Exam topics year 2015

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Mission analysis - Explain and discuss Tisserand's method. - What is the Tissersnd’s plane? - Define the impact parameter. Is it sufficient to univoquely determine the GA parameters? - Which are the assumptions on the CR3BP? - What are the halo orbits? - Differences between AGA and GA. - How may stable and unstable manifolds be used? - Initial conditions to make the chaser hover around the target on a closed orbit? - Drivers of MA design. - What can be determined once 𝑉∞ ±are known for a GA? - Critically describe the different strategies to face an atmospheric entry phase. - Which are the driving quantities to compute the heat peak during the atmospheric entry phase? - Constraints of the launchers. - Assumptions of CW approach for proximity dynamics. - Compute the propellant mass needed to go from a 500 km LEO to a 100 km LLO (Low Lunar Orbit). (You have to make assumptions on dry mass, specific impulse and transfer trajectory, try to remember μ and radius of Earth and Moon). Propulsion - Classification of chemical propellants. - Pros, cons and applications of cryogenic liquid propellants. - Typical sp and thrust of Ion Gridded Electric engines? - Drawbacks and issues with gridded ion engine. - What is the working principle of the main electric thrusters? - Describe the steps to be followed in the propulsion subsystem design, the main drivers, trade-offs and alternatives and the typical applied margins. EPS - Steps to size the EPS. - Difference btw primary and secondary batteries. - Drivers for the battery technology selection? - Main driver design for battery in LEO. - Drivers for the choice of batteries in LEO. - From the photovoltaic cell efficiency on to the final panel efficiency, which are the main causes of performance degradation? TMTC - Which kind of antenna…