A preliminary study of a fin-stabilized solid-fuel rocket booster, the Little Joe Senior, was completed by members of STG. The booster would be capable of propelling a full-size Apollo reentry spacecraft to velocities sufficient to match critical portions of the Saturn trajectory.

The purpose was to provide a simple and fairly inexpensive means of determining, from flight tests, full-scale configuration concepts, systems hardware performance, and vehicle structural integrity. Of particular importance would be the flight testing of the Apollo spacecraft escape system under simulated maximum conditions. On April 6, 1962, NASA submitted a Request for Proposal to bidders on the Little Joe Senior, by that time renamed Little Joe II.