A5015734367- Astro and Planetary Science
- Planetary Science and Exploration
- Spacecraft and Cryogenic Technologies
- Space Exploration and Technology
- Nuclear Physics and Applications
- Atmospheric Ozone and Climate
- NMR spectroscopy and applications
- Scientific Research and Discoveries
- Chemical Reactions and Isotopes
- Radioactive contamination and transfer
- Tunneling and Rock Mechanics
- Astronomy and Astrophysical Research
- Advanced Mathematical Modeling in Engineering
- Granular flow and fluidized beds
- Isotope Analysis in Ecology
- Heat and Mass Transfer in Porous Media
- Landslides and related hazards
- Enhanced Oil Recovery Techniques
Technische Universität Braunschweig
2023-2024
University of Münster
2024
Aims . This paper focuses on how insolation affects the nucleus of comet 67P/Churyumov-Gerasimenko over its current orbit. We aim to better understand thermal environment nucleus, in particular surface temperature variations, erosion, relationship with topography, and interior for location volatile species (H 2 O CO ). Methods have developed two models calculate subsurface temperatures 67P 6.45-year The first model, high resolution (300 000 facets), calculates temperatures, taking shadows...
When comets approach the Sun, they release micrometer-sized solid particles, which thereafter form dust tail. The cohesion among grains with these sizes is typically on order of 1 kPa. Typical gas pressures sublimating volatiles are $<1$ Pa so that a model describing has to overcome this bottleneck. bottleneck does, however, not exist for centimeter-sized aggregates (``pebbles''), might be building blocks and whose Pa, due their reduced contact area. We propose new, purely geometrical...
The mechanism of dust emission from a cometary nucleus is still an open question and thermophysical models have problems reproducing outgassing productions rates simultaneously. In this study, we investigate the capabilities rather simple model to match observations Rosetta instruments at comet 67P/Churyumov-Gerasimenko influence variations. We assume macro-porous surface structure composed pebbles different assumptions. Besides scenario in which layers are ejected when vapour pressure...
We investigate the ability of a simultaneous fitting comet 67P/Churyumov-Gerasimenko's non-gravitational forces, torques, and total water-outgassing rate, as observed by Rosetta, to constrain complex thermophysical models cometary material. extend previous work geographically defined surface outgassing Rosetta observations testing effects more detailed geomorphological mapping, resolution shape-model used, self-heating neighbouring facets on shape-model, thermal inertia in solution,...
IntroductionThe molecular diffusion of gas is an essential process in our understanding cometary activity. Gas that produced through sublimation active sub-surface layers builds up a pressure, while at the same time diffusing towards comet&#8217;s surface and escaping into space. The governing constant strongly dependent on microscopic structure material, i.e., its grain size porosity (G&#252;ttler et al., 2023) but also shape arrangement (Zivithal accepted). Its detailed therefore...
In the research presented, a quantitative assessment is conducted on multiple publicly available methods for generating random porous media. The creation and examination of such media are fundamental to various models that offer more advanced level physical analysis concerning transfer energy matter. These foundational facilitate quantification crucial parameters like radiative thermal conductivity volumetric absorption external radiation. parameters, in turn, play critical role simulating...
Cometary activity is not yet fully understood. One goal to determine thelocations on a comet more likely be active. This work focuses how surfacestructures influence cometary activity. Therefore, laboratory experiments wereconducted examine different surface structures. To simulate the most simpleversion of comet, samples were made out granular water ice. Differentstructures embedded into samples. Three structures chosen forthe experiment some possible find surface. A nar-row but deep hole,...
Understanding cometary activity gives us an insight into the materials properties, and therefore formation evolution processes of these relatively pristine protoplanetary objects. We will present results International Space Science Institute project to investigate phenomenon through effects outgassing on orbit spin-state comet 67P/Churymov-Gerasimenko, e.g. its non-gravitational dynamics. This Team gathered experts in orbital dynamics trajectory reconstruction together with thermophysical...
For the future of sustainable space exploration, In-Situ Resource Utilization (ISRU) plays a key role. Thus, investigation and development new technologies focusing on utilizing local resources is crucial to cost-effective robotic human missions with less logistical effort. Water does not only serve as consumable for astronauts plants but also rocket propellant by electrolysing it into hydrogen oxygen.Therefore, LUWEX (Validation Lunar Extraction Purification Technologies Propellant...
For the thermal modelling of activity and evolution cometary nuclei, it is utmost importance to understand heat transfer in granular media. To help with understanding underlying physical processes, laboratory simulation experiments were conducted within Comet Physics Laboratory (CoPhyLab) project [1]. A three-dimensional thermophysical model was developed simulate selected CoPhyLab better microphysics.Samples media illuminated a halogen lamp either continuously or sinusoidal cycles...
The formation of a cometary dust tail is phenomenon that has been known for very long time and can be seen from earth with the naked eye if comet close enough. mechanism believed to caused by sublimation volatile components, which drag away particles. In lab, we aim reproduce this effect placing mixtures ice in cooled vacuum chamber illuminating them an artificial sun. preparation these experiments, placed samples consisting entirely &#181;m-sized spherical water-ice grains chamber. As...
We investigate the ability of a simultaneous fitting comet 67P/Churyumov-Gerasimenko's non-gravitational forces, torques and total water-outgassing rate, as observed by Rosetta, to constrain complex thermophysical models cometary material. extend previous work geographically defined surface outgassing Rosetta observations testing effects more detailed geomorphological mapping, resolution shape-model used, self-heating neighbouring facets on shape-model, thermal inertia in solution, variation...
ABSTRACT We extend an existing thermophysical activity model of comet 67P/Churyumov–Gerasimenko to include pressure build-up inside the pebbles making up nucleus. test various quantities H$_{2}$O and CO$_{2}$, in order simulate material outside proposed water enriched bodies (WEBs). find that WEBs can reproduce peak flux observed by Rosetta, but addition a time-resolved heat-flow reduces fluxes away from perihelion as compared previously assumed equilibrium model. Our modelled eject dust...
We extend an existing thermophysical activity model of comet 67P/Churyumov-Gerasimenko to include pressure buildup inside the pebbles making up nucleus. test various quantities H$_{2}$O and CO$_{2}$, in order simulate material outside proposed water enriched bodies (WEBs). find that WEBs can reproduce peak flux observed by Rosetta, but addition a time-resolved heat-flow reduces fluxes away from perihelion as compared previously assumed equilibrium model. Our modelled eject dust continuously...
Water ice in micro-granular form is the most common volatile comets, and its behaviour when approaching Sun must be understood before cometary activity can properly modelled. To assess properties of granular water ice, we investigated evolution under illumination a cryogenic high-vacuum environment. We produced sample consisting micrometre-sized particles, placed it inside thermal vacuum chamber, exposed to high-intensity visible/near-infrared (VIS/NIR) illumination. Due energy absorption...
&lt;p&gt;The activity evolution of comets along their orbits around the Sun has not yet been fully understood. Especially perihelion, show an abnormally high dust and water activity, growing far more rapidly than increase in energy from incoming sunlight (e.g. Skorov et al., 2020; Combi 2020). To better understand this complex phenomenon, we developed a thermophysical model that encompasses mass-transfer volatile species resulting build-up pressure. We based our on assumption comet...