Yup, and notice that the autonomous voyage was "interrupted by a small mechanical problem" and "no one on board to repair". It doesn't take much to shut down m

Yup, and notice that the autonomous voyage was "interrupted by a small mechanical problem" and "no one on board to repair". It doesn't take much to shut down mechanical devices. The problem with the "machine screws that never snap" is that we are still dealing with physical materials - everything is a trade-off; we could spec a screw with 100x the strength of the max expected load instead of a standard 2.4x margin, but we've probably blown both the weight and dollar budgets, and/or merely shifted the failure point to another component. And this doesn't even count for disasters to the mission from unexpected events. Seems that we'll need to get well into the realm of self-repair and self-replicating devices before such massive remote autonomous are reasonably feasible.