GEO Stationkeeping Example

Utilizes pause. ------------------------------------------------------------------------- See also NewFig, DVGeoTrx, DVIDrift -------------------------------------------------------------------------

Contents

%--------------------------------------------------------------------------
%  Copyright 2007 Princeton Satellite Systems, Inc.
%  All rights reserved.
%--------------------------------------------------------------------------

clear area; % area is often times a var, make sure its open for function
echo on

FIRST COMPUTE ANNUAL DELTA-V for NORTH-SOUTH STATION-KEEPING

% tracking tolerance
tol = 0.1;          % deg
year = 2007:2016;   % consider these years

% north-south station-keeping
[dVNS,dTNS] = DVIDrift( .1, year ); % Spacecraft Control Toolbox function

annualDV = 365./dTNS*dVNS;

NewFig('GEOStationKeeping');
bar(year,annualDV)
xlabel('Year'), ylabel('Annual Delta-V (m/s)')
title('Delta-V Requirement for North-South GEO Stationkeeping')

%% FIRST COMPUTE ANNUAL DELTA-V for NORTH-SOUTH STATION-KEEPING

% tracking tolerance
tol = 0.1;          % deg
year = 2007:2016;   % consider these years

% north-south station-keeping
[dVNS,dTNS] = DVIDrift( .1, year ); % Spacecraft Control Toolbox function

annualDV = 365./dTNS*dVNS;

NewFig('GEOStationKeeping');
bar(year,annualDV)
xlabel('Year'), ylabel('Annual Delta-V (m/s)')
title('Delta-V Requirement for North-South GEO Stationkeeping')

NEXT COMPUTE ANNUAL DELTA-V for EAST-WEST STATION-KEEPING

% east-west station-keeping
[dVEWy, acc, dTEW] = DVGeoTrx( 1:360, .1 ); % Spacecraft Control Toolbox function

NewFig('GEOStationKeeping');
area(dVEWy)
xlabel('Longitude (deg)'), ylabel('Annual Delta-V (m/s)')
title('Delta-V Requirement for East-West GEO Stationkeeping')

%% NEXT COMPUTE ANNUAL DELTA-V for EAST-WEST STATION-KEEPING

% east-west station-keeping
[dVEWy, acc, dTEW] = DVGeoTrx( 1:360, .1 ); % Spacecraft Control Toolbox function

NewFig('GEOStationKeeping');
area(dVEWy)
xlabel('Longitude (deg)'), ylabel('Annual Delta-V (m/s)')
title('Delta-V Requirement for East-West GEO Stationkeeping')

NOW COMPUTE TOTAL DELTA-V REQUIREMENT

% approximate total delta-v requirement
dVEWyMSP = DVGeoTrx( 267, .1 );
dVTotal = sum(annualDV)+dVEWyMSP*length(year)

%% NOW COMPUTE TOTAL DELTA-V REQUIREMENT

% approximate total delta-v requirement
dVEWyMSP = DVGeoTrx( 267, .1 );
dVTotal = sum(annualDV)+dVEWyMSP*length(year)
dVTotal =
     4.492461011228953e+02

NOW COMPUTE PROPELLANT MASS

% compute propellant mass
mf = 4000;
ISP = 220;
g = 9.81;
mp = mf*( exp(dVTotal/g/ISP)-1 );

%% NOW COMPUTE PROPELLANT MASS

% compute propellant mass
mf = 4000;
ISP = 220;
g = 9.81;
mp = mf*( exp(dVTotal/g/ISP)-1 );

NOW double ISP and recompute

mp2 = mf*( exp(dVTotal/g/(2*ISP))-1 );

echo off

fprintf('Propellant Mass for ISP of %d sec: %4.2f kg,\n',ISP,mp);
fprintf('Propellant Mass for ISP of %d sec: %4.2f kg,\n',2*ISP,mp2);

fprintf('\nOnly %3.1f %% of the original propellant mass is needed.\n',100*mp2/mp);

echo off

%--------------------------------------

%% NOW double ISP and recompute
mp2 = mf*( exp(dVTotal/g/(2*ISP))-1 );

echo off
Propellant Mass for ISP of 220 sec: 925.63 kg,
Propellant Mass for ISP of 440 sec: 438.75 kg,

Only 47.4 % of the original propellant mass is needed.

Published with MATLAB® R2019a