Burner top stages

by Jean-Jacques Serra
Altair, the old solid fuel third stage of the Vanguard rocket was spin stabilized. It was used the same way as top stage for Delta and Scout. The X-248, which was the motor of the Altair, had a plastic structure reinforced by fiberglass. It was developped by Alleghany Ballistics Laboratories and provided 13.8 kN thrust during 27 seconds.
Boeing's Burner used the same booster but equipped with a 3-axis stabilization system. It was associated to Thor in 1965 to launch meteorological satellites (6 flights: 5 successful).

An enhanced version designated Burner-2 was introduced in Sep 1966. It was based on the use of the Thiokol Star-37B (TE-M-364-2) derived from the retro-rocket of the Surveyor lunar probes. This 94 cm diameter motor weighed 807 kg (including 654 kg propellant) and provided 44.5 kN suring 42 seconds. It was placed inside a 1.65 m diameter cap. This stage was used upon:
- Thor first stage to launch 10 DMSPs and 2 STP satellite
- Atlas first stage to launch STP payloads (2 flights: 1 failure)

Burner-2A was introduced in 1971. It was a 2-stage version with the second stage based on a Star-37D (TE-M-364-15) which performances were close to Star-37B. Il was mounted on Thor first stages to launch DMSP meteorology satellites (13 flights: 2 failures).

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