Many spacecrafts run out of electricity.
Batteries and fuel cells can run out of fuel and RTG's can cease to provide enough heat to be effective. Solar panels can keep providing electrical power as long as the panels are functional and the ship is in the direct light of the Sun and close enough to the Sun to make enough power. But DS1 will travel far enough away from the Sun so that there is not enough electricity generated by the solar panels to power the ship adequately. At this point, shipboard systems will begin to fail. Remote Agent, solar ion propulsion, and communications will all cease to function.