BIO rolled to a halt beside the little logistics lander. As though on cue, the spring loaded cover of its cargo bay popped open, revealing components neatly packed in foam, looking as pristine as the day they left the builder. The rover, in contrast, looked on close inspection like a dusty and dented machine that had been driving over an unforgiving landscape for six years. Which it had.
The cargo: six new wheel units with their integral motors. Replacements for the primary and secondary arms, with upgraded sensors. A new sensor package for the masthead. And, of course, the usual plug-in memory upgrade.
The relief mission had arrived. In time, if barely so. Arrival was nicely calculated: the mission was funded years before it was needed: anything later would be too late. The planners had estimated when the rover was likely to need resupply, subtracted travel time dictated by the cold equations of planetary mechanics, subtracted the time needed to build spacecraft and launcher, and added a year for cushion. It was barely enough.
With exquisite care the rover deployed an Allen Wrench from the end of its primary arm and began to replace the right rear wheel unit.
It is a good thing to do good work, work of value, work that is valued. The relief mission was a fraction of the cost of sending a new rover. It's a good life, if you don't weaken.