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The Smoke Particle Impact Detector (SPID) was flown on the G-Chaser student rocket that was launched from Andøya on 13 January 2019. SPID is a Faraday cup instrument with applied bias voltages to deflect the ambient plasma and a target area inside the probe designed to measure the dust particles by charge detection. The charging process of the dust particles in the detector is important for interpretation of the measurements and the influence of the charging models is discussed. Preliminary analysis of the SPID observations shows that ambient plasma and sunlight had an influence on the signals; further analysis is needed to retrieve information on impacting dust from the data.

An edited version of this paper was published by AGU. Copyright (2017) American Geophysical Union. Antonsen, T., Havnes, O. & Mann, I. (2017). Estimates of the size distribution of meteoric smoke particles from rocket-borne impact probes. Journal of Geophysical Research: Atmospheres, 12353-12365. https://doi.org/10.1002/2017JD027220. Ice particles populating noctilucent clouds and being responsible for polar mesosphericsummer echoes exist around the mesopause in the altitude range from 80 to 90 km during polar summer.The particles are observed when temperatures around the mesopause reach a minimum, and it is presumedthat they consist of water ice with inclusions of smaller mesospheric smoke particles (MSPs). This workprovides estimates of the mean size distribution of MSPs through analysis of collision fragments of the iceparticles populating the mesospheric dust layers. We have analyzed data from two triplets of mechanicallyidentical rocket probes, MUltiple Dust Detector (MUDD), which are Faraday bucket detectors with impactgrids that partly fragments incoming ice particles. The MUDD probes were launched from Andøya SpaceCenter (69∘17’N, 16∘1’E) on two payloads during the MAXIDUSTY campaign on 30 June and 8 July 2016,respectively. Our analysis shows that it is unlikely that ice particles produce significant current to thedetector, and that MSPs dominate the recorded current. The size distributions obtained from these currents,which reflect the MSP sizes, are described by inverse power laws with exponents of k ∼ [3.3 ± 0.7, 3.7 ± 0.5]and k ∼ [3.6 ± 0.8, 4.4 ± 0.3] for the respective flights. We derived two k values for each flight dependingon whether the charging probability is proportional to area or volume of fragments. We also confirm thatMSPs are probably abundant inside mesospheric ice particles larger than a few nanometers, and the volumefilling factor can be a few percent for reasonable assumptions of particle properties.

International audience; The investigation of comet 67P by Rosetta has allowed the comprehensive characterisation of pristine cometary dust particles ejected from the nucleus. Flying alongside the comet at distances as small as a few kilometres, and with a relative velocity of only centimetres per second, the Rosetta payload sampled almost unaltered dust. A key instrument to study this dust was MIDAS (the Micro-Imaging Dust Analysis System), a dedicated atomic force microscope that scanned the surfaces of hundreds of (sub- )micrometre sized particles in 3D with resolutions down to nanometres. This offers the unique opportunity to explore the morphology of smallest cometary dust and expand our current knowledge about cometary material.Here we give an overview of dust collected and analysed by MIDAS and highlight its most important features. These include the ubiquitous agglomerate nature of the dust, which is found at all size scales from the largest (>10 μm) through to the smallest (

Proc. ‘22nd ESA Symposium on European Rocket and Balloon Programmes and Related Research’, Tromsø, Norway, 7–12 June 2015 We have studied the relationship between particle precipitation and PMSE strength on days where we observe PMSE layers both with the EISCAT VHF and UHF radars. The UHF observations of the ionization and its variation, above the PMSE layer, is used as a measure of precipitation. Variations of the precipitation is compared with variations of the PMSE strengths observed with both radars. Although many cases apparently show a clear connection between precipitation and PMSE, where an increased precipitation leads to a strengthening of the PMSE, our findings confirm that there is no general and simple proportionality between the two. For the weakest PMSE there appears to be no correlation between precipitation and PMSE strength. For PMSEs around average strength of our observations there appears to be a weak positive correlation, which can be predicted by a timedependent dust cloud charge model. On some occasions an increased precipitation can, apparently, initially lead to an increase of PMSE strength which at some point starts to decline even if the precipitation continue to increase. This feature can also be seen in the results from the statistical analysis, however the number of occurrences is too low to conclude with significance and the time-dependent charge model described here does not reproduce such features. We have studied to what degree models for the PMSE scattering can explain the various cases of reaction of PMSE to changes in precipitation

We present an analysis of relatively strong Polar Mesospheric Winter Echoes (PMWE) under artificial electron heating that changes the PMWE intensity. A major purpose is to find reliable estimates of the relaxation time of the heater modified PMWE to their undisturbed state during the heater switch-off phase; the implications regarding charge/discharge mechanisms; and to exploit the diagnostic potential of artificial electron heating. The relaxation time is between 60 to 70 s for the regions with strong PMWE layers and substantial electron heating. This short relaxation time, related to the variation of charges on the nanometer dust which most likely is present in PMWE, rules out ion attachment as the mechanism to bring the dust charges to their equilibrium state. Neutral winds, sweeping the heated electrons out of the radar beam, are unlikely to be the cause of the observed relaxation, since this requires winds of around 100 m s−1. The most probable cause is photo detachment by which negatively charged dust can lose excess electrons by photon absorption with energies less than the dust material's work function. By comparing the observed heating with heating model profiles, the electron density at 65 km height must have been of the order of 3 × 109 m−3. This agrees with PMWE occurring mainly during disturbed conditions with high electron densities. Our results also indicate that in the strongest PMWE layers, electron bite-outs exist consistent with the role of charged dust particles in the mechanism of PMWE and implying larger dust densities.

The Cassini-Huygens Cosmic Dust Analyzer (CDA) is intended to provide direct observations of dust grains with masses between 10(-19) and 10(-9) kg in interplanetary space and in the jovian and saturnian systems, to investigate their physical, chemical and dynamical properties as functions of the distances to the Sun, to Jupiter and to Saturn and its satellites and rings, to study their interaction with the saturnian rings, satellites and magnetosphere. Chemical composition of interplanetary meteoroids will be compared with asteroidal and cometary dust, as well as with Saturn dust, ejecta from rings and satellites. Ring and satellites phenomena which might be effects of meteoroid impacts will be compared with the interplanetary dust environment. Electrical charges of particulate matter in the magnetosphere and its consequences will be studied, e.g. the effects of the ambient plasma and the magnetic held on the trajectories of dust particles as well as fragmentation of particles due to electrostatic disruption. The investigation will be performed with an instrument that measures the mass, composition, electric charge, speed, and flight direction of individual dust particles. It is a highly reliable and versatile instrument with a mass sensitivity 106 times higher than that of the Pioneer 10 and I I dust detectors which measured dust in the saturnian system. The Cosmic Dust Analyzer has significant inheritance from former space instrumentation developed for the VEGA, Giotto, Galileo, and Ulysses missions. It will reliably measure impacts from as low as I impact per month up to 104 impacts per second. The instrument weighs 17 kg and consumes 12 W, the integrated time-of-flight mass spectrometer has a mass resolution of up to 50. The nominal data transmission rate is 524 bits/s and varies between 50 and 4192 bps

This article is part of Ottar (1980), nr 121-122, "Nordlysobservatoriet 50 år", available in Munin at http://hdl.handle.net/10037/5177 Vi vil ikke her gå inn i nordlyset som vi kjenner det fra jorden, men kort omtale andre steder i verdensrommet hvor vi har observert nordlyslignende fenomen eller hvor vi kan vente å finne beslektede fenomen.