Mission: The Lost City of Paradise/Walkthrough
The crew members which you need to rescue are out in the desert usually guarded by scorpions.
The sandworms are found near a ruined temple off to the side. Also there are some consoles in the ruins. Just kill the sandworms and come back. The sandworms near the Satellite Towers won't help you with the quest.
Afterwards you have to walk around the town and beam down various away teams to bolster morale.
Then go up into the mountains, kill the mobs and then you finish the quest.