Spirit completed the rover's longest 5-wheel drive to date en route to a platy rock surface nicknamed "Texas Chili" in an area scientists are calling a "stratigraphic wonderland." The platy outcrop is at site 3 on top of "Home Plate" and is the focus of in-depth scientific investigation.
Two sols after not receiving a scheduled data transmission, Spirit drove19.21 meters (63.02 feet) to the rover's current location about 15 meters (49 feet) away from a field of boulders.
Meanwhile, atmospheric dust levels continued to decline. Tau measurements of atmospheric opacity dropped to 1.06 on sol 1327 (Sept.27, 2007), with a dust factor of 0.48. Spirit has been averaging 350 watt-hours per Martian day (100 watt-hours is the amount of electricity needed to light a 100-watt bulb for one hour).
Scientific studies of the platy outcrop included alpha-particle X-ray spectrometer measurements both before and after brushing the surface, analysis with the Moessbauer spectrometer, and acquisition of microscopic images as well as a 360-degree panorama.
Spirit began each Martian day by measuring atmospheric dust with the panoramic camera, checking for drift (changes with time) in the miniature thermal emission spectrometer, and surveying the sky and ground with the miniature thermal emission spectrometer. In addition to those tasks, Spirit completed the following activities:
Sol 1321 (Sept. 21, 2007): Rather than completing the drive toward Home Plate as intended, Spirit executed the previous sol's activities. As a result of an internal failure in a station at the Deep Space Network in Madrid, rover handlers were unable to transmit instructions to Spirit via the rover's high-gain antenna.
Sol 1322: Spirit spent the first sol of a three-sol weekend collecting remote science data, including panoramic camera images of a target known as "Ambrosia" and miniature thermal emission spectrometer measurements of Ambrosia as well as targets known as "Bisque" and "Cobbler."
Sol 1323: Spirit acquired panoramic camera images of Bisque and Cobbler before completing the 19.21-meter (63.02-foot) drive to site 3 on Home Plate. The rover took images with the hazard avoidance cameras before and after ending the drive and acquired post-drive image mosaics with the navigation and panoramic cameras.
Sol 1324: Spirit acquired near-field panoramic camera images and spent the third sol of a three-sol weekend collecting untargeted remote sensing data. Observations included movie frames in search of dust devils with the navigation camera and a systematic foreground survey with the miniature thermal emission spectrometer.
Sol 1325: Spirit surveyed rock clasts with the panoramic camera and scanned the sky for clouds with the navigation camera. The rover began work on a 360-degree panorama as well as scientific studies of Texas Chili. Spirit acquired navigation camera images in support of observations with the miniature thermal emission spectrometer, completed a full-color, systematic, foreground survey using all 13 filters of the panoramic camera, and acquired a mosaic of images of site 3 with the panoramic camera. Spirit studied targets known as "Hardy Point," "Harmony Point," and "Ohridiski" with the miniature thermal emission spectrometer. The rover unstowed the robotic arm and placed the alpha-particle X-ray spectrometer on Texas Chili.
Sol 1326: In the morning, Spirit monitored dust on the rover mast. Later, the rover acquired more panoramic camera images of site 3, brushed the surface of Texas Chili with the rock abrasion tool, and acquired images of the microscopic imager with the front hazard avoidance camera to monitor dust accumulation. Spirit placed the alpha-particle X-ray spectrometer back on the target and collected data for about 18 hours.
Sol 1327: In the morning, Spirit received communications via the European Space Agency's Mars Express orbiter. The rover acquired more panoramic camera images of site 3, switched tools from the alpha-particle X-ray spectrometer to the Moessbauer spectrometer, and collected Moessbauer data from Texas Chili for about 21 hours.
Sol 1328 (Sept. 28, 2007): Spirit took thumbnail images of the sky with the panoramic camera, re-started the Moessbauer spectrometer, and collected Moessbauer data from Texas Chili for about 25 hours. The rover took more panoramic camera images of site 3 and was slated to continue doing so the following morning.
As of sol 1327 (Sept. 27, 2007), Spirit's total odometry was 7,234.09 meters (4.49 miles).