Conceptual study on concise flight test for development of space plane powered by air breathing engine

It is widely recognized that the air breathing engine is one of the key technologies to be acquired to realize future space transportation, especially if it is expected to be cost effective and reliable. Still, as a nature of the air breathing engine, the flight test data are needed for its development. In this paper, the authors propose the flight test plan which utilizes the balloon to test the pre-cooled turbo jet engine. By utilizing the balloon, it is possible to create the preferable test conditions regardless of the engine performance, which is under development and to be tested. As the 1st attempt of a series of flight tests of this type, the simple drop test is planned. At that test, the vehicle will be dropped from the balloon at the altitude of 40km and will be accelerated up to Mach 2. The flight is scheduled in the winter of FY2007, as a part of micro gravity test campaign. Besides the 1st flight campaign, further tests are also discussed. At the latter tests, the vehicle will be equipped with the solid motor, and will achieve Mach 4 and more.