Last April, we dissected the worlds most advanced fighter jet, the F-35B Lightning II, in the pages of our annual How It Works issue. Now military contractor Lockheed Martin is firing up the jets 40,000-pound-thrust engine (the most powerful ever built for a fighter jet) in preparation for flight tests. The jet can soar at supersonic speeds (1,000 mph) and deflect radar signals, but by the end of the month, pilots are expected to show off its most highly anticipated feature: the ability to stop mid-flight and touch down virtually anywhere.