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• 201.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
University of Glasgow. University of Glasgow.
Attitude and Orbital Dynamics of a Variable-Geometry, Spinning Solar Sail in Earth Orbit2017Conference paper (Refereed)

At the ISSS 2013, a novel concept of variable-geometry solar sail was introduced: deployed in the shape of a three-dimensional quasi-rhombic pyramid (QRP), the sail exploited its shape and shift between center of mass and center of pressure to naturally achieve heliostability (stable sun-pointing) throughout the mission. In addition, mechanisms allowed to vary the flare angle of the four booms in opposite pairs, thus allowing to control the area exposed to the sun without the need of slew maneuvers. Using these adjustments in favorable orbital positions, it is possible to build a regular pattern of acceleration to achieve orbit raising or lowering without the need of propulsion system or attitude control. Subsequent more detailed investigations revealed that eclipses, even if lasting only a fraction of the orbit, have a substantial (and negative) impact on the heliostability effect: and even a small residual angular velocity, or disturbance torque, are enough to cause the spacecraft to tumble. In this work, we present a novel and improved concept which allows the sail to preserve its attitude not only with eclipses, but also in presence of disturbance torques such as the gravity gradient. The solution we propose is to add a moderate spin to the solar sail, combined with ring dampers. The gyroscopic stiffness due to the spin guarantees stability during the transient periods of the eclipses, while the heliostability effect, combined with the dampers, cancels any residual unwanted oscillation during the parts of the orbit exposed to the sun, and at the same time guarantees continuous sun-pointing as the apparent direction of the sun rotates throughout the year. Both theoretical and numerical analyses are performed. First, stability bounds on the sail design are calculated, obtaining conditions on the flare angles of the sail, in the different orbital regimes, to test the robustness of the concept. Then, a numerical analysis is performed to validate the study in a simulated scenario where all perturbations are considered, over extended amount of time. The concept targets equatorial orbits above approximately 5,000 km. Results show that an increase of 2,200 km per year for a small device at GEO can be achieved with a CubeSat-sized sail.

• 202.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Centre for Planetary Science and Exploration (CPSX), Department of Earth Sciences, University of Western Ontario. ESCET-Área de Geología, Universidad Rey Juan Carlos. Institute for Planetary Materials, Okayama University, Misasa. Planetology and Habitability Department, Center of Astrobiology (INTA-CSIC) .
A mineralogical archive of the biogeochemical sulfur cycle preserved in the subsurface of the Río Tinto system2018In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 103, no 3, p. 394-411Article in journal (Refereed)

The search for extinct and extant life on Mars is based on the study of biosignatures that could be preserved under Mars-like, extreme conditions that are replicated in different terrestrial analog environments. The mineral record in the subsurface of the Río Tinto system is one example of a Mars analog site that has been exposed to weathering conditions, including the biogeochemical activity of Fe and S chemolithotrophic bacteria, for millions of years. The SEM-EDAX analysis of different samples recovered in the Peña de Hierro area from four boreholes, ranging from 166 to 610 m in depth, has provided the identification of microbial structures that have affected a suite of hydrothermal minerals (~345 Ma) as well as minerals likely produced by biological activity in more recent times (<7 Ma). The hydrothermal minerals correspond to reduced sulfur or sulfate-bearing compounds (e.g., pyrite and barite) that are covered by bacilli- or filamentous-like microbial structures and/or secondary ferrous carbonates (e.g., siderite) with laminar to spherical structures. The secondary iron carbonates can be in direct contact or above an empty interphase with the primary hydrothermal minerals following a wavy to bent contact. Such an empty interphase is usually filled with nanoscale, straight filamentous structures that have a carbonaceous composition. The occurrence of a sulfur and iron chemolithotrophic community in the Río Tinto basement strongly suggests that the association between sulfur-bearing minerals, dissolution scars and secondary minerals of biological origin is a complex process involving the microbial attack on mineral surfaces by sulfur reducing bacteria followed by the precipitation of iron-rich carbonates. In this scenario, iron sulfide compounds such as pyrite would act as electron donors under microbial oxidation, while sulfate minerals such as barite would act as electron acceptors through sulfate reduction. Furthermore, the formation of siderite would have resulted from carbonate biomineralization of iron chemoheterotrophic organims or other microorganisms that concentrate carbonate through metabolic pathways. Although the distribution of the mineral biosignatures at depth clearly follows a redox gradient, they show some irregular allocation underground, suggesting that the geochemical conditions governing the microbial activity are affected by local changes associated with the fracturing pattern of the Río Tinto basement. The abundance of sulfur- and iron-bearing minerals in the Mars crust suggests that the Río Tinto mineral biosignatures can be useful in the search for extant and extinct subsurface life on the red planet

• 203.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Research Unit Analytical Biogeochemistry, Department of Environmental Sciences, Helmholtz Zentrum München, Neuherberg, Germany. Centro de Astrobiología (INTA-CSIC), Torrejón de Ardoz, Madrid, Spain. Research Unit Analytical Biogeochemistry, Department of Environmental Sciences, Helmholtz Zentrum München, Neuherberg, Germany. Centro de Astrobiología (INTA-CSIC), Torrejón de Ardoz, Madrid, Spain. Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Madrid, Spain.
Productivity contribution of Paleozoic woodlands to the formation of shale hosted massive sulfide deposits in the Iberian Pyrite Belt (Tharsis, Spain)2018In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 123, no 3, p. 1017-1040Article in journal (Refereed)

The geological materials produced during catastrophic and destructive events are an essential source of paleobiological knowledge. The paleobiological information recorded by such events can be rich in information on the size, diversity, and structure of paleocommunities. In this regard, the geobiological study of late Devonian organic matter sampled in Tharsis (Iberian Pyrite Belt) provided some new insights into a Paleozoic woodland community,which was recorded as massive sulfides and black shale deposits affected by a catastrophic event. Sample analysis using TOF-SIMS (Time of Flight Secondary Ion Mass Spectrometer), and complemented by GC/MS (Gas Chromatrograph/Mass Spectrometer) identified organic compounds showing a very distinct distribution in the rock. While phytochemical compounds occur homogeneously in the sample matrix that is composed of black shale, the microbial-derived organics are more abundant in the sulfide nodules. The co-occurrence of sulfur bacteria compounds and the overwhelming presence of phytochemicals provide support for the hypothesis that the formation of the massive sulfides resulted from a high rate of vegetal debris production and its oxidation through sulfate reduction under suboxic to anoxic conditions. A continuous supply of iron from hydrothermal activity coupled with microbial activity was strictly necessary to produce this massive orebody. A rough estimate of the woodland biomass was made possible by accounting for the microbial sulfur production activity recorded in the metallic sulfide. As a result, the biomass size of the late Devonian woodland community was comparable to modern woodlands like the Amazon or Congo rainforests.

• 204.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
Thermal modelling of the PICSAT nanosatellite platform and synergetic prestudies of the CIRCUS nanosatellite2016Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis

In the present paper, which was written in collaboration with the Observatory of Paris, thermal models of two CubeSat missions were created. The first goal of this work was to create a nodal simulation of the PicSat satellite to verify the survivability of the system within the extreme space environment. In a second step suitable countermeasures were suggested, if parts of the satellite exceeded a critical temperature limit. Additionally, the impacts of three failure modes were investigated. The second goal was to perform thermal pre-studies of different satellite configurations of the CIRCUS satellite based on the model of PicSat.

The simulation conducted in this work showed that PicSat fulfils its thermal requirements, except for three components. Out of the failure modes considered in this study, only an error of the attitude determination and control systems (ADCS) showed a critical impact on the thermal state of PicSat. As the outcome of the pre-studies of CIRCUS, two of the considered configurations were recommended for further analysis. The results of this work will contribute to the future development of the PicSat and CIRCUS missions.

• 205.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Earth Observatory of Singapore, Nanyang Technological University, Singapore.
Earth Observatory of Singapore, Nanyang Technological University, Singapore; UC, Singapore University of Social Sciences, Singapore. UC, Singapore University of Social Sciences, Singapore; Centre for Climate Research Singapore, Meteorological Services Singapore, Singapore.
Multi-scale interactions in a high-resolution tropical-belt experiment and observations2019In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 52, no 5-6, p. 3503-3532Article in journal (Refereed)

The Weather Research and Forecasting (WRF) model is used to dynamically downscale 27 years of the Climate Forecast System Reanalysis (CFSR) in a tropical belt configuration at 36 km horizontal grid spacing. WRF is found to give a good rainfall climatology as observed by the Tropical Rainfall Measuring Mission (TRMM) and to reproduce well the large-scale circulation and surface radiation fluxes. The impact of conventional and Modoki-type El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) are confirmed by linear regression. Madden–Julian Oscillation (MJO) and Boreal Summer Intra-seasonal Oscillation (BSISO) are also well-simulated. The WRF simulation shows that conventional El Niño increases (La Niña decreases) the MJO amplitude in the boreal summer while Modoki-type ENSO and IOD impacts are MJO-phase dependent. While WRF is found to perform well on seasonal to sub-seasonal timescales, it does not capture well the diurnal cycle of precipitation over the Maritime Continent. For the investigation of multi-scale interactions through the local diurnal cycle, TRMM data is used instead. In the Maritime Continent, moderate El Niño and La Niña causes anti-symmetric enhancement/reduction of the MJO’s influence on the diurnal cycle amplitudes with little change in the diurnal phase. Non-linear impacts on the diurnal amplitude with changes in diurnal phase manifest during strong ENSO. Given that the simulation does not employ data assimilation, this modified version of WRF submitted to the model developers is a suitable downscaling tool of CFSR for sub-seasonal to seasonal tropical atmospheric research.

• 206.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Granada. Swedish Space Corporation, Esrange Space Center, Kiruna.
Wind Forecasts for Rocket and Balloon Launches at the Esrange Space Center Using the WRF Model2018In: Weather and forecasting, ISSN 0882-8156, E-ISSN 1520-0434, Vol. 33, no 3, p. 813-833Article in journal (Refereed)

High-altitude balloons and rockets are regularly launched at the Esrange Space Center (ESC) in Kiruna, Sweden, with the aim of retrieving atmospheric data for meteorological and space studies in the Arctic region. Meteorological conditions, particularly wind direction and speed, play a critical role in the decision of whether to go ahead with or postpone a planned launch. Given the lack of high-resolution wind forecasts for this remote region, the Weather Research and Forecasting (WRF) Model is used to downscale short-term forecasts given by the Global Forecast System (GFS) for the ESC for six 5-day periods in the warm, cold, and transition seasons. Three planetary boundary layer (PBL) schemes are considered: the local Mellor-Yamada-Janjic' (MYJ), the nonlocal Yonsei University (YSU), and the hybrid local-nonlocal Asymmetric Convective Model 2 (ACM2). The ACM2 scheme is found to provide the most skillful forecasts. An analysis of the WRF Model output against the launch criteria for two of the most commonly launched vehicles, the sounding rockets Veículo de Sondagem Booster-30 (VSB-30) and Improved Orion, reveals probability of detection (POD) values that always exceeds 60% with the false alarm rate (FAR) generally below 50%. It is concluded that the WRF Model, in its present configuration, can be used to generate useful 5-day wind forecasts for the launches of these two rockets. The conclusions reached here are applicable to similar sites in the Arctic and Antarctic regions.

• 207.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), 18100 Granada, Spain.
High-Resolution Dynamical Downscaling of Re-Analysis Data over the Kerguelen Islands using the WRF Model2019In: Journal of Theoretical and Applied Climatology, ISSN 0177-798X, E-ISSN 1434-4483, Vol. 135, no 3-4, p. 1259-1277Article in journal (Refereed)

We have used the Weather Research and Forecasting (WRF) model to simulate the climate of the Kerguelen Islands (49° S, 69° E) and investigate its inter-annual variability. Here, we have dynamically downscaled 30 years of the Climate Forecast System Reanalysis (CFSR) over these islands at 3-km horizontal resolution. The model output is found to agree well with the station and radiosonde data at the Port-aux-Français station, the only location in the islands for which observational data is available. An analysis of the seasonal mean WRF data showed a general increase in precipitation and decrease in temperature with elevation. The largest seasonal rainfall amounts occur at the highest elevations of the Cook Ice Cap in winter where the summer mean temperature is around 0 °C. Five modes of variability are considered: conventional and Modoki El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Subtropical IOD (SIOD) and Southern Annular Mode (SAM). It is concluded that a key mechanism by which these modes impact the local climate is through interaction with the diurnal cycle in particular in the summer season when it has a larger magnitude. One of the most affected regions is the area just to the east of the Cook Ice Cap extending into the lower elevations between the Gallieni and Courbet Peninsulas. The WRF simulation shows that despite the small annual variability, the atmospheric flow in the Kerguelen Islands is rather complex which may also be the case for the other islands located in the Southern Hemisphere at similar latitudes.

• 208.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
MARSWRF Prediction of Entry Descent Landing Profiles: Applications to Mars Exploration2019In: Earth and Space Science, E-ISSN 2333-5084, Vol. 6, no 8, p. 1440-1459Article in journal (Refereed)

In this paper we use the Mars implementation of the Planet Weather Research and Forecasting model, MarsWRF, to simulate the Entry, Descent and Landing (EDL) vertical profiles from six past missions: Pathfinder, Mars Exploration Rovers Opportunity and SpiritPhoenix, Mars Science Laboratory Curiosity rover and ExoMars 2016 (Schiaparelli), and compare the results with observed data. In order to investigate the sensitivity of the model predictions to the atmospheric dust distribution, MarsWRF is run with two prescribed dust scenarios. It is concluded that the MarsWRF EDL predictions can be used for guidance into the design and planning stage of future missions to the planet, as it generally captures the observed EDL profiles, although it has a tendency to underestimate the temperature and overestimate the density for heights above 15 km. This could be attributed to an incorrect representation of the observed dust loading. We have used the model to predict the EDL conditions that may be encountered by two future missions: ExoMars 2020 and Mars 2020. When run for Oxia Planum and Jezero Crater for the expected landing time, MarsWRF predicts a large sensitivity to the dust loading in particular for the horizontal wind speed above 10‐15 km with maximum differences of up to ±30 m s‐1 for the former and ±15 m s‐1 for the latter site. For both sites, the best time for EDL, i.e. when the wind speed is generally the weakest with smaller shifts in direction, is predicted to be in the late morning and early afternoon.

• 209.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Centro de Astrobiología (INTA-CSIC), Madrid, Spain. Centro de Astrobiología (INTA-CSIC), Madrid, Spain. Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile. Facultad de Ciencias, Universidad de Tarapacá, Iquique, Chile. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Instituto Andaluz de Ciencias de la Tierra (UGR-CSIC), Granada, Spain.
A surface temperature and moisture intercomparison study of the Weather Research and Forecasting model, in‐situ measurements and satellite observations over the Atacama Desert2019In: Quarterly Journal of the Royal Meteorological Society, ISSN 0035-9009, E-ISSN 1477-870X, Vol. 145, no 722, p. 2202-2220Article in journal (Refereed)

Good knowledge of the environmental conditions of deserts on Earth is relevant forclimate studies. The Atacama Desert is of particular interest as it is considered tobe the driest region on Earth. We have performed simulations using the WeatherResearch and Forecasting (WRF) model over the Atacama Desert for two week-longperiods in the austral winter season coincident with surface temperature and relativehumidity in-situ observations at three sites. We found that the WRF model generallyoverestimates the daytime surface temperature, with biases of up to 11◦C, despitegiving a good simulation of the relative humidity. In order to improve the agree-ment with observed measurements, we conducted sensitivity experiments in whichthe surface albedo, soil moisture content and five tuneable parameters in the NoahLand Surface Model (namely soil porosity, soil suction, saturated soil hydraulic con-ductivity, thebparameter used in hydraulic functions and the quartz fraction) areperturbed. We concluded that an accurate simulation is not possible, most likelybecause the Noah Land Surface Model does not have a groundwater table that maybe shallow in desert regions. The WRF-predicted land surface temperature is alsoevaluated against that estimated from the Moderate Resolution Imaging Spectrora-diometer (MODIS) instrument. While at night the satellite-derived and ground-basedmeasurements are generally in agreement, during the day MODIS estimates aretypically lower by as much as 17◦C. This is attributed to the large uncertainty inthe MODIS-estimated land surface temperatures in arid and semi-arid regions. Thefindings of this work highlight the need for ground-based observational networksin remote regions such as the Atacama Desert where satellite-derived and modelproducts may not be very accurate.

• 210.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Centro de Astrobiología (INTA-CSIC). Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR).
Planetary Boundary Layer and Circulation Dynamics at Gale Crater, Mars2018In: Icarus (New York, N.Y. 1962), ISSN 0019-1035, E-ISSN 1090-2643, Vol. 302, p. 537-559Article in journal (Refereed)

The Mars implementation of the Planet Weather Research and Forecasting (PlanetWRF) model, MarsWRF, is used here to simulate the atmospheric conditions at Gale Crater for different seasons during a period coincident with the Curiosity rover operations. The model is first evaluated with the existing single-point observations from the Rover Environmental Monitoring Station (REMS), and is then used to provide a larger scale interpretation of these unique measurements as well as to give complementary information where there are gaps in the measurements.

The variability of the planetary boundary layer depth may be a driver of the changes in the local dust and trace gas content within the crater. Our results show that the average time when the PBL height is deeper than the crater rim increases and decreases with the same rate and pattern as Curiosity's observations of the line-of-sight of dust within the crater and that the season when maximal (minimal) mixing is produced is Ls 225°-315° (Ls 90°-110°). Thus the diurnal and seasonal variability of the PBL depth seems to be the driver of the changes in the local dust content within the crater. A comparison with the available methane measurements suggests that changes in the PBL depth may also be one of the factors that accounts for the observed variability, with the model results pointing towards a local source to the north of the MSL site.

The interaction between regional and local flows at Gale crater is also investigated assuming that the meridional wind, the dynamically important component of the horizontal wind at Gale, anomalies with respect to the daily mean can be approximated by a sinusoidal function as they typically oscillate between positive (south to north) and negative (north to south) values that correspond to upslope/downslope or downslope/upslope regimes along the crater rim and Mount Sharp slopes and the dichotomy boundary. The smallest magnitudes are found in the northern crater floor in a region that comprises Bradbury Landing, in particular at Ls 90° when they are less than 1 m s−1, indicating very little lateral mixing with outside air. The largest amplitudes occur in the south-western portions of the crater where they can exceed 20 m s−1. Should the slope flows along the crater rims interact with the dichotomy boundary flow, which is more likely at Ls 270° and very unlikely at Ls 90°, they are likely to interact constructively for a few hours from late evening to nighttime (∼17-23 LMST) and from pre-dawn early morning (∼5-11 LMST) hours at the norther crater rim and destructively at night (∼22-23 LMST) and in the morning (∼10-11 LMST) at the southern crater rim.

We conclude that a better understanding of the PBL and circulation dynamics has important implications for the variability of the concentration of dust, non-condensable and trace gases at the bottom of other craters on Mars as mixing with outside air can be achieved vertically, through changes in the PBL depth, and laterally, by the transport of air into and out of the crater.

• 211.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Providing Air Traffic Control Services for Small Unmanned Aircraft Through LTE2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
• 212.
Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland.
Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland. Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland. Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland. Laboratoire de Génie des Procédés et les Matériaux, Ecole Centrale Paris. Laboratoire Atmosphères, Milieux, Observations Spatiales, Univ. Pierre et Marie Curie, Univ. Versailles Saint-Quentin & CNRS, Paris. Jacobs Technology, NASA Johnson Space Center. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland. Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland. Laboratoire Atmosphères, Milieux, Observations Spatiales, Univ. Pierre et Marie Curie, Univ. Versailles Saint-Quentin & CNRS, Paris. Laboratoire Interuniversitaire des Systèmes Atmosphériques, Université Paris-Est Créteil, Univ. Paris Diderot and CNRS. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland. Exobiology Branch, NASA Ames Research Center, Moffett Field, Kalifornien. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland. Department of Astronomy, Cornell University, Ithaca, New York. Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor. Division of Geological and Planetary Sciences, California Institute of Technology. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland. Earth Sciences Department, Utrecht University. Department of Earth and Environmental Science and School of Science, Rensselaer Polytechnic Institute, Troy, New York. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Centro de Astrobiologia, INTA-CSIC, Madrid.
Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars2015In: Journal of Geophysical Research - Planets, ISSN 2169-9097, E-ISSN 2169-9100, Vol. 120, no 3, p. 495-514Article in journal (Refereed)

The Sample Analysis at Mars (SAM) instrument [Mahaffy et al., 2012] onboard the Mars Science Laboratory (MSL) Curiosity rover is designed to conduct inorganic and organic chemical analyses of the atmosphere and the surface regolith and rocks to help evaluate the past and present habitability potential of Mars at Gale Crater [Grotzinger et al., 2012]. Central to this task is the development of an inventory of any organic molecules present to elucidate processes associated with their origin, diagenesis, concentration and long-term preservation. This will guide the future search for biosignatures [Summons et al., 2011]. Here we report the definitive identification of chlorobenzene (150–300 parts per billion by weight (ppbw)) and C2 to C4 dichloroalkanes (up to 70 ppbw) with the SAM gas chromatograph mass spectrometer (GCMS), and detection of chlorobenzene in the direct evolved gas analysis (EGA) mode, in multiple portions of the fines from the Cumberland drill hole in the Sheepbed mudstone at Yellowknife Bay. When combined with GCMS and EGA data from multiple scooped and drilled samples, blank runs and supporting laboratory analog studies, the elevated levels of chlorobenzene and the dichloroalkanes cannot be solely explained by instrument background sources known to be present in SAM. We conclude that these chlorinated hydrocarbons are the reaction products of martian chlorine and organic carbon derived from martian sources (e.g. igneous, hydrothermal, atmospheric, or biological) or exogenous sources such as meteorites, comets or interplanetary dust particles.

• 213.
NASA Goddard Space Flight Center.
NASA Goddard Space Flight Center. NASA Johnson Space Center, Houston. Ecole Centrale Paris, Chatenay-Malabry. NASA Goddard Space Flight Center. NASA Goddard Space Flight Center. NASA Goddard Space Flight Center. NASA Johnson Space Center, Houston. Universidad Nacional Autónoma de México. Carnegie Institution of Washington, Washington, DC.. NASA Goddard Space Flight Center. NASA Goddard Space Flight Center. Centro de Astrobiología (CSIC-INTA), Madrid.
Detection of reduced sulfur and other S-bearing species evolved from Rocknest sample in the Sample Analysis at Mars (SAM) experiment2013Conference paper (Refereed)
• 214.
National Astronomy and Ionosphere Center, Arecibo Observatory.
National Astronomy and Ionosphere Center, Arecibo Observatory. National Astronomy and Ionosphere Center, Arecibo Observatory. Manufacturing and Mechanical Engineering Department, Miami University. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. University of Puerto Rico, Department of Chemistry.
Potassium Doppler-resonance lidar for the study of the mesosphere and lower thermosphere at the Arecibo Observatory2003In: Journal of Atmospheric and Solar-Terrestrial Physics, ISSN 1364-6826, E-ISSN 1879-1824, Vol. 65, no 16-18, p. 1411-1424Article in journal (Refereed)

We have developed a lidar to study the temperature structure of the nighttime mesopause region over the Arecibo Observatory (18.35°N, 66.75°W) by measuring the lineshape of the fluorescence spectrum of atomic potassium that is deposited in the mesosphere and lower thermosphere (MLT) by meteors. To demonstrate how the potassium lidar can enhance MLT studies at Arecibo, we show recent results for: (1) comparisons with airglow temperature measurements; (2) simultaneous operations with stratospheric and mesospheric temperature profiling by Rayleigh lidar; (3) simultaneous observations of K, Ca+, and E-region electron density profiles; and (4) occurrences of sporadic K layers, and relationships to sporadic E layers.

• 215.
Instituto de Astrofísica de Andalucía CSIC, Granada.
Instituto de Astrofísica de Andalucía CSIC, Granada. Instituto de Astrofísica de Andalucía CSIC, Granada. Instituto de Astrofísica de Andalucía CSIC, Granada. Instituto de Astrofísica de Andalucía CSIC, Granada.
New non-LTE retrieval method for atmospheric parameters from MIPAS/ENVISAT emission spectra at 5.3 μm2002In: Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X, Vol. 4539, p. 396-405Article in journal (Refereed)

Atmospheric emissions at 5.3 μm will be measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), a high-resolution limb sounder on board the European polar platform ENVISAT, scheduled to be launched in 2001. Measured spectra at 5.3 μm contain information on important atmospheric quantities such as NO volume mixing ratio, thermospheric temperature, and chemical NO production rates. However, the scientific analysis of this spectral region has to deal with complex non-local thermodynamic equilibrium (non-LTE) effects. A conventional non-LTE retrieval approach using ab initio vibrational temperatures cannot be applied due to rotational and spin-orbit non-LTE of NO in the thermosphere, and the dependence of NO state populations on the NO abundance itself caused by chemical excitations. An innovative non-LTE retrieval method enabling the treatment of vibrational, rotational, and spin non-LTE as well as a dependence of the non-LTE state distribution on the retrieval target quantities has thus been developed for the MIPAS data analysis. The ability of the developed non-LTE inversion tool to retrieve NO abundance profiles, thermospheric temperature profiles, and NO mean production rates by NO2 photolysis in the stratosphere and N+O2 combination in the thermosphere is demonstrated by means of a feasibility study.

• 216.
Inst. de Matemat./Fis. Fundamental, CSIC.
Centro de Astrobiología, CSIC-INTA.
Nonlinear spherical gravitational downfall of gas onto a solid ball: Analytic and numerical results2003In: Physica D: Non-linear phenomena, ISSN 0167-2789, E-ISSN 1872-8022, Vol. 183, no 1-2, p. 102-116Article in journal (Refereed)

The process of downfall of initially homogeneous gas onto a solid ball due to the ball's gravity (relevant in astrophysical situations) is studied with a combination of analytic and numerical methods. The initial explicit solution soon becomes discontinuous and gives rise to a shock wave. Afterwards, there is a crossover between two intermediate asymptotic similarity regimes, where the shock wave propagates outwards according to two self-similar laws, initially accelerating and eventually decelerating and vanishing, leading to a static state. The numerical study allows one to investigate in detail this dynamical problem and its time evolution, verifying and complementing the analytic results on the initial solution, intermediate self-similar laws and static long-term solution.

• 217.
Department of Automation, Shanghai Jiaotong University.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Department of Automation, Shanghai Jiaotong University.
Enhanced NEH method in solving permutation flow shop problem2007In: Shanghai Jiaotong University. Journal, ISSN 1007-1172, Vol. 12E, no 1, p. 47-52Article in journal (Refereed)

This paper proposed an enhanced NEH with full insertion moves to solve the permutation flow shop problem. The characteristics of the original NEH are investigated and analyzed, and it is concluded that the given method would be promising to find better solutions, while the cost would be increased. Fast makespan calculating method and eliminating non-promising permutation policy are introduced to reduce the evaluation effort. The former decreases the time complexity from O(n4m) to O(n3m), which is an acceptable cost for medium and small size instances considering the obtained solution quality. The results from computational experience show that the latter also can eliminate a lot of non-promising solutions.

• 218.
Stewart Radiance Laboratory, Bedford.
Instituto de Astrofísica de Andalucía CSIC, Granada. Science Directorate, NASA Langley Research Center, Hampton. Instituto de Astrofísica de Andalucía CSIC, Granada. Analytical Services and Materials Inc., Hampton. Center for Atmospheric Sciences, Hampton University. Air Force Research Laboratory, Space Vehicles Directorate, Hanscom Air Force Base, Massachusetts. Air Force Research Laboratory, Space Vehicles Directorate, Hanscom Air Force Base, Massachusetts. Air Force Research Laboratory, Space Vehicles Directorate, Hanscom Air Force Base, Massachusetts.
Comparison of nighttime nitric oxide 5.3 μm emissions in the thermosphere measured by MIPAS and SABER2007In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 112, no A10Article in journal (Refereed)

A comparative study of nitric oxide (NO) 5.3 μm emissions in the thermosphere measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) spectrometer and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) radiometer satellite instruments was conducted for nighttime data collected on 14 June 2003. The agreement between the data sets was very good, within ∼25% over the entire latitude range studied from −58° to + 4°. The MIPAS and SABER data were inverted to retrieve NO volume emission rates. Spectral fitting of the MIPAS data was used to determine the NO(v = 1) rotational and spin-orbit temperatures, which were found to be in nonlocal thermodynamic equilibrium (non-LTE) above 110 km. Near 110 km the rotational and spin-orbit temperatures converged, indicating the onset of equilibrium in agreement with the results of non-LTE modeling. Because of the onset of equilibrium the NO rotational and spin-orbit temperatures can be used to estimate the kinetic temperature near 110 km. The results indicate that the atmospheric model NRLMSISE-00 underestimates the kinetic temperature near 110 km for the locations investigated. The SABER instrument 5.3 μm band filter cuts off a significant fraction of the NO(Δv = 1) band, and therefore modeling of NO is necessary to predict the total band radiance. The needed correction factors were directly determined from the MIPAS data, providing validation of the modeled values used in SABER operational data processing. The correction factors were applied to the SABER data to calculate densities of NO(v = 1). A feasibility study was also conducted to investigate the use of NO 5.3 μm emission data to derive NO(v = 0) densities in the thermosphere.

• 219.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
Interactive Schedule Visualisation, Status Tracking and Execution Verification for Goal-Based Operation of Multi-Satellite Formations2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
• 220.
Meteorologisches Institut, Ludwig-Maximilians-Universität.
Meteorologisches Institut, Ludwig-Maximilians-Universität. Meteorologisches Institut, Ludwig-Maximilians-Universität. Meteorologisches Institut, Ludwig-Maximilians-Universität. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Representative wavelengths absorption parameterization applied to satellite channels and spectral bands2014In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 148, p. 99-115Article in journal (Refereed)

Accurate modeling of wavelength-integrated radiative quantities, e.g. integrated over a spectral band or an instrument channel response function, requires computations for a large number of wavelengths if the radiation is affected by gas absorption which typically comprises a complex line structure. In order to increase computational speed of modeling radiation in the Earth׳s atmosphere, we parameterized wavelength-integrals as weighted means over representative wavelengths. We parameterized spectral bands of different widths (1 cm−1, 5 cm−1, and 15 cm−1) in the solar and thermal spectral range, as well as a number of instrument channels on the ADEOS, ALOS, EarthCARE, Envisat, ERS, Landsat, MSG, PARASOL, Proba, Sentinel, Seosat, and SPOT satellites. A root mean square relative deviation lower than 1% from a “training data set” was selected as the accuracy threshold for the parameterization of each band and channel. The training data set included high spectral resolution calculations of radiances at the top of atmosphere for a set of highly variable atmospheric states including clouds and aerosols. The gas absorption was calculated from the HITRAN 2004 spectroscopic data set and state-of-the-art continuum models using the ARTS radiative transfer model. Three representative wavelengths were required on average to fulfill the accuracy threshold. We implemented the parameterized spectral bands and satellite channels in the uvspec radiative transfer model which is part of the libRadtran software package. The parameterization data files, including the representative wavelengths and weights as well as lookup tables of absorption cross sections of various gases, are provided at the libRadtran webpage.In the paper we describe the parameterization approach and its application. We validate the approach by comparing modeling results of parameterized bands and channels with results from high spectral resolution calculations for atmospheric states that were not part of the training data set. Irradiances are not only compared at the top of atmosphere but also at the surface for which this parameterization approach was not optimized. It is found that the parameterized bands and channels provide a good compromise between computation time requirements and uncertainty for typical radiative transfer problems. In particular for satellite radiometer simulations the computation time requirement and the parameterization uncertainty is low. Band-integrated irradiances at any level as well as heating and cooling rates below 20 km can also be modeled with low uncertainty.

• 221.
Universität Hamburg, Freie Universität Berlin.
Space Science Institute, Boulder, Colorado. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
In Situ Compositional Measurements of Rocks and Soils with the Alpha Particle X-ray Spectrometer on NASA's Mars Rovers2015In: Elements, ISSN 1811-5209, E-ISSN 1811-5217, Vol. 11, no 1, p. 39-44Article in journal (Refereed)

The Alpha Particle X-ray Spectrometer (APXS) is a soda can–sized, arm-mounted instrument that measures the chemical composition of rocks and soils using X-ray spectroscopy. It has been part of the science payload of the four rovers that NASA has landed on Mars. It uses 244Cm sources for a combination of PIXE and XRF to quantify 16 elements. So far, about 700 Martian samples from about 50 km of combined traverses at the four landing sites have been documented. The compositions encountered range from unaltered basaltic rocks and extensive salty sandstones to nearly pure hydrated ferric sulfates and silica-rich subsurface soils. The APXS is used for geochemical reconnaissance, identification of rock and soil types, and sample triage. It provides crucial constraints for use with the mineralogical instruments. The APXS data set allows the four landing sites to be compared with each other and with Martian meteorites, and it provides ground truth measurements for comparison with orbital observations.

• 222.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Optical Analysis of Plasma: Flame Emission in Cryogenic Rocket Engines2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

This thesis contains the results of optical flame emission measurements of the Vulcain 2.1engine and the plasma emission spectroscopy of the Lumen Project engine. The plume spectroscopyis analyzed, ordered and studied in detail to offer the best possible molecular composition.The main focus relied on the hydroxide radical, blue radiation and other moleculesanalysis of the intensities encountered during the tests. The plasma emission spectroscopy isfocused on the determination of the plasma temperature value in LIBS measurements. Thehydrogen plasma temperature determination of the local thermodynamic equilibrium, followedby the carbon and sequentially oxygen plasma is obtained. The quality of the LTE isto be determined to judge the truthworthness of the determined temperatures. Both the testsare analyzed thanks to the use of spectrographs, cameras and dedicated software for opticalapplications. The results related to the Vulcain 2.1 LOX/LH2 engine showed the evolutionof the plume in different ROF or pressure variations. Furthermore, the results of the LumenProject LOX/methane engine led to the determination of the plasma temperatures and a firstestimation of the LTE quality.

• 223. Glatthor, N.
Retrieval of stratospheric ozone profiles from MIPAS/ENVISAT limb emission spectra: a sensitivity study2006In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 6, no 10, p. 2767-2781Article in journal (Refereed)

We report on the dependence of ozone volume mixing ratio profiles, retrieved from limb emission infrared spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), on different retrieval setups such as the treatment of the background continuum, cloud filtering, spectral regions used for analysis and a series of further more technical parameter choices. The purpose of this investigation is to better understand the error sources of the ozone retrieval, to optimize the current retrieval setup and to document changes in the data versions. It was shown that the cloud clearing technique used so far (cloud index 1.8) does not reliably exclude all cloud-contaminated spectra from analysis. Through analysis of spectra calculated for cloudy atmospheres we found that the cloud index should be increased to a value of 3.0 or higher. Further, it was found that assignment of a common background continuum to adjacent microwindows within 5 cm−1 is advantageous, because it sufficiently represents the continuum emission by aerosols, clouds and gases as reported in the literature, and is computationally more efficient. For ozone retrieval we use ozone lines from MIPAS band A (685–970 cm−1) and band AB (1020–1170 cm−1) as well. Therefore we checked ozone retrievals with lines from bands A or AB only for a systematic difference. Such a difference was indeed found and could, to a major part, be attributed to the spectroscopic data used in these two bands, and to a minor part to neglection of modelling of non-local thermodynamic (non-LTE) emissions. Another potential explanation, a bias in the radiance calibration of level-1B spectra of bands A and AB, could largely be ruled out by correlation analysis and inspection of broadband spectra. Further upgrades in the ozone retrieval consist of application of an all-zero a-priori profile and a weaker regularization. Finally, the ozone distribution obtained with the new retrieval setup (data versions V3o_O3_7) was compared to the data version used before (V2_O3_2). Differences are smaller than $\pm$0.4 ppmv in the altitude region 15–50 km. Further, differences to ozone measured by the HALogen Occultation Experiment (HALOE) on the Upper Atmospheric Research Satellite (UARS) are partly reduced with the new MIPAS data version.

• 224.
Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe. Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe. Instituto de Astrofísica de Andalucía CSIC, Granada. Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe. Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe. Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe. Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe. Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe. Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe. Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
Global peroxyacetyl nitrate (PAN) retrieval in the upper troposphere from limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS)2007In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 7, no 11, p. 2775-2787Article in journal (Refereed)

We use limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard the ENVIronmental SATellite (ENVISAT) to derive the first global distribution of peroxyacetyl nitrate (PAN) in the upper troposphere. PAN is generated in tropospheric air masses polluted by fuel combustion or biomass burning and acts as a reservoir and carrier of NOx in the cold free troposphere. PAN exhibits continuum-like broadband structures in the mid-infrared region and was retrieved in a contiguous analysis window covering the wavenumber region 775–800 cm−1. The interfering species CCl4, HCFC-22, H2O, ClONO2, CH3CCl3 and C2H2 were fitted along with PAN, whereas pre-fitted profiles were used to model the contribution of other contaminants like ozone. Sensitivity tests consisting in retrieval without consideration of PAN demonstrated the existence of PAN signatures in MIPAS spectra obtained in polluted air masses. The analysed dataset consists of 10 days between 4 October and 1 December 2003. This period covers the end of the biomass burning season in South America and South and East Africa, in which generally large amounts of pollutants are produced and distributed over wide areas of the southern hemispheric free troposphere. Indeed, elevated PAN amounts of 200–700 pptv were measured in a large plume extending from Brasil over the Southern Atlantic, Central and South Africa, the South Indian Ocean as far as Australia at altitudes between 8 and 16 km. Enhanced PAN values were also found in a much more restricted area between northern subtropical Africa and India. The most significant northern midlatitude PAN signal was detected in an area at 8 km altitude extending from China into the Chinese Sea. The average mid and high latitude PAN amounts found at 8 km were around 125 pptv in the northern, but only between 50 and 75 pptv in the southern hemisphere. The PAN distribution found in the southern hemispheric tropics and subtropics is highly correlated with the jointly fitted acetylene (C2H2), which is another pollutant produced by biomass burning, and agrees reasonably well with the CO plume detected during end of September 2003 at the 275 hPa level (~10 km) by the Measurement of Pollution in the Troposphere (MOPITT) instrument on the Terra satellite. Similar southern hemispheric PAN amounts were also observed by previous airborne measurements performed in September/October 1992 and 1996 above the South Atlantic and the South Pacific, respectively.

• 225.
Max-Planck-Institut für Solar System Research.
Niels Bohr Institute, University of Copenhagen. Malin Space Science Systems, San Diego. Space Science Institute, Boulder, Colorado. IRAP, CNRS/UPS, Toulouse. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Applied Physics Laboratory, Laurel, Maryland. University of Oregon, Corvallis, Oregon. DLR, Berlin. University of Texas, Austin. IRAP, CNRS/UPS, Toulouse. IRAP, CNRS/UPS, Toulouse. University of New Mexico, Albuquerque. University of Michigan. U.S. Geological Survey, Flagstaff. Cornell University, Ithaca. Los Alamos National Laboratory. Centro de Astrobiología (CSIC-INTA), Madrid.
Compositional Variations of Rocknest Sand, Gale Crater, Mars2013Conference paper (Refereed)
• 226.
California Institute of Technology, Pasadena, Division of Geological and Planetary Sciences, California Institute of Technology.
Indiana University, Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Curiosity's Mission of Exploration at Gale Crater, Mars2015In: Elements, ISSN 1811-5209, E-ISSN 1811-5217, Vol. 11, no 1, p. 19-26Article in journal (Refereed)

Landed missions to the surface of Mars have long sought to determine the material properties of rocks and soils encountered during the course of surface exploration. Increasingly, emphasis is placed on the study of materials formed or altered in the presence of liquid water. Placed in the context of their geological environment, these materials are then used to help evaluate ancient habitability. The Mars Science Laboratory mission—with its Curiosity rover—seeks to establish the availability of elements that may have fueled microbial metabolism, including carbon, hydrogen, sulfur, nitrogen, phosphorus, and a host of others at the trace element level. These measurements are most valuable when placed in a geological framework of ancient environments as interpreted from mapping, combined with an understanding of the petrogenesis of the igneous rocks and derived sedimentary materials. In turn, the analysis of solid materials and the reconstruction of ancient environments provide the basis to assess past habitability.

• 227.
Division of Geological and Planetary Sciences, California Institute of Technology.
Department of Earth and Planetary Sciences, University of California, Davis. Department of Earth and Planetary Sciences, University of Tennessee, Knoxville. Division of Geological and Planetary Sciences, California Institute of Technology. Department of Earth Science and Engineering, Imperial College London. School of Earth and Space Exploration, Arizona State University. U.S. Geological Survey, Santa Cruz. Department of Geosciences, Princeton University, New Jersey. Indiana University, Department of Geological Sciences, Bloomington. Laboratoire Planétologie et Géodynamique de Nantes, LPGN/CNRS and Université de Nantes. Department of Geological Sciences, Brown University, Providence. NASA Goddard Space Flight Center. Department of Space Sciences, NASA Ames Research Center, Moffett Field. School of Earth and Space Exploration, Arizona State University, Tempe. Division of Geological and Planetary Sciences, California Institute of Technology. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Department of Geosciences, State University of New York, Stony Brook. Department of Geosciences, State University of New York, Stony Brook. Jacobs Technology, NASA Johnson Space Center. Planetary Science Institute, Tucson. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Malin Space Science Systems. Malin Space Science Systems. Department of Space Sciences, NASA Ames Research Center, Moffett Field. Planetary Science Institute, Tucson.
A habitable fluvio-lacustrine environment at Yellowknife Bay, Gale Crater, Mars2014In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 343, no 6169, article id 1242777Article in journal (Refereed)

The Curiosity rover discovered fine-grained sedimentary rocks, which are inferred to represent an ancient lake and preserve evidence of an environment that would have been suited to support a martian biosphere founded on chemolithoautotrophy. This aqueous environment was characterized by neutral pH, low salinity, and variable redox states of both iron and sulfur species. Carbon, hydrogen, oxygen, sulfur, nitrogen, and phosphorus were measured directly as key biogenic elements; by inference, phosphorus is assumed to have been available. The environment probably had a minimum duration of hundreds to tens of thousands of years. These results highlight the biological viability of fluvial-lacustrine environments in the post-Noachian history of Mars.

• 228.
Cloud Physics and Severe Weather Research Section, Environment Canada.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. NOAA, NESDIS, Madison, WI. CIMSS, University of Wisconsin-Madison, Madison, WI. NOAA, NESDIS, Greenbelt, MD. NCAR, Boulder, Colorado. Cloud Physics and Severe Weather Research Section, Environment Canada. I.M. Systems Group, NOAA/NWS/NCEP, Camp Springs, MD. Radiometrics Corporation, CIRES, University of Colorado, Boulder, CO. I.M. Systems Group, NOAA/NWS/NCEP, Camp Springs, MD. RPN, CMC, Environment Canada. Leading Edge Atmospherics, Boulder, CO.
Ice fog in arctic during fram-ice fog project aviation and nowcasting applications2014In: Bulletin of The American Meteorological Society - (BAMS), ISSN 0003-0007, E-ISSN 1520-0477, Vol. 95, no 2, p. 211-226Article in journal (Refereed)

Increased understanding of ice fog microphysics can improve frost and ice fog prediction using forecast models and remote-sensing retrievals, thereby reducing potential hazards to aviation

• 229.
Cloud Physics and Severe Weather Research Section, Environment Canada.
I.M. Systems Group, NOAA/NWS/NCEP, Camp Springs, MD. RPN, CMC, Environment Canada. Meteorolooieches lnstitut, University of Bonn. Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing. National Center for Atmospheric Research, Boulder, Colorado. I.M. Systems Group, NOAA/NWS/NCEP, Camp Springs, MD. Radiometrics Corporation, CIRES, University of Colorado, Boulder, CO. NOAA, NESDIS, Madison, WI. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. NOAA, NESDIS, Greenbelt, MD. Cloud Physics and Severe Weather Research Section, Environment Canada. Ruhr-Universität Bochum, Department of Geography.
A review on ice fog measurements and modeling2015In: Atmospheric research, ISSN 0169-8095, E-ISSN 1873-2895, Vol. 151, p. 2-19Article in journal (Refereed)

The rate of weather-related aviation accident occurrence in the northern latitudes is likely 25 times higher than the national rate of Canada. If only cases where reduced visibility was a factor are considered, the average rate of occurrence in the north is about 31 times higher than the Canadian national rate. Ice fog occurs about 25% of the time in the northern latitudes and is an important contributor to low visibility. This suggests that a better understanding of ice fog prediction and detection is required over the northern latitudes. The objectives of this review are the following: 1) to summarize the current knowledge of ice fog microphysics, as inferred from observations and numerical weather prediction (NWP) models, and 2) to describe the remaining challenges associated with measuring ice fog properties, remote sensing microphysical retrievals, and simulating/predicting ice fog within numerical models. Overall, future challenges related to ice fog microphysics and visibility are summarized and current knowledge is emphasized.

• 230.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering. CNES.
Analysis of the Representation of Orbital Errors and Improvement of their Modelling2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

In Space Situational Awareness (SSA), it is crucial to assess the uncertainty related to thestate vector of resident space objects (RSO). This uncertainty plays a fundamental role in, forexample, collision risk assessment and re-entry predictions. A realistic characterization of thisuncertainty is, therefore, necessary.The most common representation of orbital uncertainty is through a Gaussian (or normal)distribution. However, in the absence of new observations, the uncertainty grows over timeand the Gaussian representation is no longer valid under nonlinear dynamics like spacemechanics. This study evaluates the time when the uncertainty starts becoming non-Gaussianin nature.

Different algorithms for evaluating the normality of a distribution were implemented andMonte Carlo tests were performed on them to assess their performance. Also, the distancesbetween distributions when they are propagated under linear and nonlinear algorithms werecomputed and compared to the results from the Monte Carlo statistics tests in order to predictthe time when the Gaussianity of the distribution breaks. Uncertainty propagation using StateTransition Tensors and Unscented Transform methods were also studied. Among theimplemented algorithms for evaluating the normality of a distribution, it was found thatRoyston’s method gives the best performance. It was also found that if the Normalized L 2distance between the linear and non-linear propagated distributions is greater than 95%, thenuncertainty starts to become non-Gaussian. In the best case scenario of unperturbed two-bodymotion, it is observed that the Gaussianity is preserved for at least three orbital periods in thecase of Low-Earth and Geostationary orbits when initial uncertainty corresponds to the meanprecision of the space debris catalog. If the initial variances are reduced, then Gaussianity ispreserved for a longer period of time. Time for which Gaussian assumption is valid on orbitaluncertainty is also dependent on the initial mean anomaly. Effect of coordinatestransformation on Gaussianity validity time is also analyzed by considering uncertainty inCartesian, Keplerian and Poincaré coordinate systems.

This study can therefore be used to improve space debris cataloguing.

• 231.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
Model for Touchdown Dynamics of a Lander on the Solar Power Sail Mission2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

The ISAS/JAXA Solar Power Sail mission, bound to explore the Jupiter trojans, will face many challenges during its journey. The landing manoeuvre is one of the most critical parts of any space mission that plans to investigate the surface of celestial bodies. Asteroids are mostly unknown bodies and in order to plan a successful landing on their surface, a great number of landing scenarios need to be taken into account. For the future mission to the Jupiter trojans, a study of the landing dynamics and their effects on the lander has to be done. A simple model of a lander has been created based on a design for the ISAS/JAXA Solar Power Sail mission, and the possible landing scenarios have been simulated. For this case, only the last part of the landing, which will be a free-fall has been taken into account. The lander is modelled as a rigid structure with a landing gear composed of four legs. The surface has been modelled as a flat plane with different inclinations and the possibility of including small obstacles or terrain roughness has been implemented. In the model, the lander is allowed 6 degrees of freedom. Several landing possibilities are tested with residual velocities and deviations in the starting point, and the stability of the lander is evaluated respect its geometry. Damping strategies have been considered to protect the instruments and reduce the impact, allowing for a safer landing. The effect of including crushable honeycomb dampers in the legs is also implemented, simulated and evaluated, by using a model of crushable honeycombs with different characteristics. In addition, the model includes also the position, direction and characteristics of the thrusters. Thus, it could be used to study other phases of the landing sequence where active control of the lander is needed, and evaluate the behaviour and response of different control-loop algorithms for attitude and position control of the lander.

• 232.
NASA Goddard Spaceflight Center,Greenbelt, MD, USA.
Space Science Institute, College Station, TX, USA. Department of Earth and Space Science and Engineering, York University, Toronto, Ontario, Canada. College of Engineering, University of Michigan, Ann Arbor, MI, USA. College of Engineering, University of Michigan, Ann Arbor, MI, USA. Aeolis Research, Pasadena, CA, USA. Department of Earth and Planetary Science, The Johns Hopkins University, Baltimore, MD, USA. Department of Earth and Space Science and Engineering, York University, Toronto, Ontario, Canada. Department of Earth and Space Science and Engineering, York University, Toronto, Ontario, Canada. Centro de Astrobiología (INTA-CSIC), Madrid, Spain. Finnish Meteorological Institute, Helsinki, Finland. Southwest Research Institute, Boulder, CO, USA. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Instituto Andaluz de Ciencias de la Tierra (CSIC‐UGR), Armilla, Granada, Spain. Department of Astronomy, University of Maryland, College Park, MD, USA. Department of Earth and Space Science and Engineering, York University, Toronto, Ontario, Canada. Finnish Meteorological Institute, , Helsinki, Finland; School of Electrical Engineering, Aalto University, , Espoo, Finland. NASA Goddard Spaceflight Center, Greenbelt, MD, USA;CRESST II and Department of Astronomy, University of Maryland, College Park, MD, USA. Aeolis Research, Pasadena, CA, USA. NASA Goddard Spaceflight Center, Greenbelt, MD, USA. Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY, USA. Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY, USA. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. Centro de Astrobiología (INTA-CSIC), Madrid, Spain. Leidos, Houston, TX, USA. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Mars Science Laboratory Observations of the 2018/Mars Year 34 Global Dust Storm2019In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 46, no 1, p. 71-79Article in journal (Refereed)

Mars Science Laboratory Curiosity rover observations of the 2018/Mars year 34 global/planet‐encircling dust storm represent the first in situ measurements of a global dust storm with dedicated meteorological sensors since the Viking Landers. The Mars Science Laboratory team planned and executed a science campaign lasting approximately 100 Martian sols to study the storm involving an enhanced cadence of environmental monitoring using the rover's meteorological sensors, cameras, and spectrometers. Mast Camera 880‐nm optical depth reached 8.5, and Rover Environmental Monitoring Station measurements indicated a 97% reduction in incident total ultraviolet solar radiation at the surface, 30K reduction in diurnal range of air temperature, and an increase in the semidiurnal pressure tide amplitude to 40 Pa. No active dust‐lifting sites were detected within Gale Crater, and global and local atmospheric dynamics were drastically altered during the storm. This work presents an overview of the mission's storm observations and initial results.

• 233.
Universities Space Research Association/NASA Goddard Space Flight Center.
Ashima Research Inc. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Texas A&M University, College Station, TX. Texas A&M University, College Station, TX. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Earth and Space Science and Engineering , York University. Earth and Space Science and Engineering , York University. Earth and Space Science and Engineering , York University. Uni-versity of Michigan, Ann Arbor. NASA Goddard Space Flight Center, Greenbelt.
The Mars Science Laboratory dust storm campaign2017Conference paper (Other academic)
• 234.
NASA Goddard Spaceflight Center, Greenbelt, MD.
Aeolis Research, Pasadena, CA. NASA Goddard Spaceflight Center, Greenbelt, MD. Department of Earth and Space Science and Engineering, York University, Toronto, ON, Canada. Department of Earth and Space Science and Engineering, York University, Toronto, ON, Canada. Department of Earth and Space Science and Engineering, York University, Toronto, ON, Canada. Aeolis Research, Pasadena, CA. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Granada, Spain. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Centro de Astrobiología (INTA-CSIC), Torrejón de Ardoz, Madrid, Spain. Department of Atmospheric Sciences, Texas A&M University, College Station, TX.
The Vertical Dust Profile over Gale Crater, Mars2017In: Journal of Geophysical Research - Planets, ISSN 2169-9097, E-ISSN 2169-9100, Vol. 122, no 12, p. 2779-2792Article in journal (Refereed)

We create a vertically coarse, but complete, vertical profile of dust mixing ratio from the surface to the upper atmosphere over Gale Crater, Mars, using the frequent joint atmospheric observations of the orbiting Mars Climate Sounder (MCS) and the Mars Science Laboratory (MSL) Curiosity rover. Using these data and an estimate of planetary boundary layer (PBL) depth from the MarsWRF general circulation model, we divide the vertical column into three regions. The first region is the Gale Crater PBL, the second is the MCS-sampled region, and the third is between these first two. We solve for a well-mixed dust mixing ratio within this third (middle) layer of atmosphere to complete the profile.

We identify a unique seasonal cycle of dust within each atmospheric layer. Within the Gale PBL, dust mixing ratio maximizes near southern hemisphere summer solstice (Ls = 270°) and minimizes near winter solstice (Ls = 90-100°) with a smooth sinusoidal transition between them. However, the layer above Gale Crater and below the MCS-sampled region more closely follows the global opacity cycle and has a maximum in opacity near Ls = 240° and exhibits a local minimum (associated with the “solsticial pause” in dust storm activity) near Ls = 270°. With knowledge of the complete vertical dust profile, we can also assess the frequency of high-altitude dust layers over Gale. We determine that 36% of MCS profiles near Gale Crater contain an “absolute” high-altitude dust layer wherein the dust mixing ratio is the maximum in the entire vertical column.

• 235.
Centro de Astrobiologia, INTA-CSIC, Madrid.
Centro de Astrobiologia, INTA-CSIC, Madrid. Universidad Politécnica de Cataluña. Universidad Politécnica de Cataluña. FMI-Arctic Research Centre, Sodankylä. Centro de Astrobiologia, INTA-CSIC, Madrid. NASA Ames Research Center. FMI-Arctic Research Centre, Sodankylä. Universidad Politécnica de Cataluña. FMI-Arctic Research Centre, Sodankylä. Universidad Politécnica de Cataluña. Centro de Astrobiologia, INTA-CSIC, Madrid. Centro de Astrobiologia, INTA-CSIC, Madrid. Centro de Astrobiologia, INTA-CSIC, Madrid. Ashima Research, Pasadena. Centro de Astrobiologia, INTA-CSIC, Madrid. EADS-CRISA. Centro de Astrobiologia, INTA-CSIC, Madrid. Universidad de Alcalá de Henares. Centro de Astrobiologia, INTA-CSIC, Madrid. EADS-CRISA. FMI-Arctic Research Centre, Sodankylä. Universidad de Alcalá de Henares. Michigan University. Universidad Politécnica de Cataluña. Centro de Astrobiología (CSIC-INTA). Centro de Astrobiologia, INTA-CSIC, Madrid.
REMS: The environmental sensor suite for the Mars Science Laboratory rover2012In: Space Science Reviews, ISSN 0038-6308, E-ISSN 1572-9672, Vol. 170, no 1-4, p. 583-640Article in journal (Refereed)

The Rover Environmental Monitoring Station (REMS) will investigate environmental factors directly tied to current habitability at the Martian surface during the Mars Science Laboratory (MSL) mission. Three major habitability factors are addressed by REMS: the thermal environment, ultraviolet irradiation, and water cycling. The thermal environment is determined by a mixture of processes, chief amongst these being the meteorological. Accordingly, the REMS sensors have been designed to record air and ground temperatures, pressure, relative humidity, wind speed in the horizontal and vertical directions, as well as ultraviolet radiation in different bands. These sensors are distributed over the rover in four places: two booms located on the MSL Remote Sensing Mast, the ultraviolet sensor on the rover deck, and the pressure sensor inside the rover body. Typical daily REMS observations will collect 180 minutes of data from all sensors simultaneously (arranged in 5 minute hourly samples plus 60 additional minutes taken at times to be decided during the course of the mission). REMS will add significantly to the environmental record collected by prior missions through the range of simultaneous observations including water vapor; the ability to take measurements routinely through the night; the intended minimum of one Martian year of observations; and the first measurement of surface UV irradiation. In this paper, we describe the scientific potential of REMS measurements and describe in detail the sensors that constitute REMS and the calibration procedures. © 2012 Springer Science+Business Media B.V.

• 236.
Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid.
Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Finnish Meteorological Institute, Helsinki. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. NASA Ames Research Center, Moffett Field, CA. Southwest Research Institute, Boulder, CO. Finnish Meteorological Institute, Helsinki. Finnish Meteorological Institute, Helsinki. Finnish Meteorological Institute, Helsinki. Centro de Astrobiología (CSIC - INTA), Torrejón de Ardoz, Madrid. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Ashima Research Inc. Universidad de Alcalá de Henares, Alcalá de Henares. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Finnish Meteorological Institute, Helsinki. Southwest Research Institute, Boulder, CO. Universidad de Alcalá de Henares, Alcalá de Henares. University of Michigan, Ann Arbor, MI. Ashima Research, Pasadena, CA. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Ingeniería de Sistemas Para la Defensa de España, Madrid. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid. Centro de Astrobiología (CSIC-INTA), Torrejõn de Ardoz, Madrid.
Curiosity's rover environmental monitoring station: Overview of the first 100 sols2014In: Journal of Geophysical Research - Planets, ISSN 2169-9097, E-ISSN 2169-9100, Vol. 119, no 7, p. 1680-1688Article in journal (Refereed)

In the first 100 Martian solar days (sols) of the Mars Science Laboratory mission, the Rover Environmental Monitoring Station (REMS) measured the seasonally evolving diurnal cycles of ultraviolet radiation, atmospheric pressure, air temperature, ground temperature, relative humidity, and wind within Gale Crater on Mars. As an introduction to several REMS-based articles in this issue, we provide an overview of the design and performance of the REMS sensors and discuss our approach to mitigating some of the difficulties we encountered following landing, including the loss of one of the two wind sensors. We discuss the REMS data set in the context of other Mars Science Laboratory instruments and observations and describe how an enhanced observing strategy greatly increased the amount of REMS data returned in the first 100 sols, providing complete coverage of the diurnal cycle every 4 to 6 sols. Finally, we provide a brief overview of key science results from the first 100 sols. We found Gale to be very dry, never reaching saturation relative humidities, subject to larger diurnal surface pressure variations than seen by any previous lander on Mars, air temperatures consistent with model predictions and abundant short timescale variability, and surface temperatures responsive to changes in surface properties and suggestive of subsurface layering. Key Points Introduction to the REMS results on MSL mission Overiview of the sensor information Overview of operational constraints

• 237.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
Field-Site Prototype for HABIT (FSP-HABIT): Characterizing Martian Salts Prior to the ExoMars 2020 Mission2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

One of the major remaining question about Mars is its habitability - if the requirements necessary to allow for life are presently fulfilled. One of the most relevant ingredients for life, as we know it, is water. Indirect evidence of transient liquid water on Mars has been retrieved from both rover [Martín-Torres et al., 2015] and orbiter [Ojha et al., 2015].

[Martín-Torres et al., 2015] inferred the existence of an active water cycle, driven by chlorate and perchlorate salts, which are commonly found on the Martian surface, and absorb atmospheric water to form stable hydrated compounds and liquid solutions. This happens through a process called deliquescence (absorption of moisture from the atmosphere by the salts and dissolving into a liquid solution). One of the goals of HABIT is to confirm the hypothesis about the water cycle on Mars. HABIT will record the behavior of a selection of salts on Mars, and will also record Martian environmental conditions (UVdose, air and ground temperatures).

The Field-Site Prototype for HABIT (FSP-HABIT) was the first prototype of HABIT deployed during field-site campaigns. Three campaigns took place during summer 2016: First, a short preparatory campaign in Abisko, Sweden, was carried out. The second campaign took place in Iceland, within the EU COST Action TD1308 ORIGINS (Origins and evolution of life on Earth and in the Universe), and the third campaign was conducted within the NASA Spaceward Bound India Program in Ladakh. After providing the corresponding background on the mission framework and the scientific background, this document covers the mechanical, electrical, and software design of the instrument. Afterwards, the steps taken to test the instrument and their results are covered, followed by a rating of the instrument and ideas for future improvements. Instruments like FSP-HABIT will enable the characterization of hygroscopic salts by their conductivity as liquid brines are good conductors, hydrated salts are poor conductors, and dehydrated salts are insulators. During the field-site campaigns, the measurements of FSP-HABIT were used to characterize the near surface environment by its temperature, pressure and relative humidity. Now, these measurements are available for comparison with microbiological studies of the water, ice and soils to characterize the habitability of the explored site. The lessons learned while designing and building FSP-HABIT can be used to inform the development of further prototypes for space missions such as HABIT.

• 238.
NASA Ames Research Center.
Centro de Astrobiologia, INTA-CSIC, Madrid. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Finnish Meteorological Institute, Helsinki. NASA Ames Research Center. Finnish Meteorological Institute, Helsinki. NASA Ames Research Center. Texas A&M University, College Station. Instituto Andaluz de Ciencias de la Tierra, Granada. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. York University, Toronto. Ashima Research, Pasadena. Southwest Research Institute, Boulder. University of Michigan, Ann Arbor. Ashima Research, Pasadena. Cornell University, Ithaca. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. University of Michigan, Ann Arbor. Centro de Astrobiologia, INTA-CSIC, Madrid.
Secular Climate Change on Mars: An Update Using MSL Pressure Data2013Conference paper (Refereed)

The South Polar Residual Cap (SPRC) on Mars is an icy reservoir of CO2. If all the CO2 trapped in the SPRC were released to the atmosphere the mean annual global surface pressure would rise by ~20 Pa. Repeated MOC and HiRISE imaging of scarp retreat rates within the SPRC have led to the suggestion that the SPRC is losing mass. Estimates for the loss rate vary between 0. 5 Pa per Mars Decade to 13 Pa per Mars Decade. Assuming 80% of this loss goes directly into the atmosphere, and that the loss is monotonic, the global annual mean surface pressure should have increased between ~1-20 Pa since the Viking mission (19 Mars years ago). Surface pressure measurements by the Phoenix Lander only 2 Mars years ago were found to be consistent with these loss rates. Here we compare surface pressure data from the MSL mission with that from Viking Lander 2 (VL-2) to determine if the trend continues. We use VL-2 because it is at the same elevation as MSL (-4500 m). However, based on the first 100 sols of data there does not appear to be a significant difference between the dynamically adjusted pressures of the two landers. This result implies one of several possibilities: (1) the cap is not losing mass and the difference between the Viking and Phoenix results is due to uncertainties in the measurements; (2) the cap has lost mass between the Viking and Phoenix missions but it has since gone back to the cap or into the regolith; or (3) that our analysis is flawed. The first possibility is real since post-mission analysis of the Phoenix sensor has shown that there is a 3 (±2) Pa offset in the data and there may also be uncertainties in the Viking data. The loss/gain scenario for the cap seems unlikely since scarps continue retreating, and regolith uptake implies something unique about the past several Mars years. That our analysis is flawed is certainly possible owing to the very different environments of the Viking and MSL landers. MSL is at the bottom of a deep crater in the southern tropics (~5°S), whereas VL-2 is at a high latitude (~48°N) in the northern plains. And in spite of the fact that the two landers are at nearly identical elevations, they are in very different thermal environments (e.g., MSL is warm when VL-2 is cold), which can have a significant affect on pressures. For these reasons, our confidence in the comparison will increase as more MSL data become available. We will report the results up through sol 360 at the meeting.

• 239.
NASA Ames Research Center.
Centro de Astrobiologia, INTA-CSIC, Madrid. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Finnish Meteorological Institute. NASA Ames Research Center. Finnish Meteorological Institute. NASA Ames Research Center. Department of Atmospheric Sciences, Texas A&M University, College Station, Texas. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Centro de Astrobiologia, Madrid. Department of Earth and Space Science and Engineering, York University. Ashima Research, Pasadena. Southwest Research Institute, San Antonio, Texas. Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor. Ashima Research, Pasadena. Centro de Astrobiologia, INTA-CSIC, Madrid. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Centro de Astrobiologia, INTA-CSIC, Madrid.
Preliminary interpretation of the REMS pressure data from the first 100 sols of the MSL mission2014In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 119, no 3, p. 440-453Article in journal (Refereed)

We provide a preliminary interpretation of the Rover Environmental Monitoring Station (REMS) pressure data from the first 100 Martian solar days (sols) of the Mars Science Laboratory mission. The pressure sensor is performing well and has revealed the existence of phenomena undetected by previous missions that include possible gravity waves excited by evening downslope flows, relatively dust-free convective vortices analogous in structure to dust devils, and signatures indicative of the circulation induced by Gale Crater and its central mound. Other more familiar phenomena are also present including the thermal tides, generated by daily insolation variations, and the CO2 cycle, driven by the condensation and sublimation of CO2 in the polar regions. The amplitude of the thermal tides is several times larger than those seen by other landers primarily because Curiosity is located where eastward and westward tidal modes constructively interfere and also because the crater circulation amplifies the tides to some extent. During the first 100 sols tidal amplitudes generally decline, which we attribute to the waning influence of the Kelvin wave. Toward the end of the 100 sol period, tidal amplitudes abruptly increased in response to a nearby regional dust storm that did not expand to global scales. Tidal phases changed abruptly during the onset of this storm suggesting a change in the interaction between eastward and westward modes. When compared to Viking Lander 2 data, the REMS daily average pressures show no evidence yet for the 1-20 Pa increase expected from the possible loss of CO 2 from the south polar residual cap. Key Points REMS pressure sensor is operating nominally New phenomena have been discovered Familiar phenomena have been detected ©2014. American Geophysical Union. All Rights Reserved.

• 240.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
A Bluetooth based intra-satellite communication system2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

This thesis presents a wireless communication system for intra-satellite communication based on Bluetooth Low Energy technology, which can have many benefits regarding the design and operation of satellites. The proposed design based on the nRF53832 chip from Nordic Semiconductor is described, followed by the results of several tests regarding the most important design criteria for its application in small satellites. The tested aspects include the power consumption of the wireless module in different operation modes, which is sufficiently low for the application even in small satellites. Signal strength measurements for various output power settings and obstacles show that reliable communication is possible in a satellite mockup. No packet error was detected, and latencies of less than 30 ms combined with achievable data rates between 200 and 700 kbps should be sufficient for most CubeSat satellites. Additionally, details are given to successfully integrate the chip with existing satellite subsystems. A code library is provided to simplify the communication between the modules, and a concept of a redundant system is established to increase the reliability for critical satellite subsystems. The overall assessment of the technology suggests that the presented system is suitable for in-orbit deployment with the Aalto-3 satellite (currently being developed at Aalto University), which will provide further validation of the technology.

• 241.
Department of Space Studies, Southwest Research Institute.
Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Centro de Astrobiologia, INTA-CSIC, Madrid. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Departamento de Física y Matemática, University of Alcalá. Centro de Astrobiologia, INTA-CSIC, Madrid. Department of Earth and Planetary Sciences, Washington University, St. Louis. Centro de Astrobiologia, INTA-CSIC, Madrid. School of Earth and Space Exploration, Arizona State University. Departamento de Geología, Geografía y Medio Ambiente, University of Alcalá. Max-Planck-Institut für Solar System Research. Centro de Astrobiologia, INTA-CSIC, Madrid. Department of Atmospheric Sciences, Texas A&M University, College Station, Texas. Niels Bohr Institute, Copenhagen University. Centro de Astrobiologia, INTA-CSIC, Madrid , Instituto Andaluz de Cienccias de la Tierra (CSIC-UGR), Grenada. Centro de Astrobiologia, INTA-CSIC, Madrid , Instituto de Geociencias (CSIC-UCM), Ciudad Universitaria. Centro de Astrobiologia, INTA-CSIC, Madrid , Departamento de Física y Matemática, University of Alcalá. Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles. Department of Space Studies, Southwest Research Institute. Ashima Research, Pasadena. Planetary Science Institute, Tucson. Centro de Astrobiologia, INTA-CSIC, Madrid.
Observations and preliminary science results from the first 100 sols of MSL Rover Environmental Monitoring Station ground temperature sensor measurements at Gale Crater2014In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 119, no 4, p. 745-770Article in journal (Refereed)

We describe preliminary results from the first 100 sols of ground temperature measurements along the Mars Science Laboratory's traverse from Bradbury Landing to Rocknest in Gale. The ground temperature data show long-term increases in mean temperature that are consistent with seasonal evolution. Deviations from expected temperature trends within the diurnal cycle are observed and may be attributed to rover and environmental effects. Fits to measured diurnal temperature amplitudes using a thermal model suggest that the observed surfaces have thermal inertias in the range of 265-375?J m-2 K-1 s-1/2, which are within the range of values determined from orbital measurements and are consistent with the inertias predicted from the observed particle sizes on the uppermost surface near the rover. Ground temperatures at Gale Crater appear to warm earlier and cool later than predicted by the model, suggesting that there are multiple unaccounted for physical conditions or processes in our models. Where the Mars Science Laboratory (MSL) descent engines removed a mobile layer of dust and fine sediments from over rockier material, the diurnal temperature profile is closer to that expected for a homogeneous surface, suggesting that the mobile materials on the uppermost surface may be partially responsible for the mismatch between observed temperatures and those predicted for materials having a single thermal inertia. Models of local stratigraphy also implicate thermophysical heterogeneity at the uppermost surface as a potential contributor to the observed diurnal temperature cycle. Key Points Diurnal ground temperatures vary with location Diurnal temperature curves are not well matched by a homogeneous thermal model GTS data are consistent with a varied stratigraphy and thermophysical properties.

• 242.
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
Aerodynamics Modeling of Sounding Rockets: A Computational Fluid Dynamics Study2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
• 243.
Finnish Meteorological Institute, Division of Earth Observation.
Finnish Meteorological Institute, Division of Earth Observation. Finnish Meteorological Institute, Division of Earth Observation. Finnish Meteorological Institute, Division of Earth Observation. Centro de Astrobiología (CAB). Centro de Astrobiología (CAB). NASA Ames Research Center. Finnish Meteorological Institute, Division of Earth Observation. Finnish Meteorological Institute, Division of Earth Observation. Finnish Meteorological Institute, Division of Earth Observation. Finnish Meteorological Institute, Division of Earth Observation. Finnish Meteorological Institute, Division of Earth Observation. Ashima Research, Pasadena. Finnish Meteorological Institute, Division of Earth Observation. Finnish Meteorological Institute, Division of Earth Observation. NASA Jet Propulsion Laboratory, Pasadena. Ashima Research, Pasadena. Southwest Research Institute, Boulder. Texas A&M University. NASA Jet Propulsion Laboratory, Pasadena. Finnish Meteorological Institute, Division of Earth Observation. Finnish Meteorological Institute, Division of Earth Observation. Centro de Astrobiologia, INTA-CSIC, Madrid. Centro de Astrobiología (CAB). Centro de Astrobiología (CAB). University of Michigan.
Pressure observations by the curiosity rover: Initial results2014In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 119, no 1, p. 82-92Article in journal (Refereed)

REMS-P, the pressure measurement subsystem of the Mars Science Laboratory (MSL) Rover Environmental Measurement Station (REMS), is performing accurate observations of the Martian atmospheric surface pressure. It has demonstrated high data quality and good temporal coverage, carrying out the first in situ pressure observations in the Martian equatorial regions. We describe the REMS-P initial results by MSL mission sol 100 including the instrument performance and data quality and illustrate some initial interpretations of the observed features. The observations show both expected and new phenomena at various spatial and temporal scales, e.g., the gradually increasing pressure due to the advancing Martian season signals from the diurnal tides as well as various local atmospheric phenomena and thermal vortices. Among the unexpected new phenomena discovered in the pressure data are a small regular pressure drop at every sol and pressure oscillations occurring in the early evening. We look forward to continued high-quality observations by REMS-P, extending the data set to reveal characteristics of seasonal variations and improved insights into regional and local phenomena. Key Points The performance and data quality of the REMS / MSL pressure observations. MSL pressure observations exhibit local phenomena of the Gale crater area. Small pressure oscillations possibly linked to gravity waves. ©2013. American Geophysical Union. All Rights Reserved.

• 244.
Finnish Meteorological Institute, Helsinki.
Finnish Meteorological Institute, Helsinki. Finnish Meteorological Institute, Helsinki. Centro de Astrobiologia, Madrid. NASA Ames Research Center, Moffett Field. Finnish Meteorological Institute, Helsinki. Finnish Meteorological Institute, Helsinki. Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor. Centro de Astrobiología (CAB). Finnish Meteorological Institute, Helsinki. Ashima Research, Pasadena. Finnish Meteorological Institute, Helsinki. Finnish Meteorological Institute, Helsinki. NASA Jet Propulsion Laboratory, Pasadena. Finnish Meteorological Institute, Helsinki. Ashima Research, Pasadena. Southwest Research Institute, Boulder. NASA Jet Propulsion Laboratory, Pasadena. Finnish Meteorological Institute, Helsinki. Finnish Meteorological Institute, Helsinki. Centro de Astrobiologia, Madrid. Finnish Meteorological Institute, Helsinki. Centro de Astrobiologia, Madrid. Centro de Astrobiologia, Madrid. Department of Applied Mathematics, Complutense University of Madrid. Centro de Astrobiología (CAB).
Mars Science Laboratory relative humidity observations: Initial results2014In: Journal of Geophysical Research - Planets, ISSN 2169-9097, E-ISSN 2169-9100, Vol. 119, no 9, p. 2132-2147, article id 16Article in journal (Refereed)

The Mars Science Laboratory (MSL) made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as a part of its scientific payload. REMS comprises instrumentation for the observation of atmospheric pressure, temperature of the air, ground temperature, wind speed and direction, relative humidity (REMS-H), and UV measurements. We concentrate on describing the REMS-H measurement performance and initial observations during the first 100 MSL sols as well as constraining the REMS-H results by comparing them with earlier observations and modeling results. The REMS-H device is based on polymeric capacitive humidity sensors developed by Vaisala Inc., and it makes use of transducer electronics section placed in the vicinity of the three humidity sensor heads. The humidity device is mounted on the REMS boom providing ventilation with the ambient atmosphere through a filter protecting the device from airborne dust. The final relative humidity results appear to be convincing and are aligned with earlier indirect observations of the total atmospheric precipitable water content. The water mixing ratio in the atmospheric surface layer appears to vary between 30 and 75 ppm. When assuming uniform mixing, the precipitable water content of the atmosphere is ranging from a few to six precipitable micrometers.

• 245.
Southwest Research Institute, Boulder.
Southwest Research Institute, Boulder. Christian Albrechts University, Kiel. Southwest Research Institute, Boulder. Southwest Research Institute, Boulder. NASA Goddard Space Flight Center. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Southwest Research Institute, San Antonio, Texas. Christian Albrechts University, Kiel. Christian Albrechts University, Kiel. Christian Albrechts University, Kiel. Christian Albrechts University, Kiel. Christian Albrechts University, Kiel. Christian Albrechts University, Kiel. German Aerospace Center (DLR), Cologne. University of Nevada Las Vegas. Universities Space Research Association, Houston, Texas. Denver Museum of Nature and Science, Denver, Colorado. Southwest Research Institute, Boulder. NASA Headquarters, Washington. Centro de Astrobiologia, INTA-CSIC, Madrid. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Jet Propulsion Laboratory, California Institute of Technology, Pasadena. Centro de Astrobiología (CAB).
Mars’ surface radiation environment measured with the Mars Science Laboratory’s Curiosity Rover2014In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 343, no 6169Article in journal (Refereed)

The Radiation Assessment Detector (RAD) on the Mars Science Laboratory’s Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment.

• 246.
Southwest Research Institute, Boulder.
Southwest Research Institute, Boulder. Christian Albrechts University, Kiel. Southwest Research Institute, Boulder. Southwest Research Institute, Boulder. Christian Albrechts University, Kiel. Christian Albrechts University, Kiel. Christian Albrechts University, Kiel. Christian Albrechts University, Kiel. Jet Propulsion Laboratory, Pasadena, Kalifornien. German Aerospace Center (DLR), Cologne. NASA Headquarters, Washington. Centro de Astrobiología (CSIC-INTA), Madrid.
The Radiation Environment on the Martian Surface and during MSL’s Cruise to Mars2013Conference paper (Refereed)
• 247.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
An Analysis of the New Threat Environment for Satellites2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
• 248.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
Analysis of Passive Attitude Stabilisation and Deorbiting of Satellites in Low Earth Orbit2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

Orbital debris poses a serious threat to ongoing operations in space.  Recognising this threat, the European Commission has funded the three-year Technology for Self Removal (TeSeR) project with the goal of developing a standard scalable Post Mission Disposal (PMD) module to remove satellites from orbit following the completion of their mission.  As the project coordinator and key member of the TeSeR Project, Airbus Defence and Space Germany will invest significant resources in achieving this goal over the course of the project.

This thesis details the initial analysis of potential PMD module designs conducted by the author during an internship within the AOCS/GNC department of Airbus Defence and Space Friedrichshafen between 1 April 2016 and 31 August 2016.  Three main concepts, drag sails, drag balloons and Electrodynamic Tethers (EDTs), were evaluated during this time with an emphasis on determining the ability of each design to permit passive attitude stabilisation of the satellite during PMD.

Following the required modification of a pre-existing MATLAB/Simulink model, several key findings were made for each device concept.  It was found that no drag sail designs investigated permitted passive aerodynamic attitude stabilisation at orbit heights above 550 km.  When deorbiting from 800 km, however, the lack of the desired and stable attitude was not found to have a significant increase on the deorbit time or the area‑time product.

Drag balloon designs were predicted to be comparatively unstable and less mass efficient for deorbiting purposes, with area‑time products up to approximately 50 per cent higher than the equivalent mass drag sail designs.  In spite of this, unstable drag balloons were found to provide shorter deorbit times than stable balloons due to the contribution of the satellite body and solar array to the total frontal area of the satellite.  This indicated that attitude stabilisation is not required for satellites equipped with drag balloon devices.

Modelling of bare EDTs suggested that tethers with lengths of 1000 metres or more would not permit passive attitude stabilisation at an orbit height of 800 km.  Simulation of a 500 metre EDT, however, indicated that passive attitude stabilisation can be achieved with EDT devices and proved that EDTs can generate significantly higher drag forces than aerodynamic devices while possessing a significantly lower device mass.  Following the analysis of these results, a recommendation was made for future work to be aimed at improving the EDT model used in this investigation.

• 249.
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
Mission Analysis of the Nanosatellite Sonate2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

The objective of this thesis is the development of a software application facilitating a quick and extensive mission analysis including all subsystems of the satellite. Furthermore mission analysis for the Sonate mission is done, utilizing the developed program.

Usually mission analysis is done by applying separately different tools which are specific for each subsystem. The drawback of this method is that the system is not analyzed as a whole; rather all subsystems are investigated separately from each other. In case one or more system parameters should change, the effect of this variation onto other parts of the system will not directly be accessible and visible.

A simulation tool considering all these subsystems overcomes this weaknesses and helps to develop a balanced system. Different system configurations and operation scenarios can be evaluated quickly and compared to each other in order to find an optimal solution.

The simulation system developed during this thesis exhibits a client-server structure, where the subsystems are separated modules acting as clients. The program has a highly modular structure which renders it possible to have an arbitrary extension in the future.

Aside from the server, connecting all modules, the following modules were implemented:

• orbital dynamics module containing orbit propagation and attitude determination
• power subsystem consisting of the subparts power production, power consumption and power storage
• archiving module saving all results generated for further evaluation
• simulation clock providing the simulation time
• configuration module with a GUI to facilitate the configuration of all simulation parameters
• simple thermal module providing temperatures for the satellite panels

Mission analysis was done for the Sonate satellite utilizing the developed program in order to find a configuration for the solar panels of the satellite such that all the subsystems of the satellite can be supplied with sufficient power during the mission.

• 250.
CERN, SL Division.
CERN, SL Division. TRIUMF, Vancouver.
Hybrid fast multipole method applied to beam-beam collisions in the strong-strong regime2001In: Physical Review Special Topics. Accelerators and Beams, ISSN 1098-4402, E-ISSN 1098-4402, Vol. 4, no 5, p. 37-45Article in journal (Refereed)

The strong-strong interactions of two colliding beams are simulated by tracking the motion of a set of macroparticles. The field generated by each distribution is evaluated using the fast multipole method together with some elements of particle-mesh methods. This technique allows us to check the exact frequencies of the coherent modes and the frequencies of oscillations of individual particles in the beam. The agreement between the simulations and analytical calculations is largely improved. Furthermore, it is an efficient method to study the coherent modes in the case of separated beams.

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