Technicians keep the ship and its accessories in working order and make repairs after the ship is damaged. Technicians wear uniforms with red (#96081C) panels.
A starship is a large, complex collection of equipment, comprised of several dangerous and volatile systems which, if left to run unattended, would very likely degenerate to the point of self-destruction (or worse) within the span of a week. The humble Hei ensures that these systems remain operational using both routine scheduled maintenance and emergency maintenance, and furthermore it is the Hei who advances Yamataian technology with ingenious skill so that we remain ahead of our contemporaries in other services. It is, in short, engineers - you people - who keep the Empire alive today. It is a grave oversight that the Empire does not award medals specifically for excellence in this important field, but such is the life of a Hei!
Read more here: Engineer's Guide to the Galaxy (WIP)