Mars Rovers Break Driving Records, Examine Salty Soil

MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov
Guy Webster (818) 354-6278 Jet Propulsion Laboratory, Pasadena, Calif.
Dolores Beasley (202) 358-1753 NASA Headquarters, Washington
News Release: 2005-038 March 2, 2005
Mars Rovers Break Driving Records, Examine Salty Soil
On three consecutive days, NASA's Mars Exploration Rover Opportunity accomplished unprecedented feats of martian motion, covering more total ground in that period than either Opportunity or its twin, Spirit, did in their first 70 days on Mars.
Spirit, meanwhile, has uncovered soil that is more than half salt, adding to the evidence for Mars' wet past. The golf- cart-size robots successfully completed their three-month primary missions in April 2004 and are continuing extended mission operations.
Opportunity set a one-day distance record for martian driving, 177.5 meters (582 feet), on Feb. 19. That was the first day of a three-day plan transmitted to the rover as a combined set of weekend instructions. During the preceding week, engineers at NASA's Jet Propulsion Laboratory had sent Opportunity and Spirit an upgrade of the rovers' software, onboard intelligence the rovers use for carrying out day-to- day commands.
The new record exceeded a two-week old former best by 13 percent. As on all previous long drives by either rover, the traverse began with "blind" driving, in which the rover followed a route determined in advance by rover planners at JPL using stereo images. That portion lasted an hour and covered most of the day's distance. Then Opportunity switched to "autonomous" driving for two and a half hours, pausing every 2 meters (6.6 feet) to look ahead for obstacles as it chose its own route ahead.
The next day, Opportunity used its new software to start another drive navigating for itself. "This is the first time either rover has picked up on a second day with continued autonomous driving," said Dr. Mark Maimone, rover mobility software engineer at JPL. "It's good to sit back and let the rover do the driving for us."
Not only did Opportunity avoid obstacles for four hours of driving, it covered more ground than a football field. Opportunity has a favorable power situation, due to relatively clean solar panels and increasing minutes of daylight each day as spring approaches in Mars' southern hemisphere. This allows several hours of operations daily.
On the third day of the three-day plan, the robotic geologist continued navigating itself and drove even farther, 109 meters (357 feet), pushing the three-day total to 390 meters (nearly a quarter mile). In one long weekend, Opportunity covered a distance equivalent to more than half of the 600 meters that had been part of each rover's original mission- success criteria during their first three months on Mars.
Opportunity has now driven 3,014 meters (1.87 miles) since landing; Spirit even farther, 4,157 meters (2.58 miles). Opportunity is heading south toward a rugged landscape called "etched terrain," where it might find exposures of deeper layers of bedrock than it has seen so far. Spirit is climbing "Husband Hill," with a pause on a ridge overlooking a valley north of the summit to see whether any potential targets below warrant a side trip.
As Spirit struggled up the slope approaching the ridgeline, the rover's wheels churned up soil that grabbed scientists' attention. "This was an absolutely serendipitous discovery," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rovers' science instruments. "We said, 'My gosh, that soil looks very bright. Before we go away, we should at least take a taste."
The bright patch of disturbed soil, dubbed "Paso Robles," has the highest salt concentration of any rock or soil ever examined on Mars. Combined information gained from inspecting it with Spirit's three spectrometers and panoramic camera suggests its main ingredient is an iron sulfate salt with water molecules bound into the mineral. The soil patch is also rich in phosphorus, but not otherwise like a high- phosphorus rock, called "Wishstone," that Spirit examined in December. "We're still trying to work out what this means, but clearly, with this much salt around, water had a hand here," Squyres said.
Meanwhile, scientists are re-calibrating data from both rovers' alpha particle X-ray spectrometers. These instruments are used to assess targets' elemental composition. The sensor heads for the two instruments were switched before launch. Therefore, data that Opportunity's spectrometer has collected have been analyzed using calibration files for Spirit's, and vice-versa. Fortunately, because the sensor heads are nearly identical, the effect on the elemental abundances determined by the instruments was very small. The scientists have taken this opportunity to go back and review the results for the mission so far and re-compute using correct calibration files. "The effect in all cases was less than the uncertainties in results, so none of our science conclusions are affected," Squyres said.
JPL, a division of the California Institute of Technology in Pasadena, has managed NASA's Mars Exploration Rover project since it began in 2000. Images and additional information about the rovers and their discoveries are available on the Internet at http://www.nasa.gov/vision/universe/solarsystem/mer_main.html and http://marsrovers.jpl.nasa.gov . -end-
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snipped-for-privacy@earthlink.net wrote:

But the Opportunitiy site is almost at the equator, so the length of the day is not changing considerably. What changes is the angle of the sun, and the distance Mars - Sun. They are telling us the same bullshit as last year. If they are not willing to provide correct information on such simple matters how can we believe the rest of the story where we are not able to verify the truth ?
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wrote:

He didn't say it was changing considerably. He said it was by increasing "minutes." That could be just 2. If the sun is at a higher angle, couldn't it be above the horizon for 2 or more minutes each day?
rj
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randyj wrote:

May be, but that would not change the energy output of the solar cells substancially. I thought that he meant it was increasing minutes each day such as it is on Earth north of 45 latitude now. That would change something, but this cannot happen at opportunity site.

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wrote:

couldn't
He never said the output of the solar cells changed "substancially." He simply said Opportunity "has a favorable power situation"
Your characterization of bs is way off the mark.
rj
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randyj wrote:

He clearly attributes the favorable power situation to increasing minutes of daylight, and that is bs: ".. due to ... and increasing minutes of daylight..."
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Carla Schneider wrote:

Hmm...lets see. The rovers shut themselves down at night. This is a situation where every second of available uptime is worth it's weight in gold to the science these rovers are doing. The longer the sun is up and power is available to the panels, the longer the science can continue for that day. Nobody ever said anyhitng about an increased power output of the panels due to the sun. They did attribute a lack of LOSS of efficiency of the panels due to the fact of them being relatively clean, and the lengthening day (even by minutes) means that more science can go on for a longer period each day.
Wheres all the bs your talking about?
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Clearly it's in her posts, as witness that elision above. She has to leave out part of what he says in order to bolster her case, and even that doesn't work.
rj
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Andy P wrote:

Only in deep sleep mode.

It is total power per day that matters.

That the day didn't lengthen .
They have more power now than a few months ago, because Mars is now nearer to the sun, and the angle incidence of the sun is steeper, but the lenght of the day is immaterial because they are at the equator.
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On a sunny day (Thu, 03 Mar 2005 08:35:26 +0100) it happened Carla Schneider

And they never went to the moon either ;-( Can't wait for the 2005 'Mars Rover Races'.
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Anyone that finds pictures of of the salt-patch are welcome to post it here.
Carsten
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I'll guess sol 404:
<http://origin.mars5.jpl.nasa.gov/gallery/all/2/p/404/2P162233695EFFA618P2559L7M1.HTML
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Silicon Valley
Thanks.
The reasonable assumption that it is an in-situ developement puts general sedimentary processes in some perspective.
Carsten
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