The Impacters are weapons of varying designs. They can be large armed satellites equiped with missiles or beam weapons, or large robots, such as the Earth Engine.
The first known mecha Impacter is the Star Emblem used by the late Taiyou Manatsu prior to his death after stopping Amarok nine years ago before the series timeline. Eventually the Earth Engine is developed and piloted by the Daichi Manatsu Taiyou's son and used to combat Malkin and eventually Amarok himself.
During their assaults on Earth several satellite Impacters are lost to the Kiltgangs, leaving the mechas as some of the more recurring and powerful assets to combat the Kiltgangs as aside from advanced weaponry they can engage in direct-physical combat against the Kiltgangs, an ability that has proved pivotal in their defeat as the Kiltgangs can use several barriers to block weapon fire.
As the series progresses, Globe develops a new series of Impacters for use in Earth, namely the Earth Engine Ordinary to combat the Kiltgangs while they pilot their Machine Goodfellows and eventually the Nebula Engine to support spacial combat like the regular Earth Engine.