Hypersonic manned reconnaissance spaceplane project of the 1950's. Predecessor to Dynasoar.

WS-459L, Brass Bell, was the topic of a $746,000 contract awarded to Bell on 20 March 1956. This superseded earlier work on their Bomi concept. In November 1956 the Air Force asked NACA to review the Bell and Boeing work on hypersonic manned aircraft. By December 1956 Bell had had firmed up their design. A derivative of the Atlas ICBM would boost the basic manned glider to 5.4 km/sec at 50 km, allowing a glide range of 8800 km. Use of two such boosters in parallel as a first stage, with the basic booster as a second stage, would provide the glider with a maximum speed of 6.7 km/sec, and a range of 18,500 km, similar to that of the MX-2276 study of a year earlier. This concept was similar to that the company would submit for the Robo space bomber contract. Brass Bell work was rolled into the Dynasoar program in 1957. By that time total Brass Bell expenditures had reached $1.2 million.

• 1956 March 20 - Brass Bell. -
  The Air Force and Bell Aircraft Company completed negotiations for a study contract involving Reconnaissance System 459L, Brass Bell.

• 1957 April 30 - Development plan encompassing all hypersonic weapon systems. -
  Air Force headquarters directed the Air Research and Development Command to formulate a development plan encompassing all hypersonic weapon systems.

• 1957 October 10 - Hywards, Brass Bell, and Robo consolidated into Dyna-Soar. -
  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.