Example_3_06.m

% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
% Example_3_06
% ~~~~~~~~~~~~
%{
  This program uses Algorithm 3.3 and the data of Example 3.6
  to solve the universal Kepler's equation.

  mu  - gravitational parameter (km^3/s^2)
  x   - the universal anomaly (km^0.5)
  dt  - time since x = 0 (s)
  ro  - radial position when x = 0 (km)
  vro - radial velocity when x = 0 (km/s)
  a   - semimajor axis (km)

  User M-function required: kepler_U
%}
% ----------------------------------------------

clear all; clc
global mu
mu = 398600;

%...Data declaration for Example 3.6:
ro  = 10000;
vro = 3.0752;
dt  = 3600;
a   = -19655;
%...

%...Pass the input data to the function kepler_U, which returns x
%...(Universal Kepler's requires the reciprocal of semimajor axis):
x   = kepler_U(dt, ro, vro, 1/a);

%...Echo the input data and output the results to the command window:
fprintf('-----------------------------------------------------')
fprintf('\n Example 3.6\n')
fprintf('\n Initial radial coordinate (km) = %g',ro)
fprintf('\n Initial radial velocity (km/s) = %g',vro)
fprintf('\n Elapsed time (seconds)         = %g',dt)
fprintf('\n Semimajor axis (km)            = %g\n',a)
fprintf('\n Universal anomaly (km^0.5)     = %g',x)
fprintf('\n-----------------------------------------------------\n')
% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~