X-248 Altair

The Altair was a solid-fuel rocket with a fiberglass casing, initially developed for use as the third stage of Vanguard rockets. It was manufactured by Allegany Ballistics Laboratory (ABL) as the X-248. It was also sometimes called the Burner 1.

The X-248 was one of two third-stage designs used during Project Vanguard. Early launches used a stage developed by the Grand Central Rocket Company, but later launches used the X-248 which enabled the Vanguard to launch more massive payloads.

The X-248 was used as the second stage of some early Thor flights. These vehicles were designated "Thor-Burner".

Altairs were used as the third stage of early Delta rockets.

The fourth stage of the Scout rocket also used the "Altair" stage.

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