How do solar panels supply energy for spacecraft?
Solar panels are very hardy. Compared to alternative power sources, they wear out very slowly. Their effectiveness decreases around 1 to 2 percent a year. This means after a five year mission (boldly going where no probe has gone before), the solar panels will still be making more than 90% of what they made at the beginning of the mission (as long as they haven't gotten farther away from the Sun).
There are two major dangers to solar panels in space besides regular wear-and-tear:
Of course, if a satellite's mission path takes it away from the Sun (farther out into the solar system) solar panels will become less and less useful.
What are solar panels?
How do solar concentrators work?
How do solar panels convert the Sun's energy into electricity?
What is a micrometeorite?
What is a satellite?
Why do solar panels become less effective the farther they are from the Sun?
How are solar panels made?
What is a solar flare?