Low-Thrust Transfers from GEO to Earth-Moon Lagrange Point Orbits Andrew Abraham Moravian College, 2013
Newton’s Laws
Orbits: Inertial Reference Frame
Orbital Trajectories
Circular Orbit
Applications of Various Orbits
Low Earth Orbit (LEO)
Medium Earth Orbit (MEO)
Geosynchronous Earth Orbit (GEO)
Molniya Orbit (HEO) Russia Visible 83% of the time
Non-Chemical vs. Chemical Fuel + Oxidizer Ions + Electric/Magnetic Fields
Atmospheric Operation Ion Engine Chemical Engine
Rocket ACTION RE-ACTION
Rocket Equation
Mass vs. Specific Impulse (I sp ) Chemical Propellant: I sp = s %Mass = 25.0% Low Thrust: I sp = 3000s %Mass = 89.5%
Ion Engine
Constant Thrust of mN About the weight of 8 quarters or 0.1lbs Consumes 2-8KW of electrical power from solar arrays
High Thrust (Chemical) Low Thrust (Ion) Orbit Maneuvers: High vs. Low Thrust
Example: LEO to GEO
Add the Moon!?
The 3 Body Problem
Make Simplifying Assumptions
24 Circular Restricted 3-Body Problem (CR3BP) Define: WARNING!!! Non-Inertial Reference Frame (Rotating)
25 CR3BP Equations of Motion
26 CR3BP: 5 Equilibrium (Lagrange) Points
27 Characterization of Lagrange Points m m Pendulum (Stable) Inverted Pendulum (Unstable)
28 Unstable Lagrange Point L2L2 Applications: Communications Navigation (GPS) Observation
29 Lyapunov, Halo, and Lissajous Orbits Image Credit: NASA Moon L1L1 L1L1 Earth Halo Lyapunov Lissajous
30 Merging Low-Thrust & Halo Orbits in the Earth-Moon System L4L4 L5L5 L3L3 L1L1 L2L2 moon
31 Merging Low-Thrust & Halo Orbits in the Earth-Moon System L3L3 Different View L5L5 L4L4 L2L2 L1L1 moon
32 One More View 1000kg Spacecraft 69kg of fuel used for 60 day flight GEO-like orbit to Halo orbit
33 NASA Space Station Resupply Mission(s)
34 Thank You! Questions?
35 Applications: Sun-Earth System Wilkinson Microwave Anisotropy Probe (WMAP) 1.Solar & Heliospheric Observatory Sun-Earth L 1 2.WMAP, James Webb Telescope, Sun-Earth L 2 Sun-Earth L 3 4.Trojan Sun-Earth L 4 & L 5
Centrifugal Force
“Weightlessness” (Non-Inertial Reference Frame) y x FgFg v FcFc F = ma F = F g + F c = 0
Orbits: Inertial Reference Frame y x FgFg v