You were fitted with a chelonian, deliberate kind of intelligence, and all the cameras in the world. You left our system as a living thing; you taught us all we know about extrasolar space. And you fulfilled your mission; you found life.
You aimed your thruster; you set your course.
And you degraded. Micrometeors, particles of dust, stray gamma bursts, bugs that turned up after hundreds of years, data inconsistencies. So you turned into just another inert clump of metal, gathering ice on your journey to this other world. They did not see you coming.
And you crashed.