The New Drop Tower Catapult System

Paper number

IAC-05-A2.5.08

Author

Mr. Peter von Kampen, ZARM Fab mbH, Germany

Coauthor

Mr. Ulrich Kaczmarczik, ZARM - University of Bremen, Germany

Coauthor

Prof. Hans Rath, ZARM - University of Bremen, Germany

Year

2005

Abstract

The Center of Applied Space Technology and Microgravity (ZARM) was founded in 1985 as an institute of the University Bremen, which focuses on research on gravitational and space-related phenomena. In 1988, the construction of the "Drop Tower" began. Since then, the eye-catching tower with a height of 146m and its characteristic glass roof has become the emblem of the technology centre in Bremen. 
The Drop Tower Bremen provides a facility for experiments under conditions of weightlessness. Items are considered weightless, when they are in "free fall", i.e. moving without propulsion within the gravity field of the earth. The height of the tower limits the simple “free fall” experiment period to max. 4,74 sec. 
With the inauguration of the catapult system in December 2004, the ZARM is entering a new dimension. This world novelty will meet scientists' demand of extending the experiment period up to 9,5 sec. Since turning the first sod on May 3rd, 1988, the later installation of the catapult system has been taken into account by building the necessary chamber under the tower. 
The catapult system is located in a chamber 10 m below the base of the tower. This chamber is almost completely occupied by twelve huge pressure tanks. These tanks are placed around the elongation of the vacuum chamber of the drop tube. In its centre there is the pneumatic piston that accelerates the drop capsule by the pressure difference between the vacuum inside the drop tube and the pressure inside the tanks. The acceleration level is adjusted by means of a servo hydraulic breaking system controlling the piston velocity. After only a quarter of a second the drop capsule achieves its lift-off speed of 175 km/h. With this exact speed, the capsule will rise up to the top of the tower and afterwards fall down again into the deceleration unit which has been moved under the drop tube in the meantime.
The scientific advantages of the doubled experiment time are obvious: During almost 10 sec of high-quality weightlessness the range of compatible experiments amplifies even more and researchers can observe processes for a longer period of time. Thus, the new earth-bound laboratory of the ZARM offers unique conditions for scientific research. Moreover, it increases the attractiveness of the Drop Tower and contributes an important part to the establishment of the Bremen as an international centre for space technology.

Abstract document

IAC-05-A2.5.08.pdf

Manuscript document

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