RM 20 (P72-2)

RM 20 (P72-2) [USAF]

RM 20 (Radiometer 20) was a low-altitude satellite in circular orbit carrying four experiments. Two of the experiments were to study radiation from the earth horizon. A third experiment was to observe solar extinction through the stratosphere, and the fourth was to study ionospheric radio propagation. The spacecraft experiment support equipment included a three-axis stabilization system and a tape recorder.

The main instruments were the highly complex RM-20A/B satellite sensors, which were intended to collect infrared target and background data while approximating several features of potential operational concepts. The RM-20A was a scanning instrument operating within two spectral regions with sophisticated onboard data processing such as automatic thresholding and field-of-view sectoring. The instrument was gimbaled and incorporated a passive thermal control system, and produced data at 1.024 Mbps. The RM-20B was a mosaic sensor operating in one selected spectral region. It was gimbaled to compensate for orbital and earth rotation and provided data at 512 Kbps.

Following experiments were on board:

• UV Horizon (SAMSO-206)
  was to map the UV spectrum at Earth's horizon
• IR Mapping (SAMSO-207)
  was to map the celestial sphere at infrared
• Aerosol Monitor (ONR-123)
  was to measure the concentration and vertical distribution of aerosols in the stratosphere by observing the solar extinction
• Wide Band Radio Propagation (DNA-002)
  was an experiment to investigate ionospheric radio propagation