(1) The GHz radiometer module, which includes the 118 through 640 GHz receivers and a scanning offset antenna with 0.8 x 1.6 m primary mirror.

(2) The THz radiometer module which contains the 2250 GHz receivers and the THz telescope and scan mirror, whose scan is synchronized with that of the GHz antenna.

(3) The Spectrometer module which receives signals from the GHz and THz radiometer modules, detects and digitizes them, and passes the digitized signals to the spacecraft for telemetry to the ground.

• temperature
• geopotential height

• tangent pressure
• contributes to cirrus ice product

• H₂O
• HNO₃
• HCN

• contributes to cirrus ice product,
• ClO (lower quality than from 640 GHz),
• N₂O (lower quality than from 640 GHz),
• O₃ (but not in upper trop),
• volcanic SO₂,
• CH₃CN

• O₃
• CO

• improves quality of upper trop H₂O

• HCl
• ClO
• HOCl
• HO₂
• BrO
• N₂O
• volcanic SO₂

• contributes to cirrus ice product
• stratospheric O₃ with better vertical
  resolution than 240 GHz
  (but not in upper troposphere)
  
• improves quality of upper trop H₂O
• CH₃CN

• OH

• O₃ (lower quality than from
  other radiometers)