The newest Update 17.5, introduces a 5-part quest that will lead you to the renewed J-3 Golem. It also is required to be completed if you want to make Atlas, if you want to opt out of having to buy it with Platinum.
The Quest is automically given to the player if they have Eris unlocked, if you have unlocked Eris and you don’t have it. You have to defeat Tyl Regor on Uranus first.
The Quest starts with an inbox message
CALLING ALL CEPHALONS, PRECEPT 44
CEPHALON STRANDED. SHIP IMMOBILIZED. POWER FAILING. EXTINCTION EVENT.
Please help me! Assemble this communication endpoint to establish contact.
Then Ordis, prompts you to aid Cephalon Jordas. You will be first be told to acquire Pherliac Pods. These Pherliac Pods are only available from the Infested Juggernauts released a few updates back. You can find these Infested Juggernauts on any of the infested mission, I would prefer doing Histo, Eris which is an extermination.
After completing the Pherliac Pods and equipping it, the player is asked to go to Acanth, Eris to test the Pherliac Pod. Jordas finds the pods weak and gives the player an Potent Pherliac Pod. It requires the same components as the Pherliac Pods but requires 3 Argon Crystals.
Lastly, upon completing the Potent Pherliac Pod and equipping it, you will be sent to Naeglar, Eris. Progressing through the mission, you will encounter a Juggernaut Behemoth which after defeating, the player has the fight the Jordas Golem. I would suggest a party of 4 with Corrosive Projection.
After defeating, the Jordas Golem, you will be rewarded the Atlas Warframe Blueprint and unlocking the Jordas Golem Assassination mission which you need to farm to make Atlas.