scholarly journals Gravity, Geodesy and Fundamental Physics with BepiColombo’s MORE Investigation

2021 ◽  
Vol 217 (1) ◽  
Author(s):  
L. Iess ◽  
S. W. Asmar ◽  
P. Cappuccio ◽  
G. Cascioli ◽  
F. De Marchi ◽  
...  
Keyword(s):  
Accurate Estimation ◽  
Radio Link ◽  
Fundamental Physics ◽  
Radio Science ◽  
Tests Of General Relativity ◽  
Space Navigation ◽  
Scientific Results ◽  
Range Rate ◽  
Pseudo Noise ◽  
Free Environment

AbstractThe Mercury Orbiter Radio Science Experiment (MORE) of the ESA mission BepiColombo will provide an accurate estimation of Mercury’s gravity field and rotational state, improved tests of general relativity, and a novel deep space navigation system. The key experimental setup entails a highly stable, multi-frequency radio link in X and Ka band, enabling two-way range rate measurements of 3 micron/s at nearly all solar elongation angles. In addition, a high chip rate, pseudo-noise ranging system has already been tested at 1-2 cm accuracy. The tracking data will be used together with the measurements of the Italian Spring Accelerometer to provide a pseudo drag free environment for the data analysis. We summarize the existing literature published over the past years and report on the overall configuration of the experiment, its operations in cruise and at Mercury, and the expected scientific results.

scholarly journals Geodesy, Geophysics and Fundamental Physics Investigations of the BepiColombo Mission

2021 ◽  
Vol 217 (2) ◽  
Author(s):  
Antonio Genova ◽  
Hauke Hussmann ◽  
Tim Van Hoolst ◽  
Daniel Heyner ◽  
Luciano Iess ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Surface Composition ◽  
Current Knowledge ◽  
Laser Altimeter ◽  
Fundamental Physics ◽  
Radio Science ◽  
Nasa Mission ◽  
Gravity And Magnetic ◽  
Working Groups ◽  
Science Investigations

AbstractIn preparation for the ESA/JAXA BepiColombo mission to Mercury, thematic working groups had been established for coordinating the activities within the BepiColombo Science Working Team in specific fields. Here we describe the scientific goals of the Geodesy and Geophysics Working Group (GGWG) that aims at addressing fundamental questions regarding Mercury’s internal structure and evolution. This multidisciplinary investigation will also test the gravity laws by using the planet Mercury as a proof mass. The instruments on the Mercury Planetary Orbiter (MPO), which are devoted to accomplishing the GGWG science objectives, include the BepiColombo Laser Altimeter (BELA), the Mercury orbiter radio science experiment (MORE), and the MPO magnetometer (MPO-MAG). The onboard Italian spring accelerometer (ISA) will greatly aid the orbit reconstruction needed by the gravity investigation and laser altimetry. We report the current knowledge on the geophysics, geodesy, and evolution of Mercury after the successful NASA mission MESSENGER and set the prospects for the BepiColombo science investigations based on the latest findings on Mercury’s interior. The MPO spacecraft of the BepiColombo mission will provide extremely accurate measurements of Mercury’s topography, gravity, and magnetic field, extending and improving MESSENGER data coverage, in particular in the southern hemisphere. Furthermore, the dual-spacecraft configuration of the BepiColombo mission with the Mio spacecraft at higher altitudes than the MPO spacecraft will be fundamental for decoupling the internal and external contributions of Mercury’s magnetic field. Thanks to the synergy between the geophysical instrument suite and to the complementary instruments dedicated to the investigations on Mercury’s surface, composition, and environment, the BepiColombo mission is poised to advance our understanding of the interior and evolution of the innermost planet of the solar system.

Didymos Gravity Science Investigations through Ground-based and Inter-Satellite Links Doppler Tracking

2021 ◽  
Author(s):  
Paolo Tortora ◽  
Marco Zannoni ◽  
Edoardo Gramigna ◽  
Riccardo Lasagni Manghi ◽  
Sebastien Le Maistre ◽  
...  
Keyword(s):  
Gravity Field ◽  
Low Frequency ◽  
Imaging Data ◽  
Satellite Link ◽  
Asteroid Impact ◽  
Radio Science ◽  
Combining Data ◽  
Planetary Defense ◽  
Global Mapping ◽  
Range Rate

<p>The Asteroid Impact and Deflection Assessment (AIDA) is an international collaboration supported by ESA and NASA to assess the feasibility of the kinetic impactor technique to deflect an asteroid, combining data obtained from NASA’s DART and ESA’s Hera missions. Together the missions represent the first humankind’s investigations of a planetary defense technique. In 2022, DART will impact Dimorphos, the secondary of the binary near-Earth asteroid (65803) Didymos.  After 4 years, Hera will follow-up with a detailed post-impact survey of Didymos, to fully characterize and validate this planetary defense technique. In addition, Hera will deploy two CubeSats around Didymos once the Early Characterization Phase has completed, to augment the observations of the mother spacecraft. Juventas, the first Cubesat, will complete a low-frequency radar survey of the secondary, to unveil its interior. Milani, the second Cubesat, will perform a global mapping of Didymos and Dimorphos, with a focus on their compositional difference and their surface properties. One of the main objectives of Hera is to determine the binary system’s mass, gravity field, and dynamical state using radio tracking data in combination with imaging data. The gravity science experiment includes classical ground-based radiometric measurements between Hera and ground stations on Earth by means of a standard two-way X-band link, onboard images of Didymos, and spacecraft-to-spacecraft inter-satellite (ISL) radiometric tracking between Hera and the Cubesats. The satellite-to-satellite link is a crucial add-on to the gravity estimation of low-gravity bodies by exploiting the Cubesats’ proximity to the binary, as the range-rate measurements carried out by the inter-satellite link contain information on the dynamics of the system, i.e., masses and gravity field of Didymos primary and secondary.</p><p>We will describe the updated mission scenario for the Hera radio science experiment to be jointly carried out by the three mission elements, i.e., Hera, Juventas and Milani. To conclude, our updated analysis and latest results, as well as the achievable accuracy for the estimation of the mass and gravity field of Didymos and Dimorphos, are presented.</p>

scholarly journals Аstronomical observatory of Taras Shevchenko National University of Kyiv in 2018

2019 ◽  
pp. 48-51
Author(s):  
V. Efimenko
Keyword(s):  
Cosmic Rays ◽  
Solar System ◽  
High Energy ◽  
Astronomical Observatory ◽  
Small Bodies ◽  
Fundamental Physics ◽  
Potential Source ◽  
National University ◽  
Wave Research ◽  
Scientific Results

At the beginning of 2017, 53 workers worked in the State Astronomical Observatory, of which 28 were scientists, including 6 doctors of sciences and 17 candidates of sciences. The structure of the observatory includes the sector astrometry and the small bodies of the solar system (the head of the sector is Kleshchonok V.V., Ph.D), the department of astrophysics (the head of the department is professor Zhdanov V.I., doctor of Science) and 2 observation stations (Lisnyky, Pylypovychi). During the year budget topics were carried out: “Fundamental physics and models of high-energy astrophysical phenomena”, scientific leader professor Zhdanov V.I., doctor of Science; “Cosmic factors of terrestrial cataclysms: observation, analysis, informatization”, scientific leader Rosenbush V.K., doctor of Science. Young scientists of the Observatory won the competition for financing the youth theme “Multi-wave research of cosmic sources of gamma radiation in the framework of the STA project”, scientific leader Ponomarenko V.O., Ph.D. Main scientific results. The potential source of the triplet of cosmic rays with energies above 1020 eV – magnetar SGR 1900 + 14 is found. The possible manifestations of the acceleration of the cosmic rays by the remnant of the Nebula, in which the magnetar SGR 1900 + 14 was born, was investigated. In order to monitor potentially dangerous bodies of the solar system at the observatory station (Lisnyky) 3323 observations were received from 70 comets and 103 asteroids, 3 new asteroids (2017 ST39, 2017 SV39, 2017 TS7) were officially confirmed by the International Center for Small Planets. In 2017, the staff of the Observatory published 4 monographs, 81 scientific articles, 36 of them in foreign publications; 78 reports have been made at 12 conferences.

Inflight performance of the state-of-the-art BepiColombo MORE radio-tracking system 

2021 ◽  
Author(s):  
Paolo Cappuccio ◽  
Luciano Iess ◽  
Daniele Durante ◽  
Ivan di Stefano ◽  
Paolo Racioppa ◽  
...  
Keyword(s):  
Water Vapor ◽  
Tracking System ◽  
Weather Conditions ◽  
Integration Time ◽  
Path Delay ◽  
Noise Component ◽  
Ka Band ◽  
Range Measurements ◽  
Radio Science ◽  
Range Rate

<p>The ESA/JAXA mission BepiColombo, launched on 20 October 2018 is in cruise towards Mercury and will arrive at Mercury in 2025 to investigate its surface, interior structure and magnetosphere. The Mercury Orbiter Radio-science Experiment (MORE) onboard the Mercury Planetary Orbiter (MPO) aims at determining the gravity field, the rotational state and librations of the planet, using precise tracking of the spacecraft during its orbital phase around Mercury. Range and range-rate measurements collected during the cruise phase will be used to test the theory of general relativity starting in March 2021. The MORE experiment exploits two-way multifrequency microwave links from ESA and NASA: two downlinks in X- and Ka-band coherent with the X-band uplink and one Ka-band downlink coherent with the Ka-band uplink. The range-rate and range measurements accurately BepiColombo’s line-of-sight velocity and the round-trip light-time of the signal, respectively. The calibration of the dispersive plasma noise component through the combination of the X/X, X/Ka and Ka/Ka links and the use of water vapor radiometers to correct for the path delay due to Earth’s troposphere will result in an accuracy of ~3 µm/sec (at 1000-s integration time) on the Doppler and centimeter-level range accuracies. We report on the analysis of dedicated tests executed on range and Doppler data collected by ESA and NASA stations at X and Ka-band. The comparison of the observed noise with the predictions shows results exceeding the expectations. In particular, the 24 Mcps pseudo-noise modulation of the Ka-band carrier, enabled by MORE’s KaT transponder built by Thales Alenia Space Italia, provided two-way range measurements accurate to ~3 cm with just 4 s integration time, at a distance of 0.7 AU, September 2021, and 1.3 AU, November 2021. Under favorable weather conditions, the range rate has shown an accuracy of 25 µm/s at 10 s integration time, in line with the expected end-to-end performance. Under unfavorable weather conditions the performance was slightly over the requirements. We must remark that calibrations from water vapor radiometers were not available during these tests and only GNSS calibration were applied.</p>

ATOMIC CLOCKS AND PRECISION MEASUREMENTS

2007 ◽  
Vol 16 (12b) ◽  
pp. 2495-2497 ◽  
Author(s):  
KURT GIBBLE
Keyword(s):  
High Stability ◽  
Systematic Errors ◽  
Precision Measurements ◽  
Atomic Clocks ◽  
Fundamental Physics ◽  
Space Navigation ◽  
Microwave Cavities ◽  
Physics Program ◽  
Atomic Recoil ◽  
Stability And Accuracy

We present a review of our clock science conducted under the NASA Microgravity Fundamental Physics program. Our work has led to the development of rubidium atomic clocks, designs for ground- and space-based clocks that juggle atoms to achieve ultrahigh stability and accuracy, improved microwave cavities for atomic clocks, and elucidation of new systematic errors such as the atomic recoil from microwave photons. High stability clocks can be used for precise tests of fundamental physics and accurate deep-space navigation.

MoMo’s prediction of Mars’ ionosphere contribution to InSight RISE Doppler data

2020 ◽  
Author(s):  
sebastien Le Maistre ◽  
Nicolas Bergeot ◽  
Olivier Witasse ◽  
Pierre-Louis Blelly ◽  
Wlodek Kofman ◽  
...  
Keyword(s):  
Liquid Core ◽  
Radio Link ◽  
Electron Content ◽  
Interior Structure ◽  
Science Data ◽  
Total Electron ◽  
Radio Science ◽  
The Earth ◽  
X Band ◽  
Doppler Data

<p><span>The NASA InSight mission is operating from the surface of Mars for more than a year. RISE (for Rotation and Interior Structure Experiment) is one of the scientific payloads of InSight. This radio-science experiment consisting in an X-band transponder and two horn-antennas enabling two-way coherent radio-link between Mars and the Earth [Folkner et al., 2018]. The main goal of RISE is to measure the slight modulations of the nutational motion of the spin axis of Mars induced by the liquid core of the planet in order to constrain its interior structure and core properties. To increase our chance to achieve this challenging goal, we must calibrate the RISE Doppler data by accounting to 2<sup>nd</sup> order effects like the Mars atmospheric noise. </span></p><p><span>This study shows the predicted contribution of the Martian ionosphere to the RISE data collected so far. To do so, we use a new empirical model of the Mars’ ionosphere called MoMo [Bergeot et al. 2019]. This model is based on the large database of Total Electron Content (TEC) derived from the subsurface mode of the Mars Express MARSIS radar. The model provides the vertical TEC as a function of solar zenith angle, solar activity, solar longitude and the location. Using MoMo, we produce vTEC maps for Mars that are then used to estimate the slant TEC in the Earth line of sight, enabling to infer the phase delay and Doppler shift affecting the RISE X-band measurements. These computed effects are shown to be of the order of 10<sup>-3</sup>mm.s<sup>-1</sup> in Doppler observables, with a larger effect around sunrise and sunset. This is about one order of magnitude below the typical measurement noise of RISE, but it is comparable to the contribution of the liquid core in the Doppler (~10<sup>-3</sup>-10<sup>-2</sup>mm.s<sup>-1</sup>).</span></p><p><span>The MoMo model is suitable for any Mars radio-science data calibration, and in particular the forthcoming ExoMars 2020 LaRa measurements [Dehant et al. 2019]. The predictions made with MoMo will be of great use either for the data corrections or to define the timing of observations in order to avoid operating when the TEC rapidly varies (i.e. close to sunrise and sunset). The model output is further discussed here in terms of climatologic behavior of the Mars’ ionosphere. For comparison, we also investigate the contribution of the Earth ionosphere using Global Ionospheric Maps (GIMs) based on GNSS data.</span></p>

scholarly journals Pulsars as probes of gravity and fundamental physics

2016 ◽  
Vol 25 (14) ◽  
pp. 1630029 ◽  
Author(s):  
Michael Kramer
Keyword(s):  
Strong Field ◽  
Direct Detection ◽  
Field Tests ◽  
Dense Matter ◽  
Experimental Tests ◽  
Fundamental Physics ◽  
Tests Of General Relativity ◽  
Pulsar Timing ◽  
Wide Range ◽  
Tests Of Gravity

Radio-loud neutron stars known as pulsars allow a wide range of experimental tests for fundamental physics, ranging from the study of super-dense matter to tests of General Relativity (GR) and its alternatives. As a result, pulsars provide strong-field tests of gravity, they allow for the direct detection of gravitational waves in a “pulsar timing array” (PTA), and they promise the future study of black hole properties. This contribution gives an overview of the on-going experiments and recent results.

scholarly journals Sensitivity limit investigation of a Sagnac gyroscope through linear regression analysis

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Angela D. Di Virgilio ◽  
Carlo Altucci ◽  
Francesco Bajardi ◽  
Andrea Basti ◽  
Nicolò Beverini ◽  
...  
Keyword(s):  
Rotation Rate ◽  
Linear Regression Analysis ◽  
Sensitivity Limit ◽  
Angular Rotation ◽  
Fundamental Physics ◽  
Tests Of General Relativity ◽  
The Earth ◽  
Theoretical Investigations ◽  
Sagnac Gyroscope

AbstractThe sensitivity to angular rotation of the top class Sagnac gyroscope GINGERINO is carefully investigated with standard statistical means, using 103 days of continuous operation and the available geodesic measurements of the Earth angular rotation rate. All features of the Earth rotation rate are correctly reproduced. The unprecedented sensitivity of fractions of frad/s is attained for long term runs. This excellent sensitivity and stability put Sagnac gyroscopes at the forefront for fundamental physics, in particular for tests of general relativity and Lorentz violation, where the sensitivity plays the key role to provide reliable data for deeper theoretical investigations.

The Gran Sasso National Laboratory

2020 ◽  
Author(s):  
Matthias Laubenstein
Keyword(s):  
Dark Matter ◽  
Nuclear Physics ◽  
Earth Science ◽  
National Laboratory ◽  
Central Italy ◽  
Solar Neutrinos ◽  
Double Beta Decay ◽  
Fundamental Physics ◽  
Scientific Results ◽  
Rare Phenomena

<p><span>In order to explore the highest energy scales that cannot be reached with accelerators, underground laboratories provide the low radioactive background environment necessary to search for extremely rare phenomena. Experiments range from the direct search for dark matter that constitutes the largest fraction of matter in the Universe, to the exploration of the properties of the neutrinos, the most elusive of the known particles and which might be particle and antiparticle at the same time, and to the investigation on why our universe contains only matter and almost no antimatter, and much more.</span></p><p><span>The Gran Sasso underground laboratory is one of the four Italian national laboratories run by the INFN (Istituto Nazionale di Fisica Nucleare). It is located under the Gran Sasso massif, in central Italy. To date it is one of the largest underground laboratories for astroparticle physics in the world and the most advanced in terms of complexity and completeness of its infrastructures. The scientific program at the Gran Sasso National Laboratory (Laboratori Nazionali del Gran Sasso, LNGS) is mainly focused on astroparticle, particle and nuclear physics. The laboratory presently hosts many experiments as well as R&D activities, including world-leading research in the fields of solar neutrinos, dark matter, neutrinoless double-beta decay and nuclear cross-section measurements of astrophysical interest. Other branches of sciences like earth science, biology and fundamental physics complement the activities carried out. The laboratory is operated as an international science facility and hosts experiments whose scientific merit is assessed by an international advisory Scientific Committee. A review of the main experiments carried out at LNGS will be given, together with the most recent and relevant scientific results achieved.</span></p>

scholarly journals REVIEW OF NOISE FILTERING ALGORITHM FOR PHOTON DATA

2020 ◽  
Vol XLII-3/W10 ◽  
pp. 105-110
Author(s):  
J. P. Huang ◽  
Y. Q. Xing ◽  
L. Qin
Keyword(s):  
Forest Structure ◽  
Structural Parameters ◽  
Photon Counting ◽  
Accurate Estimation ◽  
Noise Filtering ◽  
Laser Altimeter ◽  
Cloud Data ◽  
Filtering Algorithm ◽  
Ice Cloud ◽  
Scientific Results

Abstract. As a continuation of Ice, Cloud, and Land Elevation Satellite-1 (ICESat-1)/Geoscience Laser Altimeter System (GLAS), the Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) , which is equipped with the Advanced Topographic Laser Altimeter (ATLAS) system, was successfully launched in 2018. Since ICESat-1/GLAS has facilitated scientific results in the field of forest structure parameter estimation, how to use the ICESat-2/ATLAS photon cloud data to estimate forest structure parameters has become a hotspot in the field of spaceborne photon data application. However, due to the weak photon characteristics of the ICESat-2/ATLAS system, the system is extremely susceptible to noise, which poses a challenge for its subsequent accurate estimation of forest structural parameters. Aiming to filter out the noise photons, the paper introduces the advantages of the spaceborne lidar system ICESat-2/ATLAS than ICESat-1/GLAS. The paper summarizes the research of the simulated photon-counting lidar (PCL) noise filtering algorithm and noise filtering on spaceborne.

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