fought off the droids, before Master Plo severed the Separatist boarding craft's hold on the pod, and sent them hurtling off into a piece of debris, causing a violent explosion, and the destruction of the rocket battle droids.