SM-65B Atlas

Atlas B (SM-65B)
Atlas B (10B) before the launch of SCORE (USAF)
FunctionPrototype ICBM
Expendable launch system
ManufacturerConvair
Country of originUnited States
Launch history
StatusRetired
Launch sitesLC-11, LC-13 & LC-14, CCAFS
Total launches10
Success(es)6
Failure(s)4
First flight19 July 1958
Last flight4 February 1959
Boosters
No. boosters1
Powered by2 XLR-89-5
Total thrust341,130 lbf (1,517.4 kN)
Specific impulse282 s
Burn time135 s
PropellantRP-1/LOX
First stage
Powered by1 XLR-105-5
Maximum thrust86,844 lbf (386.30 kN)
Specific impulse309 s
Burn time240 s
PropellantRP-1/LOX

The Convair SM-65B Atlas, or Atlas B, also designated X-12[1] was a prototype of the Atlas missile. First flown on 19 July 1958, the Atlas B was the first version of the Atlas rocket to use the stage and a half design with an operational sustainer engine and jettisonable booster engine section. Unlike later Atlas models, the Atlas B used explosive bolts to jettison the booster section.

Ten flights were made. Nine of these were sub-orbital test flights of the Atlas as an Intercontinental Ballistic Missile, with five successful missions and four failures. The seventh flight, launched on 18 December 1958, was used to place the SCORE satellite into low Earth orbit, the first orbital launch conducted by an Atlas rocket.