The Burner and Burner 2 rocket stages have been used as upper stages of launch vehicles such as the Thor-Burner and Delta since 1965. The currently available Burner 2 is powered by a Star 37 solid rocket motor. Thor Altair and Thor Burner were mainly used for US military meteorological programs (DMSP), although they also launched technological satellites.
The Burner 1 stage was based on the Allegany Ballistics Laboratory (ABL) X-248 Altair rocket stage used for the third stage of some Vanguard launch vehicles. For the Burner designation, Boeing equipped the stage with 3-axis control. The solid rocket engine later designated Thiokol FW-4 (TE 364-1). The first Thor Burner launch occurred on January 19, 1965 for the US military meteorological program DMSP B4A-01 satellite (first Block 4A).
In March 1964, the Defense Meteorological Satellite Program (DMSP) office approved plans to develop a more powerful Thor Burner 2 launch vehicle.
The Burner 2 was developed for the Air Force Space Systems Division in 1965. The Boeing Company served as prime contractor with major subcontractors: Thiokol Chemical Corporation (solid rocket motor); Honeywell Inc. (pre-programmed inertial guidance system); Walter Kidde Co. (reaction control system).
Burner 2 featured a Thiokol Star-37B motor (TE-M-364-2) which was derived from the Surveyor lunar retro-rocket. The first Thor Burner 2 launch occurred on September 16, 1966 for the US military meteorological program DMSP B4A-07 satellite
It was the first solid-fuel upper-stage used for general space applications that had full control and guidance capability. Its general assignment was to place small- and medium size payloads into orbit. The Burner II motor, guidance system and reaction control system were integrated to provide attitude stability and precise control of flight rate and burnout velocity for orbital injection and earth-escape missions. Burner II was designed for use with the Thor booster, but was readily adapted for use on the complete range of standard launch vehicles. The Burner II was used as an upper stage by NASA for deep space probes. The first Burner II flight was on 1966-09-15.
Boeing delivered 8 flight vehicles under its original contract. Under terms of a follow-on contract, it built 6 additional flight models.
Four Thor-Burner II combinations were launched successfully from Vandenberg Air Force Base, California. The third launch placed 2 unclassified satellites in Earth orbit. A SECOR satellite, built for the U.S. Army Corps of Engineers by the Cubic Corporation, and an Aurora satellite, developed by Rice University for the Office of Naval Research, were placed in circular orbits 3,300 km above the Earth. As integration contractor for the Air Force Space Experiment Support Program (SESP) Office, Boeing designed, built and tested the injection stage, or "payload dispenser," which carried the 2 satellites on top of a standard Burner II stage and placed them in precise orbits. The satellites were mounted on opposite sides of the injection stage, which housed a 640 kgf thrust, solid-propellant rocket motor, Star 37.