Despite the emphasis placed on Peacekeeper, there were those who believed that the missile was actually too capable, and thus presented a first-strike threat to the USSR that could lead to instability. A smaller, single warhead missile that was mobile would allow for a more survivable force that would not be as threatening, and as part of its work, the Scowcroft Commission endorsed the development of a Small ICBM, leading to work on the MGM-134, dubbed by many the Midgetman.
SICBM was to use some of the Peacekeeper's technology to save time and money; the AIRS guidance system would be used in modified form, and a higher-yield version of the W87 warhead would be used with the Mk.21 RV. This would be substantially more powerful than a single Peacekeeper warhead, giving the SICBM even more capability against superhardened targets. Maneuvering and terminally-guided RVs were possible follow-on payloads.
Although it never had the chance to become quite as heated as the MX basing debate, there was some question as to how best to base the SICBM. Of the many alternatives, there were several serious contenders:
- A return to silo basing, albeit using facilities built to extremely hardened specifications.
- Making the system road-mobile, which was the method preferred by many. Keeping the missiles mobile would provide a degree of survivability in itself, and the proposed carrier vehicle, termed the Hard Mobile Launcher, would increase this by being resistant to radiation, EMP, and other effect from nearby nuclear detonations.
Martin Marietta and Boeing were awarded contracts to produce HML prototypes; these were to be of tracked and wheeled configurations, respectively. Both contenders used the concept of a separate missile-carrying segment attached to a tow vehicle In the event of an imminent nuclear strike nearby, the missile section would be disengaged and lowered to the ground to prevent it from being flipped over from blast pressure getting underneath. The tractor, equipped for sealed operations in an NBC environment, could then move to cover until the worst of the blast effects had passed. Separate mobile launch control centers would be used, and to maximize survivability the missiles could also be commanded from fixed centers and ABCP aircraft as well. Subscale models of HMLs were subjected to conventional explosives to mimic the effects of nuclear detonations near full-size vehicles.
By early 1987, the SICBM had been defined as having a MX-type configuration of three solid stages and a Post-Boost Control System fueled by storable liquid fuel. The planned 30,000-33,000lb weight target was abandoned in favor of a slightly longer vehicle weighing in at 37,000lbs. The main stages would all have graphite cases to cut weight; the contract for the first stage was awarded to Morton Thiokol, while Aerojet had responsibility for the second, and Hercules the third. The overall contractor would be Martin Marietta. Boeing's HML design was selected as the launch vehicle.
Where to put the road-mobile missiles was another question. Millions of acres of secure military controlled lands in the west and southwest offered maximum survivability, but keeping the vehicles at Minuteman launch control centers meant that significant infrastructure economies could be realized. This plan was later adjusted to base the missile vehicles at silo sites, which would have necessitated some above ground construction of support facilities.
Enthusiasm for the program within the Reagan Administration waned in later years, and although the missile was kept alive, this was mostly due to Congressional pressure and the desire to keep future strategic options open. Even as its future was being debated, SICBM made its first test launch, from a pad at Vandenberg on May 11, 1989. The result was not wholly successful, as the missile had to be destroyed after the third stage began experiencing problems, but much data was gathered nonetheless. A second launch was conducted on April 18, 1991. Like so many other new US nuclear weapons programs of the late 1980s, SICBM was cancelled by President Bush in September 1991.
"USAF Awards Initial Contracts for Small ICBM Missile Project" Aviation Week & Space Technology January 23, 1984 p.22-23 1 illustration
Bruce A. Smith "USAF, Contractors Defining Small ICBM" Aviation Week & Space Technology February 6, 1984 p.54-55 1 illustration
Clarence A. Robinson, Jr. "Parallel Programs Advanced Small ICBM" Aviation Week & Space Technology March 5, 1984 p.14-16 4 illustrations
“USAF Awards Small ICBM Launcher Contracts” Aviation Week & Space Technology January 28, 1985 p.19
“Aerojet Test-Fires Small ICBM Second-Stage Rocket Motor” Aviation Week & Space Technology March 4, 1985 p.14 1 illustration
“Martin Marietta Wins Midgetman Award” Aviation Week & Space Technology July 8, 1985 p.22
Robert R. Ropelewski “USAF Awards Three Contracts For Small ICBM Launch Controls” Aviation Week & Space Technology July 22, 1985 p.19-20
Brendan M. Greeley, Jr. “Caterpillar, Martin Marietta Roll Out Prototype Hard Mobile ICBM Launcher” Aviation Week & Space Technology September 16, 1985 p.24-25 2 illustrations
Cecilia Preble “Boeing/Goodyear Roll Out Mobile Launcher Test Vehicle” Aviation Week & Space Technology September 30, 1985 p.23-24 2 illustrations
“Hard Mobile Launcher Designed To Transport Midgetman Missile” Aviation Week & Space Technology October 28, 1985 p.80 4 illustrations
“USAF Cites Improved Silo Hardness Capability” Aviation Week & Space Technology October 28, 1985 p.85
“Air Force Considers Missile Collocation” Aviation Week & Space Technology November 18, 1985 p.24
John D. Morrocco "Reagan Will Pursue Rail-Based MX, Full-Scale Midgetman Development" Aviation Week & Space Technology January 5, 1987 p.20-21 1 illustration
"USAF Tests Midgetman Second Stage" Aviation Week & Space Technology February 2, 1987 p.18 1 illustration
John D. Morrocco “Defense Official Challenges Continuing SICBM Development” Aviation Week & Space Technology March 16, 1987 p.18-19
Bruce A. Smith "USAF Plans Single Launch Control Facility for First Small ICBM Force" Aviation Week & Space Technology May 18, 1987 p.47-48 2 illustrations
"Morton Thiokol Fires SICBM in Static Test" Aviation Week & Space Technology June 1, 1987 p.19
“Data Show Guidance System Was Trying to Stabilize SICBM” Aviation Week & Space Technology May 22, 1989 p.25 1 illustration
"SICBM Hard Mobile Launcher Completes Winter Road, Shock Tests" Aviation Week & Space Technology July 13, 1987 p.25 1 illustration
David F. Bond “USAF Extends SICBM Contracts In Face of Test, Budget Hurdles” Aviation Week & Space Technology July 10, 1989 p.23-24
Brian Green “The Math of Midgetman” Air Force Magazine July 1990 p.20