Over the last five decades, thermal modelling of airless minor planetary bodies such as asteroids have experienced significant improvements. However, at lower wavelengths of the mid-infrared range, thermal models such as the widely used Near-Earth Asteroid Model (NEATM) are still considered unreliable since reflected light starts contributing significantly towards the observed flux density. Through a controversy related to the Wide-field Infrared Survey Explorer (WISE) mission, which was an infrared survey telescope with four observational bands found at 3.4, 4.6, 12, and 22 microns, Nathan Myhrvold suggested that the thermal modelling carried out did not properly account for reflected light and that the results, especially derived from the first two observation bands, were compromised since Kirchhoff's law of thermal radiation was violated. To date, the WISE mission is considered the highest yielding mission with more than 158,000 asteroids detected, however Myhrvold's findings state that the result derived for about half of those detections are compromised. This controversy motivated this master thesis project to create a numerical code, which properly combines thermal and reflected light modelling, to further investigate the influence of the latter at the four WISE observational bands. The initial aim of this master thesis was the create an advanced thermal model, but due to the time scope of this master thesis, an intermediate thermal model named the Asteroid Thermal and Reflected light Model (ATRM) was achieved. On top of being able to model simple spherical and ellipsoidal shapes, the ATRM can model irregularly-shaped asteroids with precise orbital and rotational properties taken into account as do advanced thermal models, but assumes instantaneous thermal equilibrium as do simple thermal models such as the NEATM. Furthermore, the ATRM caters to mostly convex-shaped asteroids due to the simple shadowing algorithm implemented, and not taking into account multiple scattering. However, the ATRM is able to vary the surface albedo distribution pattern of an asteroid through an octant method, which is typically not the case for simple and advanced thermal models which all assume a homogeneous surface albedo. With the aforementioned capabilities of the ATRM, the percentage of reflected light in the total flux density at the four wavelength bands of WISE were estimated for different albedo values covering the majority of asteroids falling under the three broad Bus-DeMeo taxonomic classification system (C-, S-, X-types). Furthermore, the influence of the heliocentric distance, emissivity, and shape of the asteroid on the contribution of reflected light were investigated. Ultimately, this project is another step-wise progress in the field of physical characterisation of airless planetary bodies, especially asteroids, and has far-reaching consequences in terms of planetary formation, in-situ resource utilisation (ISRU), commercial asteroid mining, and planetary defence. ... Read more

This report details the design of a mission aimed to find and analyse active Venusian volcanoes, if they exist. These volcanoes are interesting because active volcanism would significantly contribute to the understanding of the Venusian atmosphere, its extreme climate and geological processes. This knowledge would in turn help us understand Earth better. The design is based on the concept selected previously in the Midterm report and consists of five vehicles: a spacecraft, an aeroshell, an aircraft and two landers. The spacecraft with aeroshell will be launched into a Hohmann transfer orbit to Venus in 2023. Upon arrival, the satellite will map the surface, and find the most promising region for volcanic activity. It will then deploy the aeroshell containing the aircraft and landers. The satellite then changes its orbit to one that allows for it to act as a relay between the Venusian vehicles and Earth. After entry and having slowed down sufficiently to deploy a parachute, the first lander will be dropped. This lander will act as a reference for the lander inside the aircraft. Next, the aircraft is deployed after which it will start following flight tracks that allow for it to stay in the Sunlight. These tracks are designed by taking into consideration the power systems, thermal system and propulsion system, and then optimising such that the electronics do not overheat and that the battery size is reasonable. While flying, the aircraft will take measurements to locate volcanoes. Once a very promising location is found, the aircraft will deploy the second lander from an altitude of about 32 km. This lander will then descend further down and land on the surface where it will perform measurements. Combining the measurements of all vehicles it is expected that the mission can also complete a number of secondary objectives to further improve the knowledge of Venus... ... Read more