ARGOS (Advanced Research and Global Observation Satellite) is the most advanced research and development satellite ever launched by the United States Air Force. It carries an ion propulsion experiment, ionospheric instruments, a space dust experiment, a high-temperature semiconductor experiment, and the Naval Research Laboratory's hard X-ray astronomy detectors for X-ray binary star timing observations. Much delayed, it was finally placed into orbit on the eleventh launch attempt along with the secondary payloads Ørsted and Sunsat.