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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. Requirements. The Penetrator shall:
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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 Okina Simplifications: The apoapsis is at -90° lattitude Selene I – Satellite information Tommy Yuen
Geometric Visibility Ideal Case 0.8° 80° 80° 2.5 m 0.45 m Worst and Ideal Case Comparison 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
Geometric Visibility Tommy Yuen
Theoretical Hohmann Transfer Circular Orbit Elliptical Orbit Ra Rp Change in Velocity Required Tommy Yuen
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 Isp 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