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  • 101.
    Buehler, Stefan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Östman, S.
    Luleå tekniska universitet.
    Melsheimer, C.
    Institute of Environmental Physics, University of Bremen.
    Holl, Gerrit
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Eliasson, Salomon
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    John, V.O.
    Met Office Hadley Centre, Exeter.
    Blumenstock, T.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Hase, F.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Ekgered, G.
    Chalmers University of Technology, Department of Earth and Space Sciences.
    Raffalski, U.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Nasuno, T.
    Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama.
    Satho, M.
    Atmosphere and Ocean Research Institute, University of Tokyo.
    Milz, Mathias
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Mendrok, Jana
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    A multi-instrument comparison of integrated water vapour measurements at a high latitude site2012In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 12, no 22, p. 10925-10943Article in journal (Refereed)
    Abstract [en]

    We compare measurements of integrated water vapour (IWV) over a subarctic site (Kiruna, Northern Sweden) from five different sensors and retrieval methods: Radiosondes, Global Positioning System (GPS), ground-based Fourier-transform infrared (FTIR) spectrometer, ground-based microwave radiometer, and satellite-based microwave radiometer (AMSU-B). Additionally, we compare also to ERA-Interim model reanalysis data. GPS-based IWV data have the highest temporal coverage and resolution and are chosen as reference data set. All datasets agree reasonably well, but the ground-based microwave instrument only if the data are cloud-filtered. We also address two issues that are general for such intercomparison studies, the impact of different lower altitude limits for the IWV integration, and the impact of representativeness error. We develop methods for correcting for the former, and estimating the random error contribution of the latter. A literature survey reveals that reported systematic differences between different techniques are study-dependent and show no overall consistent pattern. Further improving the absolute accuracy of IWV measurements and providing climate-quality time series therefore remain challenging problems.

  • 102.
    Cabane, Michel
    et al.
    LATMOS, Université Pierre et Marie Curie, Université Versailles Saint-Quentin & CNRS, Guyancourt.
    Coll, Patrice
    Laboratoire Interuniversitaire des Systèmes Atmosphériques, Université Paris-Est Créteil, Université Paris Diderot and CNRS, Créteil.
    Szopa, Cyril
    LATMOS, Université Pierre et Marie Curie, Université Versailles Saint-Quentin & CNRS, Guyancourt.
    Coscia, David
    LATMOS, Université Pierre et Marie Curie, Université Versailles Saint-Quentin & CNRS, Guyancourt.
    Buch, Aranaud
    LGPM, Ecole Centrale Paris, Chatenay-Malabry.
    Teinturier, Samuel
    LATMOS, Université Pierre et Marie Curie, Université Versailles Saint-Quentin & CNRS, Guyancourt.
    Navarro-Gonzalez, Rafael
    Universidad Nacional Autónoma de México.
    Gaboriaud, Alain
    CNES.
    Mahaffy, Paul
    NASA Goddard Space Flight Center.
    Martin-Torres, Javier
    Centro de Astrobiología (CSIC-INTA), Madrid.
    Gas-chromatographic analysis of Mars soil samples at Rocknest site with the SAM instrument onboard Curiosity2013Conference paper (Refereed)
  • 103.
    Caldarelli, Antonella
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Dimensioning of Vega E Cryogenic Stage Fuelling System2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 104.
    Carlsson, Ella
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Barabash, Stas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Cold Mars2006Conference paper (Other academic)
  • 105.
    Carlsson, Ella
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Swedish Institute of Space Physics, Kiruna, Sweden.
    Barabash, Stas
    Swedish Institute of Space Physics, Kiruna, Sweden.
    Fedorov, A.
    Centre d’Etude Spatiale des Rayonnements, Toulouse, France.
    Budnik, E.
    Centre d’Etude Spatiale des Rayonnements, Toulouse, France.
    Grigoriev, Alexander
    Swedish Institute of Space Physics, Kiruna, Sweden.
    Futaana, Y.
    Swedish Institute of Space Physics, Kiruna, Sweden.
    Gunell, H.
    Swedish Institute of Space Physics, Kiruna, Sweden.
    Nilsson, H.
    Swedish Institute of Space Physics, Kiruna, Sweden.
    Lundin, R.
    Swedish Institute of Space Physics, Kiruna, Sweden.
    Analysis of the mass composition of the escaping plasma at Mars2006In: 2006 European Geosciences Union General Assembly (EGU 2006), Austria Center Vienna, Vienna (Austria), 2-7 Apr 2006, European Geosciences Union (EGU), 2006Conference paper (Other academic)
    Abstract [en]

    Results from Mars Express, Mars Exploration Rovers and Mars Global Surveyor indicate that Mars harbored large amounts of liquid water on the surface in the past. In order for the water-associated geomorphologic features to form, the pressure in the atmosphere must have been at least a hundred times higher to produce the necessary greenhouse effect required to hold liquid water stable. The present atmospheric pressure is only 6-9 mbar and moreover, the spectral imaging of Mars suggests that the amount of carbonates stored in the surface is too low in order to explain the denser atmosphere in the past. This controversy led us to investigate the escaping plasma by analyzing the data from the IMA sensor (Ion Mass Analyzer) of the ASPERA-3 instrument suite onboard Mars Express. The IMA sensor measures the differential flow of ion components in the energy range of 0.01-30 keV/q.Since the instrument design was optimized for studies of plasma dynamics, the mass resolution is not adequate enough to directly resolve CO+2 from O+2 , which is the main molecular ion composing the Mars ionosphere according to theoretical models. Therefore, a special multi-species fitting technique, using calibration and in-flight data, was developed to resolve the CO+2 peak from the neighboring and much more intense O+2 peak. This technique was applied to the observations covering the period from April 4, 2004 to October 2, 2005. The events of heavy ion escape were identified inside the induced magnetosphere boundary and the Martian eclipse. We report the results of statistical studies of these ion-beam events which permitted to determine CO+2 / O+ and the O+2 / O+ ratio of the escaping plasma at Mars.

  • 106. Carlsson, Ella
    et al.
    Brain, D.
    Space Science Laboratory, University of California, Berkeley.
    Luhmann, J.
    Space Science Laboratory, University of California, Berkeley.
    Barabash, Stas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Grigoriev, Alexander
    Nilsson, H.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Lundin, R.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Influence of IMF draping direction and crustal magnetic field location on Martian ion beams2008In: Planetary and Space Science, ISSN 0032-0633, E-ISSN 1873-5088, Vol. 56, no 6, p. 861-867Article in journal (Refereed)
    Abstract [en]

    Data from the Ion Mass Analyzer (IMA) sensor of the ASPERA-3 instrument suite onboard Mars Express and data from the Magnetometer/Electron Reflectometer (MAG/ER) on Mars Global Surveyor have been analyzed to determine whether ion beam events (IBEs) are correlated with the direction of the draped interplanetary magnetic field (IMF) or the proximity of strong crustal magnetic fields to the subsolar point. We examined 150 IBEs and found that they are organized by IMF draping direction. However, no clear dependence on the subsolar longitude of the strongest magnetic anomaly is evident, making it uncertain whether crustal magnetic fields have an effect on the formation of the beams. We also examined data from the IMA sensor of the ASPERA-4 instrument suite on Venus Express and found that IBEs are observed at Venus as well, which indicates the morphology of the Martian and Venusian magnetotails are similar.

  • 107. Carlsson, Ella
    et al.
    Fedorov, A.
    Budnik, E.
    Barabash, Stas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Fredriksson, Sverker
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    First results from ASPERA-3 Ion Mass Analyzer (IMA) on CO2+ escape2005Conference paper (Other academic)
  • 108.
    Castro, Juan Francisco Buenestado
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Mier, Maria-Paz Zorzano
    Centro de Astrobiologia, INTA-CSIC, Madrid.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Liquid water at crater Gale, Mars2015In: Journal of Astrobiology and Outreach, ISSN 2332-2519, Vol. 3, no 3, article id 131Article in journal (Refereed)
    Abstract [en]

    Suspicion that Mars could have transient liquid water on its surface through deliquescence of salts to form aqueous solutions or brines is an old proposal whose inquiry was boosted by Phoenix Lander observations. It provided some images of what were claimed to be brines, the presence of which at its landing site was compatible with the atmospheric parameters and the composition of the soil observed. On the other hand, the so called Recurrent Slope Lineae (RSL) often imaged by orbiters, were considered as another clue pointing to the occurrence of the phenomenon, since it was thought that they might be caused by it. Now, Curiosity rover has performed the first in-situ multi-instrumental study on Mars’ surface, having collected the most comprehensive environmental data set ever taken by means of their instruments Rover Environmental Monitoring Station (REMS), Dynamic Albedo of Neutrons (DAN), and Sample Analysis at Mars (SAM). REMS is providing continuous and accurate measurements of the relative humidity and surface and air temperatures among other parameters, and DAN and SAM provide the water content of the regolith and the atmosphere respectively. Analysis of these data has allowed to establish the existence of a present day active water cycle between the atmosphere and the regolith, that changes according to daily and seasonal cycles, and that is mediated by the presence of brines during certain periods of each and every day. Importantly, the study shows that the conditions for the occurrence of deliquescence are favourable even at equatorial latitudes where, at first, it was thought they were not due to the temperature and relative humidity conditions. This study provides new keys for the understanding of martian environment, and opens interesting lines of research and studies for future missions which may even have a bearing on extant microbial life.

  • 109.
    Castro, Juan Francisco Buenestado
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Mier, Maria-Paz Zorzano
    Centro de Astrobiologia, INTA-CSIC, Madrid.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Planetary exploration; Mars on the scope2015In: Journal of Astrobiology and Outreach, ISSN 2332-2519, Vol. 3, no 3, article id 133Article in journal (Refereed)
    Abstract [en]

    This article summarizes a practical case of introduction to research and planetary exploration through the analysis of data from the Rover Environmental Monitoring Station (REMS), one of the ten scientific instruments on board the Curiosity rover of the Mars Science Laboratory (MSL), currently operating at the impact crater Gale, on Mars. It is the main aim of this work to show how the data that are publicly available at the Planetary Data System (PDS) can be used to introduce undergraduate students and the general public into the subject of surface exploration and the environment of Mars. In particular, the goal of this practice was to investigate and quantify the heat flux between the rover spacecraft and the Martian surface, the role of the atmosphere in this interaction, and its dependence with seasons, as well as to estimate the thermal contamination of the Martian ground produced by the rover. The ground temperature sensor (GTS) of the REMS instrument has measured in-situ, for the first time ever, the diurnal and seasonal variation of the temperature of the surface on Mars along the rover traverse. This novel study shows that the rover radiative heat flux varies between 10 and 22 W/m2 during the Martian year, which is more than 10% of the solar daily averaged insolation at the top of the atmosphere. In addition, it is shown that the radiative heat flux from the rover to the ground varies with the atmospheric dust load, being the mean annual amplitude of the diurnal variation of the surface temperature of 76 K, as a result of solar heating during the day and infrared cooling during the night. As a remarkable and unexpected outcome, it has been established that the thermal contamination produced by the rover alone induces, on average, a systematic shift of 7.5 K, which is indeed about 10% of the one produced by solar heating. This result may have implications for the design and operation of future surface exploration probes such as InSight.

  • 110.
    Catanoso, Damiana
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Nasa Ames Research Center.
    Networked Model Predictive Control for Satellite Formation Flying2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A novel continuous low-thrust fuel-efficient model predictive control strategy for multi-satellite formations flying in low earth orbit is presented. State prediction relies on a full nonlinear relative motion model, based on quasi-nonsingular relative orbital elements, including earth oblateness effects and, through state augmentation, differential drag. The optimal control problem is specically designed to incorporate latest theoretical results concerning maneuver optimality in the state-space, yielding to a sensible total delta-V reduction, while assuring feasibility and stability though imposition of a Lyapunov constraint. The controller is particularly suitable for networked architectures since it exploits the predictive strategy and the dynamics knowledge to provide robustness against feedback losses and delays. The Networked MPC is validated through real missions simulation scenarios using a high-fidelity orbital propagator which accounts for high-order geopotential, solar radiation pressure, atmospheric drag and third-body effects.

  • 111.
    Charlton, J E
    et al.
    Sula systems.
    Buehler, Stefan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Defer, E.
    L'Observatoire de Paris-LERMA.
    Prigent, C.
    L'Observatoire de Paris-LERMA.
    Moyna, B.
    Rutherford Appleton Laboratory.
    Lee, C.
    Met Office Hadley Centre, Exeter.
    Magt, P. De
    European Space Agency.
    Kangas, V.
    European Space Agency.
    A sub-millimetre wave airborne demonstrator for the observation of precipitation and ice clouds2010In: International Geoscience and Remote Sensing Symposium (IGARSS): Cape Town, South Africa, 12 - 17 July 2009, Piscataway, NJ: IEEE Communications Society, 2010, Vol. 3, p. 1023-1026Conference paper (Refereed)
    Abstract [en]

    Sub-millimetre remote sensing instruments can provide critical information on cirrus clouds and an alternative way of measuring precipitation with a much smaller antenna than those which microwave sensors currently use. Two satellite concepts CIWSIR and GOMAS were proposed as ESA Earth Explorer missions; these were not funded, however they were recommended for an aircraft demonstrator. ESA studies have been performed to identify the optimum instrument and platform to demonstrate these satellite concepts. This paper reports on one of these preparatory activities; the design of a sub-millimetre wave airborne demonstrator for both ice cloud and precipitation observations which will be able to prove the feasibility of the scientific principles of both satellite missions. The paper will describe the derivation of the demonstrator requirements, consideration of the available platform and instrument options, the design of the selected concept, performance prediction and the outline of a proof of concept flight campaign. It will present the outcome of the study which describes a demonstrator design based upon the new Met Office International Sub-Millimetre Airborne Radiometer (ISMAR).

  • 112.
    Chauhan, Swarup
    et al.
    Forschungszentrum Karlsruhe.
    Höpfner, M.
    Stiller, G.P.
    Clarmann, T. von
    Funke, B.
    Glatthor, N.
    Grabowski, U.
    Linden, A.
    Kellmann, S.
    Milz, Mathias
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Steck, T.
    Fischer, H.
    Froidevaux, L.
    Lambert, A.
    Santee, M. L.
    Schwartz, M.
    Read, W.G.
    Livesey, N.
    MIPAS reduced spectral resolution UTLS-1 mode measurements of temperature, O3, HNO3, N2O, H2O and relative humidity over ice: retrievals and comparison to MLS2009In: Atmospheric Measurement Techniques, ISSN 1867-1381, E-ISSN 1867-8548, no 2, p. 337-353Article in journal (Refereed)
    Abstract [en]

    During several periods since 2005 the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat has performed observations dedicated to the region of the upper troposphere/lower stratosphere (UTLS). For the duration of November/December 2005 global distributions of temperature and several trace gases from MIPAS UTLS-1 mode measurements have been retrieved using the IMK/IAA (Institut für Meteorologie und Klimaforschung/Instituto de Astrofísica de Andalucía) scientific processor. In the UTLS region a vertical resolution of 3 km for temperaure, 3 to 4 km for H2O, 2.5 to 3 km for O3, 3.5 km for HNO3 and 3.5 to 2.5 km for N2O has been achieved. The retrieved temperature, H2O, O3, HNO3, N2O, and relative humidity over ice are intercompared with the Microwave Limb Sounder (MLS/Aura) v2.2 data in the pressure range 316 to 0.68 hPa, 316 to 0.68 hPa, 215 to 0.68 hPa, 215 to 3.16 hPa, 100 to 1 hPa and 316 to 10 hPa, respectively. In general, MIPAS and MLS temperatures are biased within ±4 K over the whole pressure and latitude range. Systematic, latitude-independent differences of −2 to −4 K (MIPAS-MLS) at 121 hPa are explained by previously observed biases in the MLS v2.2 temperature retrievals. Temperature differences of −4 K up to 12 K above 10.0 hPa are present both in MIPAS and MLS with respect to ECMWF (European Centre for Medium-Range Weather Forecasts) and are likely due to deficiencies of the ECMWF analysis data. MIPAS and MLS stratospheric volume mixing ratios (vmr) of H2O are biased within ±1 ppmv, with indication of oscillations between 146 and 26 hPa in the MLS dataset. Tropical upper tropospheric values of relative humidity over ice measured by the two instruments differ by ±20% in the pressure range ~146 to 68 hPa. These differences are mainly caused by the MLS temperature biases. Ozone mixing ratios agree within 0.5 ppmv (10 to 20%) between 68 and 14 hPa. At pressures smaller than 10 hPa, MIPAS O3 vmr are higher than MLS by an average of 0.5 ppmv (10%). General agreement between MIPAS and MLS HNO3 is within the range of −1.0 (−10%) to 1.0 ppbv (20%). MIPAS HNO3 is 1.0 ppbv (10%) higher compared to MLS between 46 hPa and 10 hPa over the Northern Hemisphere. Over the tropics at 31.6 hPa MLS shows a low bias of more than 1 ppbv (>50%). In general, MIPAS and MLS N2O vmr agree within 20 to 40 ppbv (20 to 40%). Differences in the range between 100 to 21 hPa are attributed to a known 20% positive bias in MIPAS N2O data.

  • 113.
    Chen, Emily
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Thermal Loads in Space Turbines2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Prediction of thermal loads within cavities in space turbine, has as been a challenging task  in aspects of achieving accurate and reasonable estimations that are crucial for design concepts. The difficulty lies within the turbulent flow and its thermal interaction with the structure inside such section. It does not exist a method that works perfectly for prediction of thermal loads in any cavity and the taken approach to perform this kind of analysis has been differently chosen. The objectives of this work have been to improve methods for assessment of thermal loads in space turbines, especially calculation of the heat transfer coefficient and bulk temperature. As the thesis was conducted at GKN Aerospace Sweden, Trollhättan, one of theirs demonstrator turbine was chosen for the study case. Its first stage rotor blade and the nearby cavity were the main research regions. The flow can enter and exit the cavity through one slot and is characterized with a very low axial speed. For the studied regions, the wall surface has been subdivided into a number of segments. With prescribed wall temperatures and use of computational fluid dynamics (CFD) to compute the wall heat flux at the sections, the heat transfer coefficient and bulk temperatures were determined in three different ways. One of them was based on evaluating one single CFD result and derive the thermal loads from formulas. The others used by point-plotting approach, whereas one of them focused on formulating a model that describes the thermal interaction between the section walls. The results demonstrate that this model was able to predict a section's wall heat flux as a function of the wall temperatures in fair agreement with CFD results for a range of temperature variations. Further more, some of the predicted heat transfer coefficient at a section shows to be highly sensitive to the prescribed wall temperatures in the cavity and rotor blade.

  • 114.
    Chen, Fengxiang
    et al.
    Department of Automation, Shanghai Jiaotong University.
    Chen, Lin
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Zhang, Weidong
    Department of Automation, Shanghai Jiaotong University.
    Robust control of chaos in the Lorenz system with the variable structure control approach2008In: Physica scripta. T, ISSN 0281-1847, Vol. 77, no 2Article in journal (Other academic)
    Abstract [en]

    This paper is concerned with the robust control for a class of the uncertain Lorenz system subject to sector nonlinear input. Based on rigorous mathematical analysis, the proposed variable structure controller can drive the system state exactly to a class of a specific point or in the predictable neighborhood of an arbitrary desired point in the state space even with mismatch uncertainties. Moreover, the controller ensures that one of the error components can approach zero as time approaches infinity. Finally, numerical simulation results show the effectiveness of our work.

  • 115.
    Chen, Fengxiang
    et al.
    Department of Automation, Shanghai Jiaotong University.
    Chen, Lin
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Zhang, Weidong
    Department of Automation, Shanghai Jiaotong University.
    Stabilization of parameters perturbation chaotic system via adaptive backstepping technique2008In: Applied Mathematics and Computation, ISSN 0096-3003, E-ISSN 1873-5649, Vol. 200, no 1, p. 101-109Article in journal (Refereed)
    Abstract [en]

    The work of Yassen [M.T. Yassen, Chaos control of chaotic dynamical systems using backstepping design, Chaos Soliton Fract. 27 (2006) 537-548] which mainly investigated the stabilization problem for a class of chaotic systems without the parameters perturbation. This paper is concerned with stabilization problem for a class of parameters perturbation chaotic systems via both backstepping design method and adaptive technique. The proposed controllers can guarantee that the parameters perturbation systems will be stabilized at a fixed bounded point. Furthermore, the paper also proposes controllers to stabilize the uncertain chaotic system at equilibrium point with only backstepping design method. Finally, numerical simulations are given to illustrate the effectiveness of the proposed controllers

  • 116.
    Chen, Fengxiang
    et al.
    Shanghai Jiao Tong University.
    Wang, Wei
    Shanghai Jiao Tong University.
    Chen, Lin
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Zhang, Weidong
    Shanghai Jiao Tong University.
    Adaptive chaos synchronization based on LMI technique2007In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 75, no 3, p. 285-288Article in journal (Refereed)
    Abstract [en]

    The paper investigates the robust synchronization for two identical uncertain chaotic systems with different parameters perturbation and external disturbances. Based on Lyapunov stability theory, linear matrix inequality (LMI) techniques and adaptive techniques, a novel controller is proposed. With the resulting controller, global asymptotical synchronization between two identical uncertain chaotic systems is achieved. Finally, a Lorenz system is given as an example to verify the effectiveness of the proposed controller.

  • 117.
    Chmiela, Kevin
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. University of Würzburg.
    Development and testing of a high precision sun sensor for the UWE-4 satellite2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis addresses the development, implementation and calibration of the sun sensors used in the UWE-4 satellite which is a CubeSat built by the University of Würzburg. It has several sensors for determining the attitude in space including six digital sun sensors. The chosen sun sensor is a miniature pinhole camera called "NanEye" by AWAIBA with a footprint size of about 1x1 mm. At first a short overview of the state of the art of digital sun sensors and the UWE-4 satellite are given. A concept based on traditional camera calibration methods is developed and implemented for calibrating one sun sensor, which can be enhanced for calibrating multiple sun sensors at once, described in the outlook. The calibration procedure utilizes a method of having the camera sensing a single fixed artificial sun as reference point at many different orientations and thus acquiring enough data to refine camera models and further possibilities of modelling errors. Applying the calibration on the NanEye yielded accuracies of about less than 0.5 deg for the pinhole camera model considering radial distortion, and less than 0.3 deg for the used fisheye camera model (RMS-values). Further the problem of efficiently handing over the sun detecting task between all sun sensors during sun tracking is addressed. In the third part an energy controller, monitoring and controlling the energy consumption of the UWE-4 sun vector sampling device by actively changing the clock speeds of the used microcontroller is developed and implemented. To test the applicability of the developed concepts several experiments were performed and the results evaluated.

  • 118.
    Clark, Matteo
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Analysis of Proportional Navigation Guidance Algorithms in the Context of a Near-Earth Object Intercept Mission2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    An impact of a Near-Earth Object with the Earth is rare but possible, and can have negative consequences ranging from localized annoyance and injury to global devastation and the end of the world as we know it. Considering the magnitude of the consequences and the lack of an ability to respond to such a threat, it is important that these Planetary Defense capabilities are developed.

    The research conducted for this project analyzes the spacecraft design trade-space in the context of a conceptual kinetic impact mission with Asteroid 101955 Bennu. To accomplish the research objectives, an orbit propagator was developed, proportional nav- igation guidance algorithms were implemented and simulations were run with difference combinations of design parameters.

    It was found that both studied guidance algorithms performed very similarly in most regards, yet the augmented three-plane proportional guidance algorithm appeared to achieve impact more efficiently. There is uncertainty as to whether this is a characteristic of the algorithm or a consequence of the initial conditions.

    Additionally, it was seen that the more significant performance enhancements for the kinetic impact mission were more significantly influenced by the design of a spacecraft as opposed to the selection of a guidance algorithm over another.

    The full text will be freely available from 2020-12-13 08:36
  • 119.
    Clarmann, T. Von
    et al.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Ceccherini, S.
    Istituto di Fisica Applicata “Nello Carrara,”, Florence.
    Doicu, A.
    Deutsches Zentrum für Luft-und Raumfahrt (DLR).
    Dudhia, A.
    Atmospheric, Oceanic, and Planetary Physics, Oxford University.
    Funke, B.
    Instituto de Astrofísica de Andalucía CSIC, Granada.
    Grabowski, U.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Hilgers, S.
    Deutsches Zentrum für Luft-und Raumfahrt (DLR).
    Jay, V.
    Rutherford Appleton Laboratory, Oxfordshire.
    Linden, A.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    López-Puertas, M.
    Instituto de Astrofísica de Andalucía CSIC, Granada.
    Martin-Torres, Javier
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe, Analytical Services and Materials Inc., Hampton.
    Payne, V.
    Atmospheric, Oceanic, and Planetary Physics, Oxford University.
    Reburn, J.
    Rutherford Appleton Laboratory, Oxfordshire.
    Ridolfi, M.
    Dipertemento di Chimica Fisica e Inorganica, Universitá di Bologna.
    Schreier, F.
    Deutsches Zentrum für Luft-und Raumfahrt (DLR).
    Schwarz, G.
    Deutsches Zentrum für Luft-und Raumfahrt (DLR).
    Siddans, R.
    Rutherford Appleton Laboratory, Oxfordshire.
    Steck, T.
    Institut für Meteorologie und Klimaforschung, Universität Karlsruhe.
    A blind test retrieval experiment for infrared limb emission spectrometry2003In: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 108, no D23Article in journal (Refereed)
    Abstract [en]

    The functionality and characteristics of six different data processors (i.e., retrieval codes in their actual software and hardware environment) for analysis of high-resolution limb emission infrared spectra recorded by the space-borne Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) have been validated by means of a blind test retrieval experiment based on synthetic spectra. For this purpose a self-consistent set of atmospheric state parameters, including pressure, temperature, vibrational temperatures, and abundances of trace gases and aerosols, has been generated and used as input for radiative transfer calculations for MIPAS measurement geometry and configuration. These spectra were convolved with the MIPAS field of view, spectrally degraded by the MIPAS instrument line shape, and, finally, superimposed with synthetic measurement noise. These synthetic MIPAS measurements were distributed among the participants of the project “Advanced MIPAS level-2 data analysis” (AMIL2DA), who performed temperature and species abundance profile retrievals by inverse radiative transfer calculations. While the retrieved profiles of atmospheric state parameters reflect some characteristics of the individual data processors, it was shown that all the data processors under investigation are capable of producing reliable results in the sense that deviations of retrieved results from the reference profiles are within the margin that is consistent with analytical error estimation.

  • 120.
    Clarmann, T. von
    et al.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Glatthor, N.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Koukouli, M.E.
    Laboratory of Atmospheric Physics, Physics Department, Aristotle University of Thessaloniki.
    Stiller, G.P.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Funcke, B.
    Instituto de Astrofísica de Andalucía CSIC, Granada.
    Grabowski, U.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Höpfner, M.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Kellmann, S.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Linden, A.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Milz, Mathias
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Steck, T.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    Fischer, H.
    Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe.
    MIPAS measurements of upper tropospheric C2H6 and O3 during the southern hemispheric biomass burning season in 20032007In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 7, no 22, p. 5861-5872Article in journal (Refereed)
    Abstract [en]

    Under cloud free conditions, the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) provides measurements of spectrally resolved limb radiances down to the upper troposphere. These are used to infer global distributions of mixing ratios of atmospheric constituents in the upper troposphere and the stratosphere. From 21 October to 12 November 2003, MIPAS observed enhanced amounts of upper tropospheric C2H6 (up to about 400 pptv) and ozone (up to about 80 ppbv). The absolute values of C2H6, however, may be systematically low by about 30% due to uncertainties of the spectroscopic data used. By means of trajectory calculations, the enhancements observed in the southern hemisphere are, at least partly, attributed to a biomass burning plume, which covers wide parts of the Southern hemisphere, from South America, the Atlantic Ocean, Africa, the Indian Ocean to Australia. The chemical composition of the part of the plume-like pollution belt associated with South American fires, where rainforest burning is predominant appears different from the part of the plume associated with southern African savanna burning. In particular, African savanna fires lead to a larger ozone enhancement than equatorial American fires. In this analysis, MIPAS observations of high ozone were disregarded where low CFC-11 (below 245 pptv) was observed, because this hints at a stratospheric component in the measured signal. Different type of vegetation burning (flaming versus smouldering combustion) has been identified as a candidate explanation for the different plume compositions

  • 121.
    Cockell, Charles S.
    et al.
    UK Centre for Astrobiology, SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, Midlothian, UK.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. UK Centre for Astrobiology, SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, Midlothian, UK; Instituto Andaluz de Ciencias de la Tierra (UGR-CSIC), Granada, Spain .
    Zorzano, Maria-Paz
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Centro de Astrobiología (CSIC-INTA), Torrejon de Ardoz, 28850 Madrid, Spain.
    Bhardwaj, Anshuman
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Soria-Salinas, Álvaro
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Mathanla, Thasshwin
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Israel Nazarious, Miracle
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Vakkada Ramachandran, Abhilash
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Suckling, Barbara
    Boulby Underground Laboratory, Boulby, UK.
    Subsurface scientific exploration of extraterrestrial environments (MINAR 5): analogue science, technology and education in the Boulby Mine, UK2019In: International Journal of Astrobiology, ISSN 1473-5504, E-ISSN 1475-3006, Vol. 18, no 2, p. 157-182Article in journal (Refereed)
    Abstract [en]

    The deep subsurface of other planetary bodies is of special interest for robotic and human exploration. The subsurface provides access to planetary interior processes, thus yielding insights into planetary formation and evolution. On Mars, the subsurface might harbour the most habitable conditions. In the context of human exploration, the subsurface can provide refugia for habitation from extreme surface conditions. We describe the fifth Mine Analogue Research (MINAR 5) programme at 1 km depth in the Boulby Mine, UK in collaboration with Spaceward Bound NASA and the Kalam Centre, India, to test instruments and methods for the robotic and human exploration of deep environments on the Moon and Mars. The geological context in Permian evaporites provides an analogue to evaporitic materials on other planetary bodies such as Mars. A wide range of sample acquisition instruments (NASA drills, Small Planetary Impulse Tool (SPLIT) robotic hammer, universal sampling bags), analytical instruments (Raman spectroscopy, Close-Up Imager, Minion DNA sequencing technology, methane stable isotope analysis, biomolecule and metabolic life detection instruments) and environmental monitoring equipment (passive air particle sampler, particle detectors and environmental monitoring equipment) was deployed in an integrated campaign. Investigations included studying the geochemical signatures of chloride and sulphate evaporitic minerals, testing methods for life detection and planetary protection around human-tended operations, and investigations on the radiation environment of the deep subsurface. The MINAR analogue activity occurs in an active mine, showing how the development of space exploration technology can be used to contribute to addressing immediate Earth-based challenges. During the campaign, in collaboration with European Space Agency (ESA), MINAR was used for astronaut familiarization with future exploration tools and techniques. The campaign was used to develop primary and secondary school and primary to secondary transition curriculum materials on-site during the campaign which was focused on a classroom extra vehicular activity simulation.

  • 122.
    Cockell, Charles S.
    et al.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK.
    McMahon, Sean
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK.
    Lim, Darlene S.S.
    NASA Ames Research Center, Moffett Field, USA.
    Rummel, John
    SETI Institute, Friday Harbor, USA.
    Stevens, Adam
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK.
    Hughes, Scott S.
    Dept. of Geosciences, Idaho State University, Pocatello, USA.
    Nawotniak, Shannon E. Kobs
    Dept. of Geosciences, Idaho State University, Pocatello, USA.
    Brady, Allyson L.
    School of Geography and Earth Sciences, McMaster University, Hamilton, Canada.
    Marteinsson, Viggo
    School of Geography and Earth Sciences, McMaster University, Hamilton, Canada.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh,Edinburgh, UK. Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Armilla, Spain.
    Zorzano Mier, María-Paz
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Centro de Astrobiología (CSIC-INTA), Madrid, Spain.
    Harrison, Jesse
    Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland.
    Sample Collection and Return from Mars: Optimising Sample Collection Based on the Microbial Ecology of Terrestrial Volcanic Environments2019In: Space Science Reviews, ISSN 0038-6308, E-ISSN 1572-9672, Vol. 215, no 7, article id 44Article, review/survey (Refereed)
    Abstract [en]

    With no large-scale granitic continental crust, all environments on Mars are fundamentally derived from basaltic sources or, in the case of environments such as ices, evaporitic, and sedimentary deposits, influenced by the composition of the volcanic crust. Therefore, the selection of samples on Mars by robots and humans for investigating habitability or testing for the presence of life should be guided by our understanding of the microbial ecology of volcanic terrains on the Earth. In this paper, we discuss the microbial ecology of volcanic rocks and hydrothermal systems on the Earth. We draw on microbiological investigations of volcanic environments accomplished both by microbiology-focused studies and Mars analog studies such as the NASA BASALT project. A synthesis of these data emphasises a number of common patterns that include: (1) the heterogeneous distribution of biomass and diversity in all studied materials, (2) physical, chemical, and biological factors that can cause heterogeneous microbial biomass and diversity from sub-millimetre scales to kilometre scales, (3) the difficulty of a priori prediction of which organisms will colonise given materials, and (4) the potential for samples that are habitable, but contain no evidence of a biota. From these observations, we suggest an idealised strategy for sample collection. It includes: (1) collection of multiple samples in any given material type (∼9 or more samples), (2) collection of a coherent sample of sufficient size (∼10 cm3∼10 cm3) that takes into account observed heterogeneities in microbial distribution in these materials on Earth, and (3) collection of multiple sample suites in the same material across large spatial scales. We suggest that a microbial ecology-driven strategy for investigating the habitability and presence of life on Mars is likely to yield the most promising sample set of the greatest use to the largest number of astrobiologists and planetary scientists.

  • 123.
    Cockell, C.S.
    et al.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Bush, T.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Bryce, C.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Direito, S.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Fox-Powell, M.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Harrison, J.P
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Lammer, H.
    Austrian Academy of Sciences, Space Research Institute, Graz.
    Landenmark, H.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Nicholson, N.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Noack, L.
    Department of Reference Systems and Planetology, Royal Observatory of Belgium, Brussels.
    O'Malley-James, J.
    School of Physics and Astronomy, University of St Andrews, St Andrews.
    Payler, S.J.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Rushby, A.
    Centre for Ocean and Atmospheric Science (COAS), School of Environmental Sciences, University of East Anglia, Norwich.
    Samuels, T.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Schwendner, P.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Wadsworth, J.
    UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh.
    Mier, Maria-Paz Zorzano
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Habitability: a review2016In: Astrobiology, ISSN 1531-1074, E-ISSN 1557-8070, Vol. 16, no 1, p. 89-117Article in journal (Refereed)
    Abstract [en]

    Habitability is a widely used word in the geoscience, planetary science, and astrobiology literature, but what does it mean? In this review on habitability, we define it as the ability of an environment to support the activity of at least one known organism. We adopt a binary definition of “habitability” and a “habitable environment.” An environment either can or cannot sustain a given organism. However, environments such as entire planets might be capable of supporting more or less species diversity or biomass compared with that of Earth. A clarity in understanding habitability can be obtained by defining instantaneous habitability as the conditions at any given time in a given environment required to sustain the activity of at least one known organism, and continuous planetary habitability as the capacity of a planetary body to sustain habitable conditions on some areas of its surface or within its interior over geological timescales. We also distinguish between surface liquid water worlds (such as Earth) that can sustain liquid water on their surfaces and interior liquid water worlds, such as icy moons and terrestrial-type rocky planets with liquid water only in their interiors. This distinction is important since, while the former can potentially sustain habitable conditions for oxygenic photosynthesis that leads to the rise of atmospheric oxygen and potentially complex multicellularity and intelligence over geological timescales, the latter are unlikely to. Habitable environments do not need to contain life. Although the decoupling of habitability and the presence of life may be rare on Earth, it may be important for understanding the habitability of other planetary bodies

  • 124.
    Conrad, P.G.
    et al.
    NASA Goddard Space Flight Center, Greenbelt, Maryland.
    Eigenbrode, J.L.
    NASA Goddard Space Flight Center, Greenbelt, Maryland.
    Atreya, S.K.
    University of Michigan, Ann Arbor.
    Blake, D.F.
    NASA Ames Research Center, Moffett Field.
    Coll, P.J.
    LISA, Université Paris-Est Créteil, Université Denis Diderot & CNRS Center, Créteil.
    Juarez, M. de la Torre
    Jet Propulsion Laboratory, California Institute of Technology, Pasadena.
    Edgett, K.S.
    Malin Space Science Systems.
    Fairen, A.
    Cornell University, Ithaca.
    Fisk, M.R.
    Oregon State University, Corvallis.
    Franz, H.
    NASA Goddard Space Flight Center.
    Glavin, D.P.
    NASA Goddard Space Flight Center, Greenbelt, Maryland.
    Gómez, F.G.
    Centro de Astrobiología (CSIC-INTA), Madrid.
    Haberle, R. M.
    NASA Ames Research Center.
    Hamilton, V.E.
    Southwest Research Institute, Boulder.
    Leshin, L.A.
    Rensselaer Polytechnic Institute, Troy, New York.
    Martin-Torres, Javier
    Instituto Andaluz de Ciencias de la Tierra, Granada.
    Martinez-Frias, J.
    Centro de Astrobiología (CSIC-INTA), Madrid.
    McAdam, A.
    NASA Goddard Space Flight Center.
    McKay, C.P.
    NASA Ames Research Center, Moffett Field.
    Ming, D.W.
    NASA Johnson Space Center, Houston.
    Navarro-Gonzalez, R.
    Universidad Nacional Autónoma de México.
    Pavlov, A.
    NASA Goddard Space Flight Center, Greenbelt, Maryland.
    Steele, A.
    Carnegie Institution of Washington, Washington, DC..
    Stern, J.C.
    NASA Goddard Space Flight Center.
    Zorzano, M.
    Centro de Astrobiología (CSIC-INTA), Madrid.
    Grotzinger, J.P.
    California Institute of Technology, Pasadena.
    Environmental Dynamics and the Habitability Potential at Gale Crater, Mars2013Conference paper (Refereed)
    Abstract [en]

    The assessment of environmental habitability potential involves measurement of the chemical and physical attributes of the system as well as their dynamic interplay. The environmental dynamics describe the availability of both energy sources and raw materials for meeting the requirements of organisms and for altering the environment. Energetic exchange can also determine the preservation potential for organic materials in the rock record. During its first year at Gale Crater, the Mars Science Laboratory payload has directly measured the chemistry and physical attributes, e.g., temperature, humidity, radiation, pressure, etc. of the martian atmosphere. Curiosity has also acquired chemical and mineralogical data, both from a wind drift deposit of fines and from two examples of a sedimentary rock formation in a region of Gale Crater called Yellowknife Bay, some 445 meters to the east of Bradbury Landing, where Curiosity initially touched down. These data enabled inferences to be made regarding depositional environment and past habitability potential at Gale Crater. The rock chemistry data reveal signs of aqueous interaction i.e., H2O, OH and H2 and sufficient elemental basis (C, H, O, S and possibly N) for plausible nutrient supply, should Mars have ever had autotrophic prokaryotes to exploit it, and a range of redox conditions tolerable to Earth microbes is indicated by the presence of clay minerals. Curiosity’s observations of the chemical, physical and geologic features of Yellowknife Bay point to a formerly habitable environment.

  • 125.
    Cordoba-Jabonero, Carmen
    et al.
    Centro de Astrobiología.
    Patel, Manish R.
    Planetary and Space Sciences Research Institute, The Open University, Walton Hall, Milton Keynes .
    Zorzano, María Paz
    Centro de Astrobiología.
    Cockell, Charles Seaton
    British Antarctic Survey, High Cross, Madingley Road, Cambridge .
    Assessments for possible habitability in Martian polar environments: Fundaments based in ice screening of UV radiation2004In: ESA SP, ISSN 0379-6566, E-ISSN 1609-0438, Vol. 545, p. 187-188Article in journal (Refereed)
    Abstract [en]

    We present a study of the solar UV radiation in Martian high latitude environments covered by ice, where the UV propagation through the polar cover depends on the ice radiative properties (layers of H2O or CO 2 ice). But also we will investigate the changes in the subsurface UV levels induced by the seasonal variations of solar UV flux on the surface, as well as by the seasonal freezing-thawing and related CO2 sublimation processes. The biological dose relative to DNA-damage will be also estimated for biological implication assessments. All these studies will be compared with the biological dose received in the Antarctic snow-ice covered environment which is seasonally exposed to high UV radiation levels (formation of "ozone hole"), where the environmental conditions could be similar to those present on Mars

  • 126.
    Cordoba-Jabonero, Carmen
    et al.
    Instituto Nacional de Técnica Aeroespacial, Área de Investigación e Instrumentación Atmosférica.
    Zorzano, María Paz
    Centro de Astrobiología, CSIC-INTA.
    Selsis, Franck
    Centro de Astrobiología, CSIC-INTA.
    Patel, Manish R.
    Planetary and Space Sciences Research Institute, The Open University, Walton Hall, Milton Keynes .
    Cockell, Charles Seaton
    British Antarctic Survey, High Cross, Madingley Road, Cambridge .
    Radiative habitable zones in martian polar environments2005In: Icarus (New York, N.Y. 1962), ISSN 0019-1035, E-ISSN 1090-2643, Vol. 175, no 2, p. 360-371Article in journal (Refereed)
    Abstract [en]

    The biologically damaging solar ultraviolet (UV) radiation (quantified by the DNA-weighted dose) reaches the martian surface in extremely high levels. Searching for potentially habitable UV-protected environments on Mars, we considered the polar ice caps that consist of a seasonally varying CO2 ice cover and a permanent H2O ice layer. It was found that, though the CO2 ice is insufficient by itself to screen the UV radiation, at ∼1 m depth within the perennial H2O ice the DNA-weighted dose is reduced to terrestrial levels. This depth depends strongly on the optical properties of the H2O ice layers (for instance snow-like layers). The Earth-like DNA-weighted dose and Photosynthetically Active Radiation (PAR) requirements were used to define the upper and lower limits of the northern and southern polar Radiative Habitable Zone (RHZ) for which a temporal and spatial mapping was performed. Based on these studies we conclude that photosynthetic life might be possible within the ice layers of the polar regions. The thickness varies along each martian polar spring and summer between ∼1.5 and 2.4 m for H2O ice-like layers, and a few centimeters for snow-like covers. These martian Earth-like radiative habitable environments may be primary targets for future martian astrobiological missions. Special attention should be paid to planetary protection, since the polar RHZ may also be subject to terrestrial contamination by probes.

  • 127.
    Cousin, A.
    et al.
    Los Alamos National Laboratory.
    Meslin, P.Y.
    Institut de Recherche en Astrophysique et Planetologie, Toulouse.
    Wiens, R.C.
    Los Alamos National Laboratory.
    Rapin, W.
    Institut de Recherche en Astrophysique et Planetologie, Toulouse.
    Mangold, N.
    Laboratoire Planétologie et Géodynamique, LPGNantes, CNRS UMR 6112, Université de Nantes.
    Fabre, C.
    Université de Lorraine, Nancy.
    Gasnault, O.
    Institut de Recherche en Astrophysique et Planetologie, Toulouse.
    Forni, O.
    Institut de Recherche en Astrophysique et Planetologie, Toulouse.
    Tokar, R.
    Planetary Science Institute, Tucson.
    Ollila, A.
    University of New Mexico, Albuquerque.
    Schröder, S.
    Institut de Recherche en Astrophysique et Planetologie, Toulouse.
    Lasue, J.
    Institut de Recherche en Astrophysique et Planetologie, Toulouse.
    Maurice, S.
    Institut de Recherche en Astrophysique et Planetologie, Toulouse.
    Sautter, V.
    Museum National d’Histoire Naturelle, Paris.
    Newsom, H.
    University of New Mexico, Albuquerque.
    Vaniman, D.
    Planetary Science Institute, Tucson.
    Mouélic, S. Le
    Laboratoire Planétologie et Géodynamique, LPGNantes, CNRS UMR 6112, Université de Nantes.
    Dyar, D.
    Mount Holyoke College, South Hadley.
    Berger, G.
    Institut de Recherche en Astrophysique et Planetologie, Toulouse.
    Blaney, D.
    Jet Propulsion Laboratory, California Institute of Technology, Pasadena.
    Nachon, M.
    Laboratoire Planétologie et Géodynamique, LPGNantes, CNRS UMR 6112, Université de Nantes.
    Dromart, G.
    Laboratoire de Géologie de Lyon.
    Lanza, N.
    Los Alamos National Laboratory.
    Clark, B.
    Space Science Institute, Boulder, Colorado.
    Clegg, S.
    Los Alamos National Laboratory.
    Delapp, D.
    Los Alamos National Laboratory.
    Compositions of coarse and fine particles in martian soils at gale: A window into the production of soils2015In: Icarus (New York, N.Y. 1962), ISSN 0019-1035, E-ISSN 1090-2643, Vol. 249, p. 22-42Article in journal (Refereed)
    Abstract [en]

    The ChemCam instrument onboard the Curiosity rover provides for the first time an opportunity to study martian soils at a sub-millimeter resolution. In this work, we analyzed 24 soil targets probed by ChemCam during the first 250 sols on Mars. Using the depth profile capability of the ChemCam LIBS (Laser-Induced Breakdown Spectroscopy) technique, we found that 45% of the soils contained coarse grains (>500 μm). Three distinct clusters have been detected: Cluster 1 shows a low SiO2 content; Cluster 2 corresponds to coarse grains with a felsic composition, whereas Cluster 3 presents a typical basaltic composition. Coarse grains from Cluster 2 have been mostly observed exposed in the vicinity of the landing site, whereas coarse grains from Clusters 1 and 3 have been detected mostly buried, and were found all along the rover traverse. The possible origin of these coarse grains was investigated. Felsic (Cluster 2) coarse grains have the same origin as the felsic rocks encountered near the landing site, whereas the origin of the coarse grains from Clusters 1 and 3 seems to be more global. Fine-grained soils (particle size < laser beam diameter which is between 300 and 500 μm) show a homogeneous composition all along the traverse, different from the composition of the rocks encountered at Gale. Although they contain a certain amount of hydrated amorphous component depleted in SiO2, possibly present as a surface coating, their overall chemical homogeneity and their close-to-basaltic composition suggest limited, or isochemical alteration, and a limited interaction with liquid water. Fine particles and coarse grains from Cluster 1 have a similar composition, and the former could derive from weathering of the latter. Overall martian soils have a bulk composition between that of fine particles and coarse grains. This work shows that the ChemCam instrument provides a means to study the variability of soil composition at a scale not achievable by bulk chemical analyses.

  • 128.
    Córdoba-Jabonero, Carmen
    et al.
    Instituto Nacional de Técnica Aeroespacial (INTA), Área de Investigación e Instrumentación Atmosférica, Madrid, Spain.
    Sicard, Michaël
    CommSensLab, Dept. of Signal Theory and Communications, Universitat Politècnica de Catalunya (UPC), Barcelona, Spain. Ciències i Tecnologies de l'Espai-Centre de Recerca de l'Aeronàutica i de l'Espai/Institut d'Estudis Espacials de Catalunya (CTE-CRAE/IEEC), Universitat Politècnica de Catalunya (UPC), Barcelona, Spain.
    Del Águila, Ana
    nstituto Nacional de Técnica Aeroespacial (INTA), Área de Investigación e Instrumentación Atmosférica, Madrid, Spain. emote Sensing Technology Institute, German Aerospace Centre (DLR), Oberpfaffenhofen, Germany.
    Jiménez, Marcos
    Instituto Nacional de Técnica Aeroespacial (INTA), Área de Sistemas de Teledetección, Madrid, Spain.
    Zorzano, María-Paz
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Centro de Astrobiología (CSIC-INTA), Madrid, Spain.
    Performance of a dust model to predict the vertical mass concentration of an extreme Saharan dust event in the Iberian Peninsula: Comparison with continuous, elastic, polarization-sensitive lidars2019In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 214, article id 116828Article in journal (Refereed)
    Abstract [en]

    An intense dusty event unusually occurred in wintertime over the Iberian Peninsula was detected over two Spanish NASA/MPLNET sites: the temporary Torrejón Observational Tower for Environmental Monitoring (TOTEM, 40.5°N 3.5°W) and the Barcelona station (BCN, 41.4°N 2.1°E). The highest dust incidence was observed from 22 to 23 February 2017; this two-day dusty scenario is examined in order to evaluate the performance of the operational NMMB/BSC-Dust model on forecasted mass concentration profiling in comparison with polarized Micro-Pulse (P-MPL) mass estimates for dust particles. First, the optical properties of the dust (DD) were effectively separated from the non-dust (ND) component by using the combined P-MPL/POLIPHON method. Lidar-derived DD optical depths reached maximums of 1.6–1.7 (±0.1) at both stations. Typical features for dust were obtained: linear particle depolarization ratios between 0.3 and 0.4, and lidar ratios in the range of 41–70 sr and 36–66 sr, respectively, for TOTEM and BCN. Lower AERONET Ångström exponents were reported for TOTEM (0.12 ± 0.04) than at BCN (0.5 ± 0.3). HYSPLIT back-trajectory analysis showed air masses coming from the Sahara region, mostly transporting dust particles. AERONET-derived Mass Extinction Efficiencies (MEE) under dusty conditions were used for the extinction-to-mass conversion procedure as applied to the P-MPL measurements: MEE values were lower at TOTEM (0.57 ± 0.01 m2 g−1) than those found at BCN (0.87 ± 0.10 m2 g−1). Those results reveal that dust particles were predominantly larger at TOTEM than those observed at BCN, and a longer transport of dust particles from the Sahara sources to BCN could favour a higher gravitational settling of coarser particles before reaching BCN than TOTEM. A comparative analysis between profiles as obtained from the lidar DD component of the mass concentration and those forecasted by the NMMB/BSC-Dust model (25 available dusty profiles) was performed. The degree of agreement between both datasets was determined by the percentage of dusty cases satisfying selected model performance criteria (favourable cases) of two proxies: the Mean Fractional Bias, M&#x2062;F&#x2062;B" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;">MFBM⁢F⁢B, and the correlation coefficient, C&#x2062;C" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;">CCC⁢C. A good agreement is found (72% and 76%, respectively, of favourable cases); however, large discrepancies are found at low altitudes between the dust model and the lidar observations, mostly at early stages of the arrival of the dust intrusion. Higher model-derived centre-of-mass (CoM) heights are found in 60% of the cases (with differences < 15% w.r.t. the lidar CoM, whose values ranged between 1.8 and 2.3 km height). In addition, modelled mass loading (ML) values were generally higher than the lidar-derived ones. However, the evolution of the mass loading along the two days, 22 and 23 February, was rather similar for both the model forecasting and lidar observations at both stations. The relative ML differences (<50%) of the mass loading represented 60% of all cases. Discrepancies can be based on the uncertainties in the lidar retrievals (mainly, the use of single extinction-to-mass conversion factors). In general, a moderately good agreement is observed between the P-MPL-derived dust mass concentration profiles and the NMMB/BSC-Dust model ones at both sites; large discrepancies are found at lower altitudes, plausibly due to a lower sedimentation of dust particles coming from upper layers by gravitational settling than that introduced by the NMMB/BSC-Dust model in the simulations. The methodology described for the dust model evaluation against the continuous P-MPL observations can be easily adopted for an operational use of the NMMB/BSC-Dust model for forecasting the mass concentration profiling in frequently dust-affected regions with serious climate and environmental implications, as long as a typical MEE for dust could be accurately specified. Hence, a statistical analysis for determining AERONET-based MEE values over the Iberian Peninsula is on-going.

  • 129.
    Dalin, Peter A.
    et al.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Kirkwood, Sheila
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Hervig, M.
    GATS Inc., Driggs, ID 83422.
    Mihalikova, Maria
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Mikhaylova, Daria
    Swedish Institute of Space Physics / Institutet för rymdfysik , Polar Atmospheric Research, Swedish Institute of Space Physics, Box 812, 98128, Kiruna.
    Wolf, Ingemar
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Osepian, Aleftina
    Polar Geophysical Institute, Murmansk.
    Wave influence on polar mesosphere summer echoes above Wasa: experimental and model studies2012In: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 30, no 8, p. 1143-1157Article in journal (Refereed)
    Abstract [en]

    Comprehensive analysis of the wave activity in the Antarctic summer mesopause is performed using polar mesospheric summer echoes (PMSE) measurements for December 2010–January 2011. The 2-day planetary wave is a statistically significant periodic oscillation in the power spectrum density of PMSE power. The strongest periodic oscillation in the power spectrum belongs to the diurnal solar tide; the semi-diurnal solar tide is found to be a highly significant harmonic oscillation as well. The inertial-gravity waves are extensively studied by means of PMSE power and wind components. The strongest gravity waves are observed at periods of about 1, 1.4, 2.5 and 4 h, with characteristic horizontal wavelengths of 28, 36, 157 and 252 km, respectively. The gravity waves propagate approximately in the west-east direction over Wasa (Antarctica). A detailed comparison between theoretical and experimental volume reflectivity of PMSE, measured at Wasa, is made. It is demonstrated that a new expression for PMSE reflectivity derived by Varney et al. (2011) is able to adequately describe PMSE profiles both in the magnitude and in height variations. The best agreement, within 30%, is achieved when mean values of neutral atmospheric parameters are utilized. The largest contribution to the formation and variability of the PMSE layer is explained by the ice number density and its height gradient, followed by wave-induced perturbations in buoyancy period and the turbulent energy dissipation rate

  • 130.
    Davis, C. P.
    et al.
    University of Edinburgh, Institute of Atmospheric and Environmental Science.
    Evans, K. F.
    University of Colorado, Department of Atmosphere and Oceanic Sciences.
    Buehler, Stefan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Wu, D. L.
    California Institute of Technology, Jet Propulsion Laboratory.
    Pumphrey, H. C.
    University of Edinburgh, Institute of Atmospheric and Environmental Science.
    3-D polarised simulations of space-borne passive mm/sub-mm midlatitude cirrus observations: a case study2006In: Atmospheric Chemistry and Physics Discussions, ISSN 1680-7367, E-ISSN 1680-7375, Vol. 6, p. 12701-12728Article in journal (Other academic)
  • 131.
    Davis, Cory
    et al.
    University of Edinburgh, Institute of Atmospheric and Environmental Science.
    Evans, K. F.
    Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder.
    Buehler, Stefan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Wu, D. L.
    Jet Propulsion Laboratory, California Institute of Technology, Pasadena.
    Pumphrey, H. C.
    University of Edinburgh, Institute of Atmospheric and Environmental Science.
    3-D polarised simulations of space-borne passive mm/sub-mm midlatitude cirrus observations: a case study2007In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 7, no 15, p. 4149-4158Article in journal (Refereed)
    Abstract [en]

    Global observations of ice clouds are needed to improve our understanding of their impact on earth's radiation balance and the water-cycle. Passive mm/sub-mm has some advantages compared to other space-borne cloud-ice remote sensing techniques. The physics of scattering makes forward radiative transfer modelling for such instruments challenging. This paper demonstrates the ability of a recently developed RT code, ARTS-MC, to accurately simulate observations of this type for a variety of viewing geometries corresponding to operational (AMSU-B, EOS-MLS) and proposed (CIWSIR) instruments. ARTS-MC employs an adjoint Monte-Carlo method, makes proper account of polarisation, and uses 3-D spherical geometry. The actual field of view characteristics for each instrument are also accounted for. A 3-D midlatitude cirrus scenario is used, which is derived from Chilbolton cloud radar data and a stochastic method for generating 3-D ice water content fields. These demonstration simulations clearly demonstrate the beamfilling effect, significant polarisation effects for non-spherical particles, and also a beamfilling effect with regard to polarisation.

  • 132.
    Delgado-Bonal, A.
    et al.
    Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR).
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Human vision is determined based on information theory2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 36038Article in journal (Refereed)
    Abstract [en]

    It is commonly accepted that the evolution of the human eye has been driven by the maximum intensity of the radiation emitted by the Sun. However, the interpretation of the surrounding environment is constrained not only by the amount of energy received but also by the information content of the radiation. Information is related to entropy rather than energy. The human brain follows Bayesian statistical inference for the interpretation of visual space. The maximization of information occurs in the process of maximizing the entropy. Here, we show that the photopic and scotopic vision absorption peaks in humans are determined not only by the intensity but also by the entropy of radiation. We suggest that through the course of evolution, the human eye has not adapted only to the maximum intensity or to the maximum information but to the optimal wavelength for obtaining information. On Earth, the optimal wavelengths for photopic and scotopic vision are 555 nm and 508 nm, respectively, as inferred experimentally. These optimal wavelengths are determined by the temperature of the star (in this case, the Sun) and by the atmospheric composition.

  • 133.
    Delgado-Bonal, Alfonso
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Evaluation of the Atmospheric Chemical Entropy Production of Mars2015In: Entropy, ISSN 1099-4300, E-ISSN 1099-4300, Vol. 17, no 7, p. 5047-5062Article in journal (Refereed)
    Abstract [en]

    Thermodynamic disequilibrium is a necessary situation in a system in which complex emergent structures are created and maintained. It is known that most of the chemical disequilibrium, a particular type of thermodynamic disequilibrium, in Earth's atmosphere is a consequence of life. We have developed a thermochemical model for the Martian atmosphere to analyze the disequilibrium by chemical reactions calculating the entropy production. It follows from the comparison with the Earth atmosphere that the magnitude of the entropy produced by the recombination reaction forming O 3 (O + O 2 + CO 2 O 3 + CO 2) in the atmosphere of the Earth is larger than the entropy produced by the dominant set of chemical reactions considered for Mars, as a consequence of the low density and the poor variety of species of the Martian atmosphere. If disequilibrium is needed to create and maintain self-organizing structures in a system, we conclude that the current Martian atmosphere is unable to support large physico-chemical structures, such as those created on Earth.

  • 134.
    Delgado-Bonal, Alfonso
    et al.
    Centro de Astrobiologia, INTA-CSIC, Madrid.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Solar cell temperature on Mars2015In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 118, p. 74-79Article in journal (Refereed)
    Abstract [en]

    The operating temperature of a solar cell determines its efficiency and performance. This temperature depends on the materials used to build the cell but also on the environmental variables surrounding it (i.e., radiation, ambient temperature, wind speed and humidity). Several equations have been proposed to calculate this temperature, depending on these variables. Also, for Earth conditions, simplifiedequations have been developed, but are not valid for other planets, as Mars, where the environmental conditions are extremely different.In this paper, we develop a simplified equation to calculate the temperature of a solar cell under Mars environmental conditions and discuss the effect that altitude and wind on Mars might have on the solar cell temperature. The correct determination of the operating temperature of the cell will help to optimize the design of the next solar cell powered rovers for the exploration of Mars.

  • 135.
    Delgado-Bonal, Alfonso
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Martín, Sandra Vázquez
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Mier, Maria-Paz Zorzano
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Solar and wind exergy potentials for Mars2016In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 102, p. 550-558Article in journal (Refereed)
    Abstract [en]

    The energy requirements of the planetary exploration spacecrafts constrain the lifetime of the missions, their mobility and capabilities, and the number of instruments onboard. They are limiting factors in planetary exploration. Several missions to the surface of Mars have proven the feasibility and success of solar panels as energy source. The analysis of the exergy efficiency of the solar radiation has been carried out successfully on Earth, however, to date, there is not an extensive research regarding the thermodynamic exergy efficiency of in-situ renewable energy sources on Mars. In this paper, we analyse the obtainable energy (exergy) from solar radiation under Martian conditions. For this analysis we have used the surface environmental variables on Mars measured in-situ by the Rover Environmental Monitoring Station onboard the Curiosity rover and from satellite by the Thermal Emission Spectrometer instrument onboard the Mars Global Surveyor satellite mission. We evaluate the exergy efficiency from solar radiation on a global spatial scale using orbital data for a Martian year; and in a one single location in Mars (the Gale crater) but with an appreciable temporal resolution (1 h). Also, we analyse the wind energy as an alternative source of energy for Mars exploration and compare the results with those obtained on Earth. We study the viability of solar and wind energy station for the future exploration of Mars, showing that a small square solar cell of 0.30 m length could maintain a meteorological station on Mars. We conclude that the low density of the atmosphere of Mars is responsible of the low thermal exergy efficiency of solar panels. It also makes the use of wind energy uneffective. Finally, we provide insights for the development of new solar cells on Mars.

  • 136.
    Delgado-Bonal, Alfonso
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Mier, Maria-Paz Zorzano
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Martian Top of the Atmosphere 10–420 nm spectral irradiance database and forecast for solar cycle 242016In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 134, p. 228-235Article in journal (Refereed)
    Abstract [en]

    Ultraviolet radiation from 10 to 420 nm reaching Mars Top of the Atmosphere (TOA) and surface is important in a wide variety of fields such as space exploration, climate modeling, and spacecraft design, as it has impact in the physics and chemistry of the atmosphere and soil. Despite the existence of databases for UV radiation reaching Earth TOA, based in space-borne instrumentation orbiting our planet, there is no similar information for Mars. Here we present a Mars TOA UV spectral irradiance database for solar cycle 24 (years 2008–2019), containing daily values from 10 to 420 nm. The values in this database have been computed using a model that is fed by the Earth-orbiting Solar Radiation and Climate Experiment (SORCE) data. As the radiation coming from the Sun is not completely isotropic, in order to eliminate the geometrically related features but being able to capture the general characteristics of the solar cycle stage, we provide 3-, 7- and 15-days averaged values at each wavelength. Our database is of interest for atmospheric modeling and spectrally dependent experiments on Mars, the analysis of current and upcoming surface missions (rovers and landers) and orbiters in Mars. Daily values for the TOA UV conditions at the rover Curiosity location, as well as for the NASA Insight mission in 2016, and ESA/Russia ExoMars mission in 2018 are provided.

  • 137. Demaison, J.
    et al.
    Verdes, C.
    Buehler, Stefan
    Characterization of millimetre-wave spectroscopic signatures2004Report (Other academic)
  • 138.
    Dhanaya, M.B.
    et al.
    Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum.
    Bhardwaj, A.
    Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum.
    Futaana, Y.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Fatemi, Shahab
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Holmström, M.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Barabash, Stas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Wieser, M.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Wurz, P.
    Physikalisches Institut, University of Bern.
    Thampi, R.S.
    Space Physics Laboratory, Vikram Sarabhai Space Center, Trivandrum.
    Proton entry into the near-lunar plasma wake for magnetic field aligned flow2013In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 40, no 2, p. 2913-2917Article in journal (Refereed)
    Abstract [en]

    We report the first observation of protons in the near-lunar (100–200 km from the surface) and deeper (near anti-subsolar point) plasma wake when the interplanetary magnetic field (IMF) and solar wind velocity (vsw) are parallel (aligned flow; angle between IMF and vsw≤10°). More than 98% of the observations during aligned flow condition showed the presence of protons in the wake. These observations are obtained by the Solar Wind Monitor sensor of the Sub-keV Atom Reflecting Analyser experiment on Chandrayaan-1. The observation cannot be explained by the conventional fluid models for aligned flow. Back tracing of the observed protons suggests that their source is the solar wind. The larger gyroradii of the wake protons compared to that of solar wind suggest that they were part of the tail of the solar wind velocity distribution function. Such protons could enter the wake due to their large gyroradii even when the flow is aligned to IMF. However, the wake boundary electric field may also play a role in the entry of the protons into the wake.

  • 139.
    Dieval, Catherine
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Solar wind ions inside the induced magnetosphere of Mars2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The subject of the thesis is analysis and modeling of the entry, transport, and atmospheric precipitation of solar wind ions, H+ and He2+, into the induced magnetosphere of Mars. The solar wind is a flow of charged particles emitted by the Sun. The solar wind carries with it a magnetic field, the interplanetary magnetic field (IMF). The IMF piles up on the dayside of the non-magnetized Mars and is then convected towards the nightside. The solar wind ions can normally not cross the magnetic barrier, formed by the pile up IMF. However, in situ observations by the Mars Express spacecraft reveal that downward moving solar wind H+ and He2+ are sometimes present in the Martian ionosphere, below the magnetic barrier. The gyroradii of shocked solar wind ions may be comparable to the size of the dayside Martian magnetic barrier and for certain circumstances, these ions can gyrate through. Observations by Mars Express are used to analyze H+ and He2+ penetrating through the magnetic barrier and precipitating into the Martian ionosphere, identified by the presence of ionospheric photo-electrons. A case study shows evidence of narrower energy distributions for H+ (with energy ≥ solar wind energy), as the spacecraft moves down in altitude. From this, the study concludes that the magnetic barrier prevents the lower energy H+, from reaching low altitudes. The thesis also describes a statistical study of precipitating H+ fluxes, which indicate that H+ precipitation is rare (detected during 3% of the dayside observation time only) and carries on average 0.2% of the upstream solar wind particle flux. In another statistical study, the thesis shows that the precipitation of H+ and He2+ decreases even further when Mars encounters solar wind pressure pulses. A possible explanation is that the enhanced mass loading of the magnetic field flux tubes by planetary heavy ions, while the tubes drag through the ionosphere at lower altitudes, slows down their velocity and allows more magnetic flux to pile up. The magnetic barrier becomes a more effective obstacle to the solar wind ion precipitation. Furthermore, the thesis describes a model of H+ precipitation onto the Martian upper atmosphere using a hybrid code of the Mars solar wind interaction. The spatial patterns of the precipitation depend on the H+ energy, on the H+ origin (solar wind or generated from the hydrogen corona) and on the altitude. Some features of the observed H+ distributions are reproduced by simulations, while others are not, indicating a more complex physics than in the model. The thesis also describes amodel study of transport of H+, fast H atoms and He2+ through the atmosphere using a Direct Simulation Monte Carlo model. This study demonstrates the crucial role of the magnetic field in determining the energy deposition of the solar wind ions in the topside atmosphere. For instance, a horizontal magnetic field with strength of 50 nT backscattered almost all H+, thus preventing these particles to deposit their energy at lower altitudes. The conclusion of the thesis work is that although some solar wind ions do precipitate, the magnetic barrier effectively protects the onospherefrom precipitating solar wind ions.

  • 140.
    Dieval, Catherine
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    The solar wind protons inside the induced magnetosphere of Mars2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mars is an unmagnetized planet. Mars has no intrinsic magnetic field but has local magnetic anomalies in the crust. The solar wind, which is the plasma flowing from the Sun at supersonic speed, interacts with the magnetic fields of the currents induced in the conductive Martian ionosphere, deviates and slows down to subsonic speeds. A void in the solar wind is formed around the planet as an induced magnetosphere.At the boundary of the induced magnetosphere, the plasma composition changes from being dominated by the major ion in the solar wind (protons) to being dominated by heavy ions of planetary origin. Also, the interplanetary magnetic field, being carried by the solar wind, starts to pile up against the planet to form a magnetic barrier on the dayside, drapes around the planet, stretches due to mass loading, and forms a magnetotail.The gyroradius of a heated proton in the magnetosheath is large in comparison with the size of the induced magnetosphere. Therefore, a fraction of the proton population penetrates the induced magnetosphere boundary, enters the upper layer of the atmosphere (the ionosphere) and subsequently neutralizes at low altitudes. We have conducted a detailed study of an event, in which the magnetosheath protons penetrate the Martian induced magnetosphere boundary (IMB). The spatial extent of the proton precipitation region reached several thousands of kilometers along the orbit of the Mars Express spacecraft.The interaction of the precipitating protons with the Martian atmosphere was modeled using a direct simulation Monte Carlo method. The inclusion of a horizontal magnetic field in the model significantly increased the backscattering of protons compared to the case without a magnetic field. More than 50% of the incoming energy is reflected backwards for a magnetic field of strength 30 nT, compared to 4% in the case of no magnetic field. We have also used hybrid modeling to study the spatial pattern of the precipitation onto the Martian atmosphere both for solar wind protons and protons originating from the planetary atmosphere. The solar wind protons and the exospheric (planetary) protons contribute 60% and 40%, respectively, of the deposition of mass at the exobase for the given input parameters. The precipitating flux decreases substantially at the subsolar point, due to the backscattering of the incoming protons by the more intense piled-up magnetic field.

  • 141.
    Dieval, Catherine
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Kallio, E.
    Finnish Meteorological Institute.
    Barabash, Stas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Stenberg, G.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Nilsson, H
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Futaana, Y.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Holmström, M.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Fedorov, A.
    Institut de Recherche en Astrophysique et Planetologie, Toulouse.
    Frahm, R.A.
    Southwest Research Institute, San Antonio, Texas.
    Jarvinen, R.
    Finnish Meteorological Institute, Helsinki.
    Brain, D.A.
    Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado.
    A case study of proton precipitation at Mars: Mars Express observations and hybrid simulations2012In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 117Article in journal (Refereed)
    Abstract [en]

    Using the data from the Analyzer of Space Plasma and Energetic Atoms (ASPERA-3) experiment on board Mars Express and hybrid simulations, we have investigated the entry of protons into the Martian induced magnetosphere. We discuss one orbit on the dayside with observations of significant proton fluxes at altitudes down to 260 km on 27 February 2004. The protons observed below the induced magnetosphere boundary at an altitude of less than 700 km have energies of a few keV, travel downward, and precipitate onto the atmosphere. The measured energy flux and particle flux are 108–109 eV cm−2 s−1 and 105–106 H+ cm−2 s−1, respectively. The proton precipitation occurs because the Martian magnetosheath is small with respect to the heated proton gyroradius in the subsolar region. The data suggest that the precipitation is not permanent but may occur when there are transient increases in the magnetosheath proton temperature. The higher-energy protons penetrate deeper because of their larger gyroradii. The proton entry into the induced magnetosphere is simulated using a hybrid code. A simulation using a fast solar wind as input can reproduce the high energies of the observed precipitating protons. The model shows that the precipitating protons originate from both the solar wind and the planetary exosphere. The precipitation extends over a few thousand kilometers along the orbit of the spacecraft. The proton precipitation does not necessarily correlate with the crustal magnetic anomalies.

  • 142. Dieval, Catherine
    et al.
    Kallio, Esa
    Finnish Meteorological Institute.
    Stenberg, Gabriella
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Barabash, Stas
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Järvinen, Riku
    Finnish Meteorological Institute.
    Hybrid simulations of proton precipitation patterns onto the upper atmosphere of Mars2012In: Earth Planets and Space, ISSN 1343-8832, E-ISSN 1880-5981, Vol. 64, no 2, p. 121-134Article in journal (Refereed)
    Abstract [en]

    We study the dependence of proton precipitation patterns onto the Martian upper atmosphere on altitude, proton energy, proton origin, and in a lesser extent, solar zenith angle, using the HYB-Mars model, a 3D quasi-neutral hybrid model. We find that the flux of precipitating protons has a strong altitude dependence: on the dayside, the flux of precipitating protons decreases substantially when the altitude over Mars decreases. We also find that the contribution of exospheric protons to the deposition is significant and its spatial distribution is not identical to that of the solar wind protons. In addition, the low energy proton population comes mainly from the newborn planetary protons. The energized pick-up protons and solar wind protons contribute to the higher energy proton population. The study also confirms that the proton precipitation is highly asymmetric with respect to the direction of the convection electric field in the solar wind. The study implies that the Martian induced magnetosphere protects the upper atmosphere effectively against proton precipitation.

  • 143.
    Dieval, Catherine
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Stenberg, G.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Nilsson, H.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Barabash, Stas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    A statistical study of proton precipitation onto the Martian upper atmosphere: Mars Express observations2013In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, p. 1972-1983Article in journal (Refereed)
    Abstract [en]

    Due to the small size of the Martian magnetic pile-up region, especially at the subsolar point, heated protons with high enough energy can penetrate the induced magnetosphere boundary (IMB) without being backscattered, i.e., they precipitate. We present a statistical study of the downgoing ~ keV proton fluxes measured in the Martian ionosphere by the Analyzer of Space Plasma and Energetic Atoms (ASPERA-3) experiment onboard the Mars Express spacecraft. We find that on the dayside, the events of proton penetration occur during 3% of the observation time: the precipitation is an intermittent phenomenon. The proton events carry on average ~0.2% of the incident solar wind flux. Therefore, the induced magnetosphere is an effective shield against the magnetosheath protons. The events are more frequent during fast solar wind conditions than during slow solar wind conditions. The sporadic proton penetration is thought to be caused by transient increases in the magnetosheath temperature. The precipitating flux is higher on the dayside than on the nightside, and its spatial deposition is controlled by the solar wind convective electric field. The largest crustal magnetic anomalies tend to decrease the proton precipitation in the Southern hemisphere. The particle and energy fluxes vary in the range 104-106 cm-2 s-1 and 107-109 eVcm-2 s-1, respectively. The corresponding heating for the dayside atmosphere is on average negligible compared to the solar extreme ultraviolet heating, although the intermittent penetration may cause local ionization. The net precipitating proton particle flux input to the dayside ionosphere is estimated as 1.2 · 1021 s-1.

  • 144.
    Dieval, Catherine
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Stenberg, G.
    Swedish Institute of Space Physics / Institutet för rymdfysik.
    Nilsson, Hans
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Edberg, N.J.T.
    Swedish Institute of Space Physics, Uppsala.
    Barabash, Stas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Reduced proton and alpha particle precipitations at Mars during solar wind pressure pulses: Mars Express results2013In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 118, no 6, p. 3421-3429Article in journal (Refereed)
    Abstract [en]

    1] We performed a statistical study of downward moving protons and alpha particles of ~keV energy (assumed to be of solar wind origin) inside the Martian induced magnetosphere from July 2006 to July 2010. Ion and electron data are from the Analyzer of Space Plasma and Energetic Atoms (ASPERA-3) package on board Mars Express. We investigated the solar wind ion entry into the ionosphere, excluding intervals of low-altitude magnetosheath encounters. The study compares periods of quiet solar wind conditions and periods of solar wind pressure pulses, including interplanetary coronal mass ejections and corotating interaction regions. The solar wind ion precipitation appears localized and/or intermittent, consistent with previous measurements. Precipitation events are less frequent, and the precipitating fluxes do not increase during pressure pulse encounters. During pressure pulses, the occurrence frequency of observed proton precipitation events is reduced by a factor of ~3, and for He2+ events the occurrence frequency is reduced by a factor of ~2. One explanation is that during pressure pulse periods, the mass loading of the solar wind plasma increases due to a deeper penetration of the interplanetary magnetic flux tubes into the ionosphere. The associated decrease of the solar wind speed thus increases the pileup of the interplanetary magnetic field on the dayside of the planet. The magnetic barrier becomes thicker in terms of solar wind ion gyroradii, causing the observed reduction of H+/He2+ precipitations.

  • 145.
    Dikmen, Serkan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Development of Star Tracker Attitude and Position Determination System for Spacecraft Maneuvering and Docking Facility2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Attitude and position determination systems in satellites are absolutely necessary to keep the desired trajectory. A very accurate, reliable and most used sensor for attitude determination is the star tracker, which orient itself in space by observing and comparing star constellations with known star patterns. For on earth tests of movements and docking maneuvers of spacecrafts, the new Spacecraft Maneuvering and Docking (SMD) facility at the chair of Aerospace Information Technology at the University of Würzburg has been built. Air bearing systems on the space ve- hicles help to create micro gravity environment on a smooth surface and simulate an artificial space-like surrounding. A new star tracker based optical sensor for indoor application need to be developed in order to get the attitude and position of the vehicles. The main objective of this thesis is to research on feasible star tracking algorithms for the SMD facility first and later to implement a star detection software framework with new developed voting methods to give the star tracker system its fully autonomous function of attitude determination and position tracking. Furthermore, together with image processing techniques, the software framework is embedded into a controller board. This thesis proposes also a wireless network system for the facility, where all the devices on the vehicles can uniquely communicate within the same network and a devel- opment of a ground station to monitor the star tracker process has also been introduced. Multiple test results with different scenarios on position tracking and attitude determination, discussions and suggestions on improvements complete the entire thesis work. 

  • 146.
    Dillibabu, Surender
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Design,Analysis, and prototype of underwater glider2016Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
  • 147.
    Dirri, Fabrizio
    et al.
    IAPS-INAF, Via Fosso del Cavaliere 100 Rome, 00133, Italy.
    Palomba, Ernesto
    IAPS-INAF, Via Fosso del Cavaliere 100 Rome, 00133, Italy.
    Longobardo, Andrea
    IAPS-INAF, Via Fosso del Cavaliere 100 Rome, 00133, Italy.
    Biondi, David
    IAPS-INAF, Via Fosso del Cavaliere 100 Rome, 00133, Italy.
    Boccaccini, Angelo
    IAPS-INAF, Via Fosso del Cavaliere 100 Rome, 00133, Italy.
    Galiano, Anna
    IAPS-INAF, Via Fosso del Cavaliere 100 Rome, 00133, Italy.
    Zampetti, Emiliano
    IIA-CNR, via Salaria km 29,300 Monterotondo Rome, Italy.
    Saggin, Bortolino
    Politecnico di Milano, Polo Territoriale di Lecco Lecco, Italy.
    Scaccabarozzi, Diego
    Politecnico di Milano, Polo Territoriale di Lecco Lecco, Italy.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    VISTA instrument: a PCM-based sensor for organics and volatiles characterization by using Thermogravimetric technique2018Conference paper (Refereed)
    Abstract [en]

    VISTA (Volatile In Situ Thermogravimetry Analyser) is a µ-Thermogravimeter sensor developed by Consortium of Italian Institutes. ThermoGravimetric Analysis (TGA) is a widely used technique to monitor thermal processes involving volatile compounds, e.g. deposition/sublimation and absorption/ desorption. The instrument core is composed by a Piezoelectric Crystal Microbalance (PCM), equipped with built-in heater and built-in temperature sensor, and provided of its own Proximity Electronics (PE). The PCM oscillation frequency linearly depends on the mass deposited on its sensible area (according to Sauerbrey equation) while the PCM temperature can be increased by means of integrated heaters. Thus, mass and volatile composition can be inferred by the frequency change and by desorption temperature, respectively. The instrument is divided in two sensor heads: VISTA1, able to monitor outgassing processes in space, and VISTA2, able to reach higher temperatures, studying the dehydration and organics decomposition in minerals in different environmental conditions. An Engineering Model of VISTA1 and a laboratory breadboard of VISTA2 have been developed. Pure organic compounds and contaminant have been characterized by using deposition processes and TGA cycles obtaining some physical-chemical parameters, i.e. enthalpy of sublimation/evaporation, ΔHHsub,evap , deposition rates, kk and vapor pressures, Pvap . The instrument concept, the scientific objectives and the laboratory measurements are explained in this work.

  • 148.
    Downs, R.T.
    et al.
    University of Arizona, Department of Geosciences, University of Arizona, Tucson, Department of Geology, University of Arizona, Tucson.
    Martin-Torres, Javier
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Determining Mineralogy on Mars with the CheMin X-Ray Diffractometer2015In: Elements, ISSN 1811-5209, E-ISSN 1811-5217, Vol. 11, no 1, p. 45-50Article in journal (Refereed)
    Abstract [en]

    The rover Curiosity is conducting X-ray diffraction experiments on the surface of Mars using the CheMin instrument. The analyses enable identification of the major and minor minerals, providing insight into the conditions under which the samples were formed or altered and, in turn, into past habitable environments on Mars. The CheMin instrument was developed over a twenty-year period, mainly through the efforts of scientists and engineers from NASA and DOE. Results from the first four experiments, at the Rocknest, John Klein, Cumberland, and Windjana sites, have been received and interpreted. The observed mineral assemblages are consistent with an environment hospitable to Earth-like life, if it existed on Mars.

  • 149.
    Dundar, Ismail Ugur
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Improvement of a Space Surveillance Tracking Analysis Tool2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Since the beginning of space exploration, the amount of space debris has increased with thedevelopment of new space technologies. In fact, when a collision happens, new space debris aregenerated. Hence, collision risk between space debris and operational satellites rises. The purpose ofa surveillance network system consists of the detection of space objects, their classification and theirtracking. To avoid collisions, space debris objects’ orbit must be computed with sufficient accuracy.

    The goal of this thesis is the improvement of a pre-existing Space Surveillance and Tracking AnalysisTool. The tool is able to simulate different observation scenarios for radar or optical observer,which can be space-based or ground-based. To enhance the orbit determination, an ExtendedSquare Root Information Filter is implemented and incremented with a Smoother. Smoothers havebeen implemented for the existing filters as well, such as the Extended Kalman Filter and theUnscented Kalman Filter. A bias estimation method was added as part of the OD for all filter types.Additionally, different outlier detection methods were implemented for the automatic detection ofoutliers within the measurement data. To find the optimum orbit determination interval, differentscenarios were considered in LEO, MEO and GEO orbits. The methods were implemented anddifferent scenarios for validation will be discussed. A wide discussion on the methods implementationand their validation on different scenarios is presented, together with a comparison of the orbitdetermination results with the other filters.

    All the recently implemented features increase the efficiency of the tool to simulate the differentscenarios and enhance the tracking of space debris objects.

  • 150.
    Díaz, José Luis Pérez
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Álvarez-Valenzuela, Marco Antonio
    Saint George Tech Ltd.
    Rodríguez-Celis, F.
    MAG SOAR S.L., Av. de Europa, 82, Valdemoro.
    Surface freezing of water2016In: SpringerPlus, E-ISSN 2193-1801, Vol. 5, no 1, article id 629Article in journal (Refereed)
    Abstract [en]

    Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered—exclusively—by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided

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