Proj 7969 Republic Credit - © Mark Wade

Republic's studies for the Air Force or NACA initial manned space project started at the beginning of 1958. Their unique concept was a lifting re-entry vehicle, termed the Ferri sled.

Republic's spacecraft was a 1,800 kg vehicle of triangular planform with a 75 degree leading-edge sweep. A 60 cm diameter tube ran continuously around the leading and trailing edge. This tube also served as a propellant tank for final-stage, solid-propellant rockets located in each wing tip. The concept was dubbed the Ferri sled, and had been conceived in 1956 by a team led by Antonio Ferri and at the Gruen Applied Science Laboratories.

The pilot was housed in a small compartment on the top side. Aerodynamic and reaction controls would be available to the pilot, but normally he would only monitor the spacecraft systems. Deorbit would be accomplished with a modest retrofire delta V of 8 m/sec followed by varying the lift to drag of the vehicle. A heat-transfer ring in the front of the nose allowed a stabilized glide after re-entry of 5,800 kilometers per hour. The spacecraft had a ballistic coefficient (m/CdA) of 130 kg per square meter. An Inconel heat shield was used and the pilot would experience only low G forces during re-entry. The pilot would eject from the capsule at subsonic speed over the recovery area and parachute down to earth. It was expected that a first manned orbital flight could be achieved 21 months after a go-ahead.

In the January 1958 presentation the spacecraft would be boosted by an Atlas + Polaris booster into a 241 km orbit for a 240 hour mission. Later Republic advocated an all-solid propellant launch vehicle comprised three or four stages. The four stage version consisted of a Minuteman first stage, a Polaris first stage, a Minuteman upper stage, and a Jumbo rocket fourth stage. Republic Aviation representatives briefed both USAF and NACA Headquarters personnel on their concept without much success. A similar Space General concept, the FIRST re-entry Glider, was developed extensively in the 1960's, but never reached flight status.

Design Life: 10 days. Typical orbit: 240 km at 28 deg inclination. Mass: 1,800 kg (3,900 lb).