he SCV (Space Construction Vehicle) is the Terran worker unit. It harvests resources, constructs buildings and can repair all Terran mechanical units and buildings. As a building is constructed, the SCV must remain at the site until complete. If the building SCV is killed, the building's construction will halt. Building SCVs can be given queued assignments such as mining minerals and even constructing more buildings. If an SCV builds a Refinery it will automatically start mining gas unless it has been given another command in the queue.
Terran SCVs have 5 more health than the other workers and they can repair other buildings and mechanical units. Since SCVs are both mechanical and biological units, they can be repaired by other SCVs as well as healed by medivacs and medics. Moreover, their Repair ability can be set to autocast. With autocast active, an idle or patrolling SCV will automatically repair any damaged structure or mechanical unit within a close proximity. An SCV that is mining, building, moving, or attacking will not start to repair, even if repair autocast for that unit is toggled.