Low energy high angular resolution neutral atom detection by means of micro-shuttering techniques: the BepiColombo SERENA/ELENA sensor

The neutral sensor ELENA (Emitted Low-Energy Neutral Atoms) for the ESA cornerstone BepiColombo mission to Mercury (in the SERENA instrument package) is a new kind of low energetic neutral atoms instrument, mostly devoted to sputtering emission from planetary surfaces, from E ~20 eV up to E~5 keV, within 1-D (2x76 deg). ELENA is a Time-of-Flight (TOF) system, based on oscillating shutter (operated at frequencies up to a 100 kHz) and mechanical gratings: the incoming neutral particles directly impinge upon the entrance with a definite timing (START) and arrive to a STOP detector after a flight path. After a brief dissertation on the achievable scientific objectives, this paper describes the instrument, with the new design techniques approached for the neutral particles identification and the nano-techniques used for designing and manufacturing the nano-structure shuttering core of the ELENA sensor. The expected count-rates, based on the Hermean environment features, are shortly presented and discussed. Such design technologies could be fruitfully exported to different applications for planetary exploration.Comment: 11 page

Exospheric Na distributions along the Mercury orbit with the THEMIS telescope

Abstract The Na exosphere of Mercury is characterized by the variability of the emission lines intensity and of its distribution in time scales from less than one hour to seasonal variations. While the faster variations, accounting for about 10–20% of fluctuations are probably linked to the planetary response to solar wind and Interplanetary Magnetic Field variability, the seasonal variations (up to about 80%) should be explained by complex mechanisms involving different surface release processes, loss, source and migrations of the exospheric Na atoms. Eventually, a Na annual cycle can be identified. In the past, ground-based observations and equatorial density from MESSENGER data have been analyzed. In this study, for a more extensive investigation of the exospheric Na features, we have studied the local time and latitudinal distributions of the exospheric Na column density as a function of the True Anomaly Angle (TAA) of Mercury by means of the extended dataset of images, collected from 2009 to 2013, by the THEMIS solar telescope. Our results show that the THEMIS images, in agreement with previous results, registered a strong general increase in sodium abundance at aphelion and a dawn ward emission predominance with respect to dusk ward and subsolar region between 90° and 150° TAA. This behavior can be explained by desorption of a sodium surface reservoir consisting of sodium that is pushed anti-sunward and condenses preferentially in the coldest regions. Our analyses show s a predominance of subsolar line-of-sight column density along the rest of Mercury's orbit. An unexpected relationship between Northward or Southward peak emission and both TAA and local time is also shown by our analysis. This result seems to contradict previous results obtained from different data sets and it is not easily explained, thus it requires further investigations

Correction to: SERENA: Particle Instrument Suite for Determining the Sun-Mercury Interaction from BepiColombo

International audienc

SERENA:Particle Instrument Suite for Determining the Sun-Mercury Interaction from BepiColombo

International audienceThe ESA-JAXA BepiColombo mission to Mercury will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric particle dynamics at Mercury as well as their interactions with solar wind, solar radiation, and interplanetary dust. The particle instrument suite SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) is flying in space on-board the BepiColombo Mercury Planetary Orbiter (MPO) and is the only instrument for ion and neutral particle detection aboard the MPO. It comprises four independent sensors: ELENA for neutral particle flow detection, Strofio for neutral gas detection, PICAM for planetary ions observations, and MIPA, mostly for solar wind ion measurements. SERENA is managed by a System Control Unit located inside the ELENA box. In the present paper the scientific goals of this suite are described, and then the four units are detailed, as well as their major features and calibration results. Finally, the SERENA operational activities are shown during the orbital path around Mercury, with also some reference to the activities planned during the long cruise phase

Study of Radiation Enviroment for Low-Earth Orbit (LEO) Spacecraft

The design of a space mission involves study of particle fluxes and their effects on spacecraft; space environment has a strong degrading effect on materials and components, so those need to be understood and mitigated against in order to ensure the success of mission. This work focuses on the study of Low Earth Orbit (LEO) radiation environment and how the particles interact with materials for a hypotethical space mission. Mission goal is Energetic Particle Atoms (ENA) detection using gas detector (MicroMeEGAS??) on board of a CubeSat. The payload will observe phenomena due to interation between magnetosphere and solar wind measuring precipitated particles. Being gas detector sensitive to several type of radiation, it is important to evaluate both its protection in terms of charged particles, that do not contribute to the signal, and the signal-to-noise ratio, because detector must be able to separate the desired signal from the background noise. So, the choice of the orbit requires some constraints as a consequence of the set scientific objective: we want to avoid areas where radiations are more intensive (South Atlantic Anomaly and polar regions) and for this reason we analyse the environment of LEO orbit with a low inclination. We investigate the major sources of natural environmental radiation analyzing trapped electrons and protons, solar particles flux and galactic cosmic ray intensity that arrive on and inside a cubesat at different altitudes of an appropriate Low Earth Orbit (LEO). The study of the orbit and the analysis of the radiation environment around the spacecraft are done by modeling with a web simulation tool, SPENVIS (SPace ENVironment Information System), instead Monte Carlo methods are used to simulate radiation fluxes, that penetrate into the CubeSat. Simulation results will be essential to proceed to evaluate the appropriate corrections in the instrument design, with appropriate shielding studies

BepiColombo First Mercury Fly-by: first taste of the mission results on investigation of the environment around the planet

International audienceThe ESA-JAXA BepiColombo satellite suite has passed by its target planet Mercury for the first time on 1st October 2021. The trajectory was in the southern hemisphere from nightside dusk toward dayside dawn, thus crossing the magnetosheath, the magnetotail, nightside plasma sheet and exiting in dayside dawnward magnetopause and bow shock. It explored, for the first time, regions never observed by other spacecraft in the past. All the instruments able to perform science observations in cruise configurations have been operated providing the first observations of Mercury’s inner southern magnetosphere and surrounding regions. These observations include magnetic fields, solar wind and magnetospheric ions and electrons in different energy ranges, plasma waves, energetic particles and exosphere. During the pass, BepiColombo encountered a low interplanetary magnetic field and low energy solar wind. Unexpected interesting signals have been observed in the solar wind before the magnetospheric bow shock, at the magnetopause inbound as well as in the outbound solar wind. This paper will present a general overview of the observations, just as a first taste of the great results expected from this mission

BepiColombo First Mercury Fly-by: first taste of the mission results on investigation of the environment around the planet

International audienceThe ESA-JAXA BepiColombo satellite suite has passed by its target planet Mercury for the first time on 1st October 2021. The trajectory was in the southern hemisphere from nightside dusk toward dayside dawn, thus crossing the magnetosheath, the magnetotail, nightside plasma sheet and exiting in dayside dawnward magnetopause and bow shock. It explored, for the first time, regions never observed by other spacecraft in the past. All the instruments able to perform science observations in cruise configurations have been operated providing the first observations of Mercury’s inner southern magnetosphere and surrounding regions. These observations include magnetic fields, solar wind and magnetospheric ions and electrons in different energy ranges, plasma waves, energetic particles and exosphere. During the pass, BepiColombo encountered a low interplanetary magnetic field and low energy solar wind. Unexpected interesting signals have been observed in the solar wind before the magnetospheric bow shock, at the magnetopause inbound as well as in the outbound solar wind. This paper will present a general overview of the observations, just as a first taste of the great results expected from this mission

BepiColombo First Mercury Fly-by: first taste of the mission results on investigation of the environment around the planet

International audienceThe ESA-JAXA BepiColombo satellite suite has passed by its target planet Mercury for the first time on 1st October 2021. The trajectory was in the southern hemisphere from nightside dusk toward dayside dawn, thus crossing the magnetosheath, the magnetotail, nightside plasma sheet and exiting in dayside dawnward magnetopause and bow shock. It explored, for the first time, regions never observed by other spacecraft in the past. All the instruments able to perform science observations in cruise configurations have been operated providing the first observations of Mercury’s inner southern magnetosphere and surrounding regions. These observations include magnetic fields, solar wind and magnetospheric ions and electrons in different energy ranges, plasma waves, energetic particles and exosphere. During the pass, BepiColombo encountered a low interplanetary magnetic field and low energy solar wind. Unexpected interesting signals have been observed in the solar wind before the magnetospheric bow shock, at the magnetopause inbound as well as in the outbound solar wind. This paper will present a general overview of the observations, just as a first taste of the great results expected from this mission