**10. Conclusions**

184 Solar Cells – Thin-Film Technologies

**Solar Array Temperature and Illumination, Constant Sun Pointing**

Fig. 28. Solar Array Illumination and temperature, launch phase and first 3 orbits

**From Launch to Sun Acquisition**

0 0.5 1 1.5 2 2.5 3

time [sec]

**LISA PF, Solar Array Performances**

x 104

x 104

Temperature [C] Voltage [V] Current [A]

Solar Array Temperature (K) Solar Array Illumination (W/m2)

Fig. 29. Solar array temperature, output voltage and current

discharge cycling is reached.





0

50

100

150

Finally, figure 30 shows the Depth Of Discharge (DOD %) of the battery from launch. The DOD is progressively recovered the first four orbits. After the fourth one, a stable charge–

0 1 2 3 4 5 6 7 8 9

Time [sec]

Objective of this chapter was to provide guidelines for the design at system level of a solar array for satellites. Such kind of application has to be compliant with severe requirements mainly dictated by the harsh space environment mainly in terms of temperature levels, cosmic radiations which provoke wide variations of the performances together with their continuous degradation. Mass and size of the panels are main constraints with respect to the required power as well as optimal orientation towards to the sun, several times limited by other requirements at spacecraft and mission level. The actual state of the art is represented by triple junction solar cells capable to have a bulk efficiency of more than 30%.

Typical accommodations of these arrays have been illustrated and a few design examples provided. These examples have been chosen among those may be considered as particularly challenging with respect to the required power and energy budgets coupled with mission constraints.
