# # Program information file # PROGRAM_ID 2024B014 PROGRAM_TITLE Hydrogen peroxide on Mars at the northern spring period: a key for atmospheric chemistry PROGRAM_INV1 Shohei Aoki PROGRAM_INV2 Thomas Greathouse PROGRAM_INV3 Frank Daerden PROGRAM_INV4 Hideo Sagawa PROGRAM_INV5 Therese Encrenaz PROGRAM_SCICAT major planets / satellites PROGRAM_ABSTRACT_BEG An important unsolved problem in planetary science concerns the observed stability of the Martian CO2 atmosphere, because CO2 is unstable under photolysis by solar UV light. Odd hydrogen [HOx] species that result from photolysis of water vapor, may act as a catalyst for recombination of CO2, but were never directly observed on Mars. Hydrogen peroxide [H2O2] is a stable, abundant reservoir species of HOx and thus holds the key to constraining HOx abundances. H2O2 is not targeted by space missions and its detection depends critically on ground-based spectroscopy. Previous observations by IRTF/TEXES suggested that H2O2 abundances are highly variable over space and time. 3D chemical models suggested that heterogenous reactions can play an important role. Importantly, the models suggest that global distributions of H2O2 in the northern spring season are diagnostic to the role of heterogenous reactions. However, the previous H2O2 observations are unavailable at this period of the year. Hence, we propose to perform first global mapping of H2O2 in the northern spring season [corresponds to January/2025] with IRTF/TEXES in order to evaluate the role of heterogenous chemistry. As the Martian H2O2 features are narrow and tiny, we employ the high spectral resolution mode [R~80,000] of TEXES covering at 1237-1243 cm-1 that was used by the previous observations. To obtain global maps, we scan the slit over the Martian disk. The SNR calculation shows that a complete global map of H2O2 with an accuracy of 15 ppb can be obtained within 213 minutes Since Mars is available for about 7 hours above 40 deg., we request 7 hours and 6 minutes telescope time in Jam/2025, which allows us to obtain two global maps of H2O2 covering different longitudes. PROGRAM_ABSTRACT_END