Hard Mobile Launcher

Small ICBM Hard Mobile Launcher
A Hard Mobile Launcher engineering model
Type	Mobile ICBM Launcher
Place of origin	United States
Service history
In service	Prototype only (1986–1991)
Used by	United States
Specifications
Mass	239,000 lb (108,400 kg)
Length	110 ft (33.5 m)
Engine	Rolls-Royce Perkins diesel 1,200 hp (890 kW)
Maximum speed	55 mph (89 km/h) on road

The Hard Mobile Launcher(HML) is a mobile radiation-hardened truck transporter erector launcher designed to facilitate the transport and launching of the MGM-134 Midgetman missile. ^[1]

Overview

Martin Marietta-Caterpillar prototype

Boeing-Goodyear HML launcher during test phase

U.S. Air Force National Museum plaque

It can travel at speeds of up to 55 mph (89 km/h) on the road and it also has off-road capabilities. The vehicle also has a trailer mounted plow which can be used to dig the launcher into the earth in order to help protect it were it within the vicinity of a nuclear detonation.

The vehicle weighs a total of 239,000 lb (108,000 kg), with a length of over 110 feet (34 m) and it has the capability to transport objects weighing up to 80,000 lb (36,000 kg). It is powered by a Rolls-Royce Perkins diesel engine which produces 1,200 hp (890 kW) and controls all 8 wheels using an electro-hydraulic transmission. ^[2]

Design and testing

Two teams were assigned to develop a vehicle.

Caterpillar developed a tracked tractor (Mobil-Trac System) while Martin Marietta was the system integrator and also built the Mobility Test Bed missile trailer. ^[3]

A second team consisting of Boeing Aerospace and Electronics' Loral Defense Systems Division (Goodyear Aerospace) built an eight wheel drive vehicle and trailer.

The Air Force selected the Boeing-Loral prototype. Several vehicles were delivered to the US Air Force by December 1986. The Air Force tested the vehicle until 1991, after which development of the MGM-134 missile project ceased, leading to the project's cancellation.

NMUSAF Museum acquisition

Following the cancellation of the MGM-134 missile project, the last of the engineering models was acquired by the National Museum of the U.S. Air Force in Ohio in 1992. It is no longer on display and was given to the Defense Reutilization and Marketing Office. ^[4]

The Hard Mobile Launcher at Wright Patterson Air Force Base was auctioned and sold for scrap in July 2015. ^[5] It was broken up in September 2015.

Hill Aerospace Museum

The Boeing-Loral prototype is currently stored at Hill Aerospace Museum in Utah ^[6]

References

1. "Return of the Hard Mobile Launcher". www.armscontrolwonk.com.
2. "Small ICBM Hard Mobile Launcher". Archived from the original on 1 April 2017. Retrieved 31 March 2017.
3. Orlemann, Eric C. Caterpillar Chronicle : History of the Greatest Earthmovers. MotorBooks International. ISBN   9781610605779.
4. Jeffrey Lewis. "Return of the Hard Mobile Launcher" . Retrieved 31 March 2017.
5. "Event Details". www.govliquidation.com. Archived from the original on 5 October 2017. Retrieved 5 October 2017.
6. "HUGE LAUNCHER COMES TO HILL". Deseret News. 30 May 1996. Retrieved 15 November 2025.