Imagine a spacecraft which orbits or follows an object like Dawn, Rosetta and Cassini do today, not being decommissioned and deliberately crashed, but instead put in hibernation. With enough fuel and other consumables left in store for this purpose: To be reactivated for a while whenever useful. For example as the seasons vary or when the next spacecraft approaches, or as has happened on Jupiter and the Sun when a comet strikes. Imagine reactivating the Galileo orbiter to have a look at those European plumes observed from Earth.
Are very long term intermittently activated space probes feasible?
Meaning that they could work on and off during many decades. JPL already designs some die hard missions. But it seems almost unintentional, with 3 years or so planned lifetimes, but still working a decade and more later. Why not plan for multi-decadal probes, to have every orbiter and lander of object "X" pile up with time, each with its specialized instruments activated briefly as needed. Especially for minisats with limited resources.
What would be the problems with this kind of concept? Long term cosmic radiation exposure? Storage of the consumables? Cost of Earth management? Instruments becoming outdated? Could the current mode of "throw-away" space missions be replaced with "sustainable" dito?