Einstein elevator
The Einstein-Elevator ( English : Elevator stands for elevator system ) is a research platform for earth-based experiments under weightlessness . Compared to the operation of drop towers , a significantly higher repetition rate can be achieved. In addition, the guides achieve less rotational movements than in free fall . The first "flight" of the capsule in the Einstein Elevator took place in October 2019 while research operations will begin in 2020. The facility is part of the Hannover Institute for Technology (HITec) at Leibniz University Hannover .
theory
Albert Einstein's thought experiment on the equivalence principle forms the theoretical basis for the Einstein Elevator , hence the name Einstein Elevator. This means that an observer in a closed room cannot experimentally prove whether the room is, for example, in the gravitational field of the earth with the acceleration of gravity or whether the room experiences an acceleration in space. Likewise, the observer cannot prove whether the room is in space under weightlessness or in free fall in the earth's gravitational field .
Concept and structure
In classic drop towers , such as the Bremen drop tower , the experiment is either dropped in a large vacuum tube in a drop capsule or shot down with a catapult. The Einstein elevator is a modification of the classic drop tower, as the entire tower tube does not serve as a vacuum chamber. Instead, the vacuum is created in a small vacuum chamber, the so-called gondola, into which the experiment carrier is placed. The nacelle is accelerated vertically with the acceleration of gravity by linear motors . This movement largely corresponds to a free fall. The experiment inside the gondola is therefore in weightlessness. It can float for four seconds without a mechanical connection to the gondola.
Unlike a drop tower, not the entire tower but only the gondola has to be evacuated. This results in a repetition rate of up to 300 attempts per day.
construction
The tower construction of the Einstein elevator consists of an inner structure for the drive guidance of the linear motors and an outer structure for the nacelle guidance, since electrical drives and roller guides, such as those used in elevator systems, always generate vibrations. The tower-in-tower construction is intended to ensure that these disruptive influences do not influence the experiments inside the nacelle. The conditions for free fall are met in the Einstein Elevator over a distance of 20 m, which results in a weightlessness of approx. 4 seconds. The payload available for experiments should be a maximum of 1,000 kg with a test vehicle diameter of 1.7 m and a height of the experimental structure of 2 m.
procedure
For an experiment, the gondola is first accelerated upwards with five times the acceleration of gravity until it has reached a speed of around 20 m / s. Linear motors are used for this acceleration. In order for the experiment to detach itself from the bottom of the gondola, after the acceleration phase the gondola is accelerated downwards for a short time, somewhat more strongly than the acceleration of gravity. The gondola is then accelerated downwards as precisely as possible with the acceleration of gravity. In addition, the linear drives compensate for the air and rolling resistance of the nacelle in the nacelle guidance. The experiment experiences a maximum residual acceleration of 10 −6 g. Shortly before the end of the free fall, the gondola is moved downwards slightly less than the acceleration of gravity, so that the experiment touches down again on the gondola in a controlled manner. The nacelle is then brought to a standstill with the help of eddy current brakes .
building
The Einstein elevator is housed in a separate part of the new HITec building, the foundation stone of which was laid in early 2015 and the topping-out ceremony for which took place in mid-2016. The completion of the research building was planned for the end of 2017. The tower-like part of the building has a height of approx. 30 m above ground level and a total height of approx. 40 m. The lowest basement is approx. 10 m below ground level. The concrete shell of the building is mechanically decoupled from the rest of the HITec building, which is intended to avoid interference in the sensitive laboratories.
research
The main research areas at HITec are in the areas of quantum physics, optics and sensors, as well as solid-state physics and geodesy. “In addition to basic research in the field of quantum technologies , the HITec research project aims at the development of new quantum technologies and the implementation of new, highly precise and sensitive quantum sensors.” The Einstein Elevator is used, among other things, to test these new technologies. Because of the high repetition rate of 300 experiments per day, experiments can be carried out statistically / quantitatively with the Einstein Elevator.
Web links
Individual evidence
- ↑ First Flight - successful debut launch of the Einstein-Elevator , press release from HITEC (English)
- ↑ a b The Einstein Elevator website of the Hanover Institute for Technology. Retrieved July 19, 2016.
- ↑ Lotz, C .; Kämper, T .; Berlin, H .; Overmeyer, L .: Innovative Drive and Guide Concept for Experiments under Microgravity in the Einstein-Elevator In: 1st Symposium on Automated Systems and Technologies (AST), reports from ITA Volume 4/2014 , pp. 1–12, Garbsen 2014, ISBN 978-3-944586-84-7 ( online )
- ↑ Lotz, C .; Overmeyer, L: Mechanical replacement models to prove the feasibility of minimal residual accelerations during the free fall phase in the Einstein Elevator In: Logistics Journal Vol. 2013, pp. 199–208.
- ↑ The foundation stone for the new HITec research building was laid on January 27, 2015, as announced by HITtec on February 2, 2015
- ↑ New research building HITec celebrates topping-out ceremony as announcement from HITtec on July 13, 2016
- ↑ Hannoversche Allgemeine Zeitung, June 23, 2016, topping-out ceremony for EUR 34 million research center.
- ↑ Wissenschaftsrat: Recommendations for the Funding of Research Buildings (2012) , pp. 43–47, Cologne 2011 ( online )
Coordinates: 52 ° 23 ′ 16.5 " N , 9 ° 42 ′ 44.7" E