In February 1961 construction began on Minuteman ICBM test launch facilities at Vandenberg. The 90 MW operates the LGM-30G Minuteman III ICBM. Titan II carried the largest single warhead of any American ICBM. I missiles, and as an emergency operational facility for Atlas ICBM. The development of the ICBM (Inter-continental Ballistic Missile) was led by the Soviet Union. This later led to the development of the Intercontinental ballistic missile (ICBM). Most Titan rockets were derivatives of the Titan II ICBM. Proton initially started its life as a "super heavy ICBM". The M-V is comparable in performance to the LGM-118 Peacekeeper ICBM. Houston claims the noises are interference from the ICBM detectors. The project was finally abandoned in favor of ICBM development. It was an SM-69D Atlas ICBM (AFSN 58-2190) on launcher 576A-1. Russia intends to replace the R-36M with a new heavy ICBM, the RS-28 Sarmat. Semyorka, the world's first ICBM. A survivable ICBM would address this issue.