Contents

Sail SMA change demo

Demonstrate for GEO, GPS, and LEO orbits.

Since version 7.

%-------------------------------------------------------------------------------
%   Copyright (c) 2011 Princeton Satellite Systems, Inc.
%   All rights reserved.
%-------------------------------------------------------------------------------

% High orbits

GEO

a0 = 42167;
area = 50; % m^2
mass = 1750; % kg
accel = SailPropsToAccel( area, mass )*1e-3; % m/s^2 converted to km/s^2
nOrbits = 352;
direction = 1;
sma = zeros(4,nOrbits);
dt = zeros(4,nOrbits);
type = 'optimal';
[sma(1,:),dt(1,:)] = SailSMAChange( type, a0, accel, nOrbits, direction );
[sma(2,:),dt(2,:)] = SailSMAChange( type, a0, 2*accel, nOrbits, direction );
[sma(3,:),dt(3,:)] = SailSMAChange( type, a0, accel, nOrbits, -direction );
[sma(4,:),dt(4,:)] = SailSMAChange( type, a0, 2*accel, nOrbits, -direction );

NewFig('GEO Sail Lowering and Raising')
dt = dt/86400;
plot([0 dt(4,end)],[a0 a0],'--'); hold on;
plot(dt(1,:),sma(1,:),dt(2,:),sma(2,:),dt(3,:),sma(3,:),dt(4,:),sma(4,:))
title(sprintf('Sail: %d/%d m^2, Mass: %d kg',area,2*area,mass))
grid on

GPS

a0 = 26600;
mass = 2032; % kg
area = 100; % m^2
nOrbits = 732;
sma = zeros(4,nOrbits);
dt = zeros(4,nOrbits);
[sma(1,:),dt(1,:)] = SailSMAChange( type, a0, accel, nOrbits, direction );
[sma(2,:),dt(2,:)] = SailSMAChange( type, a0, 2*accel, nOrbits, direction );
[sma(3,:),dt(3,:)] = SailSMAChange( type, a0, accel, nOrbits, -direction );
[sma(4,:),dt(4,:)] = SailSMAChange( type, a0, 2*accel, nOrbits, -direction );

NewFig('GPS Sail Lowering and Raising')
dt = dt/86400;
plot([0 dt(4,end)],[a0 a0],'--'); hold on;
plot(dt(1,:),sma(1,:),dt(2,:),sma(2,:),dt(3,:),sma(3,:),dt(4,:),sma(4,:))
title(sprintf('Sail: %d/%d m^2, Mass: %d kg',area,2*area,mass))
grid on

LEO

a0 = 6378+1000;
mass = 500; % kg
area = 100; % m^2
nOrbits = 5000;
sma = zeros(1,nOrbits);
dt = zeros(1,nOrbits);
[sma(1,:),dt(1,:)] = SailSMAChange( type, a0, accel, nOrbits, direction );
sma(end)-sma(1)
dt(end)/86400

ans =
       7.2024
ans =
       365.18

combined plot

area = [0:10:200];
mass = 500;
accel = SailPropsToAccel( area, mass )*1e-3; % m/s^2 converted to km/s^2
a0 = [6378+1000; 26600; 42167];
nOrbits = [5000 732 352];
NewFig('Sail Disposal');
smaChange = zeros(length(a0),length(area));
for j = 1:length(a0)
  for k = 2:length(area)
    [sma,dt] = SailSMAChange( type, a0(j), accel(k), nOrbits(j), direction );
    smaChange(j,k) = sma(end)-sma(1);
  end
end
Plot2D(area,smaChange,'Sail Area (m^2)','SMA Change (km)',sprintf('SMA Change in One Year for Mass of %d kg',mass))
legend('1000 km','GPS','GEO')

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% PSS internal file version information
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Published with MATLAB® R2020a