Browsing by Author "Anger, Marius"

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  • The Effects of Space Debris on Emerging Mega-Constellations
    (2023-05-21) Sandström, Mikko
     Sähkötekniikan korkeakoulu | Bachelor's thesis
  • Electric Sail Test Cube–Lunar Nanospacecraft, ESTCube-LuNa: Solar Wind Propulsion Demonstration Mission Concept
    (2024-03-14) Slavinskis, Andris; Palos, Mario F.; Dalbins, Janis; Janhunen, Pekka; Tajmar, Martin; Ivchenko, Nickolay; Rohtsalu, Agnes; Micciani, Aldo; Orsini, Nicola; Moor, Karl-Mattias; Kuzmin, Sergei; Bleiders, Marcis; Donerblics, Marcis; Ofodile, Ikechukwu; Kütt, Johan; Eenmae, Tonis; Allik, Viljo; Viru, Jaan; Halapuu, Pätris; Kristmann, Katriin; Sate, Janis; Briede, Endija; Anger, Marius; Aas, Katarina; Plonis, Gustavs; Teras, Hans; Allaje, Kristo; Vaivads, Andris; Niccolai, Lorenzo; Bassetto, Marco; Mengali, Giovanni; Toivanen, Petri; Iakubivskyi, Iaroslav; Pajusalu, Mihkel; Tamm, Antti
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The electric solar wind sail, or E-sail, is a propellantless interplanetary propulsion system concept. By deflecting solar wind particles off their original course, it can generate a propulsive effect with nothing more than an electric charge. The high-voltage charge is applied to one or multiple centrifugally deployed hair-thin tethers, around which an electrostatic sheath is created. Electron emitters are required to compensate for the electron current gathered by the tether. The electric sail can also be utilised in low Earth orbit, or LEO, when passing through the ionosphere, where it serves as a plasma brake for deorbiting—several missions have been dedicated to LEO demonstration. In this article, we propose the ESTCube-LuNa mission concept and the preliminary cubesat design to be launched into the Moon’s orbit, where the solar wind is uninterrupted, except for the lunar wake and when the Moon is in the Earth’s magnetosphere. This article introduces E-sail demonstration experiments and the preliminary payload design, along with E-sail thrust validation and environment characterisation methods, a cis-lunar cubesat platform solution and an early concept of operations. The proposed lunar nanospacecraft concept is designed without a deep space network, typically used for lunar and deep space operations. Instead, radio telescopes are being repurposed for communications and radio frequency ranging, and celestial optical navigation is developed for on-board orbit determination.
  • Electrical characterization of miniaturized resistojet systems
    (2021-12-17) Lepistö, Eelis
     Sähkötekniikan korkeakoulu | Bachelor's thesis
  • Foresail-2: Space Physics Mission in a Challenging Environment
    (2023-12) Anger, Marius; Niemelä, Petri; Cheremetiev, Kiril; Clayhills, Bruce; Fetzer, Anton; Lundén, Ville; Hiltunen, Markus; Kärkkäinen, Tomi; Mayank, Mayank; Turc, Lucile; Osmane, Adnane; Palmroth, Minna; Kilpua, Emilia; Oleynik, Philipp; Vainio, Rami; Virtanen, Pasi; Toivanen, Petri; Janhunen, Pekka; Fischer, David; Le Bonhomme, Guillaume; Slavinskis, Andris; Praks, Jaan
     A2 Katsausartikkeli tieteellisessä aikakauslehdessä
    Earth’s radiation belts are extremely important for space weather because they can store and accelerate particles to relativistic energies, which can have a potential impact on satellite functionality, communications, and navigation systems. The FORESAIL consortium wants to measure these high-energy particle fluxes to understand the dynamics of the radiation belts with its satellite mission Foresail-2. The mission aims to measure magnetic ultra low frequency waves and the plasma environment in the magnetosphere around Earth. The captured data will help to improve our understanding of space weather, and in particular the dynamics of Earth’s radiation belts during periods of large disturbances inside the magnetosphere. A mission design analysis and several trade-off studies are conducted to find the requirements for the science payloads and spacecraft avionics design. Deducted from these requirements, four different payloads are proposed to gather science data in a highly elliptical orbit such as a geostationary transfer orbit. The precision magnetometer uses flux-gate technology to measure magnetic waves from 1 mHz to 10 Hz. The spin scanning particle telescope is built around a detector stack to measure electron spectra in the range of 30 keV to 10 MeV. Additionally, this mission serves as a technology demonstrator for the Coulomb drag experiment which proposes a new kind of electric solar wind sail utilising the Coulomb drag force imposed onto a 300 m long tether. The fourth payload investigates multilayer radiation shielding and single event effects. All payloads will be supported by a newly developed 6U platform using mostly commercial off-the-shelf components. Its proposed avionics face several unique design requirements rising from the payloads and the preferred highly elliptical orbit for this mission.
  • Hold and release mechanism design for Foresail-2 deployable solar arrays
    (2023-12-11) Shalamov, Roman
     Sähkötekniikan korkeakoulu | Bachelor's thesis
  • Implementation and verification of attitude determination control algorithms for a 3U CubeSat
    (2023) Mata Garcia, Jordi
     Sähkötekniikan korkeakoulu | Master's thesis
    The whole ADCS system of a spacecraft is studied, following the example of the FS-1. Then, different algorithms for the determination of the attitude are proposed and evaluated: a Fast Linear Quaternion Attitude Estimator (FLAE) and a Two-Stage Unscented Kalman Filter (TSUKF). Both algorithms showed very promising results. The FLAE was fast and efficient in the estimation of the attitude quaternion using the filtered data from the Kalman filter, while the TSUKF displayed its potential in linear bias estimation as well as assumable computational costs. Four cases were analysed for the attitude estimation: no bias, bias, initialization during the eclipse and high noise mode. In all of them, the attitude stayed within 1 degree of pointing accuracy once converged, with the worst case being a high tumble mode during the eclipse that created a 5-degree divergence from the actual attitude. Still, the algorithm has a lot of potential to be improved, and would require several more iterations of implementation to unlock its full capabilities, as shown by the inability to determine magnetometer biases due to a non-optimal implementation of the FLAE-TSUKF link.
  • The Large Interferometer For Exoplanets (LIFE): a space mission for mid-infrared nulling interferometry
    (2024-08-28) Glauser, Adrian M.; Quanz, Sascha P.; Hansen, Jonah; Dannert, Felix; Ireland, Michael; Linz, Hendrik; Absil, Olivier; Alei, Eleonora; Angerhausen, Daniel; Birbacher, Thomas; Defrère, Denis; Fortier, Andrea; Huber, Philipp A.; Kammerer, Jens; Laugier, Romain; Lichtenberg, Tim; Noack, Lena; Ranganathan, Mohanakrishna; Rugheimer, Sarah; Airapetian, Vladimir; Alibert, Yann; Amado, Pedro J.; Anger, Marius
     A4 Artikkeli konferenssijulkaisussa
    The Large Interferometer For Exoplanets (LIFE) is a proposed space mission that enables the spectral characterization of the thermal emission of exoplanets in the solar neighborhood. The mission is designed to search for global atmospheric biosignatures on dozens of temperate terrestrial exoplanets and it will naturally investigate the diversity of other worlds. Here, we review the status of the mission concept, discuss the key mission parameters, and outline the trade-offs related to the mission’s architecture. In preparation for an upcoming concept study, we define a mission baseline based on a free-formation flying constellation of a double Bracewell nulling interferometer that consists of 4 collectors and a central beam-combiner spacecraft. The interferometric baselines are between 10–600m, and the estimated diameters of the collectors are at least 2m (but will depend on the total achievable instrument throughput). The spectral required wavelength range is 6–16μm (with a goal of 4–18.5μm), hence cryogenic temperatures are needed both for the collectors and the beam combiners. One of the key challenges is the required deep, stable, and broad-band nulling performance while maintaining a high system throughput for the planet signal. Among many ongoing or needed technology development activities, the demonstration of the measurement principle under cryogenic conditions is fundamentally important for LIFE.
  • Large Interferometer For Exoplanets (LIFE): XIV. Finding terrestrial protoplanets in the galactic neighborhood
    (2024-12-01) Cesario, Lorenzo; Lichtenberg, Tim; Alei, Eleonora; Carrión-González, Óscar; Dannert, Felix A.; Defrère, Denis; Ertel, Steve; Fortier, Andrea; García Muñoz, A.; Glauser, Adrian M.; Hansen, Jonah T.; Helled, Ravit; Huber, Philipp A.; Ireland, Michael J.; Kammerer, Jens; Laugier, Romain; Lillo-Box, Jorge; Menti, Franziska; Meyer, Michael R.; Noack, Lena; Quanz, Sascha P.; Quirrenbach, Andreas; Rugheimer, Sarah; Van Der Tak, Floris; Wang, Haiyang S.; Anger, Marius; Balsalobre-Ruza, Olga; Bhattarai, Surendra; Braam, Marrick; Castro-González, Amadeo; Cockell, Charles S.; Constantinou, Tereza; Cugno, Gabriele; Davoult, Jeanne; Güdel, Manuel; Hernitschek, Nina; Hinkley, Sasha; Itoh, Satoshi; Janson, Markus; Johansen, Anders; Jones, Hugh R.A.; Kane, Stephen R.; Van Kempen, Tim A.; Kislyakova, Kristina G.; Korth, Judith; Kovačević, Andjelka B.; Kraus, Stefan; Kuiper, Rolf; Mathew, Joice; Matsuo, Taro; Miguel, Yamila; Min, Michiel; Navarro, Ramon; Ramirez, Ramses M.; Rauer, Heike; Vow Ricketti, Berke; Romagnolo, Amedeo; Schlecker, Martin; Sneed, Evan L.; Squicciarini, Vito; Stassun, Keivan G.; Tamura, Motohide; Viudez-Moreiras, Daniel; Wordsworth, Robin D.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Context. The increased brightness temperature of young rocky protoplanets during their magma ocean epoch makes them potentially amenable to atmospheric characterization at distances from the Solar System far greater than thermally equilibrated terrestrial exoplanets, offering observational opportunities for unique insights into the origin of secondary atmospheres and the near surface conditions of prebiotic environments. Aims. The Large Interferometer For Exoplanets (LIFE) mission will employ a space-based midinfrared nulling interferometer to directly measure the thermal emission of terrestrial exoplanets. In this work, we seek to assess the capabilities of various instrumental design choices of the LIFE mission concept for the detection of cooling protoplanets with transient high-temperature magma ocean atmospheres at the tail end of planetary accretion. In particular, we investigate the minimum integration times necessary to detect transient magma ocean exoplanets in young stellar associations in the Solar neighborhood. Methods. Using the LIFE mission instrument simulator (LIFEsim), we assessed how specific instrumental parameters and design choices, such as wavelength coverage, aperture diameter, and photon throughput, facilitate or disadvantage the detection of protoplan-ets. We focused on the observational sensitivities of distance to the observed planetary system, protoplanet brightness temperature (using a blackbody assumption), and orbital distance of the potential protoplanets around both G- and M-dwarf stars. Results. Our simulations suggest that LIFE will be able to detect (S/N ≥ 7) hot protoplanets in young stellar associations up to distances of 100 pc from the Solar System for reasonable integration times (up to a few hours). Detection of an Earth-sized protoplanet orbiting a Solar-sized host star at 1 AU requires less than 30 minutes of integration time. M-dwarfs generally need shorter integration times. The contribution from wavelength regions smaller than 6 μm is important for decreasing the detection threshold and discriminating emission temperatures. Conclusions. The LIFE mission is capable of detecting cooling terrestrial protoplanets within minutes to hours in several local young stellar associations hosting potential targets. The anticipated compositional range of magma ocean atmospheres motivates further architectural design studies to characterize the crucial transition from primary to secondary atmospheres.
  • Radiation shielding experiment for CubeSat on highly elliptical orbit
    (2023-05-15) Fetzer, Anton; Anger, Marius; Kärkkäinen, Tomi; Eritja Olivella, Antoni; Praks, Jaan
     Poster
    The Van-Allen radiation belts around Earth have so far prevented CubeSats from operating on higher orbits despite the multitude of space physics that could be observed there. CubeSats usually rely on radiation-sensitive commercial off-the-shelf components, but shielding options for CubeSats are limited due to their strict mass and size requirements. Optimised shielding is required, but so far, there have been no in-situ measurements of the performance of CubeSat shielding in the Van-Allen belts. Foresail-2 is a 6U CubeSat proposed to measure the dynamics of the radiation belts on a highly elliptical orbit. For this purpose, it will carry a magnetometer, a plasma tether and a particle telescope for relativistic electrons and protons. The proposed geostationary transfer orbit intersects the Van-Allen belts. Despite the harsh radiation environment, Foresail-2 will attempt to make extended use of commercial off-the-shelf components, planned to be shielded by a 6 mm thick aluminium enclosure. RadFET sensors are proposed to monitor ionising dose rates inside the spacecraft. Additional to the primary scientific instruments, a Radiation Experiment (RadEx) is proposed for Foresail-2 to measure the ionising dose behind five thicknesses of aluminium shielding and four alternative shielding materials, including multilayer shielding. RadEx is still in an early stage of development, but the current plans are to use the RadFET sensors Varadis VT01 and VT05 behind cutouts in the shielding of the satellite. The five different aluminium thicknesses are 0, 1, 2, 4 and 6 mm. The alternative materials are proposed to be Polyethylene, Polyethylene on top of tungsten, FR4, FR4 covered with solder on the back side and an aluminium chip for comparison. The RadFET sensors will be read out at least once per day by an ATmegaS64M1 microcontroller, which reports the readings to the onboard computer of the spacecraft. In addition to the ionising dose measurements, RadEx will contain a shielding cutout for a Hercules RM48L952 processor to measure single-event effect rates in an elevated radiation environment. For this purpose, the processor will run codes to detect bit flips in its registers and memory. The ATmegaS64M1 microcontroller will monitor the Hercules RM48L952, which will be purely a device under test. RadEx is being developed at Aalto University by a team of doctoral and master-level students. Foresail-2 is scheduled to launch in 2025, and RadEx will undergo total ionising dose testing at a Cobalt-60 source and single event effect testing at a proton beam or heavy ion test facility. The main results of RadEx will be comparable measurements of the performance of CubeSat shielding, which can be used to design optimised shielding solutions for future CubeSat missions with elevated radiation requirements.
  • Thruster-Based Attitude Control Algorithms for a Spin-Stabilized 6U CubeSat
    (2023-12-18) Tanabe, Jiro
     Sähkötekniikan korkeakoulu | Bachelor's thesis
  • Total ionising dose multilayer shielding optimisation for nanosatellites on geostationary transfer orbit
    (2024-01-01) Fetzer, Anton; Anger, Marius; Oleynik, Philipp; Praks, Jaan
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The rising number of proposed nanosatellite missions with Commercial Off-The-Shelf electronics to higher orbits necessitates innovative, compact, and lightweight radiation shielding. In this study, several thousand multilayer radiation shielding configurations were simulated against trapped particle spectra predicted for a geostationary transfer orbit to demonstrate how material combinations and layer structures can be selected to minimise the total ionising dose inside nanosatellites with constrained mass budgets. The Geant4 Radiation Analysis for Space (GRAS) application was used to calculate ionising dose deposition behind multilayer shielding. Thousands of planar shielding stacks were procedurally generated and simulated on top of silicon plates representing sensitive semiconductor devices. To allow for comparison between configurations, all shielding stacks had a total mass of 1.5 g/cm2, and shielding performance was evaluated based on the total ionising dose absorbed by the silicon plates. The simulations consistently show that configurations with low-atomic-number (low-Z) materials on top of high-Z materials yield the lowest doses. The two- and three-layer mass allocation optimisations demonstrate the non-linear dependence of ionising dose on mass allocation between materials. Optimised polyethylene-lead shields achieved up to 30% lower ionising doses compared to an equal mass of either of the two materials or up to 50% lower than the same mass of aluminium. Contrary to previous claims about Z-graded shielding, no significant improvements were observed for using more than two different materials, and optimisation of multilayer shields tends to reduce them to two-layer structures. Optimal multilayer radiation shielding depends on various factors and must be tailored to specific radiation environments and mission requirements. The primary contributions of this article are the methods presented for achieving this tailoring using open-source software and parallel computing. The multilayer simulations performed for this work resulted in an extensive dataset for multilayer shielding performance that enabled novel visualisations of the ionising dose dependence on shielding composition based on quantitative results.