The North American Phase B design was prepared under contract NAS9-10960 and reflected the final revised shuttle specification of 11 November 1970. NAR-134-B was North American's original high cross range configuration. The delta wing had turned-up wingtips, as on the X-20 Dynasoar spaceplane of the 1960's. The orbiter was 43.4 m long, with a 38.4 m wingspan and stood 15 m high. The air-breathing cruise engines were mounted in swing-down nacelles that deployed from the belly of the orbiter. The spacecraft weighed 98,745 kg empty, and had a 9,100 kg payload. The orbiter had a 2784 km cross-range, using titanium in the wing structure, and Hynes-188 and Inconel-718 panels for the thermal protection system. The re-entry involved an initial nose-up angle of 55 deg, followed by a pitch over to 35 deg after peak heating, followed by bank manoeuvres as required to achieve the cross-range for the mission. The orbiter had a hypersonic L/D of 0.7 during the peak heating/braking manoeuvre; and 2.2 at 20 deg angle of attack for the bank manoeuvres; and 6.9 subsonic. Landing speed would be 213 kph.
The B8G booster was designed by Convair and had a conventional vertical tail and horizontal stabiliser, as opposed to the 'V' tail used for the low-cross-range orbiter's booster. In three minutes it would take the orbiter to 70,000 m and 11,000 kph, hitting a peak of 4G's. After separation of the orbiter, it would spend 10 minutes in a hypersonic braking glide, finally starting its air breathing engines at subsonic speed when 500 km downrange and 6700 m altitude. The subsonic cruise back to base would take 90 minutes. The boostter had a 0.5 hypersonic L/D, and 6.7 ?/D subsonic. It was equipped with 12 x 188,000 kgf SSME engines.
In the Phase B Final Report these shuttle designs was modified. The North American Rockwell/Convair team's booster was now the B9U configuration, 82 m long with a 43.6 m wingspan. Propulsion had grown to 12 x 249,000 kgf main engines, and 12 x JF22A-4 air breathing engines powered by JP-4 fuel. The NAR-161-C delta wing orbiter had replaced the upturned wingtips with a conventional vertical stabiliser.
In late 1969 the USAF had indicated a preference for all-aluminium structures in the shuttle due to a titanium shortage. This requirement forced a move to non-metallic thermal protection systems, which at the time it was thought would weigh 15% less but cost 300% more. Thermal protection shingles for a titanium structure would weigh 2300 to 4500 kg less, but an aluminium structure would weight about 1800 kg more - meaning there was no essential weight difference between the two approaches. Therefore at the aluminium structure was accepted as a specification requirement. In retrospect it could hardly have been necessary to apply this requirement on a project where only a few flight vehicles were be built. It made the shuttle much more vulnerable to any breach of heat shield integrity and would lead to the death of the Columbia crew 35 years later. The resulting need for a non-metallic thermal protection system would also have enormous cost and schedule consequences for the actual program.
Stage Data - Shuttle R134C
Status: Study 1970.
Gross mass: 2,188,488 kg (4,824,790 lb).
Height: 98.00 m (321.00 ft).
Diameter: 10.37 m (34.02 ft).
Thrust: 25,564.10 kN (5,747,038 lbf).