Question

Discuss at least 3 different space weather phenomenon that influence solar cell performance on a satellite.

Answer 1

In satellites, the solar panels are the most affected components due to various solar activities. The normal erosion rates for solar panels are usually 0.3% to 1% per year. The following space phenomena can influence the functioning of solar panels:

• Solar winds
• Solar flares
• Coronal Mass Ejections (CMEs)

The surface of the Sun is a very busy place. It has electrically charged gases that generate strong magnetic fields. The Sun’s gases are constantly moving, which tangles, stretches and twists the magnetic fields lines. This motion creates a lot of activity on the Sun's surface.

The solar wind is a stream of particles and magnetic field flowing away from the outer surface of the Sun known as the Corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV. The solar wind is constant but varies in intensity.

Sunspots are darker and cooler areas on the surface of the sun where the magnetic field is very strong. These high magnetic fields in the sunspot-producing active regions give rise to explosions known as solar flares. They are formed due to reorganization of twisted magnetic field lines resulting to sudden explosion of energy. These are the most extreme form of solar storms. They discharge large amounts of radiation and a highly charged cloud of protons in particular.

The magnetic field lines that twists up to form solar flares occasionally become so warped that they snap and break, and then reconnect at other points. The gaps that form no longer hold the sun's plasma on its surface and the plasma explodes into space as coronal mass ejection (CMEs). When CMEs occur, a huge amount of plasma and magnetic energy is emitted. CMEs bring an increase in radiation but unlike flares, they also bring charged particles of matter.

Solar activities causes solar panels to deteriorate over time, and powerful single events can even lead to a sudden reduction in the efficiency of a solar panel. The solar cells on the power arrays of satellites are susceptible to radiation damage, and the solar-cell radiation response strongly affects the full capability of the spacecraft and, ultimately, the mission's lifetime. Since one cannot prevent the radiation from striking the solar panels, panels are built in such a way that they are resilient to the effects of radiation damage.