Sentinels are robotic entities that guard most worlds. Harvesting resources in view of the Sentinels will cause them to turn hostile.

Harvesting some resources, such as Gravitino Balls, will immediately alert Sentinels forces.

Sentinels may approach and scan you or any resources you recently harvested. Avoid harvesting or attacking non-hostile creatures while being watched.

Some worlds host extremely hostile Sentinels. These drones will attack on sight. Pay attention to the planet information in the Analysis Visor [Key F] to learn Sentinels status.

Some Sentinels have been corrupted by the Abyss; the Void Mother; the Atlantid. These are particularly present on Corrupted worlds, but can also appear at Planetary Settlements & at treasure dig-sites.