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 infrare d and microwave range. The VIRTIS infrared imaging spectrometer should be a ble to determine the surface mineralogy and temperature of the observed are as, the abundances of minor constituents (H2O, CO), and possibly to study t he atmospheric thermal profile. VIRTIS will complement the OMEGA and PFS in frared spectrometers on-board the Mars Express mission, expected to operate in Mars orbit at the time of the ROSETTA flyby. The MIRO microwave spectro meter is expected to provide information on the thermal profile, the H2O ve rtical distribution, the temperature of the subsurface, and possibly the at mospheric winds. In addition, the Mars flyby of ROSETTA will provide the fi rst opportunity for testing the VIRTIS and MIRO instruments, in particular for wavelength/frequency and phstometry/radiometry calibration. (C) 2001 El sevier Science Ltd. All rights reserved.