# # Program information file # PROGRAM_ID 2022A028 PROGRAM_TITLE Global mapping of H2O, HCl, trace gases and their isotopic signatures in the Martian atmosphere. PROGRAM_INV1 Sara Faggi PROGRAM_INV2 Giuliano Liuzzi PROGRAM_INV3 Shohei Aoki PROGRAM_INV4 Geronimo Villanueva PROGRAM_INV5 Michael Mumma PROGRAM_SCICAT major planets / satellites PROGRAM_ABSTRACT_BEG We propose to search for the sources and sinks of water, HCl and organics on Mars, through sensitive ground-based hemispheric maps, using iSHELL, and combining them with orbital ExoMars Trace Gas Orbiter [TGO] measurements, whose data are now publicly released. Mapping the water isotopic composition will test the release from the atmosphere-equilibrated near-surface layer vs. sub-permafrost reservoirs of ancient water with low D/H. Moreover, HCl has been recently discovered in the Martian atmosphere and it appears to be present only during Southern Summer season; we will investigate the onset and growth/mature phases of the HCl increase to understand its source by quantifying atmospheric HCl through the spring-summer season when HCl is expected to appear. To investigate and comprehend its chemistry, its sources and sinks, global maps of HCl are essential. In 2022A the Martian seasons range from Ls ~ 180degrees [Spring Southern Hemisphere] in early Feb/2022 to Ls ~ 270degrees at the end of Jul/2022 [Summer Southern Hemisphere], making this semester critical for HCl investigations. iSHELL spectral setting Lp1 will be adopted. Custom setting covers from 3.71 to 3.32 um, providing simultaneous measurements of H2O, HDO, CO2, HCl, their isotopic signatures and several other trace gases. To map the planet, we will set the iSHELL slit [15'x0.375'] in the North-South direction and we will scan across the East-West direction with a step size of ~ 1', with a total number of positions depending on the angular diameter of Mars. PROGRAM_ABSTRACT_END