The CARMEN instrument measures solar and cosmic radiation reaching satellites in Earth orbit, for both scientific and pragmatic purposes.

Since 2008, CARMEN (CARactérisation et Modélisation de l'ENvironnement) has been operating in Earth orbit at an altitude of 1,336 km on the Jason-2 altimetry satellite. Another flight model was carried aboard SAC-D, launched in 2011, and a third is set to fly with Jason-3. The reason these satellites are carrying CARMEN is that, due to their orbital altitude and inclination, they regularly fly through the South Atlantic Anomaly. This zone is populated at relatively low altitude by particularly aggressive particles—notably high-energy electrons and protons—likely to interfere with their extremely precise instruments. By measuring the levels of radiation these particles emit, CARMEN is helping to assess and if necessary correct their effects on satellite systems, like for example DORIS on Jason-2 and Jason-3.

CARMEN also has scientific value, of course, as the flows of charged particles it measures serve as inputs to validate and enhance physical models of the Van Allen radiation belts. Such models are used to specify satellites’ orbital design constraints.

As the conceptor and prime contractor for the CARMEN instrument, CNES tasked French firm Erems with the construction of the CARMEN-2 (on Jason-2) and CARMEN-3 (on Jason-3) flight models. For CARMEN-1 (on SAC-D), Erems built the main ICARE-NG instrument and Steel Electronique the three SODAD micro-debris and micro-meteorite detection systems.