The Planet Detection Testbed developed at the Jet Propulsion Laboratory is being used to test direct optical detection of an Earth-like planet using nulling interferometry. Operating at infrared wavelengths, the testbed produces four near-identical beams simulating a distant star and planet. The testbed is reconfigurable to simulate different telescope array designs that are being studied. Many of the systems which will be needed for the space application of nulling stellar interferometry are incorporated. The goal of the testbed is to simulate the planet detection process which requires both a long detection period of many hours to overcome the thermal background noise and also high instrument stability to avoid introducing noise signals that could be mistaken for a planet. Numerous control systems are needed to maintain the optical path differences to about 2 nm and maintain beam alignments in shear and tilt. The testbed emulates functions of the fringe-tracking and metrology systems envisioned for the flight system including finding and tracking the fringe, controlling vibration and allowing for changing conditions. The relationship of the testbed to flight conditions is discussed and the latest results are presented showing planet detection in the presence of bright starlight.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.