In Mass Effect Andromeda, the turian ark Natanus has gone missing on arrival to the galaxy Andromeda from the Milky Way. Ryder and his pathfinder team have been asked by Director Tann to solve this mystery. The crucial part of the Turian Missing Ark Natanus mission cannot be completed until Mission 4 has been started. 

• After doing the initial part of Mission 4 Hunting the Archon on Kadara Port, go back to the Tempest to trigger an emergency meeting called by Drack which unlocks the Elaaden Planet exploration.

• Before Mission 4, and the above meeting with the Tempest crew, Ryder should go ahead and try to find leads on the missing Ark Natanus. This will take place on Havarl. Ryder will need to go and help the Angara scientist on Havarl. After helping the scientists out of stasis, talk to Kiiran Dals’ right hand scientist to advance the Turian missing Ark quest.

Then on planet Elaaden, go and find the missing Turian Ark pods, and scan for lifesigns. Follow the quest from here, and add strength to the Andromeda Initiative Allies and Relationships section, in hope of getting the maximal strength for the final fight against the kett.