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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.

Figure 1: EOS Emergency power analysis
Script - EOS Satellite in Emergency Mode
  1. % Demo: EOS satellite in emergency mode
  2. %
  3. % This demo simulates an EOS satellite in emergency
  4. % mode. The satellite is rotated about its y-axis
  5. % by 55 deg and is spinning about its x-axis with
  6. % a rate of 1 rpm
  7. %
  8.  
  9. removeAll;
  10. clearGraphic();
  11. setSimEpoch(2000,3,21,12,0,0);
  12. addEpoch('equinox',2000,3,21,12,0,0);
  13. noon   = 0;
  14. six_am = -90;
  15. addSatellite('EOS Sat',7171,0,98,six_am,0,0,'equinox');
  16.  
  17. %earthstation
  18. earth0 = "Frankfurt";
  19. addStation('Frankfurt', I_earth, 10, 50.05, 8.4, 0.1);
  20. dtime = 4;
  21. alphaleft = 55 *d2r;
  22. t = 0:dtime:2000*dtime;
  23. fleft0 = roty(alphaleft)*[ 0
  24.                            1
  25.                            0 ];
  26.  
  27. setSimTime(0);
  28. setSimStepSize(dtime);
  29.  
  30. %
  31. % Solar Panel: current(temperature, voltage) for a
  32. % reference flux of 1353
  33.  
  34. z_matrix =
  35. [   0 26.75 27.25 27.75 28.25 28.75 29.25 29.75 30.25 30.75 31.25
  36.   100 12.39 12.23 12.14 12.14 11.95 10.64 10.51 10.33 10.14  9.94
  37.    90 12.67 12.59 12.50 12.39 12.26 11.76 11.68 11.36 11.48 11.36
  38.    80 12.77 12.73 12.68 12.63 12.57 12.31 12.27 12.22 12.17 12.11
  39.    70 12.78 12.76 12.74 12.71 12.68 12.55 12.53 12.51 12.48 12.45
  40.    60 12.74 12.73 12.72 12.71 12.69 12.63 12.62 12.61 12.60 12.68
  41.    50 12.68 12.68 12.67 12.67 12.66 12.63 12.63 12.62 12.62 12.91
  42.    40 12.61 12.61 12.61 12.61 12.60 12.59 12.59 12.79 12.88 13.18
  43.    30 12.53 12.53 12.53 12.53 12.53 12.53 12.57 12.63 12.73 12.72
  44.    20 12.46 12.45 12.45 12.45 12.45 12.45 12.45 12.45 12.65 12.45
  45.    10 12.38 12.38 12.38 12.38 12.38 12.38 12.38 12.38 12.58 12.38
  46.     0 12.30 12.30 12.30 12.30 12.30 12.30 12.30 12.30 12.40 12.30
  47.   -10 12.22 12.22 12.22 12.22 12.22 12.22 12.22 12.22 12.22 12.22
  48.   -20 12.14 12.14 12.14 12.14 12.14 12.14 12.14 12.14 12.14 12.14
  49.   -30 12.06 12.06 12.06 12.06 12.06 12.06 12.06 12.06 12.06 12.06
  50.   -40 11.98 11.98 11.98 11.98 11.98 11.98 11.98 11.98 11.98 11.98
  51.   -50 11.70 11.84 11.90 11.90 11.90 11.90 11.90 11.90 11.90 11.90
  52.   -60 11.32 11.62 11.72 11.82 11.82 11.82 11.82 11.82 11.82 11.82
  53.   -70 11.14 11.24 11.44 11.64 11.74 11.74 11.74 11.74 11.74 11.74
  54.   -80 10.95 10.95 11.35 11.45 11.65 11.65 11.65 11.65 11.65 11.65 ];
  55.  
  56. j         = 0;
  57. templeft  = 0;
  58. solarflux = 1420;
  59. alpha     = 0.65;
  60. epsilon   = 0.81;
  61. albedo    = 0.3;
  62. sigma     = 5.67e-8;
  63. capacity  = 660;
  64. qir       = 0;
  65.  
  66. num_of_strings = 36;
  67. eview = 0.045;
  68. dt    = 60;
  69. gamma = 0;
  70. reference_flux_si = 1353;
  71. voltage = 28;
  72. current = zeros(size(t));
  73.  
  74. for i=t,
  75.     j=j+1;
  76.    
  77.     stepSim;
  78.     [d,r,a,e,v] = PlanetPosition();
  79.     gamma = i/30*pi;
  80.     fleft = rotx(gamma) * fleft0;
  81.     theta = fleft` * unitvector(a(2),e(2));
  82.     theta = theta*v(2);
  83.     theta = max(0,theta);
  84.     templeft = templeft+((((theta*solarflux*alpha)
  85.                + (theta*solarflux*albedo*alpha*eview))
  86.                - (epsilon*(templeft^4)*sigma)+theta*qir)
  87.                * (dt/capacity));
  88.     current(j) = ( (num_of_strings*theta)
  89.                   *table(z_matrix,(templeft-273.15),voltage)
  90.                   *((solarflux/reference_flux_si)/12));
  91. endfor
  92.  
  93. average = sum(current*voltage)/prod(size(t));
  94.  
  95. erase
  96. window('111');
  97. plot(t,current*voltage,
  98.      t,ones(size(t))*average, 'grid');
  99. title('6 a.m. Power in emergency mode')
  100. ylabel('P [Watt]');
  101. xlabel('t [sec]')
 
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