F9R Dev Program — Successor to Grasshopper at McGregor

The F9R Dev 1 vehicle (an upgraded single-engine testbed) and F9R Dev 2 at Vandenberg extended Grasshopper's work, testing landing legs, grid fin steering, and higher-altitude hops. F9R Dev 2 reached ~1,000 meters before an anomaly triggered automatic destruct. These tests directly informed Falcon 9's first stage landing algorithm.