Universität Stuttgart
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Item Open Access Science planning for the DESTINY+ Dust Analyzer : leveraging the potential of a space exploration instrument(2024) Sommer, Maximilian; Srama, Ralf (Apl. Prof. Dr.-Ing.)The DESTINY+ Dust Analyzer (DDA) is a highly sophisticated planetary science instrument to provide cutting-edge in-situ characterization of individual cosmic dust grains, with respect to their composition, as well as their physical and dynamical properties. As such, it constitutes a critical component of the upcoming JAXA mission DESTINY+, which is scheduled to launch in 2025. After a three-year cruise phase, the spacecraft will perform a flyby of the target asteroid 3200 Phaethon, with the goal of observing the enigmatic Geminids parent body with two camera instruments, and sampling particles released from its surface with the DDA. Until that flyby, DESTINY+ will execute a highly diverse, ion-engine-driven flight plan that allows DDA to extensively study the dust environments of the Earth, Moon, and interplanetary space - a breadth of science opportunities that is unique to this mission and instrument. This dissertation provides a comprehensive study of the dust types and phenomena possibly encountered by DDA during its journey to Phaethon and applies the principles and methods of science planning to prepare for the operational phase of the mission. The work synthesizes technical considerations and scientific analyses of relevant cosmic dust populations, aiming to optimize DDA’s scientific potential. Detailed examinations of spacecraft and instrument factors, such as the dynamic spacecraft attitude during the near-Earth phase or the instrument’s two-axis pointing mechanism, lay the groundwork for the scientific planning. The thorough analysis of known (and lesser known) dust populations in the inner solar system and of previous relevant measurements by other dust instruments form the core of the study. Finally, the findings are consolidated into a draft science activity plan for the entire mission, as well as exemplary pointing timelines to be executed by the instrument for optimal scientific return. The latter is accomplished with the DOPE tool, which aids in intuitive and efficient planning of DDA observations, having been developed in the scope of this project. The presented work builds the foundation for the scientific operations of DDA, setting it up for a successful and scientifically impactful mission. The findings of this study also provide a valuable perspective for other ventures of in-situ dust astronomy to the inner solar system and contribute to the field of cosmic dust as a whole.Item Open Access Extension of the plasma radiation database PARADE for the analysis of meteor spectra(2021) Loehle, Stefan; Eberhart, Martin; Zander, Fabian; Meindl, Arne; Rudawska, Regina; Koschny, Detlef; Zender, Joe; Dantowitz, Ron; Jenniskens, PeterThe advancement in the acquisition of spectral data from meteors, as well as the capability to analyze meteoritic entries in ground testing facilities, requires the assessment of the performance of software tools for the simulation of spectra for different species. The Plasma Radiation Database, PARADE, is a line‐by‐line emission calculation tool. This article presents the extensions implemented for the simulation of meteor entries with the additional atomic species Na, K, Ti, V, Cr, Mn, Fe, Ca, Ni, Co, Mg, Si, and Li. These atoms are simulated and compared to ground testing spectra and to observed spectra from the CILBO observatory. The diatomic molecules AlO and TiO have now been added to the PARADE database. The molecule implementations have been compared to the results of a simple analytical program designed to approximate the vibrational band emission of diatomic molecules. AlO and TiO have been identified during the airborne observation campaigns of re‐entering man‐made objects WT1190F and CYGNUS OA6. Comparisons are provided showing reasonable agreement between observation and simulation.Item Open Access Quantum chemical insights into the dissociation of phenol : shedding light on impact ionization mass spectrometry for icy moon exploration(2026) O’Sullivan, Thomas R.; Bera, Partha P.; Khawaja, Nozair; Napoleoni, Maryse; Abel, Bernd; Postberg, FrankIce grains emitted by the Saturnian moon Enceladus were sampled by Cassini’s Cosmic Dust Analyser (CDA) using impact ionization mass spectrometry. CDA revealed that Enceladus hosts a rich organic and inorganic chemical inventory in its subsurface ocean, hinting at its potential habitability. Analysis of fragmentation patterns with laser desorption experiments for the interpretation of CDA data has been essential; however, theoretical insights regarding both fragmentation and ionization processes are often missing. Here, we use density functional theory methods to investigate the energies for dissociation channels of phenol, a model aromatic compound for the features observed by CDA. The fragmentation channels are compared to experimental spectra obtained by using laser-induced liquid beam ion desorption (LILBID) mass spectrometry, an analogue for ice impact mass spectra. Our findings suggest that protonation is the dominant mechanism of ionization, that dissociation from the radical cation and neutral phenol molecule is limited, and that multiple isomers of the protonated molecule act as starting points for dissociation. The highest-intensity organic fragments observed in the LILBID spectrum - arising from the losses of CO, [M + H-CO]+, and water, [M + H-H2O]+ - are found to be both thermodynamically and kinetically accessible. We examined water–molecule interactions during the initial production of the protonated molecule. The presence of water significantly influences the preferred site of protonation and causes variation in the relative energy ordering of the protomers. This work builds toward a computational model of ice grain impact ionization mass spectrometry, relevant for missions such as Europa Clipper and ESA’s L4 mission to Enceladus.Item Open Access Simulating asteroid impacts and meteor events by high-power lasers : from the laboratory to spaceborne missions(2023) Ferus, Martin; Knížek, Antonín; Cassone, Giuseppe; Rimmer, Paul B.; Changela, Hitesh; Chatzitheodoridis, Elias; Uwarova, Inna; Žabka, Ján; Kabáth, Petr; Saija, Franz; Saeidfirozeh, Homa; Lenža, Libor; Krůs, Miroslav; Petera, Lukáš; Nejdl, Lukáš; Kubelík, Petr; Křivková, Anna; Černý, David; Divoký, Martin; Pisařík, Michael; Kohout, Tomáš; Palamakumbure, Lakshika; Drtinová, Barbora; Hlouchová, Klára; Schmidt, Nikola; Martins, Zita; Yáñez, Jorge; Civiš, Svatopoluk; Pořízka, Pavel; Mocek, Tomáš; Petri, Jona; Klinkner, SabineMeteor plasmas and impact events are complex, dynamic natural phenomena. Simulating these processes in the laboratory is, however, a challenge. The technique of laser induced dielectric breakdown was first used for this purpose almost 50 years ago. Since then, laser-based experiments have helped to simulate high energy processes in the Tunguska and Chicxulub impact events, heavy bombardment on the early Earth, prebiotic chemical evolution, space weathering of celestial bodies and meteor plasma. This review summarizes the current level of knowledge and outlines possible paths of future development.Item Open Access Machine learning and Monte Carlo based data analysis methods in cosmic dust research(2019) Albin, Thomas; Srama, Ralf (Priv.-Doz. Dr.-Ing.)This work applies miscellaneous algorithms from the fields Machine Learning and Computational Numerics on the research field Cosmic Dust. The task is to determine the scientific and technical potential of using different methods. Here, the methods are applied on two different projects: the meteor camera system Canary Island Long-Baseline Observatory (CILBO) and the Cassini in-situ dust telescope Cosmic-Dust-Analyzer (CDA).Item Open Access Probing the atmospheric precipitable water vapor with SOFIA, part III : atlas of seasonal median PWV maps from ERA5, implications for FIFI-LS and in situ comparison between the ERA5 and MERRA-2 atmospheric re-analyses(2022) Iserlohe, Christof; Vacca, William; Fischer, Christian; Fischer, Nadine; Krabbe, AlfredThe Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airborne observatory for far-infrared astronomy stationed at the Armstrong Flight Research Center (AFRC) in Palmdale, CA, USA. Although SOFIA flies at altitudes of ∼41,000 ft, any far-infrared observations from within the Earth’s atmosphere are nevertheless hampered by water vapor absorbing the astronomical signal. The primary atmospheric parameter governing absorption in the far-infrared is the total upward precipitable water vapor, PWV. In this paper we present global PWV maps derived from re-analyses from the European Centre for Medium-Range Weather Forecasts, ECMWF, with a geographical resolution of 0.°5, for flight altitudes ranging from 37,000 ft to 45,000 ft and each meteorological season. These maps were validated with FIFI-LS PWV measurements on board SOFIA and allow an investigation of the global morphology and seasonal dependence of the total upward PWV in the stratosphere. We additionally investigate the observing conditions, in terms of PWV, at various locations, especially around SOFIA’s home base, Palmdale, but also around sites in the southern hemisphere like Tahiti, Santiago de Chile (Chile), Buenos Aires (Argentina), and Christchurch (New Zealand). From the southern sites investigated Christchurch provides the best conditions in terms of PWV (and efficiency), Tahiti the worst. Using total power sky measurements with FIFI-LS we also derive a mean emissivity of the telescope (primary, secondary and tertiary mirror) of ϵTel = 20.5 ± 1.6% around the astronomically significant [C ii] emission line. We finally compare atmospheric re-analyses from GEOS (MERRA-2) and ECMWF (ERA5) to our FIFI-LS PWV measurements. Both re-analyses correlate linearly with our FIFI-LS PWV measurements from all flight altitudes but with different scaling factors. However, MERRA-2 correlates significantly less well than ERA5 especially for flight altitudes below 41,000 ft.Item Open Access Analysis of the technical biases of meteor video cameras used in the CILBO system(2017) Albin, Thomas; Koschny, Detlef; Molau, Sirko; Srama, Ralf; Poppe, BjörnIn this paper, we analyse the technical biases of two intensified video cameras, ICC7 and ICC9, of the double-station meteor camera system CILBO (Canary Island Long-Baseline Observatory). This is done to thoroughly understand the effects of the camera systems on the scientific data analysis. We expect a number of errors or biases that come from the system: instrumental errors, algorithmic errors and statistical errors. We analyse different observational properties, in particular the detected meteor magnitudes, apparent velocities, estimated goodness-of-fit of the astrometric measurements with respect to a great circle and the distortion of the camera. We find that, due to a loss of sensitivity towards the edges, the cameras detect only about 55 % of the meteors it could detect if it had a constant sensitivity. This detection efficiency is a function of the apparent meteor velocity. We analyse the optical distortion of the system and the "goodness-of-fit" of individual meteor position measurements relative to a fitted great circle. The astrometric error is dominated by uncertainties in the measurement of the meteor attributed to blooming, distortion of the meteor image and the development of a wake for some meteors. The distortion of the video images can be neglected. We compare the results of the two identical camera systems and find systematic differences. For example, the peak magnitude distribution for ICC9 is shifted by about 0.2–0.4 mag towards fainter magnitudes. This can be explained by the different pointing directions of the cameras. Since both cameras monitor the same volume in the atmosphere roughly between the two islands of Tenerife and La Palma, one camera (ICC7) points towards the west, the other one (ICC9) to the east. In particular, in the morning hours the apex source is close to the field-of-view of ICC9. Thus, these meteors appear slower, increasing the dwell time on a pixel. This is favourable for the detection of a meteor of a given magnitude.Item Open Access SOFIA - Mission infrarotes Universum(Stuttgart : Universität Stuttgart, Institut für Raumfahrtsysteme, 2025) Krabbe, Alfred; Mehlert, Dörte; Wolf, JürgenWarum haben die NASA und das DLR - die amerikanische und deutsche Raumfahrtagentur - eine fliegende Sternwarte betrieben? Mit welchen Tricks haben Ingenieure und Ingenieurinnen das Teleskop des Stratosphären Observatoriums Für Infrarot Astronomie (SOFIA) stabilisiert? Was ist am infraroten Universum so interessant? Wozu hatte die Universität Stuttgart eine Außenstelle in Kalifornien? Welche Rolle spielte die deutsche Wiedervereinigung während der Entwicklungsphase? Diese und viele weitere Fragen rund um die fliegende Sternwarte SOFIA beantwortet dieses von Insidern geschriebene Buch in Bildern und Texten. Lassen Sie sich auf einen Forschungsflug an Bord des einzigartigen Observatoriums mitnehmen, gewinnen Sie einen Überblick über die wissenschaftlichen Erkenntnisse des Observatoriums und fragen Sie: Wie könnte das nächste Stratosphären-Observatorium für Infrarot-Astronomie aussehen? In diesem Buch finden Sie alles, was Sie schon immer über SOFIA wissen wollten.Item Open Access Ion beam lithographic and multilayer fresnel zone plates for soft and hard X-rays: nanofabrication and characterization(2015) Keskinbora, Kahraman; Schütz, Gisela (Prof. Dr.)X-ray microscopy has become an important analytical characterization method for a plethora of applications in materials science, physics, chemistry and biology, thanks to the emergence of modern synchrotron radiation facilities. These facilities enable high brilliance, energy tunable, variable polarization X-rays which gives access to mass density, elemental, chemical, electronic and magnetic properties of materials. In the soft X-ray energies nearly all elements can be probed by spectromicroscopic methods. Another important property of synchrotron radiation is the time structure in the ns to ps range, which can be utilized for sophisticated time resolution studies. These opportunities can be combined with high spatial resolution which is determined by the focusing method and the optic. Focusing of X-rays has historically been a difficult task due to strong absorption and weak phase shift of X-rays within matter. The required phase shift of X-rays, which depends on the real part of the complex refractive index, differs from 1 (the vacuum refractive index) only on the order of 10^-2 to 10^-6 and conventional lenses do not work. One very successful X-ray optic is the Fresnel Zone Plate (FZP), a diffractive optic that act as a lens under certain conditions and can focus X-rays to nanometer sized spots. The resolution of the FZP depends on the width of the outermost zone and is highly correlated with the smallest feature that can be fabricated. Conventionally, the e-beam lithography (EBL) is used for production FZPs which could resolve up to 10 nm structures with serious limitations. One difficulty of EBL is its ever increasing complexity for many-step fabrication of smaller features or intricate geometries. Therefore, EBL is mostly constrained to planar, binary geometries with moderate efficiencies strongly decreasing with energy and not effective for hard X-rays. Special 3D geometries in the form of kinoform lenses can theoretically have 100 % focusing efficiencies. Attempts to approximate these geometries via EBL increased the number of process steps even further. The smallest FZP feature size even for low aspect ratios achievable via EBL is fundamentally limited due to the proximity effect which is the interaction and spread of electrons within the resist material. We addressed these issues by focusing our research on alternative FZP fabrication techniques as high-speed ion beam lithography (IBL), and gray scale ion lithography to realize efficient kinoforms. Another approach towards full-material multilayer FZPs with infinite aspect ratio was based on atomic layer deposition (ALD) with subsequent ion beam slicing. Each of these three methods targets specific challenges faced by the e-beam lithography based FZP fabrication techniques. All the fabricated FZPs were tested for their resolution and efficiency performances at a state of the art scanning transmission X-ray microscope at BESSY for soft X-rays and/or at optical test stations at ESRF and PETRA III for hard X-rays. Using IBL the rapid preparation of a 110 nm thick Au FZP with 50 µm diameter and 50 nm ∆r in less than 13 minutes is demonstrated. Employed for X-ray microscopy, the FZP clearly resolved 28.5 nm features with a cut-off of 24.3 nm at ~1120 eV. Additional process improvements were made towards smaller zones with higher zone quality. They allowed the preparation of a FZP with 30 nm outermost half-period remarkably, in about 8 min. This FZP was shown to clearly resolve 21 nm features on a multilayer test object with large room for improvement. This high through-put FZP production route is of special interest not only concerning the low cost and easy availability. A large array of these optical components is attractive, for experiments such as one-shot ultra-high brilliance FEL investigations due to the radiation damage or for instance for coded-aperture arrays for high-angle resolving X-ray astronomy. Towards fabrication of kinoforms for high efficiency X-ray focusing, we have performed various materials optimization studies in order to achieve a high surface quality optic. After various trials the materials were finally optimized and the fabricated lenses achieved more than 14 % absolute diffraction efficiency that is almost 90 % compared to the theoretical prediction. This confirms how closely we were able to replicate the ideal three dimensional surface relief structure for the first time. It was possible to carry out imaging with these lenses with half-pitch resolutions down to 60 nm. The kinoform lenses were tested at the soft X-ray range where a significant absorption is present in materials. These results also potentially pave the way for very high efficiency hard X-ray focusing which can in principle be utilized in laboratory based X-ray sources, X-ray astronomy and the new rising field of X-ray ptychography. To fabricate high resolution ML-FZPs, Al2O3/Ta2O5multilayers, deposited on a smooth glass optical fiber via atomic layer deposition using non-dedicated instruments were carefully cut-out, sliced and polished to a high quality surface finish using focused ion beams. Following the transfer of the slice to a TEM grid as holder the slices were polished to a high surface finish quality, also via a focused ion beam. Fabricated ML-FZPs were synchrotron tested using an in-house constructed 2-axis tilt stage specially designed for aligning ML-FZP with respect to the X-ray optical axis. The results showed that it was possible to resolve 21 nm features in direct imaging at 1200 eV and sub-30 nm focusing at 8 keV. This is the highest demonstrated resolving power for a multilayer type FZP, to date to the best of our knowledge. Results exhibit the potential for high-resolution hard X-ray focusing where this type of optics are especially efficient. For ultra-high resolution hard and soft X-ray imaging, with potentially achievable ∆r of a few nm is well below what can be achieved through any lithography method available today.Item Open Access Detection, analysis, and removal of glitches from InSight's seismic data from Mars(2020) Scholz, John‐Robert; Widmer‐Schnidrig, Rudolf; Davis, Paul; Lognonné, Philippe; Pinot, Baptiste; Garcia, Raphaël F.; Hurst, Kenneth; Pou, Laurent; Nimmo, Francis; Barkaoui, Salma; de Raucourt, Sébastien; Knapmeyer‐Endrun, Brigitte; Knapmeyer, Martin; Orhand‐Mainsant, Guénolé; Compaire, Nicolas; Cuvier, Arthur; Beucler, Éric; Bonnin, Mickaël; Joshi, Rakshit; Sainton, Grégory; Stutzmann, Eléonore; Schimmel, Martin; Horleston, Anna; Böse, Maren; Ceylan, Savas; Clinton, John; Driel, Martin van; Kawamura, Taichi; Khan, Amir; Stähler, Simon C.; Giardini, Domenico; Charalambous, Constantinos; Stott, Alexander E.; Pike, William T.; Christensen, Ulrich R.; Banerdt, W. BruceThe instrument package SEIS (Seismic Experiment for Internal Structure) with the three very broadband and three short‐period seismic sensors is installed on the surface on Mars as part of NASA's InSight Discovery mission. When compared to terrestrial installations, SEIS is deployed in a very harsh wind and temperature environment that leads to inevitable degradation of the quality of the recorded data. One ubiquitous artifact in the raw data is an abundance of transient one‐sided pulses often accompanied by high‐frequency spikes. These pulses, which we term “glitches”, can be modeled as the response of the instrument to a step in acceleration, while the spikes can be modeled as the response to a simultaneous step in displacement. We attribute the glitches primarily to SEIS‐internal stress relaxations caused by the large temperature variations to which the instrument is exposed during a Martian day. Only a small fraction of glitches correspond to a motion of the SEIS package as a whole caused by minuscule tilts of either the instrument or the ground. In this study, we focus on the analysis of the glitch+spike phenomenon and present how these signals can be automatically detected and removed from SEIS's raw data. As glitches affect many standard seismological analysis methods such as receiver functions, spectral decomposition and source inversions, we anticipate that studies of the Martian seismicity as well as studies of Mars' internal structure should benefit from deglitched seismic data.