AKA: Hypersonic Weapon And R&D System. Status: Study 1956.
On 6 November 1956 the USAF issued SR-131 for the 455L HYWARDS Hypersonic Weapon And R&D System - an experimental spaceplane to support development of an operational Robo/Brass Bell bomber. HYWARDS was to be capable of carrying out flight research up to Mach 15 and also provide a vehicle to test operational subsystems. Engines considered for the booster included the Chariot 15,900 kgf LF2/Ammonia engine from Bell; the 25,000 kgf LR-105 Atlas sustainer engine; the 27,000 kgf LR-91 Titan I second stage engine; or the 26,000 kgf XLR-99 X-15 engine. Maximum velocity was to be 3.7 km/s at 110 km altitude. First flights would be air-launched. Later tests would be boosted by an ICBM from a launch pad at Cape Canaveral. On 17 June 1957 NACA Langley completed configuration analysis for the spaceplane. For the planned Mach 18 maximum heating velocity at 5000 km range, they recommended a flat-bottomed, delta-shaped vehicle, with the fuselage on the lee side. The hot structure would be water-cooled. By contrast the alternate NACA Ames vehicle design was planned for a maximum of Mach 10 and 3200 km range. It used a mid-wing design, which would result in extreme heating on the fuselage. Langley felt that the cooling requirements of this configuration outweighed the L/D advantage of the aerodynamic configuration. HYWARDS was rolled into the Dynasoar program in October 1957.
The launch of Sputnik spurs immediate actions within the government to accelerate manned spacecraft work. ARDC headquarters consolidated Hywards, Brass Bell, and Robo studies into a three-step abbreviated development plan for System 464L, Dyna-Soar. On the same day a NACA Hypersonic Steering Committee met to consider the best configuration for such a vehicle. Langley's Faget pushed non-gliding ballistic capsules, another NACA group felt lifting bodies were the best solution, but the majority of participants favoured the flat-bottomed glider configuration.