UA120 was a family of American

solid rocket booster A solid rocket booster (SRB) is a solid propellant motor used to provide thrust in spacecraft launches from initial launch through the first ascent. Many launch vehicles, including the Atlas V, SLS and Space Shuttle, have used SRBs to give laun ...

s, manufactured by the Chemical Systems Division of

United Aircraft The United Aircraft Corporation was an American aircraft manufacturer formed by the break-up of United Aircraft and Transport Corporation in 1934. In 1975, the company became United Technologies, which in 2020 merged with Raytheon to form Rayt ...

(later

United Technologies Corporation United Technologies Corporation (UTC) was an American multinational corporation, multinational list of conglomerates, conglomerate headquartered in Farmington, Connecticut. It researched, developed, and manufactured products in numerous are ...

). They were used as strap-on boosters for the Titan rocket family. Several variants existed, with a varying number of segments.

Design

All versions of UA120 shared a common design, with the only significant differentiating factor being the length of the motor. It was a segmented design, with between five and seven motor segments possible. A solid propellant used was a

ammonium perchlorate composite propellant Ammonium perchlorate composite propellant (APCP) is a solid rocket propellant. It differs from many traditional solid rocket propellants such as black powder or zinc-sulfur, not only in chemical composition and overall performance but also by ...

with

polybutadiene acrylonitrile Polybutadiene acrylonitrile (PBAN) copolymer, also noted as polybutadiene—acrylic acid—acrylonitrile terpolymer is a copolymer compound used most frequently as a rocket propellant fuel mixed with ammonium perchlorate oxidizer. It was ...

(PBAN) binder. The stage had an external diameter of 120 inches. Attitude control in flight was provided by means of a liquid injection

thrust vector control Thrust vectoring, also known as thrust vector control (TVC), is the ability of an aircraft, rocket or other vehicle to manipulate the direction of the thrust from its engine(s) or motor(s) to control the attitude or angular velocity of the veh ...

(LITVC) system, with an external nacelle containing nitrogen tetroxide attached to the side of each booster. Solid fueled separation rockets, used to jettison the spent boosters, were affixed at the top and bottom of the stage. Thrust-termination capability, necessary for crewed rockets such as the

Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. ...

Manned Orbiting Laboratory The Manned Orbiting Laboratory (MOL) was part of the United States Air Force (USAF) human spaceflight program in the 1960s. The project was developed from early USAF concepts of crewed space stations as reconnaissance satellites, and was a succ ...

, was to be provided by two pyrotechnically triggered ports on the forward closure, which when opened would allow for the non-propulsive venting of exhaust gasses. The forward end of the stage contained an aerodynamic

nose cone A nose cone is the conically shaped forwardmost section of a rocket, guided missile or aircraft, designed to modulate oncoming fluid dynamics, airflow behaviors and minimize aerodynamic drag. Nose cones are also designed for submerged wat ...

, an ignitor, separation rockets, and the forward attachment ring. The aft end contained additional separation rockets, the nozzle, and a heat shield.

Variants

The overall design of each variant was very similar, the main difference being the number of segments used. This is indicated by the number at the end of each designation.

UA1205

UA1205 was flown between 1982 and 1992, and used as a strap-on booster on the

Titan IIIC The Titan IIIC was an expendable launch system used by the United States Air Force from 1965 until 1982. It was the first Titan (rocket family), Titan booster to feature large solid rocket motors and was planned to be used as a launcher for the D ...

, Titan 23C, Titan IIID, and

Titan IIIE The Titan IIIE or Titan 3E, also known as the Titan III-Centaur, was an American expendable launch system. Launched seven times between 1974 and 1977, it enabled several high-profile NASA missions, including the Voyager and Viking planetary pro ...

rockets, besides being proposed for use on several derivatives of the Saturn rocket family.

UA1206

The UA1206 was flown between 1982 and 1992, and used as a strap-on booster on

Titan 34D The Titan 34D was a United States expendable launch vehicle used to launch a number of satellites for military applications. Service history Derived from the Titan III, the Titan 34D featured Stage 1 and Stage 2 stretched with more powerful ...

and Commercial Titan III.

UA1207

UA1207 was first flown in 1989 and used on Titan IV-A. It was proposed for several other variants of Titan III and IV, as well as the Titan-IIIM, derivatives of the Saturn rocket family and the

References