P.E.R.C. spends most of its time sleeping, as it wanders between the stars. Location Tracking, Scoop Control, and Ramjet Control all quietly tick over keeping its course steady. But its fabbers, telescopes, signal processors, networking coordinator, and various other pieces of equipment lie dormant, folded up and secured in travel configuration.

Its guidance module, the part that decides what to do and where to go next, wakes up every decade or so to double-check Location Tracking, estimate stellar motion, investigate radiotelescope anomalies, and make sure its still on a viable course.

Guidance module: Reviewing sensor data ...

Guidance module: What? No, really, what?

P.E.R.C. wakes up more now. Something unutterably strange has just happened, because it doesn't recognize the stars. They didn't just get tweaked slightly out of alignment, they've changed completely. This indicates that P.E.R.C. probably has a serious hardware fault. It loads its core operating system from backup, and checks that there isn't any cosmic ray damage.

When the checks come back clean, P.E.R.C. determines that it needs more data, and starts running the self-checks and wakeup protocols for all of the remote instruments.

Motor controllers carefully check to make sure the circuit resistance is as expected, and then gently pull back the protective covers on P.E.R.C.'s more sensitive optical telescopes. The radiotelescope is tuned to do a full-sky scan, and the signal processors start doing fourier analysis to see if they can spot any pulsars.

While that is running, P.E.R.C. carefully reviews its emergency procedures and thinks carefully about whether they make sense. The engineers who started the P.E.R.C. project could have sent out much dumber probes, but they wanted explorers who were capable of telling when one of the programmed procedures conflicts with the project goals. If P.E.R.C. found a discrepancy, it wouldn't disobey the procedures, of course. It would just note that it had probably sustained undetectable damage, and stop self-replicating.

P.E.R.C. doesn't spot any problems with the emergency procedures, and it also doesn't spot any pulsars, but it does see one star much to close for comfort. About 0.7 light years away, directly along P.E.R.C.'s current vector.

P.E.R.C. gives itself another 10 kiloseconds to check all the sensor data just in case, and then it calculates a new course that will put it in a stable stellar orbit if all the new sensor data is correct, and into a safe (if very slow and inefficient) slingshot back towards explored space if the new sensor data is wrong and it is still on its original heading.

Ramjet Control tweaks the direction and intensity of the fusion jet, aiming to bring P.E.R.C. down from its stable cruising velocity of 0.4c to a more reasonable in-system velocity.

Normally, P.E.R.C. would go back to sleep at this point, but there's too much to do. This much confusion is orders of magnitude outside what P.E.R.C. is designed to compensate for, which means that something has gone wrong. P.E.R.C. records all of its observations and decisions so far, and a dump of its running code, to the long-term magnetic tape storage at in its central shielded area. In triplicate.

Then, it sets a time-delay on the emergency beacon to start transmitting in 400 gigaseconds. If it ends up headed back towards explored space, that should be long enough for it to get back within Network range, and then some engineers can recover it and look at its data dump and use that to figure out what went wrong and how to make the next generations of starships more robust.

Finally, it starts unpacking its fabbers from their travel configuration. If something this strange has happened, then quite possibly P.E.R.C. is damaged in some way that its self-checks can't detect. Carefully and methodically, P.E.R.C. starts disassembling all of its manufacturing equipment.

P.E.R.C. removes every screw and every plate, carefully packing them into its material storage bays for later failure and wear analysis. Each control chip is connected to the fusion engine and overvolted, to blow out its fuses, physically snapped, and then packed away in turn. The crystal lithography lenses are ground into bumpy, non-focal shapes, smashed, and then tucked away. The seed chemicals for the acid distilleries are carefully allowed to mix until they form a uniform (and useless) sludge. Its blueprints (stored on separate tapes for just this reason), are erased and then shredded. Finally, P.E.R.C. is down to only one mechanical packing/unpacking claw.

With its best handwriting, it scratches "Unknown error. Do not self-replicate." along with all of its one-letter possible misspellings or transpositions into every section of hull and interior plating that it can reach.

Finally, it twists the claw back, flips up the safety cover, and gives the claw's own fuse a huge pull, yanking it clear of the safety cover which snaps back into place.

P.E.R.C. checks off this task from their running tasklist. Now P.E.R.C. is safe, and its only job is to explore and then make it back to explored space with its data.

It sets its sights on the upcoming star. Seeing much detail through the harsh brightness of the drive plume is difficult, but the signal processors think that P.E.R.C. is coming in close to the plain of the ecliptic.

The radiotelescope finishes the full-sky scan, and P.E.R.C. re-tunes it to check for Network activity from nearby stars in order of activity.

Half a kilosecond later, the signal processors throw up a priority alert.

Signal Processing: Structured radio broadcasts, unknown protocol

P.E.R.C. cannot, actually, get more awake. But it drops some background processes and double-checks the data from the radiotelescope and the directional shortwave antenna. It confirms that the radio traffic its seeing doesn't match the spectra or framing structure it would expect, and that there are no navigation or time beacons on the expected frequencies.

P.E.R.C. tweaks its course slightly, to make an even gentler entry into the system. Either it is so damaged that it has failed to recognize a Network node or a Terran colony, and it will be able to show its data to engineers sooner than it expected, or it has finally completed its teraseconds long mission, and found the intelligent neighbors it has been seeking for so long.

P.E.R.C. doesn't know who the radio-transmitters are, but it is so, so happy to find them.