The Laser Defence Orbital (or more commonly known as a Zapsat) is a type of weapon used by Earth for defense against alien spacecraft. It is designed to look like a spy satellite so that the public doesn't realize what is going on. It uses a dozen orbaniannaquadah reactors to power its systems including the shields and cloaking device. The Zapsat can oneshot a Sectoid battleship and several of them can be a threat to a Goa'uld mothership. The first batch of zapsats was made using lots of off-the-shelf supplies to reduce the costs, however the second batch was made using Earth manufactured supplies further reducing the costs though it prevented the construction of a third Prometheus-class warship. A Mark II design was eventually created after the Battle of Antarctica.