The objective of the Science and Technology Satellite project was development and in-orbit test of an indigenously-developed Korean 100-kg class small satellite bus and demonstration of high performance 3-axis attitude control capability.

The program began in October 1998. Important objectives were the development of advanced technology for future space missions, obtaining experience in high performance scientific payload design, research in space science, and conducting communications technology experiments and oceanography research using land and sea based mobile terminals. The first STSat was launched in September 2003 aboard a Russian booster, and the second was to be lofted in 2007 by an indigenous KSLV-1 launch vehicle.

Mass: 100 kg (220 lb).

• 2003 September 27 - STSat 1 (KaistSat 4, Uribyol 4) - Launch Site: Plesetsk. Launch Complex: LC132/1. Launch Vehicle: Kosmos 3. Mass: 100 kg (220 lb). Perigee: 676 km (420 mi). Apogee: 696 km (432 mi). Inclination: 98.20 deg. Period: 98.50 min.
  Launch delayed from July 28, September 26. Payloads included the FUV Imaging Spectrograph (FIMS); Solid State Telescope (SST); Data Collection System (DCS); and Narrow Angle Star Sensor (NAST).