I would like to extend a special opportunity to those of you who are experienced in running our telescope. Once again, Dr. Albert Haldemann has asked us to assist with the Goldstone Solar System Radar (GSSR) observations. Dr. Haldemann writes, "During the Mars oppositions of 2001 and 2003, the GSSR, in conjunction with GAVRT, carried out the first four-station delay-Doppler interferometric mapping of Mars. This Earth-based technique, using 3.5 cm wavelength radio waves (X-band), can make maps of swaths of Mars at the same resolution as Hubble Space Telescope images of Mars. The experiments critically depend on the GAVRT antenna for two important scientific components. First, for the final Mars maps to be fully geographically unambiguous requires at least four receiving antennas spaced throughout the Goldstone complex, which isn't possible without the DSS-12. Second, the GAVRT program's dedicated use for scientific calibration during non-radar nights provides a quantitative anchor for the experiments that is at least as good as, and is in fact sometimes better than the calibrations GSSR can make at the 70 m Mars antenna."

"In 2001 and 2003, the maps we made contained, at their edges, the Meridiani and Gusev landing sites of the two MER rovers. This year's opposition offers us the chance to re-visit the Gusev landing site with better geographic coverage (the landing area will be closer to the middle of the map rather than at the very edge where the data were noisy). This will offer the unique opportunity to check reproducibility of the technique and to acquire further 5 km pixel data where a rover is sampling the surface at the same scale by driving >5 km!"

"Never ones to rest on our laurels, we will expand the experiment this year. With Mars once again in view of the Arecibo radar during the 2005 opposition, we propose producing similar 12.6 cm wavelength (S-band) radar maps jointly with 3.5 cm near-nadir backscatter maps to enhance the analysis of Martian surface properties. The S-band experiments and the X-band experiments will happen on different, but nearby nights to assure as similar geographic coverage as possible."

Dr. Haldemann concludes, "The above figure shows an example from 2001. In the lower panel: map of backscatter power for the near-nadir, quasi-specular echo for the Terra Meridiani region of Mars, acquired on July 14, 2001. The Mars Exploration Rover Opportunity's landing site is in the region of low SNR at around 6°W and 1°S. Best mapping is obtained within 3 degrees of the delay-Doppler sub-radar track (blacked out horizontal midline of lower panel, where we retain a delay-Doppler spatial resolution of only 5 km x 133 km). The upper panel is martian topography from the Mars Global Surveyor's laser altimeter instrument of the same region - try comparing and identifying topographic features in the radar map."

Dr. Haldemann will make himself available for teleconferences after you have had a Mars track so we all can understand our GAVRT contributions to this campaign.

Would you like your students to be part of GAVRT's GSSR 2005 Tracks? If so, I invite you at this time to go to our website and schedule one of the eight "Mars Request" sessions available on the following dates: October 13, 23, 31, November 8, 9, and 14.

As a supplement to the Mars Radar Track, here are some Mars lessons to help your students in this endeavor.