Drop tower Bremen
The drop tower Bremen is a drop tower completed in Bremen in 1990 , which is operated by the Center for Applied Space Technology and Microgravity (ZARM) at the Department of Production Technology at the University of Bremen . It is unique in Europe and enables earth-based experiments under short-term weightlessness .
Structure and technology
The Bremen drop tower is 146 meters high and has a 120 meter high evacuated drop tube inside , in which a drop capsule falls 110 m for 4.74 seconds. During this time there is weightlessness in the capsule. The duration of the capsule in weightlessness can be extended to over 9 seconds using the catapult installed in 2004. The capsule has a diameter of 0.8 meters and a length of 1.6 meters or 2.4 meters, depending on the space required for the respective experiment. It falls into an 8-meter-high collecting container filled with pin-head-sized foam polystyrene balls.
The drop tower consists of a cylindrical reinforced concrete shaft with a conical tip. Inside the tower, the actual fall space is located as a free-standing steel tube, which is decoupled from the wind-related fluctuations in the outer shell.
vacuum
The fall space is evacuated for the fall experiments . This requires 18 pumps with a nominal suction capacity of 32,000 m 3 / h. When a vacuum of 10 Pa (10 −4 bar ) is reached, the experiment can be started. Due to this low residual pressure in the drop tower, a residual acceleration of 10 −6 g 0 is achieved, which exceeds the weightlessness quality of manned orbital platforms. Before the capsule can be recovered and the experiment evaluated, the drop tower is flooded with pre-dried air. This process takes 20 minutes.
It would be sufficient to ventilate only the lower and upper part during the preparation and follow-up of the experiments. However, the cost of the four meter diameter valve at the lower end of the drop area required the developers to instead evacuate the entire 122 meter tube for 1.5 hours for each experiment.
Instead of dropping the capsule in a vacuum, the air friction could also be compensated by an additional drive in order to achieve the acceleration due to gravity . But even a system without mechanical components, for example in the sense of a vertical magnetic levitation train , would have the problem of noises and vibrations generated by the airstream , which would disrupt sensitive experiments.
The catapult
A catapult , which is located in a 10 m deep shaft under the drop tower, hurls the experimental capsule up to the end of the drop tube. The catapult table is connected to a piston that is moved with compressed air from large storage containers. A pressure difference of 3 bar between the vacuum of the drop tube and the storage containers accelerates the catapult table for about a quarter of a second on average with about twenty times the acceleration of gravity to a top speed of 168 km / h. The capsule takes just as long to climb up as it does to fall down. The capsule is weightless during the entire climb and fall phase. The time available for experiments is thus doubled by using the catapult.
Experiments
The drop tower was used to carry out experiments in the areas of fluid mechanics , rheology , combustion , thermodynamics , materials research and biology .
history
The drop tower was built from 1988 to 1990 on the initiative of ZARM founder and head Hans Josef Rath based on plans by Horst Rosengart . The shell was built in 1988/89 and cost more than 24 million DM. Rosengart wrote: “Very soon the idea arose to understand the tower shaft (...) as an integral part of a basic building. So we rejected the ideas, B. a free-standing 'campanile next to the basilica'. In addition to the fact that the placement of the tower in the center of the base building offers functional advantages, the design problem of the base zone in the slim tower structure could also be solved. "
The fall tower was sponsored by the Federal Ministry of Research and Technology, the Federal Ministry of Education and Science, the State of Bremen, the aerospace company MBB-ERNO , the electronics company Krupp Atlas Elektronik and the space company Otto Hydraulik Bremen (OHB System ).
After commissioning in September 1990, around 400 experimental drops are carried out annually in the drop tower. The state of weightlessness is achieved up to three times a day for just under 5 seconds. When the EUR 4.2 million catapult system went into operation on December 2, 2004, the time that can be achieved was doubled.
art
With the title ZARM ZentralAlarmRuheMasse , the German artist AR Penck and his Irish artist colleague Felim Egan from Dublin painted the walls of the catapult room, the underground continuation of the drop tower, in 1992 . At that time the catapult was not installed; it was first upgraded, taking care not to damage the work of art.
The art curator Susanne Hinrichs was working as a student at ZARM and established contact with AR Penck through the Weserburg Museum . She accompanied the creation of the work of art and also actively participated in the implementation. In an exhibition catalog of the Weserburg Museum she tried to interpret the work: “Penck has hardly spoken about what he is aiming at with this work, but the two figures, who come from the right and left, stretch their hands towards each other without really talking to touch, on Michelangelo's depiction of the creation of Adam in the Sistine Chapel . But Penck's Adam on the left is doomed as a human. He stumbles and falls into a black hole. One eye watchful over everything. Two large steel reliefs hang from the viewing platform, hidden from view, on the lower wall. They are the guardians whose job it is to guard the cave for the next 2000 years until one day it is discovered by cave explorers of the future. Penck wanted to create a secret place for art. The room was only open to the public for a few weeks, since then it has only been entered by ZARM's scientific staff and that is entirely in the artist's interest. "
particularities
At the top of the drop tower there is a conference room and a panorama lounge , which can be rented for weddings and other events.
Web links
Individual evidence
- ↑ WEIGHTLESS IN THE BREMEN FALLTOWER. Accessed December 31, 2019 .
- ↑ a b Der Fallturm Bremen , operator's brochure (PDF; 2.6 MB), accessed on March 23, 2016.
- ↑ architecture guide bremen: drop tower , accessed March 23, 2016.
- ↑ Susanne Hinrichs: ZARM ZentralAlarmRuheMasse. A real cave for AR Penck , in: AR Penck: Germany. Works from the Böckmann Collection and other collections , Bremen / Weserburg 2009.
- ^ ZARM website , accessed on January 21, 2018.
Coordinates: 53 ° 6 ′ 36 ″ N , 8 ° 51 ′ 29 ″ E