The #Aerojet #AJ110 #rocket #engine was selected for the #Apollo #spacecraft during the initial design phase, when the plan was to land the entire Command and Service Modules on the Moon directly.
This “direct ascent” plan was abandoned later, but the work to revise the engine would be excessive so it remained.
The AJ110 went on to power the Space Shuttle, the Delta-K upper stage and the Orion capsule.
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