Like Ghost of Promise, you can do the early legwork on this as soon as you get to Eos, but the last half will need to wait until the radiation clears, further down the storyline.
Again the clues you collect here are randomized - the goal is just to keep hitting Kett sites until you find enough Remnant Data Core Nodes for SAM to derive a navpoint
Echoing Ghost of Promise one last time, the final nav point leads to a minivault in a crater.
This minivault also has nothing in the entry hall, so gravitate on down. There's a small container on the left (northish) platform, one at the bottom of the southern ramp. There's also a Remnant cache on the high platform that needs four glyphs to open. The first is on the wall just behind the cache.
The second is in the same room, on the south side of the pillar near the door.
Exit the room and head down the corridor, clearing out entrenched kett as you go (there's also a floating data pattern to scan). At the end of the corridor is a multilevel chamber with some pillars in the middle. As ever, make an effort to prioritize Destined as you kill everything in the room.
Past this room is a large room with a scannable data core in the center.
There is a glyph on the eastern wall.
There's also a console on the west wall, which is stuffed with wildlife data. Weird, since it must be centuries old, the climate's gone crazy lately, and the source of the observation is at best suspect, but data is data. Your new objective is to return it to Prodromos, but on your way back through the pillar room, scan the westmost pillar for the final glyph.
With those you can solve the cache decryption and score your loot before heading back to town.
As with so many Prodromos quests, your mission ends by filing a report at a specifically marked terminal.