The ERCS (Emergency Rocket Communications System) provided a reliable and survivable connectivity between command posts and launch control centers. The ERCS UHF transmitters carried prerecorded force execution messages that were transmitted to all units within line of sight of a modified Minuteman ICBM's apogee. The Minuteman ERCS replaced the earlier Blue Scot ERCS and became operational in October 1967, using Minuteman II vehicles. In 1991 it was retired, replaced by satellite communications systems.
Initial Operational Capability: 1967.
Historical Essay © Andreas Parsch
Boeing LEM-70 Minuteman ERCS
Note: I have no definite confirmation that the LEM-70 designation actually refers to the Minuteman ERCS missile. However, the type designation (LEM = silo-launched special electronics missile), the time frame of the allocation (late 1965-early 1966), and the lack of an X or Z prefix in the designation (thereby indicating an operational missile) point towards this possibility.
In September 1961, the Strategic Air Command of the USAF issued a requirement for a rocket-borne UHF communication system in defense emergencies when conventional communication links were disrupted. This system, called ERCS (Emergency Rocket Communications System), was to provide a reliable and survivable connectivity between command posts and launch control centers. The ERCS UHF transmitters carried prerecorded force execution messages that were transmitted to all units within line of sight of a rocket's apogee.
As an interim ERCS, the USAF fielded the MER-6A Blue Scout rocket in 1963. However, as the ultimate ERCS missile, the Air Force developed a modified version of the LGM-30F Minuteman II ICBM. The designation LEM-70A was most probably reserved for this missile, but apparently not used. However, I haven't found reference to any other designation for the ERCS Minuteman (like, say, LEM-30F), so it appears that these missiles were also known as LGM-30F (possibly because they could be converted back to nuclear ICBMs at relatively short notice). The Minuteman ERCS became operational in October 1967, and remained in use until 1991, when modern reliable satellite communications systems had made the ERCS unnecessary.Specifications
Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!
Data for LEM-70A (based on LGM-30F data):
|Length||17.6 m (57 ft 7 in)|
|Diameter||1.7 m (5 ft 6 in) (1st stage)|
|Speed||> 24100 km-h (15000 mph)|
|Propulsion||1st stage: Thiokol M55 solid-fuel rocket; 933 kN (210000 lb)|
2nd stage: Aerojet General SR19-AJ-1 solid-fuel rocket; 268 kN (60300 lb)
3rd stage: Hercules M57 solid-fuel rocket; 156 kN (35000 lb)
 Federation of American Scientists Website
 James N. Gibson: "Nuclear Weapons of the United States", Schiffer Publishing Ltd, 1996
 Department of Defense Missile Nomenclature Records