An experimental mining technology developed by Dr Farallon above Tyrus VIIa, intended to lift material from a planet's surface in a particle stream, whose failures expose the exocomps as living beings.
The particle fountain is a new mining method under test at a station orbiting Tyrus VIIa in the Next Generation episode The Quality of Life. Its designer, Dr Farallon, hopes it will prove far more efficient than conventional techniques.
The project is behind schedule and plagued by faults. To speed up repairs Farallon has modified a set of small servo tools into the exocomps, which begin refusing dangerous orders. Data concludes that they are protecting themselves and may be alive.
When the fountain malfunctions and floods the station with radiation while Picard and La Forge are aboard, Data locks out the transporter rather than let the exocomps be sent to their destruction. The exocomps devise their own rescue, and one stays behind so that the others can escape.