Small ICBM Hard Mobile Launcher
Published January 30, 2007
Boeing Small ICBM Hard Mobile Launcher
The Boeing Small ICBM Hard Mobile Launcher (HML) was a mobile, radiation-hardened, vehicle designed to transport and launch the MGM-134A Small Intercontinental Ballistic Missile, unofficially called the "Midgetman" missile. The HML was designed and built by Boeing Aerospace and Electronics in cooperation with Loral Defense Systems Division. It was powered by a single 1,200 horsepower Rolls-Royce Perkins diesel engine that drove all eight tractor wheels through an electro-hydraulic transmission.
The tractor had a draw-bar pull capability of more than 80,000 pounds. The entire vehicle was over 110 feet long and weighed over 239,000 pounds when fully loaded, yet it could travel on paved roads at up to 55 miles per hour. The HML could also travel off-road. It could withstand moderate nuclear effects and the trailer-mounted plow allowed the tractor to bury the launcher-trailer into the ground for additional protection from nuclear blasts.
The MGM-134A Small ICBM was a single-warhead missile conceived during the early 1980s amidst the lengthy debate over the mobile basing methodology to be used with the much larger MIRVed LGM-118A Peacekeeper ICBM. The SICBM would have been quite a bit smaller (around 30,000 pounds), and consequently much more mobile, making its survivability higher in the event of a nuclear attack upon the United States. Thus, the SICBM would have complemented the silo-based Peacekeeper, but the program was cancelled in the late 1980s due to budgetary constraints.
When the SICBM program was cancelled, all development work on the HML vehicle for the missile was also terminated. This HML Mobility Testbed was placed on static display at the Ballistic Missile Office at San Bernadino ALC in California. It remained there until 1996, when the Aerospace Heritage Foundation of Utah made arrangements to have the vehicle relocated to Hill Aerospace Museum. The vehicle was overhauled so it could be driven temporarily, then it was loaded on a C-5 Galaxy cargo plane and airlifted to Hill AFB, arriving in June 1996. It was then driven one last time from the base flightline to the museum's Missile Park.