The Atmospheric Chemistry Suite (ACS) is a science payload consisting of three infrared spectrometer channels abord the ExoMars Trace Gas Orbiter (TGO) orbiting Mars since October 2016. The three channels are: the near-infrared channel (NIR), the mid-infrared channel (MIR), and the far infrared channel (FIR, also called TIRVIM).
The ACS was proposed in 2011 by Russian Academy Section and eventually accepted by the European Space Agency (ESA) and Roscosmos as one of two Russian instruments onboard TGO. The instrument was funded by Roscosmos and Centre national d'études spatiales (CNES) of France, and has components of both Russia and France. Its development and fabrication was under Russian leadership. The functionality of all the three channels was confirmed during cruise to Mars.