Asteroid Prospector Mars mission planning.
The mission starts in a GPS orbit. The spacecraft has a Xenon ion engine. The script computes the velocity changes needed for the different mission phases. The transfer to Mars is burn-coast-burn because the time needed to do the delta-v is much smaller than the transfer time so the Hohmann transfer is a reasonable approximation.
See also Constant, LowThrustEscape, OrbMnvrHohmann
Contents
%-------------------------------------------------------------------------- % Copyright (c) 2014 Princeton Satellite Systems, Inc. % All Rights Reserved. %-------------------------------------------------------------------------- % Since version 2014.1 %--------------------------------------------------------------------------
Constants
%----------- radiusMars = Constant('equatorial radius mars'); radiusEarth = Constant('equatorial radius earth'); muSun = Constant('mu sun'); muEarth = Constant('mu earth'); muMars = Constant('mu mars'); g = 9.806; % m/s^2 aU = Constant('au' ); aEarth = aU; aMars = 1.5*aU;
Spacecraft parameters
%----------------------- thrust = 1.9e-3; massDry = 15; hEarth = 20200; % GPS hMars = 800; % Above the altitude uE = 2.800*g; % Busek Ion engine (km/s)
Computed velocity changes
%--------------------------- aEarthStart = radiusEarth + hEarth; aMarsEnd = radiusMars + hMars; dVEarthEsc = LowThrustEscape( muEarth, aEarthStart ); dVMarsEnt = LowThrustEscape( muMars, aMarsEnd ); [dV, tOF] = OrbMnvrHohmann( aEarth, aMars, muSun ); dVTotal = dV.total + dVEarthEsc + dVMarsEnt; massFuel = massDry*(exp(dVTotal/uE) - 1); massInitial = massFuel + massDry; accel = thrust/massInitial; timeAccel = dV.total/accel; fprintf(1,'Total delta V %8.2f (km/s)\n',dVTotal); fprintf(1,'Earth Escape delta V %8.2f (km/s)\n',dVEarthEsc); fprintf(1,'Mars insertion delta V %8.2f (km/s)\n',dVMarsEnt); fprintf(1,'Transfer delta V %8.2f (km/s)\n',dV.total); fprintf(1,'Mass Fuel %8.2f (kg)\n',massFuel); fprintf(1,'Mass Dry %8.2f (kg)\n',massDry); fprintf(1,'Mars orbit altitude %8.2f (km)\n',hMars); fprintf(1,'Transfer delta V Time Fraction %8.2e\n',timeAccel/tOF); %-------------------------------------- % PSS internal file version information %--------------------------------------
Total delta V 12.48 (km/s) Earth Escape delta V 3.87 (km/s) Mars insertion delta V 3.19 (km/s) Transfer delta V 5.41 (km/s) Mass Fuel 8.63 (kg) Mass Dry 15.00 (kg) Mars orbit altitude 800.00 (km) Transfer delta V Time Fraction 3.05e-03