Satellite Eclipse

Satellite eclipses occur when the Earth blocks sunlight from reaching the satellite. Satellites orbiting the Earth routinely pass through a shadow region on the opposite side of the planet to the Sun, causing this loss of contact.

The Sun's radiation is the only resource that is usually needed for a satellite to function. The Sun's rays fall on the satellite's solar panels. These panels are comprised of photovoltaic materials such as silicon which absorb photons from the sunlight. Once absorbed, the photons excite electrons in the material and generate electrical current. The panels are packed with thousands of cells that are arranged to optimise the amount of power generated in order to produce the amount of electric power needed for a satellite to function and to meet the power demands of its on-board instruments.

Depending on the shape of the satellite's orbit, eclipses can happen every few hours or a number of times a year. During an eclipse the satellite's solar panels will not be able to produce the electricity it needs to power itself. Under these conditions, the satellite might not only stop functioning but would also be at risk of freezing in the sub-zero temperatures of space. Satellites are fitted with batteries to guard against such critical failures.