TABLE OF CONTENTS The Phoenix flight test vehicle was developed and tested within the framework of the German ASTRA (Advanced Systems & Technologies for RLV Applications) Program, which is a precursor to the European Future Launcher Preparatory Program (FLPP).70 ,71 The primary objective of the Phoenix project was to demonstrate the unpowered automatic landing of a representative reusable launch vehicle (RLV) configuration. The secondary goal was to generate a flight-validated database incorporating representative models of such vehicles and their systems as well as development tools for future applications. The project had its kick-off in April 2001 and reached its climax with the flight test campaign in May 2004. Although a detailed discussion of several interdisciplinary topics is not within the scope of this book, for the specific aspects of flight data analysis presented in this example, we draw heavily upon the more detailed discussion in Refs. 72 and 73.
RLV configurations compromise between partly contradicting demands derived from various system optimization aspects as well as the different flight phases covering ascent, orbital phase, reentry, hypersonic flight, and landing. The resulting vehicle typically is characterized by a compact shape with small span wings and stabilizers, and a rearward center of gravity location. Such properties challenge an automatic horizontal landing on a runway, which in addition must be performed without engine thrust. The important characteristics and their impact on the landing phase can be summarized as follows: 1) low L/D (5.5 for Phoenix), causing steep approach path;
