C1XS – X-ray Fluorescence Spectrometer (UK/ESA/ISRO)
Covering the 1–10 keV range, C1XS mapped the abundance of magnesium, aluminium, silicon, calcium, titanium and iron at the lunar surface with a ground resolution of 25 km, and monitored the incoming solar flux. The payload resulted from a collaboration between the Rutherford Appleton Laboratory (UK), ESA and ISRO, building on the earlier D-CIXS instrument flown on ESA's SMART-1.
C1XS was activated on 23 November 2008. It successfully detected the X-ray signatures of aluminium, magnesium and silicon during solar-flare-driven X-ray fluorescence events, even though solar activity was unusually low during the mission.