of Modifications of Various ICBM Silos in the USSR
1. The modification of older ICBM silos into new, much harder silos for new ICBMi is from IS toercent more expensive than would be the construction of entirel new silos on virgin land. Modification, however, is allowed within the limits of the SALT agreements while new construction is not. The modifications costed in this memorandum have been carried out at Tyuratam Missile Test Center probably to test feasibility but havo not yet been done in the field. It should bo noted that these "modifications" are so extensive that they are, in fact, building new silos in old silo shafts using almost none of the old silo except the excovation and in some cases the lining of the silo shaft as part of the new silo walla. The modification of old silos to accommodate new ICBMs without increasing the hardness of the silos involves very little in the way of construe tion and the construction costs are negligible.
6. Costs of construction have been estimatedusing Soviet handbooks and the2 dollars at the ratio for heavyofubles per dollar. Descriptionssilos and measurements were obtained fromwith personnel of OSR and IAS
Worksheets supporting these estimates are maintained in the filesM. For additional information on methodology used call