Know Your Enemy
This mission begins with an email titled Message from Voeld: Intel on Kett.
Track down Raelis in Resistance HQ on Voeld, by the giant hologram.
She'll give you a navpoint for a standard Kett base in a ravine to the south.
Wipe out the low-level grunts and then carefully sweep the building interior for data. You'll want to listen to the audio log on the datapad in the northeast corner, and read & listen to the datapad on a gurney against the east wall, and read/listen to the datapad in the southeast not-quite-a-corner-because-the-wall-is-curved-area, on a boxy console.
There are many syringes, which your scanner will highlight, but only three are the kett samples you need. One in the northeast corner, on the same desk as the audiolog. One on the table by the gurney, next to the datapad/audiolog. The last syringe is not by the last datapad, but is instead on a different boxy console just to the left of the west door.
There's also a container you can loot before hitting the next objective. That objective is in the kett base on a ridgetop, that you may have passed by while taking the back way into the mountain stronghold during Removing the Heart.
Drive around to the southeast side for easier access, or just vanguard your way in. Either way you'll find more troops than at the last base, and a goodly number of Anointed mixed up with them. They tend to bunch up in cover, so you may wish to indulge in some light explosive sniping.
When they've been cleared, follow your marker to a datapad on the main platform.
After learning that the Archon has been out of contact with his superiors, spin around for an audiolog behind you.
This indicates that the comm blockout has been on the Archon's orders. Lastly, back by the entrance, play a wall-mounted audiolog to learn that there may be trouble brewing among the Kett forces. Your verbal response here doesn't commit you to anything, but you do get 73 AVP, +5% Voeld Viability, and a rush of XP. Still, the mission isn't over, it's just put on hold until you get new intel on the Kett, which will happen in Dissension in the Ranks.