Först och främst skulle jag vilja förtydliga - Death Star byggdes INTE på Geonosis när Jedi var där vid AOTC, så Jedi kunde inte ha hittat det då. Det var bara designat där; och planerna för den designen var spända av Count Dooku exakt så att de inte skulle falla i Jedi-händer:
Poggle the Lesser: "The Jedi must not find our designs for the Ultimate Weapon. If they find out what we are planning to build, we're doomed."
Count Dooku: "I will take the designs with me to Coruscant. They will be much safer there...with my Master."
(AotC)
Det var också inte byggt på Geonosis själv (oavsett vad du läste i ett icke-citerat uttalande på Wookiepedia), men nära det, på en mån och en station som heter Sentinel Base :
For those in the know, then, it seemed inexplicable that Wilhuff Tarkin should be assigned to a desolate moon in a nameless system in a remote region of the Outer Rim. The closest planets of any note were the desert world Tatooine and equally inhospitable Geonosis, on whose irradiated surface the Clone Wars had begun and which had since become a denied outlier to all but an inner circle of Imperial scientists and engineers.
(James Luceno, "Tarkin")
Dessutom hade den stor säkerhet. Vi har inte pre-Tarkin-era detaljer, men under Tarkin:
In the three years Tarkin had been commanding Sentinel and hundreds of nearby supply and sentry outposts, as well as administering a vast slice of the Outer Rim, no group had been successful in penetrating Geonosis space.
(James Luceno, "Tarkin")
sidnot: Det var INTE byggt på Despayre - det var bara i de tidiga utkasten till Revenge of the Sith enligt Leland Chee)