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We will review the first observations and results obtained by the Radio and Plasma Waves (RPW) Instrument on the recently launched Solar Orbiter mission. RPW is designed to measure in-situ magnetic and electric fields and waves from 'DC' to a few hundreds of kHz. RPW is also capable of measuring solar radio emissions up to 16 MHz and link them to solar flares observed by the onboard remote sensing instruments. The first results concern a wide range of phenomena including: low frequency Doppler shifted ion-acoustic waves, Whistler Waves, dust impacts, Langmuir waves, shock crossings, Type III bursts, including events observed simultaneously by the Solar Orbiter Energetic Particle Detector (EPD).

On 19 April 2020, the Solar Orbiter magnetometer (MAG) observed a coronal mass ejection (CME) including a clear signature of a large- scale magnetic flux rope, the first such event seen in situ at Solar Orbiter. The spacecraft was closely aligned in heliospheric longitude with Earth at this time, and it was located at a radial distance of 0.8 AU from the Sun. Consequently, the same slow CME (v < 400 km/s) was also observed near Earth the next day, causing the first geomagnetic storm of the year. The STEREO-A spacecraft was separated from Earth and Solar Orbiter by almost 90° in longitude, providing an excellent side view of the CME with its coronagraph and heliospheric imager. The Energetic Particle Detector suite onboard Solar Orbiter is mainly intended for the study of solar energetic particles. However, in quiet time periods, its High Energy Telescope (HET) is also very well suited to observe the galactic cosmic ray (GCR) background and its time variation. The HET data for April 19 show a clear Forbush decrease (FD) related to the cosmic ray modulation by the CME's magnetic field. We explain how HET data can be used to observe such short- term variations of GCR, and compare the FD observations at Solar Orbiter to those near 1 AU. We also apply the ForbMod model to the FD measurements to investigate energy dependency and radial evolution of the FD.

The Radiation Assessment Detector, RAD, is one of the ten instruments that make up the science payload of the Mars Science Laboratory Curiosity rover. RAD is an energetic particle detector, capable of measuring the charged and neutral particles that make significant contributions to the radiation dose that will be received by future human explorers when they visit Mars. Prior to the launch of MSL in November 2011, RAD and its nearidentical twin flight spare unit were calibrated using laboratory sources, charged particle beams, and neutron fields. The initial calibration parameters obtained in these tests were used for real-time data analysis by the instrument’s onboard software. These parameters have subsequently been refined using data obtained during the cruise to Mars and during Curiosity’s mission on the surface of Mars. The most critical use of alibration is in the dosimetry analysis performed onboard. Calibration is also used in onboard analysis to determine which events should be stored for telemetry to Earth. Accelerator data obtained with the flight spare unit after Curiosity was launched provide detailed information about the response of the organic and inorganic scintillators to ion beams over a wide range of charge and energy. Here we report on the methods used to determine calibration parameters, the results obtained, as well as providing an overview of the modifications to the instrument’s software and configuration that have been made over the course of the mission.

Chang'E4, the Chinese mission to the Moon, launched on December 8, 2018 and landed on the far side of the Moon in the von Karman crater on January 3, 2019. The mission consists of a lander, a rover, and a communication relay. In this presentation we will describe first data from the Lunar Lander Neutron & Dosimetry experiment (LND) which is placed on the lander. LND consists of a stack of 10 segmented Si solid-state detectors (SSDs) which forms a particle telescope to measure charged particles (electrons fom 0.5 MeV to several MeV, protons 8-35 MeV, and heavier nuclei 17-75 MeV/nuc). A special geometrical arrangement allows observations of fast neutrons (and - rays) which are also important for dosimetry and cosmic-ray exposure of lunar soils. Thermal neutrons are measured using a very thin Gd conversion foil which is sandwiched between two SSDs. Thermal neutrons are sensitive to subsurface water and important to understand lunar surface mixing processes. [...]

Forbush decreases (FDs), short-term drops in the flux of galactic cosmic rays (GCR), can be caused by the shielding from strong and/or turbulent magnetic structures in the solar wind, i.e. interplanetary coronal mass ejections (ICMEs) and their associated shocks as well as corotating interaction regions (CIRs). FDs are often used as a proxy for detecting the arrival of ICMEs or CIRs at locations where sufficient in situ solar wind measurements are not or not always available, such as at Mars. The Radiation Assessment Detector (RAD) onboard the Mars Science Laboratory (MSL) mission's Curiosity rover has been continuously measuring the GCR environment on the surface of Mars for more than 7 years since its landing in August 2012 and is thus an excellent source for measurements of FDs at Mars (see e.g. Guo et al. 2018, A&A). Based on the large catalog of FDs at Mars compiled by Papaioannou et al. (2019, Solar Physics) as well as results from our previous work (Freiherr von Forstner et al., 2019, Space Weather), we study the parameters of FDs at Mars and their relations, focusing on events produced by ICMEs. We then compare these data with catalogs of terrestrial FDs, investigating whether and to what extent the differences of certain FD characteristics between the two planets, at two different heliospheric distances, are related to the evolution of ICMEs between Earth and Mars. Our results show that there is a linear correlation between the FD amplitude (drop percentage) and the maximum hourly GCR decrease during the FD, which was already found at Earth by previous authors (Belov et al., 2008, Abunin et al., 2012). However, this correlation has a different proprtionality factor at Mars than at Earth, especially for ICME-induced events. As we do not find a clear dependence of this relationship on the observed GCR energy range, we suggest that this difference is probably caused by the expansion of the ICME sheath region as it propagates outward from 1 AU to ∼1.5 AU. The expansion factor derived from our analysis is in line with expansion factors of ICME sheaths within the inner heliosphere observed by

Chang’E4, the next Chinese mission to the Moon, is planned to launch in December 2018 and to land on the far side of the Moon in the South Pole Aitken Basin. The mission consists of a lander, a rover, and a communication relay around the Earth-Moon L2 libration point. Here we describe the Lunar Lander Neutron Dosimetry experiment (LND) on the lander. [...]

The European space sciences landscape is very diverse as it involves two major intergovernmental organisations (The European Space Agency-ESA- and the European Commission-EC) and more than 25 countries that each have their national institutional setting and scientific planning approach. It has therefore always been essential to coordinate space science and exploration programmes throughout Europe and with international partners. The European Space Sciences Committee (ESSC - www.essc.esf.org) is offering European scientists an independent voice providing advice and guidance on space science matters to ESA, EC, national space agencies, and other stakeholders. The ESSC is not a programmatic nor a political entity; it promotes space science not as a cost but as a high-return investment with a broad and exciting leverage effect on the people and the economy. Similarly to other international advisory bodies, ESSC offers recommendations and implements other space exploration related activities; it delivers direct consolidated (solicited or proactive) input from the scientific community to programmatic institutions; but is can also represent an anchor for non-European scientific communities to interact and collaborate. The ESSC has thus kept and developed very strong links with the Space Studies Board of the US National Academies (NAS-SSB), members from both sides of the Atlantic thus affording regular insight on European and US space programmes. These two bodies are also linked in some strategic planning issues and in studies related to Planetary Protection (e.g. on PhobosDeimos categorisation), Mars (Mars Special Regions), space weather or the icy moons of the giant planets. The ESSC has also tight contacts with Chinese, Russian and Japanese space agencies and research organisations. This international bottom-up approach in space roadmapping has proven to be highly valuable in the past, a relevant example being the Cassini-Huygens mission. In the early eighties, the concept of a joint U.S.-European mission to explore the Saturnian system was delineated duringa joint European Science Foundation-US National Academies workshop, this was the spark of one of the most successful long-lived (2004-2017) planetary exploration missions to date. A coordinated integrated position on programmatic space matters is key to maximise scientific return. Since the late nineties, the ESSC and its office have conducted studies and evaluations on the ESA Life and Physical Sciences in Space programme (ELIPS) as well as defining a Science-Driven Scenario for Space Exploration or roadmaps in the fields of human space exploration or astrobiology. ESSC has also been very active in providing inputs to the European Commission on the definition of its space strategy and space research work programme. The ESSC contacts with international bodies significantly contribute to the definition and implementation of exploration programmes in their respective countries and demonstrate that common initiatives allow us to promote the inputs from the scientific communities. A network of independent non-programmatic interdisciplinary bodies covering all the regions of the world would certainly improve coordination of space exploration at the global level. References: all of the documents related to the aforementioned studies can be found at: http://www.essc.esf.org/list-of-publications/

Despite the aim of landing humans on the Moon in the not too distant future, the current knowledge about the radiation environment on the surface of the Moon is based exclusively on calculations using radiation transport models with input parameters from models for the galactic cosmic ray spectra and for solar particle events. Chang'E4 is the next Chinese mission to the Moon and is planned to launch in December 2018 and to land on the far side of the Moon in the South Pole Aitken Basin. The mission consists of a lander, a rover, and a communication relay. Here we describe the Lunar Lander Neutron & Dosimetry experiment (LND) which will be placed on the lander. It consists of a stack of 10 segmented Si solid-state detectors (SSDs) which forms a particle telescope to measure charged particles (electrons 150-500 keV, protons 12-30 MeV, and heavier nuclei 15-30 MeV/nuc). A special geometrical arrangement allows observations of fast neutrons (and -rays) which are also important for dosimetry and cosmic-ray exposure of lunar soils. Thermal neutrons are measured using a very thin Gd conversion foil which is sandwiched between two SSDs. Thermal neutrons are sensitive to subsurface water and important to understand lunar surface mixing processes.

The Mars Science Laboratory rover Curiosity, operating on the surface of Mars, is exposed to radiation fluxes from above and below. Galactic Cosmic Rays travel through the Martian atmosphere, producing a modified spectrum consisting of both primary and secondary particles at ground level. These particles produce an upward directed secondary particle spectrum as they interact with the Martian soil. Here we develop a method to distinguish the upward and downward directed particle fluxes in the Radiation Assessment Detector (RAD) instrument, verify it using data taken during the cruise to Mars, and apply it to data taken on the Martian surface. We use a combination of Geant4 and Planetocosmics modeling to find discrimination criteria for the flux directions. After developing models of the cruise phase and surface shielding conditions, we compare model-predicted values for the ratio of upward to downward flux with those found in RAD observation data. Given the quality of available information on Mars Science Laboratory spacecraft and rover composition, we find generally reasonable agreement between our models and RAD observation data. This demonstrates the feasibility of the method developed and tested here. We additionally note that the method can also be used to extend the measurement range and capabilities of the RAD instrument to higher energies.

On 2017 September 10th, the active region (AR) 2673 produced solar energetic particles (SEPs) which resulted in the first ground level enhancement (GLE) observed at the surface of two different planets: Earth and Mars. This was the biggest GLE on the surface of Mars, ̃ 160 ◦ longitudinally east of Earth, as observed by the Radiation Assessment Detector (RAD) since the landing of the Curiosity rover in August 2012. Both Earth and Mars saw a significant enhancement of the accelerated protons with energies larger than hundreds of MeV whereas STEREO-A, despite being at the back-side of the event, detected gradually increasing fluxes of particles transported there across the heliospheric magnetic fields. Such high energetic particles were mainly accelerated by the flare and shock clearly identified on the solar west limb in SDO/AIA and GOES/SUVI images. Based on STEREO-A and SOHO chronograph images and the Graduated Cylindrical Shell (GCS) model, we identify the initial 3D kinematics of an extremely fast (>2500 km/s) Coronal Mass Ejection (CME) and its shock front, as well as another two CMEs launched hours earlier with moderate speeds. The three CMEs interacted as they propagated outwards into the heliosphere and merged into a complex interplanetary CME (ICME). The arrival of the shock and ICME at Mars caused the biggest Forbush Decrease (FD) ever seen by RAD and the arrival time is only a few hours later than that at Earth, which was about 0.5 AU closer to the Sun. We investigate the interplanetary propagation of the three CMEs and the merged ICME together with the shock, using the Drag Based Model(DBM) and the WSA-ENLIL plus cone model constrained by the in-situ observations. The synergistic study of the ICME and SEP arrivals at Earth, Mars and STEREO-A suggests that to better predict potentially hazardous space weather impacts at Earth and other heliospheric locations for human exploration missions, it is essential to analyze 1) the CME kinematics, especially during their interactions, 2) the spatially and temporally varying heliospheric conditions, such as the evolution and propagation of the stream interaction regions and finally 3) the influence of such heliospheric structures on the transport and properties of SEPs in the interplanetary space.

The main functions of the space instrument structural subsystem are to enclose, protect and support the other instrument subsystems integrity and to provide a mechanical interface with the spacecraft. Depending on the mission requirements and the mechanical load envelope defined by the spacecraft, the structure should sustain the severe stresses and loads experienced during the launch. The main challenge for a successful structural design is to consider an appropriate verification method during the design phase, which discards or minimizes the potential hardware failures during the qualification tests. This is not always trivial because the design inputs and requirements at the preliminary design phase (phase B) may change when reaching to the stage that the instrument is built and needs to be qualified by test (phase D). In this paper, based on the lessons learned in the scope of the Electron Proton Telescope and High Energy Telescope (EPT-HET) instrument development for ESA?s Solar Orbiter mission, a systematic approach for a successful structural design is presented. The proposed approach not only includes the structural stress and strength analysis but also involves the fatigue life and shock damage verification for sensitive parts such as electronic components.

Solar Orbiter is a joint ESA-NASA mission planed for launch in October 2018. The science payload includes remote-sensing and in-situ instrumentation designed with the primary goal of understanding how the Sun creates and controls the heliosphere. The spacecraft will follow an elliptical orbit around the Sun, with perihelion as close as 0.28 AU. During the late orbit phase the orbital plane will reach inclinations above 30 degrees, allowing direct observations of the solar polar regions. The Energetic Particle Detector (EPD) is an instrument suite consisting of several sensors measuring electrons, protons and ions over a broad energy interval (2 keV to 15 MeV for electrons, 3 keV to 100 MeV for protons and few tens of keV/nuc to 450 MeV/nuc for ions), providing composition, spectra, timing and anisotropy information. We present an overview of Solar Orbiter from the energetic particle perspective, summarizing the capabilities of EPD and the opportunities that these new observations will provide for understanding how energetic particles are accelerated during solar eruptions and how they propagate through the Heliosphere., XXV ECRS 2016 Proceedings - eConf C16-09-04.3

Introduction: Chang'E 4 is the next Chinese mission to the Moon and is planned to land on the far side of the Moon in the South Pole Aitken Basin. The mission consists of a lander, a rover, and a communication relay. Here we describe the Lunar Lander Neutrons & Dosimetry experiment (LND) which will be placed on the lander. It consists of a stack of 10 segmented Si solid-state detectors (SSDs) which forms a particle telescope to measure charged particles (electrons 150-500 keV, protons 12-30 MeV, and heavier nuclei 15-30 MeV/nuc). A special geometrical arrangement allows observations of fast neutrons (and γ-rays) which are also important for dosimetry and cosmic-ray exposure of lunar soils. Thermal neutrons are measured using a very thin Gd conversion foil which is sandwiched between two SSDs. Thermal neutrons are sensitive to subsurface water and important to understand lunar surface mixing processes.

International audience; We discuss observations of the journey throughout the Solar System of a large interplanetary coronal mass ejection (ICME) that was ejected at the Sun on 14 October 2014. The ICME hit Mars on 17 October, as observed by the Mars Express, MAVEN, Mars Odyssey and MSL missions, 44 hours before the encounter of the planet with the Siding-Spring comet, for which the space weather context is provided. It reached comet 67P/Churyumov-Gerasimenko, which was perfectly aligned with the Sun and Mars at 3.1 AU, as observed by Rosetta on 22 October. The ICME was also detected by STEREO-A on 16 October at 1 AU, and by Cassini in the solar wind around Saturn on the 12 November at 9.9 AU. Fortuitously, the New Horizons spacecraft was also aligned with the direction of the ICME at 31.6 AU. We investigate whether this ICME has a non-ambiguous signature at New Horizons. A potential detection of this ICME by Voyager-2 at 110-111 AU is also discussed. The multi-spacecraft observations allow the derivation of certain properties of the ICME, such as its large angular extension of at least 116°, its speed as a function of distance, and its magnetic field structure at four locations from 1 to 10 AU. Observations of the speed data allow two different solar wind propagation models to be validated. Finally, we compare the Forbush decreases (transient decreases followed by gradual recoveries in the galactic cosmic ray intensity) due to the passage of this ICME at Mars, comet 67P and Saturn.

International audience; The Turbulence Heating ObserveR (THOR) mission was selected as one of the three candidates of the Call for Medium Class Missions M4 in the European Space Agency's Science Programme with a launch planned in 2026. THOR is the first mission ever flown in space dedicated to plasma turbulence. THOR will lead to an understanding of the basic plasma heating and particle energization processes, of their effect on different plasma species and of their relative importance in different turbulent regimes. The THOR mission features one single spinning spacecraft with 10 scientific instruments focusing on particular regions in three different elliptical orbits around the Earth; pristine solar wind, Earth's bow shock and interplanetary shocks, and compressed solar wind regions downstream of shocks. These regions are selected because of their differing turbulent fluctuation characteristics, and reflect similar astrophysical environments. The THOR mission, the conceptual design of the spacecraft and a summary of the payload will be presented. Furthermore, driving requirements and their implications for the spacecraft like Electromagnetic Compatibility and cleanliness will be discussed.