Aircraft

Japan plans to drop-test a subscale hypersonic engine at Mach 2 in 2008. The Japan Aerospace Exploration Agency (JAXA) is developing the pre-cooled-cycle hypersonic turbojet, the Small (S)-Engine, as a subscale testbed for air-breathing propulsion systems in future spaceplanes.

Development of the S-Engine began in 2004 and component testing is to be completed this year. A ground test using gaseous hydrogen is planned by March 2007. “The drop test will take place in 2008. We will drop S-Engine from the Balloon-based Operated Vehicle [BOV],” says JAXA Institute of Aerospace Technology associate senior researcher Tetsuya Sato.

The missile-like BOVs, carried aloft and released by a high-altitude balloon, are normally used by JAXA for microgravity experiments. In 2008 JAXA will drop the S-Engine from 131,000ft (40,000m).

The engine is planned to ignite 30s after being released. If the drop test is successful, the next stage is a M5 windtunnel test to be conducted in 2012.

The S-Engine is 2.2m long, 230mm wide, burns 0.06kg of hy­drogen per second and is ex­pected to generate 1,200N of thrust with an initial specific impulse of 2,100s. A demonstrator engine could be developed between 2013 and 2020.