* Astronomy

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RE: Mars Exploration Rover Spirit

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SPIRIT UPDATE: Spirit Completes Camera Check-Up, Puts Finishing Touches on Panorama - sol 915-921, August 04, 2006:

Spirit has finished acquiring images for the "McMurdo panorama" and began adding some finishing touches around the edges. The rover is healthy and continues to make progress on its winter science campaign of observations on Mars.
Plans called for Spirit to complete a winter check-up of all the rover's cameras by calibrating the microscopic imager. To accomplish this procedure, known as a photon transfer observation, Spirit acquired 20 pairs of images, each pair taken during a different exposure time. Engineers used these images to form a baseline for estimating unwanted electronic signals using a Poisson distribution.
The Poisson curve measures probability over a fixed time interval based on a known average. Using this probability, engineers correlated the signal measured by the camera with differences in signals acquired in the image pairs to calculate the efficiency with which the camera's imaging sensors convert photons from sunlight into electrical energy. They used the same approach to characterise the electrical system's ability to translate measurements of voltage into digital numbers.
Spirit is collecting about 280 watt-hours of electrical power each sol from the rover's solar array.

Sol-by-sol summary:

Sol 915 (July 30, 2006): Spirit acquired flat-field images for calibrating variations in the field of light in the McMurdo panorama.

Sol 916: Spirit surveyed the sky and ground using the miniature thermal emission spectrometer.

Sol 917: Spirit searched for clouds using the navigation camera.

Sol 918: Spirit added some finishing touches to the McMurdo panorama.

Sol 919: Spirit added more finishing touches to the McMurdo panorama.

Sol 920: Plans called for Spirit to conduct a photon transfer observation to measure electronic noise picked up by CCDs in the microscopic imager.

Sol 921 (Aug 5, 2006): Plans called for Spirit to acquire panoramic camera images of a soil target known as "Tyrone."

Odometry
As of sol 918 (Aug. 2, 2006), Spirit's total odometry remained at 6,876.18 metres.

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SPIRIT UPDATE: NASA's Spirit Rover Survives Record Cold on Mars - sol 908-914, July 29, 2006:

Spirit remains healthy and continues to make progress on computer upgrades and scientific research, despite winter temperatures colder than any yet experienced during the rover's two and a half years on Mars. Models show that at the coldest part of the Martian night, around 5:00 a.m. Mars time, temperatures near the surface have dipped to approximately minus 97 degrees Celsius.
With the deepest part of the Martian winter just around the corner, Spirit is collecting about 284 watt-hours of electrical power each sol from the rover's solar array (a hundred watt-hours is the amount of electricity needed to light one 100-watt bulb for one hour). The shortest day, winter solstice in Mars' southern hemisphere, will arrive on Aug. 8, 2006. The lowest amount of solar energy the rover is expected to receive is about 275 watt-hours per sol.
Spirit has put the finishing touches on a new version of its flight software -- assembling, checking, and saving 200 sections of computer code transmitted from Earth in recent weeks. The software upgrade will give the rover enhanced autonomous operational capabilities. NASA plans for Spirit to switch from its current flight software to the new version in coming weeks.
Meanwhile, Spirit is only one frame away from completing the long-anticipated "McMurdo panorama," a full-colour, 360-degree view of the rover's winter haven amid the "Columbia Hills" in Gusev Crater on Mars. The collection of images from the panoramic camera, as with all scientific data, has taken extra time to complete with the sun lower on the horizon and solar power levels on the wane. During the week, Spirit also used the microscopic imager to get a closer look at a small ripple nicknamed "Palmer."
For the next several weeks until Labour Day, Spirit will communicate with Earth only using UHF-band relay via NASA's Mars Odyssey orbiter. The X-band Spirit uses for communicating directly with Earth will not be available while that frequency is used intensively by NASA's Mars Reconnaissance Orbiter in the final stages of trimming its orbit around Mars.

Sol-by-sol summary:

Sol 908 (July 23, 2006): Spirit took microscopic images of Palmer.

Sol 909: Spirit continued work on the McMurdo panorama and used its miniature thermal emission spectrometer to study a rock target known as "Korolev2."

Sol 910: Spirit continued work on the McMurdo panorama and cleaned and calibrated the rock abrasion tool.

Sol 911: Spirit continued work on the McMurdo panorama and gathered remote-sensing information about a target known as "Druzhnaya."

Sol 912: Spirit continued work on the McMurdo panorama.

Sol 913: Spirit took microscopic images of a target known as "Palmer2."

Sol 914 (June 29, 2006): Plans call for Spirit to continue work on the McMurdo panorama.

Odometry
As of sol 911 (July 26, 2006), Spirit's total odometry remained at 6,876.18 metres.

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Spirit image from Sol 911

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A Spirit image from Sol 906.

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SPIRIT UPDATE: Spirit Clears Away Dust, Gets New Software Upgrade - sol 904-907, July 21, 2006:

Beginning July 22, 2006, in the early hours of the rover's 907th Martian day, Spirit is scheduled to begin knitting together and testing all 200 pieces of a new flight software package transmitted to the rover in recent weeks. Spirit remains healthy despite experiencing lower amounts of solar energy during the Martian winter.
The deepest part of the Martian winter - that is, the Martian winter solstice - will be on Aug. 8, 2006. The lowest amount of solar energy the rover is expected to receive is 275 watt-hours per sol (a hundred watt-hours is the amount of electricity needed to light one 100-watt bulb for one hour). The rover typically spends at least one sol recharging the batteries following each sol of heavy science activities.
During sols 904 through 907, Spirit continued work on the "McMurdo panorama," examined rock target "Halley Brunt" with the microscopic imager, and took atmospheric measurements with the miniature thermal emission spectrometer.
Spirit also completed a test of the rock abrasion tool. Rover handlers ran the grind motor on the rock abrasion tool backward three times to remove a clod of dust that was thought to be interfering with the operation of the device. After running the motor backward for three seconds at three different voltages -- 5 volts, 8 volts, and 10 volts -- engineers concluded that the tool was operating normally and that it either never had a problem or dislodged whatever was stuck beneath the bit.

Sol-by-sol summary:

Sol 904 (July 19, 2006): Spirit monitored atmospheric dust with the panoramic camera and acquired a mosaic of microscopic images of a rock and soil target known as "Halley Brunt Offset1." The rover ran the rock abrasion tool backward to remove dust. In preparation for traversing and collecting data from a laminated patch of soil known as "Palmer," the rover suspended the Mössbauer spectrometer above the target and documented the position of the instrument with the hazard avoidance cameras. Spirit continued to make progress on the McMurdo mosaic, acquiring one frame of column 24.

Sol 905: Spirit monitored atmospheric dust with the panoramic camera, acquired another frame of column 24 of the McMurdo panorama, checked for drift (changes with time) in the pointing of the miniature thermal emission spectrometer, and surveyed the sky and ground with the miniature thermal emission spectrometer.

Sol 906: Commands for uplink on sol 906 call for Spirit to monitor atmospheric dust with the panoramic camera. The plan also includes Spirit's task for the morning of sol 907, before that morning's uplink. This task is for Spirit to build the rover's new flight software package, a process that entails assembling, validating, and saving many thousands of lines of computer code sent from Earth in small packages during the past few weeks.

Sol 907 (July 22, 2006): Plans called for Spirit to monitor atmospheric dust with the panoramic camera and check for drift (changes with time) in the pointing of the miniature thermal emission spectrometer. Spirit was also scheduled to conduct surveys of the sky and ground with the miniature thermal emission spectrometer and acquire the first frame of column 25 of the McMurdo pan.

Odometry
As of sol 904 (July 19, 2006), Spirit's total odometry remained at 6,876.18 metres.

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Engineers designed NASA's Mars Exploration Rovers to be exceptionally predictable when it comes to studying specific rocks and patches of soil. For example, each rover can remove the robotic arm from a target, switch scientific instruments, and resume analysis within 1 millimetre of the original position.
Most samples analysed by the scientific instruments are large enough that a positioning accuracy of approximately 1 centimetre is acceptable. At the current winter outpost of NASA's Spirit rover, however, the science team was interested in analysing a small, reflective spot only 1 centimetre in diameter associated with a rock target called "Halley". In this instance, a positioning error of 1 centimetre could have missed the target entirely. To be sure this wouldn't happen, team members created a 2x1 microscopic image mosaic of the target based on stereo imaging models of the terrain obtained by Spirit on sol 861 (June 5, 2006). The stereo images from the hazard avoidance cameras provided detailed views as well as distance to features in the field of view. The region of interest - a bit of sparkly, light-toned material - turned out to be offset slightly, as shown in the mosaic.

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Image credit: NASA/JPL-Caltech/Cornell/USGS

Given the exceptional repeatability in positioning the robotic arm, engineers were able to transmit the desired coordinates for further study and direct the rover to place the alpha particle X-ray spectrometer and Mässbauer spectrometer in that particular spot, allowing analyses of the light-toned material. A subsequent microscopic image, 32 millimetres wide, of the target known as "Halley_Brunt," acquired on sol 880 (June 24, 2006) and shown here, documented that the rover did, in fact, place both spectrometers in the optimum position and analyse the desired patch of sparkly material on the Martian surface.

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SPIRIT UPDATE: Spirit to Get New Robotic Capabilities As Martian Winter Turns to Spring - sol 897-904, July 14, 2006:

This week Spirit greeted the 900th day, or sol, of exploration on Mars. Spirit is healthy and continues to make science observations despite winter power limitations. One file of a new software upgrade remains to be transmitted to the rover. Rover handlers plan to have Spirit start using the new software sometime in mid-August. The upgrade will enable the rover to process images more quickly and focus on a single target more efficiently and, when solar power levels increase again, demonstrate new robotic autonomous capabilities.
While studying images from the panoramic and hazard avoidance cameras to characterize dirt buildup on the rock abrasion tool, science and engineering team members discovered a possible small clod of dirt lodged in the device. They are considering running the rock abrasion tool backward in an attempt to dislodge it.
Solar array input was down to about 280 watt-hours per sol (a hundred watt-hours is the amount of electricity needed to light one 100-watt bulb for one hour).

Sol-by-sol summary:

Sol 897 (July 12, 2006): Spirit acquired panoramic camera images of a rock believed to be a meteorite known as "Zhong Shan."

Sol 898: Spirit acquired panoramic camera images of a dark rock known as "Orcadas."

Sol 899: Spirit acquired images with the panoramic camera for the "McMurdo panorama."

Sol 900: Plans called for Spirit to monitor atmospheric dust with the panoramic camera.

Sol 901: Plans called for continued analysis of the soil target known as "Halley" with the alpha particle X-ray spectrometer.

Sol 902: Spirit was scheduled to collect more images for the McMurdo panorama.

Sol 903: Plans called for Spirit to recharge the batteries.

Sols 904 (July 19, 2006): Plans called for reverse operation of the rock abrasion tool to attempt to dislodge something that looks like a clod of dirt.

Odometry:
As of sol 898 (July 13, 2006), Spirit's total odometry was at 6,876.18 metres.

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Spirit on Sol 900

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From its winter outpost at "Low Ridge" inside Gusev Crater, NASA's Mars Exploration Rover Spirit took this spectacular, colour mosaic of hilly, sandy terrain and two potential iron meteorites. The two light-coloured, smooth rocks about two-thirds of the way up from the bottom of the frame have been labelled "Zhong Shan" and "Allan Hills."

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Credit: NASA

The two rocks' informal names are in keeping with the rover science team's campaign to nickname rocks and soils in the area after locations in Antarctica. Zhong Shang is an Antarctic base that the People's Republic of China opened on Feb. 26, 1989, at the Larsemann Hills in Prydz Bay in East Antarctica. Allan Hills is a location where researchers have found many Martian meteorites, including the controversial ALH84001, which achieved fame in 1996 when NASA scientists suggested that it might contain evidence for fossilised extraterrestrial life. Zhong Shan was the given name of Dr. Sun Yat-sen (1866-1925), known as the "Father of Modern China." Born to a peasant family in Guangdong, Sun moved to live with his brother in Honolulu at age 13 and later became a medical doctor. He led a series of uprisings against the Qing dynasty that began in 1894 and eventually succeeded in 1911. Sun served as the first provisional president when the Republic of China was founded in 1912.

The Zhong Shan and Allan Hills rocks, at the left and right, respectively, have unusual morphologies and miniature thermal emission spectrometer signatures that resemble those of a rock known as "Heat Shield" at the Meridiani site explored by Spirit's twin, Opportunity. Opportunity's analyses revealed Heat Shield to be an iron meteorite.

Spirit acquired this false-colour image on the rover's 872nd Martian day, or sol (June 16, 2006), using exposures taken through three of the panoramic camera's filters, centred on wavelengths of 750 nanometres, 530 nanometres, and 430 nanometres. The image is presented in false colour to emphasise differences among materials in the rocks and soil.