Assessment of HTRB and PBAN propellant usage in the United States

Abstract

This paper discusses composite solid propellants based upon the butadiene prepolymers which make up the vast majority of current production in the United States—hydroxylterminated polybutadiene (HTPB), and the terpolymer of butadiene, acrylic acid, and acrylonitrile (PBAN). The objective of this study is to present a brief historical review of the development of HTPB and PBAN propellants, compare their characteristics, describe their applications, and present a statistical analysis of their production and usage for military, launch, and space motors manufactured in the United States. Using CPIA in-house and external resources, a tabulation of all known major systems utilizing HTPB and PBAN propellant was completed. PBAN production over the next ten years will be sustained nearly entirely by the production of the Space Shuttle Reusable Solid Rocket Motor (RSRM), while HTPB production will be limited primarily to tactical and space motors after completion of deliveries of the Titan IV Solid Rocket Motor Upgrade (SRMU) in 1999. HISTORICAL BACKGROUND Composite solid propellants using a hydroxyl-terminated polybutadiene (HTPB) or polybutadiene-acrylic acid-acrylonitrile (PBAN) binder system have been the choice for most solid rocket motor systems developed and fielded in the United States over the past twenty years. Propellant based upon these binders account for over 800 million pounds (360* 10 kg) of domestic production through the end of 1996. Comparative characteristics for typical aluminized formulations of these two types of propellant are presented in Table I. ilTailillil ^ lllllllll I°ps, lbf-sec/lbm(kN.s/kg)