The goals of SHEFEX-1 are the examination of new bevelling thermal protection system concepts based on plane panels in order to save costs and to collect sensoriy comprehensive flight measuring data, which help to confirm the aerodynamic characteristics of sharp edged configurations and to validate design tools. Using experiences from the development of thermal protection systems the allegation of curved outer contours could be identified with high accuracy as a substantial cost factor. Large, curved fiber-ceramic structures need elaborate manufacturing tools and for each independent element corresponding helping tools and optimized manufacturing procedures. A possible cost saving potential represents therefore the simplification of the outer contour by dissolution into few, flat surfaces. In general plates-shaped panels can be made of a basic form and adapted by simply cutting. This also leads to considerable savings in maintenance and the exchange of damaged elements. Flow-technically however problems at the edges and corners result during the re-entry.
On the edges and corners very high temperatures arise, which must be controlled by new technologies, such as actively cooled elements. Aerodynamically however advantages arise in the hypersonic flight as a result of this shaping, since in this speed range outlines with sharp front edges produce slighter drag. The SHEFEX-1 experiment served the investigation of this new structural and aerodynamic design approach for space transport systems. Additionally new sensors are tested, which make it possible to compare test data and computational forecasts gained on the ground in special plasma wind tunnels with real material flight data.
SHEFEX-I launched on 28 October 2005 on a two-stage sounding rocket of the Norwegian launch site on the island Andoya close to the city Andenes. After launching SHEFEX-1 reached a height of 200 km over the Norwegian Sea and re-entered the earth’s atmosphere afterwards within 20 seconds with nearly septublicate speed of sound. All measuring data of this flight section as well as live pictures of an on-board camera were transferred directly to the ground station. During activation of the parachute system however an error arose, which led to the loss of the parachute system and thus the flying unit of SHEFEX-1. Evaluation of the measuring data supplied however important realizations, which let SHEFEX-1 become a big success.
During the following project SHEFEX -II the development and flight testing of return technologies on a hypersonic altitude flight rocket engine shall be consequently continued on the basis of SHEFEX-1 and the system ability shall be further developed for the execution of flight experiments. While maintaining substantial elements of the SHEFEX -1 configuration expertise and results from this flight are used for improvements and as a basis for new experiments. The flying range can be extended with the help of a more efficient launcher system to a speed of up to Mach 11 and the re-entry phase to up to 60 seconds.
The emphasis of SHEFEX -II is on active control of the pay load in the re-entry phase, in order to obtain homogeneous flow conditions for the remaining experiments. Beside the automated aero-dynamic control and appropriate ceramic control surfaces, core experiments are integrated to the sensor technology, active thermal protection cooling, high temperature antennas and passenger experiments in the pay load. Apart from wind tunnel tests simulation tools are developed further for the determination of the flow conditions. This combination and synergetic addition of single technologies and competences of the DLR make it possible to capture a top position in Europe in the areas of space transport, return technology and the hypersonic technology. Within the DLR the competence in the domains aerodynamics, flight control, launcher system, thermal protection, structure and materials is bundled. It is further intended to take up passenger experiments from the national and/or international industry or research establishments within SHEFEX-II. The launch is planned for spring 2010 from the Andoya Rocket Range in Norway again.