Following the lead of France with its Hermes spaceplane, Germany and the major German aerospace industries are investing considerable resources in the preliminary design and technology development of an advanced transportation system with hopes that ESA will adopt the program for full-scale development and operation. Named in honor of the German engineer whose pioneering work in the first half of the 20th century fostered the present-day concept, DASA's Sanger project is based on a two-stage, fully reusable aerospace plane which would take off and land horizontally like conventional aircraft.
The first stage is a large (>80 m long, >40 m wing-span), unmanned hypersonic aircraft powered by hybrid, air-breathing turbo-ramjets to carry a smaller Hypersonic Orbital Reusable Upper Stage (HORUS) to an altitude of approximately 40 km. HORUS would then separate at a speed of more than Mach 6 and ignite conventional liquid oxygen/liquid hydrogen engines to reach LEO. With a 4-man crew, HORUS would be capable of delivering up to three metric tons to a baseline 450-km, 28.5 inclination orbit. An unmanned version of HORUS, HORUS-C, could deliver up to seven metric tons of cargo and return a like amount to Earth.
Currently sponsored by the Federal Ministry of Research and Technology under Phase 1 of the German Hypersonics Technology Program (HTP) begun in 1988 and extended to 1995, Sanger requires international cooperation to move into Phase 2 which would develop a hypersonic flight demonstrator by about the year 2000. However, in 1994 Germany joined ESA's FESTIP where it hopes to continue its hypersonics technology research.
Meanwhile, Germany is continuing state-of-the-art technology development of turbo-ram jet engines and is designing semi-reusable, single stage-to-orbit (SSTO) space transportation systems. The latter is represented by the ADLER concept with a 60 metric ton payload capacity to a 450-km, low-inclination Earth orbit. ADLER's Reusable Acceleration and Avionics Module (RAAM) may be powered by either nine Russian RD-0120 or nine US SSME cryogenic engines (References 61-67).
In the near-term Germany is working with the Russian Federation to develop two commercial, low capacity launch vehicles. In 1994 DARA funded feasibility studies for the proposed air-launched (from a Tu-160 aircraft) Burlak booster with a maximum payload capacity of 1,100 kg (Reference 68). Likewise, DASA was evaluating the commercial potential of the Russian Rokot launch vehicle (up to 2,000 kg capacity), which conducted its first orbital mission in December 1994 (see the section on Russian space transportation for additional specifications of the Burlak and Rokot launch vehicles).
61. Reusable Space Transportation Systems. Reference Concept Sanger , MBB/Deutsche Aerospace, August 1992.
62 DARA Information 1991. Space Research for a Global Perspective, DARA, June 1991.
63. A Look at the Future, DLR, April 1991.
64. E Hogenauer, "Hot Off the Runway", Space Technology International , 1989, pp. 114-115.
65. "International Cooperation in the Peaceful Uses of Outer Space: Activities of Member States - Germany", United Nations, A/AC-105/567/Add.3, 23 February 1994.
66. Germans Pledge Support for Launch Vehicle Study", Space News, 15-28 November 1993, p. 17.
67. J. Spies, "The ADLER Vehicle Concept and Its Key Technologies", Proceedings of the European Forum on Space Transportation Systems, ESA SP-362, March 1994, pp. 95-108.
68. J.M. Lenorovitz, "Germany's DARA Studies Russian Burlak Booster", Aviation Week and Space Technology, 27 June 1994, pp. 73-75.