Investigation of the solar wind-Moon interaction onboard Chandrayaan-1 mission with the SARA experiment

The SARA instrument (Sub-keV Atom Reflecting Analyser) comprises a low energy neutral atom (LENA) sensor for the energy range 10 eV-3.3 keV and an ion mass spectrometer (10 eV-15 keV). It is the first ever experiment to study the solar wind-planetary surface interaction via measurements of the sputtered atoms and neutralized back-scattered solar wind hydrogen. The neutral atom sensor uses conversion of the incoming neutrals to positive ions, which are then analysed via surface interaction technique. The ion mass spectrometer is based on the same principle. SARA performs LENA imaging of the Moon's elemental surface composition including that of permanently shadowed areas, and imaging of the lunar surface magnetic anomalies. It will also investigate processes of space weathering and sputtered sources of the exospheric gases