## SpiralToHohmann:

Path: Orbit/Demos/Interplanetary

% Spiral to a Hohmann Transfer to Apophis.
Computes the Hohmann transfer delta v and the spiral delta v.
The actual delta v for the Hohmann will be higher due to the
low thrust. The script simulates the outbound spiral plotting the
results in earth fixed and heliocentric coordinates.
The simulation also computes fuel consumption and will turn off the
engine when it runs out of fuel.
You start the spacecraft in GPS earth orbit. If there is no thrust, it
will oscillate around the earth. The control system applies
thrust in the tangential direction.
The time step must be small enough to be at least 10 times smaller than
the shortest period in the simulation. If you start orbiting earth with
a 90 minute period, the time step should be no longer than
9 minutes. You will get better results with shorter time steps.
Things to explore:
1. With the engine off vary the DT and look at the earth-centered
velocity. It should get smoother as DT decreases.
2. Turn the engine on. Change the thrust to see how long it takes
for the spacecraft to escape the earth.
Since version 2014.1
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See also ApophisOrbit, LowThrustEscape, RHSHelioWithPlanets,
SolarSysState, HelioFromPlanetInit, CEcl2Eq
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%
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Copyright (c) 2014 Princeton Satellite Systems, Inc.
All Rights Reserved
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## Children:

Common: Database/Constant
Common: Graphics/NewFig
Common: Graphics/Plot2D
Common: Graphics/Plot3D
Common: Graphics/TimeGUI
Common: Graphics/TimeLabl
Common: Time/Date2JD
Math: Integration/RK4
Math: Linear/Mag
Math: Linear/Unit
Orbit: Interplanetary/ApophisOrbit
Orbit: Interplanetary/HelioFromPlanetInit
Orbit: Interplanetary/SolarSysState
Orbit: OrbitManeuver/DVHoh
Orbit: OrbitManeuver/LowThrustEscape
Orbit: RHSOrbit/RHSHelioWithPlanets
SC: BasicOrbit/Period
SC: BasicOrbit/RVFromKepler
SC: Ephem/CEcl2Eq
SC: Ephem/Planets
SCPro: ProSensors/GPSSatellite

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