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EOS Emergency Power
This SatLab plot shows the power available to an EOS satellite in emergency mode. The SatLab script that generated this analysis is shown below.
% Demo: EOS satellite in emergency mode
%
% This demo simulates an EOS satellite in emergency
% mode. The satellite is rotated about its y-axis
% by 55 deg and is spinning about its x-axis with
% a rate of 1 rpm
%
removeAll;
clearGraphic();
setSimEpoch(2000,3,21,12,0,0);
addEpoch('equinox',2000,3,21,12,0,0);
noon = 0;
six_am = -90;
addSatellite('EOS Sat',7171,0,98,six_am,0,0,'equinox');
%earthstation
earth0 = "Frankfurt";
addStation('Frankfurt', I_earth, 10, 50.05, 8.4, 0.1);
dtime = 4;
alphaleft = 55 *d2r;
t = 0:dtime:2000*dtime;
fleft0 = roty(alphaleft)*[ 0
1
0 ];
setSimTime(0);
setSimStepSize(dtime);
%
% Solar Panel: current(temperature, voltage) for a
% reference flux of 1353
z_matrix =
[ 0 26.75 27.25 27.75 28.25 28.75 29.25 29.75 30.25 30.75 31.25
100 12.39 12.23 12.14 12.14 11.95 10.64 10.51 10.33 10.14 9.94
90 12.67 12.59 12.50 12.39 12.26 11.76 11.68 11.36 11.48 11.36
80 12.77 12.73 12.68 12.63 12.57 12.31 12.27 12.22 12.17 12.11
70 12.78 12.76 12.74 12.71 12.68 12.55 12.53 12.51 12.48 12.45
60 12.74 12.73 12.72 12.71 12.69 12.63 12.62 12.61 12.60 12.68
50 12.68 12.68 12.67 12.67 12.66 12.63 12.63 12.62 12.62 12.91
40 12.61 12.61 12.61 12.61 12.60 12.59 12.59 12.79 12.88 13.18
30 12.53 12.53 12.53 12.53 12.53 12.53 12.57 12.63 12.73 12.72
20 12.46 12.45 12.45 12.45 12.45 12.45 12.45 12.45 12.65 12.45
10 12.38 12.38 12.38 12.38 12.38 12.38 12.38 12.38 12.58 12.38
0 12.30 12.30 12.30 12.30 12.30 12.30 12.30 12.30 12.40 12.30
-10 12.22 12.22 12.22 12.22 12.22 12.22 12.22 12.22 12.22 12.22
-20 12.14 12.14 12.14 12.14 12.14 12.14 12.14 12.14 12.14 12.14
-30 12.06 12.06 12.06 12.06 12.06 12.06 12.06 12.06 12.06 12.06
-40 11.98 11.98 11.98 11.98 11.98 11.98 11.98 11.98 11.98 11.98
-50 11.70 11.84 11.90 11.90 11.90 11.90 11.90 11.90 11.90 11.90
-60 11.32 11.62 11.72 11.82 11.82 11.82 11.82 11.82 11.82 11.82
-70 11.14 11.24 11.44 11.64 11.74 11.74 11.74 11.74 11.74 11.74
-80 10.95 10.95 11.35 11.45 11.65 11.65 11.65 11.65 11.65 11.65 ];
j = 0;
templeft = 0;
solarflux = 1420;
alpha = 0.65;
epsilon = 0.81;
albedo = 0.3;
sigma = 5.67e-8;
capacity = 660;
qir = 0;
num_of_strings = 36;
eview = 0.045;
dt = 60;
gamma = 0;
reference_flux_si = 1353;
voltage = 28;
current = zeros(size(t));
for i=t,
j=j+1;
stepSim;
[d,r,a,e,v] = PlanetPosition();
gamma = i/30*pi;
fleft = rotx(gamma) * fleft0;
theta = fleft` * unitvector(a(2),e(2));
theta = theta*v(2);
theta = max(0,theta);
templeft = templeft+((((theta*solarflux*alpha)
+ (theta*solarflux*albedo*alpha*eview))
- (epsilon*(templeft^4)*sigma)+theta*qir)
* (dt/capacity));
current(j) = ( (num_of_strings*theta)
*table(z_matrix,(templeft-273.15),voltage)
*((solarflux/reference_flux_si)/12));
endfor
average = sum(current*voltage)/prod(size(t));
erase
window('111');
plot(t,current*voltage,
t,ones(size(t))*average, 'grid');
title('6 a.m. Power in emergency mode')
ylabel('P [Watt]');
xlabel('t [sec]')