New press release from ESA. MARSIS collects first data about the surface and the ionosphere.<br />It's interesting to hear they don't use the third boom yet even though it was successfully deployed in June (wasn't it?).<br /><br /><br /><br /><br />Here's ESA's press release:<br /><br />"<br />N° 38-2005: Mars Express radar collects first surface data<br /> <br /> <br />5 August 2005<br />Marsis, the sounding radar onboard ESA’s Mars Express spacecraft, is collecting the first data about the surface and ionosphere of Mars.<br /><br /> <br />This radar started its science operations on 4 July, the same day as its first commissioning phase ended. Due to the late deployment of Marsis, it was decided to split the commissioning, originally planned to last four weeks, into two phases; the second will take place in December. It has thus been possible to begin scientific observations with the instrument earlier than initially planned, while it is still Martian night-time. This is the best environmental condition for subsurface sounding, as in daytime the ionosphere is more ‘energised’ and disturbs the radio signals used for subsurface observations.<br /><br />As from the start of commissioning, the two 20m-long antenna booms have been sending radio signals towards the Martian surface and receiving echoes back. “The commissioning procedure confirmed that the radar is working very well and that it can be operated at full power without interfering with any of the spacecraft systems,” says Roberto Seu, Instrument Manager for Marsis, of University of Rome ‘La Sapienza’, Italy.<br /><br />Marsis is a very complex instrument, capable of operating at different frequency bands. Lower frequencies are best suited to probing the subsurface, the highest frequencies are used to probe shallow subsurface depths, while all frequencies are suited to studying the surface and the upper atmospheric layer of Mars. “During commissioning we worked to test all transmission modes and optimise the radar's performance a