Tactical High Energy Laser The Tactical High - Energy Laser , or THEL , is 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 laser chemical laser technologies . In 2000 and 2001 THEL shot down 28 Katyusha artillery rocket s and 5 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 bounce its beam toward speeding targets . History . On July 18 , 1996 , the United States and Israel entered into an agreement to produce a cooperative THEL called the Demonstrator , which would utilize deuterium fluoride laser chemical laser technologies . Primary among the four contractors awarded the project on September 30 , 1996 was Northrop Grumman ( formerly TRW ) . THEL conducted test firing in FY1998 , and Initial Operating Capability ( IOC ) was planned in FY1999 . However this was significantly delayed due to reorienting the project as a mobile , not fixed design , called Mobile Tactical High Energy Laser ( MTHEL ) . The original fixed location design eliminates most weight , size and power restrictions , but is not compatible with the fluid , mobile nature of modern combat . The initial MTHEL goal was a mobile version the size of three large semi trailers . Ideally it would be further downsized to a single semi trailer size . However , doing this while maintaining the original performance characteristics is difficult . Furthermore , the Israeli government , which had been providing significant funding , decreased their financial support in 2004 , postponing the IOC date to at least 2010 . In 2000 and 2001 THEL shot down 28 Katyusha artillery rocket s and 5 artillery shells . On November 4 , 2002 , THEL shot down an incoming artillery shell . A mobile version completed successful testing . During a test conducted on August 24 , 2004 the system successfully shot down multiple mortar rounds . The test represented actual mortar threat scenarios . Targets were intercepted by the THEL testbed and destroyed . Both single mortar rounds and salvo were tested . Even though military experts such as the former head of the Administration for the Development of Weapons and the Technological Industry , Aluf Yitzhak Ben Yisrael , were calling for the implementation of the THEL ; in 2005 , the U . S . and Israel decided to discontinue developing the THEL after spending over $ 300 million . The decision came as a result of " its bulkiness , high costs and poor anticipated results on the battlefield . " During the 2006 Israel - Lebanon conflict , Ben Yisrael , currently the chairman of the Israeli Space Agency , renewed his calls to implement the THEL against high - trajectory fire . In 2007 , Ehud Barak requested to recheck project Skyguard ( the next phase of THEL ) in order to fight Qassam attacks .