When the cell is exposed to direct sunlight
at Earth’s distance from the Sun (1 astronomical
unit (AU 93 million miles) a current of 1 ampere, at a quarter of a volt, can be produced by a 2.4 inch silicon cell. Closer to the sun
generates increased power.
Prolonged exposure to sunlight causes
photovoltaic’s performance to degrade in the neighborhood of a percent or two per year;
this degradation happens more rapidly if the cells are exposed to gas, dust or particle
radiation from solar flares
Solar arrays have also
been used to generate atmospheric drag for
aerobraking operations