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.
The code for the math challenge to decipher is 10, 5, 15, 20.