MARS - de missies (DEEL 5)

quote:

Dust on Mars: Before and After (Spirit

Since landing on Mars a year ago, NASA's pair of six-wheeled geologists have been constantly exposed to martian winds and dust. Both rovers have been coated by some dust falling out of the atmosphere during that time, with estimates of the dust thickness ranging from 1 to 10 micrometers, or between 1/100th and 1/10th the width of a single human hair. Of the two, NASA's Mars Exploration Rover Spirit is definitely the more dust-laden. As a result, Spirit has gradually experienced a decline in power as the thin layer of dust has accumulated on the solar panels, blocking some of the sunlight that is converted to electricity. Spirit took the left image on martian day, or sol, 9 (Jan. 11, 2004), and took the right image nearly a year later, on sol 357 (Jan. 3, 2005), using the panoramic camera. The images show the camera's calibration target, which is used as a reference point for calibrating the colors on Mars. In the later image a semi-transparent layer of reddish martian dust coats the surfaces. The panoramic camera team's analysis indicates that the layer of dust on Spirit's calibration target is about 70 percent thicker than that on Opportunity's. Both images represent the panoramic camera team's best current attempt at generating true color views of what these scenes would look like if viewed by a human on Mars. They were each generated from a combination of six calibrated, left-eye Pancam images acquired through filters ranging from 430-nanometer to 750-nanometer wavelengths. The diameter of the outer ring of the calibration target is 8 centimeters (3.15 inches).

Image credit: NASA/JPL/Cornell
Browse Image (29.5 kB) | Large (191 kB)


Dust Accumulation on Mars

Since landing on Mars a year ago, NASA’s pair of six-wheeled geologists have been constantly exposed to martian winds and dust. As a result, the Spirit rover has gradually experienced a slight decline in power as a thin layer of dust has accumulated on the solar panels, blocking some of the sunlight that is converted to electricity. In this enlarged image of a postage-stamp-size (3-centimeter-square, 1.2-inch-square) portion of one of Spirit’s solar panels, a fine layer of martian dust coats electrical connections and metal surfaces. Individual silt grains or clumps of dust are visible where sediment has accumulated in crevices between solar cells and circuits. The upper right half of the image shows the edge of one of the rover’s solar cells. The lower left half shows electrical wires bonded with silicon adhesive to the underlying composite surface; the circular abrasions are the result of sanding by hand on Earth. The braided wire is connected to a thermocouple used to measure temperature based on electrical resistance. Spirit took this image with its microscopic imager on martian day, or sol, 350 (Dec. 26, 2004).

Image credit: JPL/NASA/Cornell/USGS
Browse Image (42.5 kB) | Large (559 kB)

quote:

Dust on Mars: Before and After (Opportunity)

Since landing on Mars a year ago, NASA's pair of six-wheeled geologists have been constantly exposed to martian winds and dust. Both rovers have been coated by some dust falling out of the atmosphere during that time, with estimates of the dust thickness ranging from 1 to 10 micrometers, or between 1/100th and 1/10th the width of a single human hair. Of the two, NASA's Mars Exploration Rover Spirit is definitely the more dust-laden. The Opportunity rover, as shown here, appears to be collecting less dust, perhaps because of a cleaning by wind or even "scavenging" of dust by frost that forms on the rover some nights during the martian winter.
( See image of frost on Opportunity .)

Opportunity took the left image on martian day, or sol, 23 (Feb. 16, 2004), and took the right image about 11 months later, on sol 346 (Jan. 13, 2005), using the panoramic camera. Both images show the camera's calibration target, which is used as a reference point for calibrating the colors on Mars. In the later image, the surfaces have become only mildly dusty compared to shortly after landing. Both images represent the panoramic camera team's best current attempt at generating true-color views of what these scenes would look like if viewed by a human on Mars. They were each generated using a combination of six calibrated, left-eye Pancam images acquired through filters ranging from 430-nanometer to 750-nanometer wavelengths. The diameter of the outer ring of the calibration target is 8 centimeters (3.15 inches).

Image credit: NASA/JPL/Cornell
Browse Image (31.5 kB) | Large (194 kB)

quote:

Looking Back Across the Plains

NASA's Mars Exploration Rover Opportunity
looks through its navigation camera as it leaves
the home it has known for over 200 sols.
The rover spent 181 sols inside "Endurance Crater,"
furthering our knowledge of ancient water on Mars.
After that challenging work, it spent 25 sols investigating the heat shield
that protected it on its way through the martian atmosphere and the nearby
meteorite that was the first discovered on another planet.
Opportunity is saying 'so long' and heading south for a small crater referred to as "Argo."

This image was taken on the rover's 359th sol on Mars (January 26, 2005).

Image credit: NASA/JPL

Browse Image (41.6 kB) | Large (527 kB)

quote:

Op woensdag 23 februari 2005 11:06 schreef Doffy het volgende:
Ongelofelijk! Nu is er zulk nieuws over Mars, en dan wordt dat in dit topic niet onmiddelijk gemeld!

quote:

Op woensdag 23 februari 2005 14:48 schreef Alicey het volgende:
TT aangepast.

quote:

Op woensdag 23 februari 2005 14:48 schreef Doffy het volgende:

[..]

Ah, ok. Ik vond de TT algemeen genoeg -en de ontdekking belangrijk genoeg!- om het te posten. Hoop dat je het niet erg vindt!

quote:

Mars Rovers Break Driving Records, Examine Salty Soil
March 02, 2005



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 .


###
Guy Webster (818) 354-6278
Jet Propulsion Laboratory, Pasadena, California

Dolores Beasley (202) 358-1753
NASA Headquarters, Washington

quote:

A. B.

Churned-Up Rocky Debris and Dust

NASA's Mars Exploration Rover Spirit has been analyzing sulfur-rich rocks and surface materials in the "Columbia Hills" in Gusev Crater on Mars. This image shows rocky debris and dust, which planetary scientists call "regolith" or "soil," that has been churned up by the rover wheels. This 40-centimeter-wide (16-inch-wide) patch of churned-up dirt, nicknamed "Paso Robles," contains brighter patches measured to be high in sulfur by Spirit's alpha particle X-ray Spectrometer. Spirit's panoramic camera took this (A) false-color (B) true-color image on martian day, or sol, 400 (Feb. 16, 2005), using filters at wavelengths of 750, 530, and 430 nanometers. Darker red hues in the image correspond to greater concentrations of oxidized soil and dust. Whiter and bluer hues correspond to sulfur-rich deposits that are not as heavily coated with soils or are not as highly oxidized.


A. B.

Sulfur-Rich Rocks and Dirt

NASA's Mars Exploration Rover Spirit has been analyzing sulfur-rich rocks and surface materials in the "Columbia Hills" in Gusev Crater on Mars. This image of a very soft, nodular, layered rock nicknamed "Peace" in honor of Martin Luther King Jr. shows a 4.5-centimeter-wide (1.8-inch-wide) hole Spirit ground into the surface with the rover's rock abrasion tool. The high sulfur content of the rock measured by Spirit's alpha particle X-ray spectrometer and its softness measured by the abrasion tool are probably evidence of past alteration by water. Spirit's panoramic camera took this (A) false-color (B) true-color image on martian day, or sol, 381 (Jan. 27, 2005), using Pancam filters at wavelengths of 750, 530, and 430 nanometers. Darker red hues in the image correspond to greater concentrations of oxidized soil and dust. Bluer hues correspond to sulfur-rich rock excavated or exposed by the abrasion tool and not as heavily coated with soils or not as highly oxidized.

quote:

Mars rover gets new lease on life
_{Dust devil cleans Spirit's solar arrays}


Klik foto


Mars scientists and engineers are elated about a dust-busting blast that has struck the Spirit rover at its Gusev crater exploration site.

Turns out that a martian whirlwind – dubbed a dust devil – likely zoomed over the robot high up in the Columbia Hills. That fleeting flyby effectively cleaned Spirit’s solar arrays, giving the robot a new lease on life.

Engineers report that the rover’s power reading quickly shot up to almost as high as when the rover landed on Mars over a year ago.

Gusev: Alive with dust devils

Rover scientists suspected something was up at the Gusev site when Spirit’s wheel tracks were disappearing. Onboard cameras could look down and see the tracks vanishing. Rover team members assumed that the site was experiencing a heavy dust loading in the atmosphere.

Indeed, the rover’s energy quickly dropped. Seeing the robot’s decreasing power level, controllers started to consider cutting back on rover Mars work.

"Gusev was alive with dust devils," explained one scientist familiar with rover operations.

But suddenly Spirit’s available energy rocketed to a high level. The plus-up in power, team members believe, was due to a whirlwind passing right over the robot, removing the dust that had collected on its solar cells.

Martian squeegee men

The impact of the devilish dust-off was significant.

"The noon solar output from the panels went from a 40 percent loss to just 7 percent," said rover science team member, Larry Crumpler, a research curator in volcanology and space sciences at the New Mexico Museum of Natural History and Science in Albuquerque.

Images of the panels taken later showed "beautiful dark panels," Crumpler explained. "And all the wires and edges on the [rover] deck have little dust tails. I think it might have been the Martian squeegee men. Either that or one heck of a buffeting by a dust devil," he said.


Spirit has been busy wrapping up a spectacular panorama from the vantage point of "Larry’s Lookout."

Miracle cleaning event

Earlier this month, lead investigator for the Mars Exploration Rover mission, Steve Squyres of Cornell University, noted that Spirit’s depleted power was reducing the number of hours per day available to snap photos.

Squyres couldn’t gauge the chance of what he called a "miracle cleaning event" – akin to what occurred months ago on Opportunity, its sister robot on the other side of Mars. "If it happens, I’ll take it!"

"We have to assume the worst…that the solar panels are going to stay dirty and just get dirtier," Squyres told SPACE.com at the time.

As to what caused Opportunity’s solar panels at Meridiani Planum to become cleaned is a puzzle, Squyres said. "Wind has to be involved at some level you figure. Frost might have helped. A frost build-up on arrays could coagulate the dust…but the fact is that we don’t understand it very well. But I’ll take it."

quote:

Next Stop: 'Methuselah'



NASA's Mars Exploration Rover Spirit is approaching an outcrop dubbed "Methuselah," which scientists intend for the rover to examine in detail for several days before resuming an uphill climb. This false-color view is assembled from frames taken by Spirit's panoramic camera on the rover's 454th martian day, or sol (April 13, 2005). It shows a region in the "Columbia Hills" slightly downhill from the rover. The view features two interesting outcrops in the middle distance and "Clark Hill" in the left background. The outcrop on the right, with rover tracks leading from it, is "Larry's Lookout." On the left is the Methuselah outcrop, with apparent layering. This view combines images taken through the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.


Gusev Dust Devil Movie, Sol 456 (Plain and Isolated)

quote:

Op zaterdag 23 april 2005 20:54 schreef BabeWatcher het volgende:
Die Dust Devil lijkt mij niet meer dan een doodgewone windhoos zoals wij die hier ook wel eens boven zandvlaktes hebben.

quote:

Op woensdag 13 april 2005 19:18 schreef -CRASH- het volgende:
Lijkt wel een kleine meteoriet inslag...

quote:

Alweer een bevestiging.....

Opportunity Discovers Tiny Craters on Mars

27 April

On Earth, people tend to think of craters as giant holes in the ground like Meteor Crater in Arizona, ancient features too big to miss that mark the site of a catastrophic collision with an asteroid or comet.

But craters can also be small objects, like the two discovered recently by the Opportunity rover on the plains of Meridiani on Mars. Both are less than half an inch deep and clearly visible in images taken by the rover's navigation cameras.

"These are the smallest craters yet observed by either rover," said Matt Golombek, a veteran Mars researcher at NASA's Jet Propulsion Laboratory and principal scientist on the Mars Exploration Rover mission. "I think the smallest crater we saw in Gusev Crater (where Opportunity's twin, the Spirit rover, is exploring the other side of Mars) was 40 centimeters (15.7 inches) wide and that was in a hollow that had already been filled by sand and sediment."

The largest of the two craters discovered by Opportunity is only half as big, measuring 20 centimeters (7.9 inches) in diameter and 1 centimeter (0.4 inches) deep. The smallest of the two is 10 centimeters (3.9 inches) wide and less than 1 centimeter deep. Opportunity took pictures of the two tiny craters with its left and right navigation cameras, creating a stereo image that allowed scientists to measure their distance and size.

On Earth, small craters are not commonly recognized because they're quickly filled with dirt, pine needles, or other debris carried by water and wind. On Mars, craters are primarily filled by wind-blown sediment, though in the past they may also have been filled by lava, melting ice, or flowing water.

"Given that these two craters haven't been covered by sand even though they are surrounded by sand ripples on a flat plain lends support to the idea that they're fairly recent," said Golombek. "Of course, recent might mean any time from yesterday to 100 million years ago."

Both are impact craters formed either by an object from space that was large enough to make it through the martian atmosphere without burning up or by rock fragments ejected from a larger crater that formed when something crashed into the martian surface.

"Come to think of it," added Golombek, "there were also no small, fresh craters seen by the previous three martian landers, which include Pathfinder and the two Viking landers. These are the smallest craters yet seen on Mars." Golombek was project scientist for the Pathfinder mission.

quote:

Op donderdag 19 mei 2005 09:43 schreef Frutsel het volgende:
Cassini finds tiny moon tucked in Saturn's rings
-knip-