Cosmos 900

Cosmos 900 (or Oval) was a Soviet low earth orbiting satellite. Onboard were a number of space physics instruments: - High-Frequency Electron Temperature Probe - Differential Energy Spectrometer - Differential Low Energy Spectrometer - Relativistic Proton and Electron Counter - Auroral Photometer - Flat Retarding Potential Analyzer - Spherical Ion Trap with Floating Potential - Cylindrical Electrostatic Probe - Panoramic Electrostatic Spectrometer