Fabrizio De Marchi

Sapienza University of Rome | la sapienza · Department of Mechanical and Aerospace Engineering

Complex architectures for wireless communications, digital electronics and space-based navigation interlink several oscillator-based devices such as clocks, transponders and synthesizers. Estimators characterizing their stability are critical for addressing the impact of random fluctuations (noise) on the overall system performance. Manufacturers t...

The NASA Discovery-class mission VERITAS, selected in June 2021, will be launched toward Venus after 2027. In addition to the science instrumentation that will build global foundational geophysical datasets, VERITAS proposed to conduct a technology demonstration for the Deep Space Atomic Clock (DSAC-2). A first DSAC successfully operated in low-Ear...

This paper shows the architecture of a Lunar Radio Navigation System (LRNS) constituted by a small constellation of satellites supported from Earth by a dedicated network of small dish antennas, capable of establishing Multiple Spacecraft Per Aperture (MSPA) tracking at K band and of implementing the novel Same Beam Interferometry (SBI) technique....

The NASA Discovery-class mission VERITAS, selected in June 2021, will be launched towards Venus in 2027. In addition to the science instrumentation that will build global foundational geophysical datasets, VERITAS proposed to conduct a technology demonstration for the Deep Space Atomic Clock (DSAC-2). A first DSAC successfully operated in low-Earth...

Ganymede will be the first icy satellite in the Solar System orbited by a spacecraft, ESA’s JUpiter ICy moons Explorer (JUICE). JUICE launch is scheduled for April 2023 and the arrival at Ganymede is foreseen in 2035. Thanks to the advanced Ka-band radio tracking system, the Geodesy and Geophysics of Jupiter and Galilean Moons (3GM) experiment aboa...

Understanding the processes that led Venus to its current state and will drive its future evolution is a major objective of the next generation of orbiters. In this work we analyze the retrieval of the spin vector, the tidal response, and the moment of inertia of Venus with VERITAS, a NASA Discovery-class mission. By simulating a systematic joint a...

The 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, enabl...

The Geodesy and Geophysics of Jupiter and the Galilean Moons (3GM) experiment aboard the JUpiter ICy moons Explorer (JUICE) will measure the gravity fields of Europa, Callisto and Ganymede. For the first two moons the data will be acquired during flybys, while for Ganymede a 9-months orbital phase is planned. This latter phase is divided in a 5-mon...

The increasing precision of spacecraft radiometric tracking data experienced in the last number of years, coupled with the huge amount of data collected and the long baselines of the available datasets, has made the direct observation of Solar System dynamics possible, and in particular relativistic effects, through the measurement of some key para...

The increasing precision of spacecraft radiometric tracking data experienced in the last number of years, coupled with the huge amount of data collected and the long baselines of the available datasets, has made the direct observation of Solar System dynamics possible, and in particular relativistic effects, through the measurement of some key para...

The precise estimation of helio- and fundamental physics parameters is essential for an accurate modeling of the solar system. The enhancement of radio tracking performances will enable unprecedented measurements of celestial mechanics, approaching the ultimate limits attainable with a single planetary mission. We report in this study the results o...

In this paper we report on measurements on actuation crosstalk, relevant to the gravitational reference sensors for LISA Pathfinder and LISA. In these sensors, a Test Mass (TM) falls freely within a system of electrodes used for readout and control. These measurements were carried out on ground with a double torsion pendulum that allowed us to esti...

A torsion pendulum with 2 soft degrees of freedom (DOF), realized by off-axis cascading two torsion fibers, has been built and operated. This instrument allows simultaneous measurement of force and torque acting on the suspended test mass, approaching free-fall condition down to a few mHz. It was developed for ground testing on two DOFs, before the...

Ground testing with torsion pendulums played a key role in the development and characterization of the Gravitational Reference Sensor (GRS) of LISA-Pathfinder (LPF). We report on a torsion pendulum facility with 2 soft degrees of freedom (DOF), realized by off-axis cascading two torsion fibers. This instrument, developed for testing on two DOFs the...

The validity of General Relativity, after 100 years, is supported by solid experimental evidence. However, there is a lot of interest in pushing the limits of precision by other experiments. Here we focus our attention on the equivalence principle, in particular the strong form. The results of ground experiments and lunar laser ranging have provide...

BepiColombo is a joint ESA/JAXA mission to Mercury with challenging objectives regarding geophysics, geodesy and fundamental physics. The Mercury Orbiter Radioscience Experiment (MORE) is one of the on-board experiments, including three different but linked experiments: gravimetry, rotation and relativity. The aim of the relativity experiment is th...

General relativity is supported by great experimental evidence. Yet there is a lot of interest in precisely setting its limits with on going and future experiments. A question to answer is about the validity of the Strong Equivalence Principle. Ground experiments and Lunar Laser Ranging have provided the best upper limit on the Nordtvedt parameter...

A torsion pendulum with 2 soft degrees of freedom (DOFs), realized by off-axis cascading two torsion fibers, has been built and operated. This instrument helps characterize the geodesic motion of a test mass for LISA Pathfinder or any other free-fall space mission, providing information on cross talk and other effects that cannot be detected when m...

Radio Science Experiments (RSEs) use radio links between spacecraft and Earth to look for changes in the frequency as well as roundtrip light time of signals to investigate geophysical phenomena and for tests of fundamental physics. BepiColombo and Juno are two space missions that will perform RSEs, thanks to a very accurate tracking: to extract th...

In this paper we propose a mathematical model to describe a theoretical device able to simulate an inverse-square force on a test mass moving on a horizontal plane. We use two pulleys, a counterweight, a wire and a smooth rail, in addition to the test mass. The tension of the wire (i.e. the attractive force on the test mass) is determined by the po...

We present a dynamical model for the double torsion pendulum nicknamed “PETER,” where one torsion pendulum hangs in cascade, but off axis, from the other. The dynamics of interest in these devices lies around the torsional resonance, that is at very low frequencies (mHz). However, we find that, in order to properly describe the forced motion of the...

LISA Pathfinder is a mission planned by the European Space Agency to test the key technologies that will allow the detection of gravitational waves in space. The instrument on-board, the LISA Technology package, will undergo an exhaustive campaign of calibrations and noise characterisation campaigns in order to fully describe the noise model. Data...

We develop an analytic model to describe the motion of the RotoTranslational Torsion Pendulum PETER in a wide range of frequencies (from 1mHz up to 10-15Hz). We also try to explain some unexpected features we found in the data with only 1 soft degree of freedom and we estimate values for the misalignment angles and other parameters of the model.

Each LISA PathFinder test mass (TM) will be sensitive to forces along all its 6 Degrees of Freedom (DoFs). Extensive ground testing is required in order to evaluate the influence of cross-talks from the read-out and actuator channels. In the INFN laboratory of Firenze we have developed a facility for a good representation of the free fall condition...

We report on VLT/UVES high-resolution spectra of four members of the old metal-rich open cluster NGC 6253: a main-sequence star, two red-clump stars and a blue straggler. We performed equivalent width analysis and derived Fe, Si, Ca, Ti, Cr and Ni abundances as well as abundance ratios. For our main-sequence star, we obtained a metallicity of (rms)...

LISA Pathfinder (LPF), the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology validation mission for future spaceborne gravitational wave detectors, such as the proposed eLISA mission. LISA Pathfinder, and its scientific payload - the LISA Technology Package - will test, in fl...

Searches for planetary transits carried out in open and globular clusters have yielded to date only a handful of weak, unconfirmed candidates. These results have been interpreted either as being insignificant, or as evidence that the cluster chemical or dynamical environment inhibits the planetary formation or survival. Most campaigns were limited...

We present a general survey of heliocentric LISA orbits, hoping that it might help in the exercise of rescoping the mission. We try to semi-analytically optimize the orbital parameters in order to minimize the disturbances coming from the Earth–LISA interaction. In a set of numerical simulations, we include non-autonomous perturbations and provide...

We derived homogeneous radial velocity measurements for stars located at the turn-off, sub-giant, red-giant branch, red-clump, and blue straggler regions of the cluster. We also analyzed a comparison sample of surrounding field stars. Spectra were obtained with the UVES and GIRAFFE spectrographs at the VLT during three epochs in August 2008. The ph...

The analysis of the noise sources perturbing a test mass (TM) geodesic motion is the main scientific objective of the LISA Technology Package experiment (LTP) on board of the LISA Pathfinder space mission. Information on force noise acting on TMs are obtained with a data reduction procedure involving system parameters. Such parameters can be estima...

Context. One of the most metal-rich open cluster of the Galaxy, NGC 6253 is a target of special interest in the search for extrasolar planets, the study of stellar populations, and the chemical/dynamical evolution of the Galactic disk. Aims: We present the results of two photometric campaigns and a VLT multi-epoch radial velocity survey toward the...

LISA is the upcoming space-based Gravitational Wave telescope. LISA Pathfinder, to be launched in the coming years, will prove and verify the detection principle of the fundamental Doppler link of LISA on a flight hardware identical in design to that of LISA. LISA Pathfinder will collect a picture of all noise disturbances possibly affecting LISA,...

The precursor ESA mission LISA-Pathfinder, to be flown in 2013, aims at demonstrating the feasibility of the free-fall, necessary for LISA, the upcoming space-born gravitational wave observatory. LISA Technology Package (LTP) is planned to carry out a number of experiments, whose main targets are to identify and measure the disturbances on each tes...

LISA Pathfinder, the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology demonstrator for the joint ESA/NASA Laser Interferometer Space Antenna (LISA) mission. The technologies required for LISA are many and extremely challenging. This coupled with the fact that some flight har...

Preparations for the LISA Pathfinder mission have reached an exciting stage. Tests of the engineering model (EM) of the optical metrology system have recently been completed at the Albert Einstein Institute, Hannover, and flight model tests are now underway. Significantly, they represent the first complete integration and testing of the space-quali...

As the launch of LISA Pathfinder (LPF) draws near, more and more effort is being put in to the preparation of the data analysis activities that will be carried out during the mission operations. The operations phase of the mission will be composed of a series of experiments that will be carried out on the satellite. These experiments will be direct...

This paper presents a quantitative assessment of the performance of the upcoming LISA Pathfinder geodesic explorer mission. The findings are based on the results of extensive ground testing and simulation campaigns using flight hardware and flight control and operations algorithms. The results show that, for the central experiment of measuring the...

We calculate the effect of the Earth-Moon (EM) system on the free-fall motion of LISA test masses. We show that the periodic gravitational pulling of the EM system induces a resonance with fundamental frequency 1 yr^-1 and a series of periodic perturbations with frequencies equal to integer harmonics of the synodic month (9.92 10^-7 Hz). We then ev...

The analysis of non-radiative sources of static or time-dependent gravitational fields in the Solar System is crucial to accurately estimate the free-fall orbits of the LISA space mission. In particular, we take into account the gravitational effects of Interplanetary Dust (ID) on the spacecraft trajectories. The perturbing gravitational field has...

The concept that particles in free-fall define geodesic reference frames is at the foundation of General Relativity. Free-falling test-masses are crucial to all experiments aimed at directly measuring curvature caused by celestial bodies, like gravitational waves observatories, and to those probing the limits of General Relativity and alternative t...

The ESA/NASA mission,LISA (Laser Interferometric Space Antenna), will measure gravita-tional waves emitted by astronomical sources, galactic and extra-galactic, at frequencies 10-4 to 10-1 Hz. LISA is a 5-million-km arm-length interferometer whose mirrors are test masses which must be nominally free-falling to a level which does not exceed 3 · 10-1...

The forthcoming generation of space-based gravitational wave observatories will open up a new and never-discovered window onto the Universe. Laser Interferometer Space Antenna is a gravitational wave detector aiming to reveal signals coming from a large number of sources and hence to start up a real gravitational wave astronomy. LISA will be a tria...

This work presents the first high-precision variability survey in the field of the intermediate-age, metal--rich open cluster NGC 6253. Clusters of this type are benchmarks for stellar evolution models. Continuous photometric monitoring of the cluster and its surrounding field was performed over a time span of ten nights using the Wide Field Imager...

The 595 files are listed in the file stars.list, together with the number of individual measurements. Each file xxxxx_y.dat contains the R timeseries of the variable xxxxx_y. The xxxxx number indicates the identifier of the variable, the y number the WFI chip it is belonging to. (4 data files).

Context. We present a photometric and astrometric catalog of 187963 stars located in the field around the old super-metal-rich Galactic open cluster NGC 6253. The total field-of-view covered by the catalog is 34' x 33'. In this field, we provide CCD BVRI photometry. For a smaller region close to the cluster's center, we also provide near-infrared J...

The total field-of-view covered by the catalog is 34'x33'. In this field, we provide CCD BVRI photometry from the MPG/ESO 2.2m telescope. For a smaller region close to the cluster's center, we also provide near-infrared JHK photometry from the Anglo-Australian 3.9m Telescope and from the 2MASS. We derived relative proper motions and calculate clust...

341 Light curves of variable stars located in an area of 42x28arcmin2 centered on the open cluster NGC 6791. Data was taken at Canada-France-Hawaii, Loiano and San Pedro Martir telescopes. (2 data files).

Aims: This work presents a high--precision variability survey in the field of the old, super metal-rich open cluster NGC 6791. Methods: The data sample consists of more than 75,000 high-precision CCD time series measurements in the V band obtained mainly at the Canada-France-Hawaii Telescope, with additional data from S. Pedro Martir and Loiano obs...

Context. Searching for planets in open clusters allows us to study the effects of dynamical environment on planet formation and evolution. Aims. Considering the strong dependence of planet frequency on stellar metallicity, we studied the metal rich old open cluster NGC 6791 and searched for close-in planets using the transit technique. Methods. A t...

Aims: This paper presents a new homogeneous catalogue of blue straggler stars (BSS) in Galactic open clusters. Methods: Photometric data for 216 clusters were collected from the literature and 2782 BSS candidates were extracted from 76 of them. Results: We found that the anticorrelation of BSS frequency vs. total magnitude identified in similar stu...

Photometric catalogue of 2782 candidate blue straggler stars in 76 open clusters, candidates were selected from their position in colour magnitude diagram in 216 open clusters. We give for each cluster and for each candidate blue straggler the basic data. (4 data files).

This PhD thesis presents the analysis of a large sample of photometric data relative to the super metal-rich open clusters NGC6791 and NGC6253. The main goal of the surveys was the search for extrasolar planets using the transits method. I contributed to the extrasolar planet search by making numerical simulations in order to estimate the number of...