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RE: The Opportunity rover

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OPPORTUNITY UPDATE: Brightening Skies Bolster Opportunity - sol 1256-1265, Aug 23, 2007:

Opportunity is healthy and remains perched near the rim of "Victoria Crater." The rover was on a low-power schedule that alternated between a 3-sol plan and a 4-sol plan.
Tau (atmospheric opacity) has begun to stabilise this week at around 3.7, resulting in solar array energy between 230-240 watt hours. Therefore in the upcoming week, the team will return to nominal planning.
The rover conducted a lot of what engineers call "runout science." This includes: panoramic camera wide-range tau measurements, navigation camera tau measurements, navigation camera cloud measurements, panoramic camera soria (imaging a rough, rocky area near the rover), front hazard avoidance camera images, rear hazard avoidance camera images, navigation camera images, panoramic camera sky spot, panoramic camera dust monitoring on the mast, miniature thermal emission spectrometer target calibration and panoramic camera high-sun surveys.

Sol-by-sol summary:

Sol 1256: Opportunity conducted one hour of runout science.

Sol 1257: On this sol, the rover's activities included the following: uplinked on high-gain antenna, panoramic camera wide-range tau, navigation camera tau, navigation camera bitty cloud, panoramic camera soria, front hazard avoidance camera images, rear hazard avoidance camera images, navigation camera images, panoramic camera wide-range tau, panoramic camera horizon survey, panoramic camera calibration target, mast dust monitoring, miniature thermal emission spectrometer calibration target and panoramic camera high-sun survey.

Sol 1258: Opportunity conducted 45 minutes of of runout science.

Sol 1259: On this sol, the rover did 30 minutes of runout science and completed a UHF data downlink.

Sol 1260: Opportunity conducted 45 minutes of runout science.

Sol 1261: Opportunity's activities included the following: uplink on high-gain antenna, engineering navigation camera tau, panoramic camera wide range tau, panoramic camera soria calibration target, front hazard avoidance camera images, rear hazard avoidance camera images, navigation camera images, panoramic camera high-sun sky survey, pancam wide range tau and UHF downlink.

Sol 1262: The rover did 30 minutes of runout science and completed a UHF downlink.

Sol 1263: Opportunity conducted 45 minutes of runout science.

Sol 1264: On this sol, the rover's activities included the following: uplink on the high-gain antenna, engineering navigation camera tau, panoramic camera wide-range tau, panoramic camera soria calibration target, front hazard avoidance camera images, rear hazard avoidance camera images, panoramic camera sky thumbs and panoramic camera wide-range tau.

Sol 1265: 45 minutes of runout science and UHF downlink.

Odometry:
Opportunity's odometery is 11,462.94 meters as of the last drive on sol 1232.

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Image taken by the Opportunity rover on Sol 1268

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Credit: NASA/JPL

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Image taken by the Opportunity rover on Sol 1254

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Credit NASA

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Mars Exploration Rover Status Report Concern Increasing About Opportunity

Rover engineers are growing increasingly concerned about the temperature of vital electronics on NASA's Mars Exploration Rover Opportunity while the rover stays nearly inactive due to a series of dust storms that has lasted for more than a month.
Dust in the atmosphere and dust settling onto Opportunity's solar panels challenges the ability of the solar panels to convert sunlight into enough electricity to supply the rover's needs. The most recent communication from Opportunity, received Monday, July 30, indicates that sunlight over the rover's Meridiani Planum location remains only slightly less obscured than during the dustiest days Opportunity survived in mid-July. With dust now accumulating on the solar panels, the rover is producing barely as much energy as it is using in a very-low-power regimen it has been following since July 18.
Keeping Opportunity's activity to a minimum has reduced the amount of energy going into the rover's electronics core, reducing the amount of heat that comes from the electronics components themselves during normal operation.

"The overnight low temperature of Opportunity's electronics module has been dropping since we implemented the very-low-power operation, even though the outside environment is actually warmer during this dust storm" - John Callas, rover project manager at NASA's Jet Propulsion Laboratory, Pasadena, California.

That temperature has dropped to minus 37 Celsius, within about 2 Celsius degrees of triggering survival heaters to turn on. Those heaters could push the rover's total use of electricity higher than what the solar panels produce, soon depleting the batteries.

"This is energy Opportunity does not have to spare" .

To forestall the survival heaters from turning on, the rover team has altered Opportunity's daily regimen to keep the electronics active for a longer period each day. This, too, could put the rover through some negative-net-energy days if the sky does not begin to clear.

"This means there is a real risk that Opportunity will trip a low-power fault sometime during this plan. When a low-power fault is tripped, the rover's systems take the batteries off-line, putting the rover to sleep and then checking each sol to see if there is sufficient available energy to wake up and perform daily fault communications. If there is not sufficient energy, Opportunity will stay asleep. Depending on the weather conditions, Opportunity could stay asleep for days, weeks or even months, all the while trying to charge her batteries with whatever available sunlight there might be" - John Callas.

Spirit, meanwhile, is also accumulating some dust on solar panels under a sky at Gusev Crater that remains nearly as dusty as the worst Spirit has recorded.

"We will continue to watch the situation on Mars and do all we can to assist our rovers in this ongoing battle against the environmental elements on the Red Planet" - John Callas.

Source NASA

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Opportunity - Waiting for the Dust to Settle

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RE: The Opportunity rover

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NASA's Opportunity rover is literally seeing some of its darkest days. Both Mars Exploration Rovers have been riding out a regional dust storm for several weeks. Conditions became particularly dreary in the Meridiani Planum region where Opportunity sits, perched on the edge of "Victoria Crater."

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This image is a time-lapse composite where each horizon-survey image has been compressed horizontally to emphasise the sky. The relative brightness and darkness of the sky from sol to sol (over a 30-sol period beginning June 14, 2007) is depicted accurately in these images, which view roughly the same part of the plains southwest of the rover. The images are approximately true colour composites, generated from calibrated radiance data files using the panoramic camera's 601-nanometer, 535-nanometer and 482-nanometer filters.
The rovers' atmospheric science team is concerned that smaller, regional dust storms could expand into a larger, globe-encircling storm. That could extend the time the sun stays obscured, challenging the capability of Opportunity's solar panels to produce enough electricity for the rover to function.
Fortunately, as of July 19, 2007, the Opportunity site is clearing slightly. When the storm ends, atmospheric scientists hope to review data from the rovers that will help them determine what sort of dust was being lifted and distributed.
The numbers across the top of the image report a measurement of atmospheric opacity, called by the Greek letter tau. The lower the number, the clearer the sky. Both Opportunity and Spirit have been recording higher tau measurements in July 2007 than they had seen any time previously in their three and a half years on Mars. The five sol numbers across the bottom correspond (left to right) to June 14, June 30, July 5, July 13 and July 15, 2007.

Source: NASA

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Huge dust storms raging on Mars pose the worst threat yet to Nasa's robot rovers, the US space agency has said.
Dust is starving the rovers of power by blocking out the sunlight needed to charge their batteries.
The six-wheeled, solar-powered rovers Opportunity and Spirit, are operating at two distant sites just south of the Martian equator.
A series of dust storms have dogged the rovers for a month, and could continue for several more days, if not weeks.
If the sunlight is further reduced over an extended period, the rovers will not be able to generate enough power to operate or keep themselves warm.

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Image taken by the Opportunity rover on Sol 1235.

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Credit NASA
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