Path: SC/Disturbances

%   Compute the total force and torque on a spacecraft generated by the CAD package. 
   Environment inputs are given in e.

   The number of points generated will equal the length of the longest
   transformation matrix in g or the longest member of e. If the number of
   points is > 1 all other members of e and transformation matrices in g
   must equal that number or 1.

   The optical input is a flux vector with magnitude in watts.
   The aerodynamic and optical computations optionally use shadowing.
   To get shadowing you must enter the shadow and scanLines fields.
   Planetary radiation assumes that the optical coefficients are zero
   except for the diffuse coefficient which is 1. 
   The defaults are:
    - AtmDens2 for the Earth, if atmosphericDensity is not entered
    - AtmDens1 for the other planets, if atmosphericDensity is not entered
    - Constant(['bond albedo ',e.planet]) for albedo fraction, if not entered
    - Constant(['mu ',e.planet]) for mu, if not entered
    - Constant(['equatorial radius ',e.planet]), if planetRadius not entered
    - Constant(['black body radiation ',e.planet]) if radiation is not entered
    - No aerodynamic disturbances unless v is entered
    - No planetary radiation unless r is entered
    - Flags computeAero and computePR override defaults
    - No shadowing
    - No scan display and 0 scanLines
    - No plots

   The output units are determined by e.units as follows:

   e.units        force      torque
   -------        -----      ------
   'm'            N          Nm
   'in'           lbf        in-lbf
   'ft'           lbf        ft-lbf

   You first call
      h = Disturbances( 'init', g, e );
   This returns a handle, h, to the display. You can then call this 
     [f, t, m, harm, angMom] = Disturbances( 'run', g, e, h, doPlots )  
   multiple times.

   Since version 2.
   e = Disturbances( 'defaults' )
   h = Disturbances( 'init', g, e )
   [f, t, m, harm, angMom] = Disturbances( 'run', g, e, h, doPlots )

   mode                'init', 'defaults' or 'run'
   g                   Spacecraft data structure
   e                   Disturbances data structure
                       .units              (1,:) 'm', 'in', 'ft'
                       .r                  (3,:) Distance from gravity center (km)
                       .v                  (3,:) Velocity vector in the inertial frame (km/sec)
                                                 - should include planetary rotation
                       .s                  (3,:) Solar optical radiation flux vector (watts)
                       .b                  (3,:) Magnetic field vector (T)
                       .planet             (1,:) Will compute density and mu for various
                       .planetRadius*       (1,:) Radius of the planet (km)
                       .atmosphericDensity* (1,:) Density
                       .mu*                 (1,1) Gravitational parameter (km^3/sec^2)
                       .albedo*             (1,1) Albedo fraction
                       .radiation*          (1,1) Planet radiation (w/m^2)
                                                  * looked up by planet if not entered or 0
                       .tGas               (1,1) Gas temperature (deg-K)
                       .mGas               (1,1) Gas molecular weight
                       .tSamp              (1,1) Sample time between transformation matrices in g
                       .shadow             (1,1) 1 for on, 0 for off
                       .nScanLines         (1,1) Number of scan lines for shadowing
                       .showScans          (1,1) True means show the HSRCAD scan display
                       .computeAero**      (1,1) True means compute aerodynamic torques
                       .computePR**        (1,1) True means compute planetary radiation torques
                                                  ** optional fields
   h                   Handle to display
   doPlots             If true, will plot outputs

   f            (:)    Force structure or handle to display if mode is 'init'
                       .total    (3,:)   Force in ECI frame
                       .aero             Aerodynamic
                       .optical          Optical
                       .thermal          Thermal
                       .rF               Radio Frequency
                       .pR               Planetary radiation
                       .al               Planetary albedo
   t            (:)    Torque structure  
                       .total   (3,:)   Torque in body frame
   m            (:)    Mass properties

   harm         (:)    Harmonic coefficients
                       .wf(3,:) Harmonic frequencies for force
												.wt(3,:) Harmonic frequencies for torque     
                       .f (3,:) Harmonic coefficents
                       .t (3,:) Harmonic coefficents
   angMom      (:)    Angular momentum
                      .eCI  (3,:) In the inertial frame
                      .body (3,:) In the body frame



AerospaceUtils: AtmosphericCalculations/AtmDens1
AerospaceUtils: AtmosphericCalculations/AtmDens2
AerospaceUtils: CAD/BHinge
AerospaceUtils: CAD/HSRCAD
Common: Database/Constant
Common: Graphics/NewFig
Common: Graphics/Plot2D
Common: Graphics/TimeLabl
Common: Time/JD2000
Math: Analysis/FourierSeries
Math: Linear/Cross
Math: Linear/Dot
Math: Linear/DupVect
Math: Linear/Mag
Math: Linear/SkewSq
Math: Linear/Unit
SC: BasicOrbit/VOrbit
SC: Environs/MagField
SC: Environs/SolarFlx
SC: Ephem/SunV1

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