 The original expectation was that the series would then move on to a very large and powerful long-range UAV known as "Tier 3", something along the lines of a B-2 Stealth bomber, but Tier 3 proved overambitious and was cancelled.In place of Tier 3, the USAF decided to develop a smaller "Tier 3-" UAV designated the "Darkstar", and a "Tier 2+" UAV, something like a "super Predator", the Teledyne-Ryan "Global Hawk".The Lockheed Martin / Boeing Tier 3- Darkstar was a stealthy design that resembled a big pumpkin seed with a long straight wing at the rear.