The Mars flyby of ROSETTA: an opportunity for infrared and microwave high-resolution sounding

The Mars flyby of ROSETTA will provide a valuable opportunity for sounding, at high spatial resolution, the Mars atmosphere and surface in the infrared and microwave range. The VIRTIS infrared imaging spectrometer should be able to determine the surface mineralogy and temperature of the observed areas, the abundances of minor constituents (H 2O, CO), and possibly to study the atmospheric thermal profile. VIRTIS will complement the OMEGA and PFS infrared spectrometers on-board the Mars Express mission, expected to operate in Mars orbit at the time of the ROSETTA flyby. The MIRO microwave spectrometer is expected to provide information on the thermal profile, the H 2O vertical distribution, the temperature of the subsurface, and possibly the atmospheric winds. In addition, the Mars flyby of ROSETTA will provide the first opportunity for testing the VIRTIS and MIRO instruments, in particular for wavelength/frequency and photometry/radiometry calibration.