Miniaturization in spacecraft is an ongoing process in which the launched satellites become smaller and smaller. This trend introduces issues, such as the choice for a reliable and efficient propulsion subsystem. The implementation of engines would enable the spacecraft to perform maneuvers such as orbit changes, drag compensation and attitude control. Solar Thermal Propulsion (STP) has been identified as a promising candidate, due to its theoretical specific impulse being well above that of the best chemical thrusters when hydrogen is the propellant of choice. The concept has never been flown in space but would benefit from ground demonstrations proving that the potential can be realized. This work will focus on demonstrating the STP performance. The goal was set to reach a Sea Level (SL) specific impulse of 90.0 s at a continuous mass flow of 300 mg s−1 and input power of 250 W. During the project, a demonstration thruster named Solar Thermal Thruster 2 was designed. The resulting engine consisted of a copper heat exchanger and nozzle with a highpowered laser as the irradiation source of choice. Concurrently, a Preliminary Design Tool was developed to assess the performance of STP engines. Verification and validation was done by comparing the tool outputs to other theoretical and experimental results. Verification was completed, but for validation STT2 experimental results were required. Preliminary test results of STT2 showed that the motor had some shortcomings, due to concessions made. Erroneously, its heat exchanger had been built with a reduced number of channels, rendering the thruster unavailable for testing. Next to that, the engine suffered from leakages. For further validation of the tool, Computational Fluid Dynamics (CFD) simulations were performed. The thermal part of the tool was validated, but the pressure loss results deviated too much. As such, further experiments are required in this area. In the end, an updated design (STT3) was made of the thruster. The number of channels in the heat exchanger was increased and its mass and area was reduced. It proved to have an SL specific impulse of 84.9 s, almost meeting the goal set for the thesis. It is recommended that the engine is built and tested at Delft University of Technology (DUT) in order to complete validation of the tool and demonstrate the feasibility of STP.

Pioneering in the aviation is dangerous, but its rewards might be worthwhile. What if the fuselage shape is challenged to be non-circular? A better volume efficiency, easier loading and a new perception of the future aircraft are within reach, but at what costs? Carry-on luggage is expected to increase in the future. Does that result in a new fuselage shape? This report shows the design process of a 200 passenger aircraft while challenging the fuselage shape and its material. Market analysis showed a great demand for sustainable, single aisle aircraft. The current competitors are the Airbus A320neo, Boeing 737MAX-8 and the Airbus A321neo. With the use of system engineering tools, such as a functional breakdown structure, a functional flow diagram and a budget breakdown, a conceptual design was constructed: the A342 Beeblebrox. It purpose is to be able to outperform state-of-the-art aircraft and remain competitive for the next 50 years. Therefore the propulsion & performance, the electronics and the control & stability were designed to surpass the current aviation standard. To this end, off the shelf geared turbofan engines are used because it has a surpassing specific fuel consumption (SFC) and an overall good performance. The A342 is slightly more stable and controllable, because of its longer fuselage length but its overall tail size is similar to the A321neo. The A342 is an All-Electric-Aircraft to reduce subsystem and fuel weight. Its accessabillity is comparable to state-of-the-art aircraft. The maintainability is slightly worse, because of the revolutionary fuselage shape, that requires more frequent checking. The direct operating costs were calculated to be comparable with the A320neo. And because the A342 can carry more payload over longer distances, this ensures its ability to outperform other aircraft. The interior is designed such to maximise volume efficiency per passenger. This defined the inner boundaries for the fuselage cross-section, for which a lightweight structure was created. From the pressurisation requirement, it follows, both analytically and using a finite element method, that rounder shapes cope better with stresses. However, the elliptical shapes might still be an option. An elliptical shape was calculated to be roughly 1500 kg heavier than the circular of the same material. The fuselage material will consist mainly of CFRP and AFRP (Carbon/Aramid Fibre Reinforced Plastics), due to their high strength and low density. For the aerodynamics of the fuselage Computational Fluid Dynamics simulation software (CFD) was used to calculate the pressure. Subsequently, the drag was calculated analytically. It can be seen that squarish fuselages decrease the wetted area which reduces the drag. The elliptical shape has an increased L/D-ratio (Lift over Drag ratio) of 2%. The final conceptual design of the A342 Beeblebrox is a 6-abreast single aisle airliner, featuring an elliptical fuselage shape with conventional tail, better SFC and all electric systems. Each passenger has 0.107 m3 overhead luggage storage and 0.05 m3 checked-in luggage. Finally, it can be concluded that the elliptical shape is feasible to compete with state-of-the-art aircraft.