% Simulate semi-major axis change in a dawn-dusk sun-synchronous orbit.
   Uses a simple specular model for the solar pressure force.
   Integration tolerance must be tight enough to produce circular
   precessing orbit when sail is edge-on.
   Multiple sail angle laws are implemented in the code. Scroll down to
   select a method or add your own.

   Default sail sizes are from 40 to 60 m square. The total spacecraft
   mass is on the order of 500 kg.

   If one axis of the sail is aligned with LVLH, which alleviates gravity
   gradient torques, the semi-major axis change is on the order of 40 km
   in 15 days. The sun-synch orbit is closely maintained.
   The oscillations in semi-major axis change are due to the inclusion of
   the J2 gravity term, which is necessary for a sun-synch orbit.

   Since version 7.
  See also Inertias, Cone, Eul2Q, QLVLH, QMult, QTForm, NPlot, Plot2D, 
  TimeLabl, Cross, Dot, RK45, Unit, Date2JD, LoadGravityModel, El2RV, 
  PltOrbit, RV2El, Eclipse, SunV1, Accel, UToConeClock, delta
   Copyright (c) 2006 Princeton Satellite Systems, Inc.
   All rights reserved.


AeroUtils: Coord/QLVLH
Common: Graphics/Plot2D
Common: Graphics/TimeLabl
Common: MassProperties/Inertias
Common: Quaternion/QMult
Common: Quaternion/QTForm
Common: Time/Date2JD
Common: Transform/Eul2Q
Math: Integration/RK45
Math: Linear/Cross
Math: Linear/Dot
Math: Linear/Unit
Orbit: GravityModels/LoadGravityModel
OrbitMiniToolbox: Support/El2RV
SC: BasicOrbit/PltOrbit
SC: BasicOrbit/RV2El
SC: Ephem/Eclipse
SC: Ephem/SunV1
Sail: Coordinates/UToConeClock