The Tactical High-Energy Laser, or THEL, was a laser developed for military use, also known as the Nautilus laser system. The mobile version is the Mobile Tactical High-Energy Laser, or MTHEL. In 1996, the United States and Israel entered into an agreement to produce a cooperative THEL called the Demonstrator, which would utilize deuterium fluoride chemical laser technologies. In 2000 and 2001 THEL shot down 28 Katyusha artillery rockets and five artillery shells. On November 4, 2002, THEL shot down an incoming artillery shell. The prototype weapon was roughly the size of six city buses, made up of modules that held a command center, radar and a telescope for tracking targets, the chemical laser itself, fuel and reagent tanks, and a rotating mirror to reflect its beam toward speeding targets. It was discontinued in 2005.