OSCAR 8 (also called AO-08, Phase 2D or Amsat P2D) is an American amateur radio satellite. It was developed and built by radio amateurs of the AMSAT and launched on March 5, 1978 as a secondary payload together with the earth observation satellite Landsat 3 from Vandenberg Air Force Base, California, United States. The satellite had two linear transponders, from the 2-meter band (uplink) to the 10-meter band and the 70-centimeter band (downlink).