Burner (rocket stage)

Burner (rocket stage). The Burner is a family of solid-propellant upper stages developed in the United States for use on various expendable launch vehicles. Primarily manufactured by Boeing, these stages were integral to numerous military and civilian satellite deployment missions throughout the latter half of the 20th century. They provided the final velocity increment to place payloads into precise orbits, including geosynchronous and polar trajectories, for agencies like the United States Air Force and NASA.

Overview

The Burner stage series was conceived to augment the performance of existing launch vehicle cores, such as the Thor and Delta rockets, derived from the Thor ballistic missile. These upper stages were designed to operate after the burnout of the vehicle's main liquid-fueled stages, providing a reliable and simple kick for final orbital insertion. Their development was closely tied to the needs of the National Reconnaissance Office for deploying intelligence-gathering satellites and NASA for scientific missions. The use of solid propellant offered advantages in storability, reliability, and mechanical simplicity compared to liquid-fueled alternatives.

Design and development

Initial design work on the Burner concept was conducted by the Aerojet corporation, with later production and development taken over by Boeing's defense and space division. The stages were essentially large, spin-stabilized solid rocket motors, with some variants incorporating their own guidance and attitude control systems for more precise orbital maneuvers. Key development milestones were driven by requirements from the United States Air Force's Space and Missile Systems Center for specific satellite programs. The design evolved significantly from the early Burner I, which was a relatively simple motor, to the more advanced Burner II that included a reaction control system, influencing later upper stages like the Star series.

Operational history

The Burner stages entered service in the 1960s, with their first recorded use on a Thor-Agena vehicle launching a Corona reconnaissance satellite. They saw extensive use throughout the Cold War on missions for the National Reconnaissance Office, including those launched from Vandenberg Space Force Base into polar orbits. NASA employed Burner stages on several Delta rocket flights, such as the launches of the Interplanetary Monitoring Platform series. One of the most notable missions was the launch of the Lincoln Experimental Satellite program, which tested advanced military communications technologies. Operational use continued into the 1990s before being supplanted by more modern upper stages like the Payload Assist Module.

Variants

Several distinct variants of the Burner stage were produced, each with different performance characteristics and avionics. The **Burner I** was a basic, unguided solid motor used primarily on early Thor-Ablestar and Thor-Agena vehicles for low Earth orbit missions. The **Burner II** introduced a more sophisticated design with an integral guidance and control system, allowing for longer burn times and in-space maneuvers, and was used on later Delta and Thorad-Agena rockets. The **Burner IIA** was an upgraded version with improved propellant and electronics. A proposed **Burner VB** variant was studied for the Space Shuttle program as an optional upper stage but was never flown.

Specifications

The Burner II, a representative and widely used variant, was a spin-stabilized stage utilizing a solid rocket motor manufactured by Thiokol. It typically contained a propellant mass of approximately 1,100 kilograms, composed of a composite solid propellant like HTPB. The stage could produce an average thrust in the range of 40 to 50 kilonewtons, with a specific impulse around 290 seconds. It stood roughly 1.4 meters in diameter and 2.5 meters in length, and its avionics suite included an inertial guidance system derived from technology used in the Minuteman program for precise attitude control during its burn phase.

Category:Upper stages Category:Rocket stages Category:Spacecraft components