Why ion propulsion?
Ion propulsion needs to be constantly fed a stream of electrical power to function properly. The only way to ensure a constant stream of electrical power to the solar ion drive is to generate power as DS1 travels. The solar panels are the best way to do just that.
What is the difference between an ion engine and a conventional one?
How does DS1's engine work?
Where does DS1 get its electricity?
What are possible power sources for satellites?
How do solar panels supply energy for spacecraft?
How is the ion propulsion in DS1 solar powered?
What role does the Sun play in space missions like DS1's?