In order to make access to space cheaper, the first stage of a launcher can be recovered. For this research, different options are investigated to make the cost per flight cheaper. Two vehicles are investigated going to two different orbits. The results show that recovering the complete stage is better for vehicles that have a lower separation velocity. When the separation velocity is higher, recovering only the engine is better. The best results are obtained when using a Ringsail parachute and a Hypersonic Inflatable Aerodynamic Decelerator. The design for these systems is optimised using a surrogate optimisation algorithm that reduces the computation time. The set target of 30% cost savings could not be achieved, but cost savings of at least 20% were achieved for both vehicles.

In the Netherlands, the ministry of Security and Justice (VenJ) has the task to ensure the safety of civilians of the Netherlands by enforcing the legal order. The ministry of VenJ wants to solve issues faster and more efficiently by using satellite technology to contribute to a safer and more just Netherlands. The ministry of VenJ asked the Delft University of Technology to perform a feasibility study and design a National Safety System (NSS). Therefore, the mission need statement of this project is to ensure the safety and security of the Netherlands by preforming the use of: an identification and tracking system (ITS) to track specific objects marked by the Ministryl. A fire and smoke detection system that uses earth observation techniques and is able to perform chemical analysis of gas and smoke clouds. Chemical analysis of the smoke clouds is performed in order to identify the presence of toxic substances. This allows populated areas to be evacuated in case the toxic clouds reach these areas. For target tracking the ministry currently uses beacons that emit radio waves to track or follow targets. This requires a lot of manpower and is easily detected, therefore a more efficient way of ensuring the safety of the citizens of the Netherlands has to be designed...