A5067027916- Geophysics and Gravity Measurements
- Spacecraft Design and Technology
- Inertial Sensor and Navigation
- Cosmology and Gravitation Theories
- Spacecraft and Cryogenic Technologies
- Pulsars and Gravitational Waves Research
- Astro and Planetary Science
- Planetary Science and Exploration
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- GNSS positioning and interference
- Ionosphere and magnetosphere dynamics
- Black Holes and Theoretical Physics
- Gamma-ray bursts and supernovae
- Space Satellite Systems and Control
- Relativity and Gravitational Theory
- Cold Atom Physics and Bose-Einstein Condensates
- Geophysics and Sensor Technology
- Quantum Electrodynamics and Casimir Effect
- Quantum Mechanics and Applications
- Advanced Frequency and Time Standards
- Gas Dynamics and Kinetic Theory
- Advanced MEMS and NEMS Technologies
- Dark Matter and Cosmic Phenomena
- Noncommutative and Quantum Gravity Theories
University of Bremen
2012-2025
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
2021-2025
Staats- und Universitätsbibliothek Bremen
2024
SpaceTech (Germany)
2009-2022
Space Micro (United States)
2019-2021
Leibniz University Hannover
2021
Carl von Ossietzky Universität Oldenburg
2005-2010
According to the weak equivalence principle, all bodies should fall at same rate in a gravitational field. The MICROSCOPE satellite, launched April 2016, aims test its validity 10^{-15} precision level, by measuring force required maintain two masses (of titanium and platinum alloys) exactly orbit. A nonvanishing result would correspond violation of or discovery new long-range force. Analysis first data gives δ(Ti,Pt)=[-1±9(stat)±9(syst)]×10^{-15} (1σ statistical uncertainty) for...
The MICROSCOPE mission was designed to test the weak equivalence principle (WEP), stating equality between inertial and gravitational masses, with a precision of 10−15 in terms Eötvös ratio η. Its experimental consisted comparing accelerations undergone by two collocated masses different compositions as they orbited Earth, measuring electrostatic forces required keep them equilibrium. This done ultrasensitive differential accelerometers onboard drag-free satellite. lasted half years,...
We consider axially symmetric, rotating boson stars. Their flat space limits represent spinning Q-balls. discuss their properties and determine domain of existence. Q-balls stars are stationary solutions exist only in a limited frequency range. The coupling to gravity gives rise spiral-like dependence the address limit strong gravitational coupling. For comparison we also spherically symmetric
On August 22, 2014, the satellites GSAT-0201 and GSAT-0202 of European GNSS Galileo were unintentionally launched into eccentric orbits. Unexpectedly, this has become a fortunate scientific opportunity since onboard hydrogen masers allow for sensitive test redshift predicted by theory general relativity. In present Letter we describe an analysis approximately three years data from these including different clocks. For one determine parameter quantifying potential violation combined effects...
We construct axially symmetric, rotating boson stars with positive and negative parity. Their flat space limits represent spinning $Q$-balls. $Q$-balls exist only in a limited frequency range. The coupling to gravity gives rise spiral-like dependence of the mass charge stars. analyze properties these solutions. In particular, we discuss presence ergoregions determine their domains existence.
The Weak Equivalence Principle (WEP), stating that two bodies of different compositions and/or mass fall at the same rate in a gravitational field (universality free fall), is very foundation General Relativity. MICROSCOPE mission aims to test its validity precision $10^{-15}$, orders magnitude better than current on-ground tests, by using masses (titanium and platinum alloys) on quasi-circular trajectory around Earth. This realised measuring accelerations inferred from forces required...
Microgravity eases several constraints limiting experiments with ultracold and condensed atoms on ground. It enables extended times of flight without suspension eliminates the gravitational sag for trapped atoms. These advantages motivated numerous initiatives to adapt operate experimental setups microgravity platforms. We describe design payload, motivations choices, capabilities Bose-Einstein Condensate Cold Atom Laboratory (BECCAL), a NASA-DLR collaboration. BECCAL builds heritage...
Using physical systems as the resource for computation in reservoir computing has two prominent reasons: high dimensional state space and its intrinsic non-linear dynamics. Quantum specifically promise even further improvements to their classical pendants, offering an exponentially scaling with respect system size. How this reflects actual performance of quantum mechanical computer remains, however, unclear. methods from field parameterized cirucits, we show that expressive power a is...
Highly precise optical clocks are advancing rapidly and hold the promise of enabling gravity measurements with unprecedented accuracy, particularly through deployment spaceborne on satellites. Satellite mission simulations need to improve their accuracy alongside, in order be able thoroughly plan such satellite missions interpret correctly. Therefore, we develop a clock model for our simulation tool that incorporates even small relativistic effects as well calculations clock’s...
Satellite formation flying has emerged as a promising approach for high-precision gravity field recovery, complementing and extending the capabilities of double-satellite missions such GRACE GRACE-FO. The use multiple satellites in formations allows improved spatial temporal resolution recovery reducing alising effects.Despite its advantages, maintaining precise satellite over long mission durations poses significant challenges. Orbital perturbations, atmospheric drag, differential...
We study rotating boson stars in five spacetime dimensions. The fields consist of a complex doublet scalar field. Considering two orthogonal planes with both angular momenta equal magnitude, special ansatz for the field and metric allows solutions nontrivial dependence on radial coordinate only. charge equals sum momenta. are globally regular asymptotically flat. For our choice sixtic potential star possess flat limit. curved spacetime.
Abstract The space mission MICROSCOPE dedicated to the test of equivalence principle (EP) operated from April 25, 2016 until deactivation satellite on October 16, 2018. In this analysis we compare free-fall accelerations ( a A and B ) two masses in terms Eötvös parameter <?CDATA $\eta (\text{A,B})=2\frac{{a}_{\mathrm{A}}-{a}_{\mathrm{B}}}{{a}_{\mathrm{A}}+{a}_{\mathrm{B}}}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mi>η</mml:mi>...
This work proposes a new cooperative architecture that using Global Navigation Satellite System (GNSS), Inertial Measurement Unit (IMU) and vehicle-to-vehicle (V2V) observations to obtain robust accurate inter-vehicle state estimation. A cascade structure of relative filter which consists float estimator fixed is presented can take advantage both the multi-sensor data information from Least-squares ambiguity decorrelation adjustment (LAMBDA). Also, baseline estimation method based on...
Modern scientific space missions pose high requirements on the accuracy of prediction and analysis satellite motion. On one hand, accurate orbit propagation models are needed for design preparation a mission. other these mission data itself, thus allowing identification unexpected disturbances, couplings, noises which may affect signals. We present numerical approach Solar Radiation Pressure modelling, is main contributors nongravitational disturbances Earth orbiting satellites. The here...
The evaluation of about 25 years Doppler data has shown an anomalous constant deceleration the deep space probes Pioneer 10 and 11. This observation became known as anomaly (PA) been confirmed independently by several groups. Many disturbing effects that could cause a craft have excluded possible source PA. However, potential asymmetric heat dissipation spacecraft surface leading to resulting acceleration still remains be analysed in detail. We developed method calculate this force with very...
We consider boson shells in scalar electrodynamics coupled to Einstein gravity. The interior of the can be empty space, or harbour a black hole naked singularity. analyze properties these types solutions and determine their domains existence. investigate energy conditions present mass formulae for composite hole--boson shell systems. demonstrate that violate uniqueness.
Abstract This paper focuses on the dedicated accelerometers developed for MICROSCOPE mission taking into account specific range of acceleration to be measured board satellite. Considering one micro-g and even less as full instrument with an objective femto-g resolution, that leads a customized concept high-performance electronics sensing servo-actuations accelerometer test-masses. performance directed payload development plan. In addition very accurate geometrical sensor core, high...
We study the ground state and first three radially excited states of a self-gravitating Bose-Einstein condensate with respect to influence two external parameters, total mass strength interactions between particles. For this we use so-called Gross-Pitaevskii-Newton system. In context especially determine case very high masses where solutions system can be approximated Thomas-Fermi limit. Furthermore, stability properties computed are examined by applying arguments catastrophe theory.
The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) satellites are equipped with high-precision three-axis accelerometers to measure all non-gravitational accelerations acting on the satellites. Precise knowledge of these perturbations is a major prerequisite for successful Field (GFR). Unfortunately, after only one month in orbit accelerometer two produced decreasingly accurate measurements. Due this, GRACE-D data has be replaced by artificial use GFR process. In most existing...
We speculate on the development and availability of new innovative propulsion techniques in 2040s, that will allow us to fly a spacecraft outside Solar System (at 150 AU more) reasonable amount time, order directly probe our (gravitational) neighborhood answer pressing questions regarding dark sector (dark energy matter). identify two closely related main science goals, as well secondary objectives could be fulfilled by mission dedicated probing local sector: (i) begin exploration...