All communications sessions between the Pathfinder lander and rover were successfully completed today, one day short of the mission's three-week anniversary on the surface of Mars.

Sol 20 began when the Earth rose over Mars' horizon at 10:30 p.m. Pacific Daylight Time last night (July 23), enabling the flight team to initiate communications with the spacecraft. The Sun later rose at 1:15 a.m. PDT this morning, supplying the lander and rover with the energy needed to carry out specific tasks.

Communications were carried out using the 70-meter (230-foot) antenna of NASA's Deep Space Network facility in Madrid, Spain. Forty-seven megabits of data during two downlink sessions were returned on Sol 20.

The data indicated that both the lander and rover remain in excellent health and are continuing to operate masterfully. Flight Director Dave Gruel reported that no further flight software resets have occurred since the team sent modified flight software three sols, or days, ago.

Today's data included numerous images taken for ongoing science experiments. The Imager for Mars Pathfinder (IMP) also completed another section of the 12-color super panorama image of the landing site, then imaged the rover to add to an ongoing "rover movie" that is being assembled. IMP took a final, end-of- the-day photo of Sojourner following completion of its activities.

Sojourner traveled a total of 7/10ths of a meter (2.3 feet) today and performed another soil mechanics experiment that involved staging a "wheely." The last of its activities was to lower the alpha proton X-ray spectrometer onto the soil near the rock named Lamb. Presently, because it is night on Mars, the rover is powered down and using only its battery to operate the spectrometer and gather data on the Martian soil near Lamb. That data will be transmitted to Earth via the lander during the next Martian day, Sol 21, which begins when Earth rises over Mars tonight at 8:48 p.m. PDT.

Activities for Sol 21 will include another rover soil mechanics test, some more autonomous driving and repositioning of Sojourner's spectrometer against the side of Lamb in preparation for data-gathering the following night.

The lander's meteorological experiment reported highs today of minus 2 degrees Celsius (28 degrees Fahrenheit) and morning low temperatures of minus 73 degrees Celsius (minus 99 degrees Fahrenheit). The weather detectors also recorded large fluctuations of 3/10ths millibars in total pressure on the surface of Mars.

On this Martian day, Sol 20, the Earth set at 11:45 a.m. PDT, ending spacecraft communications with Earth for the day. The Sun set at 1 p.m. PDT.

An audio update on Pathfinder's status can be heard by calling 1-800-391-6654.

For more information, please visit our website at http://mpfwww.jpl.nasa.gov.