The kett devices appear to spawn randomly at various Remnant sites. Only five devices need to be destroyed to finish the Task. Devices may respawn at already cleared or visited sites. The map shows six verified locaations. There are probably more locations.
After locating the five devices the Task will be complete (270 xp), but a new mission simply titled "Subjugation" will be added (under Helues > Voeld). A navpoint will be added to the map pointing to a Remnant site underground where four more devices will need to be destroyed.
Enter the Remnant faciltyEdit
Gravity well down.
Eliminate the kettEdit
Kett are down here.
Investigate the consoleEdit
SAM notes that the kett seems to have been feeding data into a nearby console. The data on the console indicates that the kett were attempting to weaponize the Remnant, though yet without success.
Destroy all outpout devices (0/4)Edit
Some more kett on the way.
When all devices are destroyed the mission completes.
In innermost room is a container with a decryption puzzle (the two glyphs are on the walls). Needed for the achievement Cryptographer.
In the same room you can scan for 100 Remnant research data, and pick up a Remnant Data Core for Task: Remnant Data Cores.
270 xp, 29 AVP. +2% Voeld viability.