Mission Analysis Geometric Visibility and Manoeuvre Calculations Tommy Yuen
Presentation Outline Requirements How Are We Getting There? Geometric Visibility Theoretical Hohmann Transfer Verifying STK Results Conclusion Future Work Tommy Yuen
Requirements The Penetrator shall: Penetrate a depth of 2 ± 0.5 m Have sufficient link time to be able to transmit segments of data in packets periodically Be able to communicate with the relay satellite of Selene I Tommy Yuen
How Are We Getting There? Selene I – Satellite information Tommy Yuen Main Orbiter (SELENE I) Circular Orbit Orbit100[km] Inclination90[°] Relay Satellite (OKINA) Elliptical Orbit Orbit100 x 2400[km] Inclination90[°] Simplifications: The apoapsis is at -90° lattitude Selene I Okina
Geometric Visibility Ideal case geometric link time: Approximately 7000 s Ideal case regolith transmission thickness: Approximately 11.8 m Worst case geometric link time: Approximately 80 s Simplifications: 90° latitude Only communicates with Okina Tommy Yuen 0.8° 80° 2.5 m 0.45 m 80° Worst and Ideal Case Comparison Ideal Case
Geometric Visibility Tommy Yuen
Theoretical Hohmann Transfer Tommy Yuen Circular Orbit Elliptical Orbit Change in Velocity Required RpRp RaRa
Theoretical Hohmann Transfer Tommy Yuen
Verifying STK Results Conservation of Energy: Tsiolkovsky's Rocket Equation: Simplifications: Tangential Velocity is Cancelled Prior to Free Fall Booster Engines Apply Impulsive Burns and have an I sp of 285 s The Mass of the Penetrator is 10 kg Tommy Yuen
Verifying STK Results Scenario 1 – A vertical burn was used to slow the penetrator down to 0 m/s at the desired altitude of about 28.1 km – Amount of fuel required is about 11.2 kg Scenario 2 – A vertical burn was used to slow the penetrator down to 300 m/s at the surface of the moon – Amount of fuel required is about 9.7 kg Tommy Yuen
Conclusion Geometric link time is about 80 to 7000 s Hohmann transfer is not a plausible option STK results agree with back of the envelope calculations Tommy Yuen
Future Work Refine communication visibility simulations for different impact locations and craters Determine post impact mission time line Tommy Yuen
Questions?