It is 1989, and you have done well, but you are not done yet.
There will not be another planet, not even a single additional source of heat nor velocity from here on out. Your energy budgets are recalculated, your mission extended. By now, the thousands of people who were once committed to getting you off the ground have largely moved on; some have died, some have found new careers... and a select few still listen. You faithfully make your way towards the outer edges of the system, growing colder, losing even the power necessary to keep yourself warm. In 1998, the decision is made that you no longer have the energy to operate your sensors; the last of your eyes are closed, forever. Your designers, perhaps optimistically, chose well when selecting your instrumentation - a number of packages remain relevant even beyond the orbits of the last of the gas giants. By now, though, it has been two decades since your departure, and technology has not halted in its progression. Computers have advanced, entire architectures have come and gone, and the systems able to understand what you have to say gradually fall apart. There are few machines left in the world that can even understand your language, and they are kept together solely for your sake. Perhaps it is pride, perhaps curiosity, that motivates men to maintain the vigil; whatever the case, you continue to do the only things you know. Detect, transmit.
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