The managers of the Mercury program recognized that the numerous early test flights would have to be accomplished by a far less expensive booster system, so NASA designed the Little Joe rocket which cost $200,000 each.

In January 1958, Max Faget and Paul Purser had worked out in considerable detail on paper how to cluster four of the solid-fuel Sergeant rockets, in standard use at the Wallops Flight Facility in Virginia, to boost a crewed nose cone above the stratosphere.

Faget's short-lived "High Ride" proposal had suffered from comparisons with "Project Adam" at that time, but in August 1958 William Bland and Ronald Kolenkiewicz had returned to their preliminary designs for a cheap cluster of solid rockets to boost full-scale and full-weight model capsules above the atmosphere.

To gain this kind of experience as soon as possible, its designers had to keep the clustered booster simple in concept; it should use solid fuel and existing proven equipment whenever possible, and should be free of any electronic guidance and control systems.

The Missile Division of North American Aviation won the contract on December 29, 1958; and began work immediately in Downey, California, on its order for seven booster airframes and one mobile launcher.

The first of only two booster systems designed specifically and solely for crewed capsule qualifications, Little Joe was also one of the pioneer operational launch vehicles using the rocket cluster principle.

Theoretically enough to lift a spacecraft of about 4,000 pounds (1,800 kg) on a ballistic path over 100 miles (160 km) high, the push of these clustered main engines should simulate the takeoff profile in the environment that the crewed Atlas would experience.

The engineers who mothered Little Joe to maturity knew it was not much to look at, but they hoped that their ungainly rocket would prove the legitimacy of most of the ballistic capsule design concepts, thereby earning its own honor.

The primary test objectives for these solid-fuel-boosted models were an integral part of the development flight program conducted within NASA by the Space Task Group, with Langley and Wallops support.