Until a few days ago – when the long-awaited epochal breakthrough of direct proof of gravitational waves was proclaimed at a press conference – in spite of intensive research scientists and researchers failed to verify the existence of gravitational waves as predicted by Albert Einstein's theory of general relativity.
Just on this account, the European Space Agency has sent a satellite into space which is to perform the preparatory work for the direct detection of gravitational waves predicted by Einstein. The central experiment of the mission involves two virtually identical high-precision cubes made of a gold-platinum alloy. These cubes were tested by engineers at Fraunhofer IZFP for their suitability and accuracy, both prerequisites for their smooth operation in space.
LISA Pathfinder is a pre-project of a possible LISA-like mission, which is to track down both, gravitational waves and, in particular, their sources in deep space: Since December 2015, the LISA Pathfinder satellite (Laser Interferometer Space Antenna) was traveling in the outer space to its final orbit. Mid-February, approximately one and a half million kilometers from Earth, LISA Pathfinder carried out the last function tests of the scientific payload.
In early March, the actual, six-month mission is to begin. LISA Pathfinder has been approved by the "Science Programme Committee" of the ESA in November 2000 and launched on December 3, 2015.
Amongst others, two gold-platinum cubes serving as test masses are on board, each being held in a separate vacuum vessel. After reaching the final position in space they are released and then, positioned in zero gravity, floating freely.
Their respective positions – the cubes float in 38 cm distance from each other – have to be stable with considerable precision and must be monitored accordingly. The measurement of the relative accuracy of the positioning in the picometer range is crucial for the success of future gravitational wave experiments.
Another serious criterion for measuring the gravitational waves is given by the shape accuracy of the cubes’ surface structure: Both cubes must have one extremely precisely shaped surface whose deviation from the ideal shape is subject to extremely narrow limits. Only within these limits the provided measures can succeed.
With regard to the fulfillment of these extreme requirements both two kilogram cubes were put to the acid test by Fraunhofer IZFP’s engineers and scientists: In the test laboratories of this Saarland Institute high-frequency ultrasound examinations of the gold cubes’ near-surface regions were carried out, which are able to detect hidden cavities and inclusions down to a scale of 50 micrometers.
These investigations resulted in insights concerning the question of whether the cubes’ gravitational homogeneity is sufficient. Likewise, they substantially affected the decision of which side of each cube is to be processed further to "specular surfaces".
Background information concerning LISA Pathfinder and gravitational waves:
Beside ESA research institutes and industrial enterprises from Italy, Germany, UK, Spain, Switzerland, France and Netherlands participate in LISA Pathfinder (information by Deutsches Raumfahrtzentrum DLR).
As a space systems company Airbus Defence and Space GmbH (Friedrichshafen) is responsible for system integration and verification of the “LISA Technology Package” (LTP) instrument. The subsystems and modules of LTP are provided via the national space agencies and the European Space Agency by a consortium of European companies and research institutes such as the Max Planck Institute for Gravitational Physics or the Albert Einstein Institute in Hannover (AEI).
Sabine Poitevin-Burbes | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP
Volcanoes and glaciers combine as powerful methane producers
20.11.2018 | Lancaster University
Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
15.11.2018 | Faculty of Science - University of Copenhagen
Innsbruck quantum physicists have constructed a diode for magnetic fields and then tested it in the laboratory. The device, developed by the research groups led by the theorist Oriol Romero-Isart and the experimental physicist Gerhard Kirchmair, could open up a number of new applications.
Electric diodes are essential electronic components that conduct electricity in one direction but prevent conduction in the opposite one. They are found at the...
Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.
Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
19.11.2018 | Event News
09.11.2018 | Event News
06.11.2018 | Event News
21.11.2018 | Life Sciences
21.11.2018 | Power and Electrical Engineering
21.11.2018 | Life Sciences