Start this mission, part of the A Dying Planet task, by talking to Kiiran Dals after the Helping Havarl's Scientists mission.
You can also talk to Torvar to hear a bit more about the sages, but this has no lasting impact. When ready, head to the chasm in the east (the same chasm where the the crashed ship from Recovering The Past) is.
There's a room at the far southern end of the chasm- you couldn't do anything there before, but now you can scan for an energy to signature to reveal a Remant Console tucked away in the corner (both your radar and a scannable energy conduit will lead you there).
This opens a tunnel to the west. Run down it, then jump up the shaft at the end.
There's a gravity well at the top that transports you horizontally rather than vertically. From there you begin the Mithrava ascent proper. Head to the next gravity well, but do stop for the container on the way.
The next well room has nothing else in it, so ride the gravitons on up. You'll emerge near the upper tower. There's a hidden cache yif ou bear left around the tower exterior as you exit.
The cache is guarded by a Nullifier, but alone and without room to maneuver, it's easily destroyed.
Follow the real path counter-clockwise around the tower, dealing with a small swarm of Breachers.
There's a container near the statue here, and Remnant Console toward the end of the platform (your scanner will ping as you get near). Use the console to alter the pillars here. The easiest way to ascend is by jumping up the small garden wall next to the newly adjusted pillars.
Up top there's another container. Follow the path then drop down a level for another Remnant Console- this one extends a horribly designed bridge.
Cross it anyway, deal with an Observer and Breacher, then hop up the block at the end to the next level.
Follow the path, then jump some hexagonal columns for another extending-rod bridge. Cross, climb the wall, then jump up the little wedge section by the ammo crate to ascend once more.
This platform has door. Loot the container in the north corner, then pass through.
This gravity well room does have some loot on the platform at the south end.
Grab it, then ascend to the city of sages.
You'll have long talk with Sage Esmus, and gain a new quest (technically a subquest) to find a family heirloom.
Before you leave, be sure to place the nearby Forward Station (I'm sure the isolationist hermit sages will be fine with it) and snag the Memory Trigger.
There are also a couple NPCs you can talk to about the Angaran's link to Remnant tech, and two quest givers. One is Sage Fleera.
Butt in on her lesson to pick up the Unearthed task. The other is Sage Amurd.
He gives you the task A Lost Sister, but it's automatically on hold until you have access to Old Pelaav, which you don't get until further along the main questline.
Finish up by scanning the statue and technode here, then hie on back to ground level to go heirloom hunting.