Planetary Magnetic Fields: Planetary Interiors and Habitability

Soon after its detection, radio emission from Jupiter was quickly identified as a product of its planetary-scale magnetic field. Subsequent spacecraft investigations have revealed that many of the planets—and even some moons—either currently have or have had in the past a planetaryscale magnetic field. Generated by dynamo processes within the planet, planetary-scale magnetic fields provide a means of constraining the properties of a planet’s interior through remote sensing, and it may even be possible to measure the magnetic fields of extrasolar planets. If so, they will offer one of the few means available of understanding the potential diversity of planetary interiors. In the case of our own planet, the presence of Earth’s magnetic field has long been suspected to be partially responsible for its habitability. Thus, knowledge of the magnetic field of an extrasolar planet may be a valuable component to assess its habitability, or to understand an absence of life on an otherwise potentially habitable planet. This report summarizes the investigations and conclusions from a William M. Keck Institute for Space Studies on planetary magnetic fields

Development of an Active Thermal Louver for CubeSats Controlled via SMA Actuator

The thesis focuses on the development and complete design of an innovative subsystem for active thermal control purposes for CubeSats. The system consists in an external movable panel (thermal louver) which operates as a modulator for waste heat power emission, based on an SMA actuator developed at the Technical University of Munich (Munich, Germany). The outcome of the work is represented by a prototype, which showed a good functioning and resisted the first vibration tests

Characterization of direct current discharge based electric microthrusters

A thesis submitted in fullment of the requirements for the degree of Doctor of Philosophy School of Physics to the Faculty of Science, University of the Witwatersrand, Johannesburg, March 2017.In this work, a novel electrostatic microthruster concept, based on a direct current gaseous discharge, is proposed. The design draws inspiration from the previously developed CorIon system, which utilizes a coupling of the corona ionization mechanism and the acceleration mechanism. The new design is an attempt to develop a space propulsion system for use on microsatellites, such as CubeSats. A proof of concept system is tested to determine if the direct current discharge can be used as a plasma generator for use in electric space propulsion systems. A system representative of the proposed microthruster concept is tested to determine if it operates in a way that will generate thrust, and boundaries on the systems stable operating parameters are ascertained. Lifetime, re- peatability and erosion tests are performed on both the proof of concept system, and the microthruster design to determine if the system is an improvement on the CorIon system. A thrust measurement stand is designed and constructed that utilizes a novel magnetic coupling mechanism to measure the thrust produced by a microthruster. The thrust measurement stand is tested with a cold gas thruster to study the thrust stands repeatability characteristics, and if it produces the expected results for such a system. A theoretical model for the thrust measurement stand is developed, so that the output of the thrust stand can be predicted for various loading conditions. Thrust measurements are performed on the microthruster design as different operating parameters are varied. Measurements of the power used by the microthruster design are taken as different op- erating parameters are varied. Ion current density measurements of the microthruster design are performed as different operating parameters are varied. Ion current density distribution measurements of the microthruster design are performed. Simulations of the microthruster design are developed, using COMSOL Multiphysics, to con rm the hypothesized mechanism of operation of the microthruster design, and to explain the trends observed in experimental data. Two types of simulation are constructed: a base case, where general features in the physical quantities extracted from the simulations are discussed, and simulations where operating parameters are varied, to study the effects these parameters have on the extracted physical quantities. Thrust values are extracted from the simulations and compared with the experimentally measured thrust. Future research to be conducted involving the novel microthruster design is listed.LG201

Planetary Science Vision 2050 Workshop : February 27–28 and March 1, 2017, Washington, DC

This workshop is meant to provide NASA’s Planetary Science Division with a very long-range vision of what planetary science may look like in the future.Organizer, Lunar and Planetary Institute ; Conveners, James Green, NASA Planetary Science Division, Doris Daou, NASA Planetary Science Division ; Science Organizing Committee, Stephen Mackwell, Universities Space Research Association [and 14 others]PARTIAL CONTENTS: Exploration Missions to the Kuiper Belt and Oort Cloud--Future Mercury Exploration: Unique Science Opportunities from Our Solar System’s Innermost Planet--A Vision for Ice Giant Exploration--BAOBAB (Big and Outrageously Bold Asteroid Belt) Project--Asteroid Studies: A 35-Year Forecast--Sampling the Solar System: The Next Level of Understanding--A Ground Truth-Based Approach to Future Solar System Origins Research--Isotope Geochemistry for Comparative Planetology of Exoplanets--The Moon as a Laboratory for Biological Contamination Research--“Be Careful What You Wish For:” The Scientific, Practical, and Cultural Implications of Discovering Life in Our Solar System--The Importance of Particle Induced X-Ray Emission (PIXE) Analysis and Imaging to the Search for Life on the Ocean Worlds--Follow the (Outer Solar System) Water: Program Options to Explore Ocean Worlds--Analogies Among Current and Future Life Detection Missions and the Pharmaceutical/ Biomedical Industries--On Neuromorphic Architectures for Efficient, Robust, and Adaptable Autonomy in Life Detection and Other Deep Space Missions

Optimal geometry and materials for nanospacecraft magnetic damping systems

A magnetic damping system for nanospacecraft attitude stabilization is proposed, based on the use of thin strips of amorphous Fe-B-Si soft magnetic ribbons. The size, number, and location of the strips is optimized, and a predictive formulation is provided. The main result of ground tests, comparing the performance of several soft magnetic materials, is that suitably heat-treated amorphous ribbons provide the best loss performance in the whole range of magnetic fields expected in orbit