MARS - de missies (DEEL 5)

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Op donderdag 24 mei 2007 03:14 schreef star_gazer het volgende:
Hmmmm.. Niet-kristallijne silicium-dioxide. Dat riekt naar (overblijfselen van) een zeer snel gestold lava (silicaglas, obsidiaan) als je het mij vraagt. Volgens mij hoeft het echt geen water te zijn. Het merkwaardige is dat het op Aarde in de natuur niet veelvuldig voorkomt, maar we er toch wilde conclusies aan verbinden.

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Dust Delays Mars Crater Entry

A giant dust storm brewing for more than a week on Mars has become worse and is affecting surface operations of the Mars Exploration Rovers, Spirit and Opportunity. Because the rovers depend on solar energy for survival, and the dust is partially blocking the sun, the storm is being watched closely by the rover scientists and engineers. Opportunity's entry into Victoria Crater is delayed for at least several days.

The storm, the most severe storm yet to hit the rovers, is expected to continue for at least another week. Opportunity is perched near "Duck Bay" as it readies to descend into Victoria Crater, but operations were scaled back on Saturday, June 30, to conserve power.

"The storm is affecting both rovers and reducing the power levels on Opportunity," said John Callas, Mars Exploration Rover project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We are keeping an eye on this as we go forward, but our entry into Victoria Crater will be delayed until no sooner than July 13."

"We have some data that show the atmospheric opacity is decreasing, so the storm might have peaked and we may have passed the worst of this. The situation could improve quickly from here, but we will have to wait and see," said Callas.

Weather reports from NASA's Mars Reconnaissance Orbiter Mars Color Imager camera are helping track the storm and plan rover operations.

Pictures from the orbiter's Mars Color Imager show the storm is regional in extent, and includes several local areas of especially high dust activity. The storm has been moving eastward and toward mid-latitudes, and is now also causing an increase in atmospheric dust at Spirit's location, on the opposite side of the planet at Gusev Crater. Dust levels at Gusev remain much lower than at the Opportunity site, however.

Both rovers take daily measurements estimating the amount of dust in the atmosphere. The less dust the better, because it means more sunlight reaches the rover's solar panels, which power the vehicles. In the last week, Opportunity has broken its dust record, with the opacity level rising from 1.0 to 3.3. Solar array energy on Opportunity dropped from 765 watt-hours to 402 watt-hours over the same period of time.

"While this only represents enough dust to coat the planet to about the thickness of a human hair, it is enough to decrease the brightness of the noon sun by 96 percent compared to a completely clear atmosphere," said Steve Squyres, principal investigator, Cornell University, Ithaca, N.Y. "Of course, the solar arrays also receive light that is scattered from the dust, so the decrease in power is not nearly that great."

"We have not seen dust measurements this high on either rover before. If the dust levels were to increase further and stay elevated for several days, there is a risk to how well Opportunity could continue to work in this darkened environment," said Callas.

credit: NASA/JPL/Cornell/University of Arizona/Ohio State University

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Evidence of A Wet Martian Past

A shallow trench made by Spirit's dragging right front wheel uncovered some of the best evidence Spirit has found for ancient water-rich environments in Gusev Crater -- bright patches of almost pure, fine-grained silica (SiO2). On ancient Earth, warm, evaporating coastal waters deposited fine silica in shallow sediments. In Yellowstone National Park, hot, mineral-laden waters deposit fine-grained silica around geysers and hot springs. The discovery of silica-rich deposits on Mars adds compelling new evidence of ancient environments that might have been favorable for life.

Spirit acquired this false-color view of the remarkable, light-colored soil patch with the panoramic camera on the rover's 1,198th sol, or Martian day of exploration (May 17, 2007), more than three years after landing on Mars.

credit: NASA/JPL-Caltech/Cornell

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For nearly a month, a series of severe Martian summer dust storms has affected the rover Opportunity and, to a lesser extent, its companion, Spirit. The dust in the Martian atmosphere over Opportunity has blocked 99 percent of direct sunlight to the rover, leaving only the limited diffuse sky light to power it. Scientists fear the storms might continue for several days, if not weeks.

"We're rooting for our rovers to survive these storms, but they were never designed for conditions this intense," said Alan Stern, associate administrator of NASA's Science Mission Directorate, Washington.

If the sunlight is further cut back for an extended period, the rovers will not be able to generate enough power to keep themselves warm and operate at all, even in a near-dormant state. The rovers use electric heaters to keep some of their vital core electronics from becoming too cold.

Before the dust storms began blocking sunlight last month, Opportunity's solar panels had been producing about 700 watt hours of electricity per day, enough to light a 100-watt bulb for seven hours. When dust in the air reduced the panels' daily output to less than 400 watt hours, the rover team suspended driving and most observations, including use of the robotic arm, cameras and spectrometers to study the site where Opportunity is located.


On Tuesday, July 17, the output from Opportunity's solar panels dropped to 148 watt hours, the lowest point for either rover. On Wednesday, Opportunity's solar-panel output dropped even lower, to 128 watt hours.

NASA engineers are taking proactive measures to protect the rovers, especially Opportunity, which is experiencing the brunt of the dust storm. The rovers are showing robust survival characteristics. Spirit, in a location where the storm is currently less severe, has been instructed to conserve battery power by limiting its activities.

"We are taking more aggressive action with both rovers than we needed before," said John Callas, project manager for the twin rovers at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

By Opportunity's 1,236th Martian day, which ended Tuesday, driving and all science observations had already been suspended. The rover still used more energy than its solar panels could generate on that day, drawing down its battery. "The only thing left to cut were some of the communication sessions," Callas said.

To minimize further the amount of energy Opportunity is using, mission controllers sent commands on Wednesday, July 18, instructing the rover to refrain from communicating with Earth on Thursday and Friday. This is the first time either of the rovers has been told to skip communications for a day or more in order to conserve energy. Engineers calculate that skipping communications sessions should lower daily energy use to less than 130 watt hours.

A possible outcome of this storm is that one or both rovers could be damaged permanently or even disabled. Engineers will assess the capability of each rover after the storm clears.

NASA will provide mission updates as events warrant. The Jet Propulsion Laboratory manages the rover project for the Science Mission Directorate.


###
Guy Webster/Gay Yee Hill 818-354-6278/5011
Jet Propulsion Laboratory, Pasadena, California

Dwayne Brown/Tabatha Thompson 202-358-1726/3895
NASA Headquarters, Washington, D.C.
NEWS RELEASE: 2007-080

http://marsrovers.jpl.nas(...)eases/20070720a.html

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MARS ROVER UPDATE:
NASA has heard from Mars rover Opportunity, and the report is promising.
On July 23rd, Opportunity's power levels had improved slightly as a result
of several days of energy-conserving silence and low activity.
The rover is struggling to survive a severe dust storm which has darkened the sky,
reducing sunlight to the rover's solar panels by as much as 99 percent:

Meanwhile on the other side of Mars, weekend communications from Spirit indicated
that the sky had cleared slightly, improving power levels for Spirit as well.
"The outlook for both Opportunity and Spirit depends on the weather, which makes it unpredictable,"
says JPL's John Callas, project manager for both rovers.
"If the weather holds where it is now or gets better, the rovers will be OK. If it gets worse,
the situation becomes more complex."

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DUST STORM UPDATE:
A global dust storm on Mars which began in late June refuses to die down. Clouds of dust are now visible in backyard telescopes and the planet is beginning to resemble a orange billiard ball as all of its underlying surface markings are hidden from view. NASA has commanded Mars rovers Spirit and Opportunity to remain in a state of low activity while solar power is in critically short supply. "We are still waiting out the storms, and we don't know how long they will last or how bad they will get," says John Callas of NASA's Jet Propulsion Laboratory

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GOOD NEWS ON MARS:
After six weeks of hunkering down during raging dust storms that limited solar power, Mars rovers Spirit and Opportunity have resumed driving. The storms, albeit not over, are abating and sunlight is beginning to stream through the clouds. Just one problem: dust is settling on the rover's solar panels, which tends to block the intensifying sunlight. On balance, though, the situation is improving and for now the rovers are back in business: more.

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^{The High Resolution Imaging Experiment (HiRISE) camera operated at The University of Arizona released this new view of the dark pit on Arsia Mons (PSP_004847_1745) today. This view is not the entire HiRISE image, but a close-up of the pit on the Arsia Mons volcano. The new image confirms that the dark pit really is a vertical shaft that cuts through lava flow on the flank of the volcano. Such pits form on similar volcanoes in Hawaii and are called "pit craters." (Credit: NASA/JPL/University of Arizona)}

The High Resolution Imaging Experiment (HiRISE) has confirmed that a dark pit seen on Mars in an earlier HiRISE image really is a vertical shaft that cuts through lava flow on the flank of the Arsia Mons volcano. Such pits form on similar volcanoes in Hawaii and are called "pit craters."
The HiRISE camera, orbiting the red planet on NASA's Mars Reconnaissance Orbiter, is the most powerful camera ever to orbit another planet. It is operated at The University of Arizona in Tucson. HiRISE Principal Investigator Alfred McEwen of the UA's Lunar and Planetary Laboratory and his team released the new image of the dark pit on Arsia Mons and several other stunning images today on the HiRISE Web site, http://hirise.lpl.arizona.edu. New HiRISE images are released on the site every Wednesday.

The UA-based HiRISE team also released another 930 images to the Planetary Data System (PDS), the U.S. space agency's mission data archive, today. These images, taken between May and July 2007, include a view of what at first glance looks deceptively like a mesa set in Swiss cheese terrain. But it's a case of "trompe l'oeil," an eye trick -- the feature is a crater.

The "Swiss cheese" terrain is carbon dioxide ice that "sublimates," or thaws from a solid directly into gas, during the summer, which it currently is at this south polar region of Mars. Carbon dioxide sublimating on steep slopes changes the shape of pits and mesas from year to year. The large depression in this image might be an impact crater, McEwen said, although it's hard to be sure because there's no raised rim or ejecta. Impact craters on the ice cap are modified as the ice-rich terrain "relaxes" over time and as they are resurfaced by the annual deposition and sublimation of frost and ice.

Another image shows a very recent "rayed" dark impact crater among older pocks in the lighter, dust-covered surface. An extremely recent impact, perhaps only a few years or decades ago, created the dark spot with radial and concentric patterns in this HiRISE image. The small central crater is only about 18 meters wide (60 feet), but it formed a dark spot 700 meters wide (two-fifths mile) with rays of secondary craters reaching as far as 3.7 kilometers (more than two miles) from the central crater, McEwen said. Secondary craters are rocks ejected from the central crater. "This region of Mars is covered by dust, and the impact event must have removed or disturbed the dust to create the dark markings," McEwen said.

All HiRISE images released to the PDS can be viewed from the HiRISE site. There also is a direct link to the full directory listing at http://hirise-pds.lpl.arizona.edu/PDS.

Today's release adds another 1.8 terabytes to the PDS. The project turned over its first 1,200 HiRISE images to PDS last May. The PDS now holds a total 3.5 terabytes of HiRISE data, one of the largest single datasets returned from a spacecraft and archived in NASA's space mission library.

Internet users can explore the images with the user-friendly "IAS Viewer" software that can be downloaded from the HiRISE Web site. IAS-Viewer technology allows users to quickly explore part of an enormous HiRISE image because the software transmits only as much data as needed to render any selected part of the image on a computer screen. The tool delivers a high-resolution view of the selected part of the image regardless of slow or limited Internet connections.

The HiRISE camera takes images of 3.5-mile wide (6 kilometer) swaths as the orbiter flies at about 7,800 mph between 155 and 196 miles (250 to 316 kilometers) above Mars' surface. HiRISE science imaging began in November 2006 and will continue at least through November 2008.

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Phoenix Mars Lander: Radar And Other Gear Pass Checkouts
^{by Staff Writers
Pasadena CA (SPX) Sep 06, 2007}

Two crucial tools for a successful landing of America's latest mission to Mars, the radar and UHF radio on NASA's Phoenix Mars Lander, have passed in-flight checkouts. The ultra-high-frequency radio won't be turned on again until landing day, May 25, 2008, when it will relay communications from Phoenix to orbiters already in service around Mars.
Since launch on Aug. 4, 2007, and until the day it reaches Mars, Phoenix is communicating directly with Earth via even higher frequency X-band radio, mounted on a part of the spacecraft that will be jettisoned shortly before Phoenix hits the top of the Martian atmosphere.

The radar will monitor the spacecraft's fast-shrinking distance to the ground during the final three minutes before touchdown on Mars, triggering descent-engine firings and other necessary events during the most challenging moments of the mission.

The Phoenix flight operations team tested the radar and UHF radio on Aug. 24. Four days earlier, the team ran the first in-flight checkout of a Phoenix science instrument. This test focused on the Thermal and Evolved-Gas Analyzer, which will check for water, carbon-containing molecules and other chemicals of interest in the icy soil of Mars. The checkout verified the health of an ion pump, which will be used during the transit to Mars to remove most water vapor carried from Earth with the instrument. Four additional science instruments are scheduled for checkouts before the spacecraft's next trajectory correction maneuver, planned for Oct. 16.

As of Sept. 1, Phoenix will have covered 81 million kilometers (50 million miles) of its 679-million kilometer (422-million-mile) flight to Mars. It is traveling at 34 kilometers per second (76,000 mph) in relation to the sun. Meanwhile, careful preparations continue for the white-knuckle minutes before landing and the potential scientific discoveries at the landing site.

"Everything is going as planned. No surprises, but this is one of those times when boring is good," said Barry Goldstein, Phoenix project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Phoenix will fly to a site farther north than any previous Mars landing. The solar-powered lander will robotically dig to underground ice and will run laboratory tests assessing whether the site could have ever been hospitable to microbial life. The instruments will also look for clues about the history of the water in the ice. They will monitor arctic weather as northern Mars' summer progresses toward fall, until solar energy fades and the mission ends.

The Phoenix mission is led by Peter Smith of the University of Arizona, Tucson, with project management at JPL and development partnership at Lockheed Martin, Denver. International contributions are provided by the Canadian Space Agency; the University of Neuchatel, Switzerland; the universities of Copenhagen and Aarhus, Denmark; the Max Planck Institute, Germany; and the Finnish Meteorological Institute. JPL is a division of the California Institute of Technology in Pasadena.

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LOS ANGELES (AP) -- Two months after surviving a giant dust storm, one of NASA's robotic rovers on Mars began a risky drive Tuesday into a crater blasted open by a meteor eons ago.

Scientists want the rover Opportunity to travel 40 feet down toward a bright band of rocks in the Victoria Crater. They believe the rocks represent the ancient surface of Mars and that studying them could shed clues on the planet's early climate.

On Tuesday morning, engineers sent commands to Opportunity to begin its journey, and the robot signaled a confirmation. It will be several hours before scientists know how well the drive is going, and the trek itself will take several days.

Opportunity's first task will be to "toe dip'' into the crater, a move that involves rolling its six wheels below the rim and immediately back out to gauge its footing.

Over the next few days, engineers will check Opportunity's instruments and command it to scale down the crater.

"We expect to have good driving,'' said John Callas, the rover project manager at NASA's Jet Propulsion Laboratory in Pasadena.

The long-awaited descent into the crater -- measuring a half-mile across and about 200 to 230 feet deep -- had been on hold since July when a series of sun-blotting dust storms raged in the southern hemisphere. At the height of the storm, Opportunity and its twin, Spirit, went into sleep mode to conserve energy. Spirit is exploring another area far from Opportunity.

Opportunity reached the lip of the crater last month and scouted for possible entry points. The route scientists eventually chose calls for a straight drive down at a 15-degree incline toward the exposed layer of bright rocks.

During a July teleconference, NASA managers admitted the latest mission was risky, but decided to proceed anyway because of the science that could be learned.

The aging but hardy rovers have been exploring Mars for 3 1/2 years -- far outlasting their primary, three-month mission.

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New images obtained by a sharp-eyed Martian satellite reveal that some Red Planet features once thought to have been carved by flowing water were in fact created by other processes.

The images were taken during the first 100 days of the Mars Reconnaissance Orbiter (MRO) mission and are detailed in a special section of the Sept. 21 issue of the journal Science.

While the results don't confirm or deny the existence of liquid water on Mars' surface, they are no less fascinating, say the scientists involved. For instance, one team found no evidence that flowing water caused bright deposits on the planet. Instead, the scientists proposed dry landslides caused the deposits.

"All findings are good findings," said one team leader Alfred McEwen, a planetary geologist at the University of Arizona.

Philip Christensen of Arizona State University said the MRO results reiterate that "Mars has been fairly dry for the recent past and we need to be careful and not overestimate how much water may have been present, or may have shaped the surface" in ancient times.

"I have been a 'dry Mars guy' for a long time," Christensen said. "These findings are basically saying you look at very high resolution and you do see some evidence for water, there's no disputing that. But you don't see an overwhelming amount of evidence for water."

Lava explosions
The bus-sized MRO orbiting spacecraft, launched in 2005, is equipped with six instruments, including the High-Resolution Imaging Science Experiment camera, or HiRISE, which provides 10 times the resolution of any past Mars imagers. While the MRO images are in some cases inconclusive on the question of Martian water, they are painting a picture of the Martian surface for scientists in unprecedented detail.

In some cases, the images refute past speculation that some of the features were created by flowing water.

A team led by Windy Jaeger of the U.S. Geological Survey in Arizona analyzed HiRISE images of the Athabasca Valles, a young outflow channel system speculated to have been carved out by past catastrophic floods.

"That entire surface is coated with a thin layer of solidified lava, very hard rock that's almost preserved the channel system," Jaeger said, adding: "Catastrophic water floods probably did carve the channel system, but lava flowed through it more recently."

The findings suggest that rather than flooding, steam explosions left behind trails of cone-shaped features found on the floor of Athabasca Valles.

"When water and lava interact it causes a steam explosion," Jaeger told SPACE.com. "And so the lava-covered ground had ground ice in it. And as that water was heated it exploded in steam explosions through the lava."

Dry landslides
McEwen led another research team, which studied a variety of landforms also thought to be associated with past water on Mars. They examined images of gully deposits that had been detected last year by the Mars Global Surveyor. The gully deposits were not present in 1999 images but appeared by 2004. The before-and-after images raised hopes that modern flows of liquid water created the deposits. However, observations from MRO suggest a dry origin, McEwen said.

Both chemical analyses and images of one of the fresh deposits showed no signs of frost or ice and no evidence for even hydrated minerals, all of which could have given the deposits a "bright" appearance.

"We think dry landsliding could've created the bright deposits," McEwen said.

The slopes above this deposit and five other locations are steep enough for sand or loose, dry dust to flow down the gullies, the scientists say. Material uphill could be the source.

In science, discrediting a theory can be just as important as supporting one. "Some science reporters are acting as if we should be disappointed these new bright deposits weren't deposited by water," McEwen said. "We're excited by any advance in understanding Mars no matter what it is."

No ocean
The researchers also ruled out a hypothesis for an ancient ocean on Mars.

The Vastitas Borealis Formation, which covers low-lying northern plains of Mars, was thought to be the result of fine-grained deposits left by an ancient ocean. The new HiRISE images reveal the area, which appeared as flat and featureless in prior missions, is peppered with large boulders.

The mixed-bag of findings intrigue scientists involved.

While Mars is dry now, there remains a lot of water locked up as ice at the poles and beneath the surface away from the poles.

"Ninety-nine percent of Mars is pretty dry and pretty average and not all that exciting," Christensen said. "But the one percent is extremely interesting. So imagine stumbling across an oasis or hot spring out in the middle of a desert. It's a barren desert but gosh that little oasis sure looks attractive."

As an astrobiologist, Christensen says Mars holds plenty of hideouts for life, "I think there are still plenty of places to look for life on Mars."

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Op woensdag 26 september 2007 14:00 schreef Frutsel het volgende:
Is het niet gewoon een krater

zou wel tof zijn... diepe grotten

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_{MarsDayly.com}
NASA aims to put man on Mars by 2037


NASA aims to put a man on Mars by 2037, the administrator of the US space agency indicated here Monday.
This year marks the half-century of the space age ushered in by the October 1957 launch of the Sputnik-1 by the then Soviet Union, NASA administrator Michael Griffin noted.

In 2057, the centenary of the space era, "we should be celebrating 20 years of man on Mars," Griffin told an international astronautics congress in this southern Indian city where he outlined NASA's future goals.

The international space station being built in orbit and targeted for completion by 2010 would provide a "toehold in space" from where humanity can travel first to the moon and then to Mars, Griffin said.

"We are looking at the moon and Mars to build a civilisation for tomorrow and after that," Griffin added in his remarks at a conference session attended by heads of the world's space agencies.

President George W. Bush in 2004 announced an ambitious plan for the US to return to the moon by 2020 and use it as a stepping stone for manned missions to Mars and beyond.

NASA's Phoenix spacecraft is scheduled to land on the northern plains of Mars next year to determine if the Red Planet could support life.

The agency's Mars rovers Opportunity and Spirit resumed their three-year-old mission this month after surviving giant dust storms that nearly destroyed the twin robots.

The rovers were placed in hibernation mode in July to save power because the dust storms were covering their solar panels, impeding their ability to absorb energy from the sun.

And on September 15, 10 gerbils took off from the Russian-run Baikonur space centre in Kazakhstan for a 12-day voyage to test the possible effects of a human mission to Mars.

Missions to the moon and Mars, amid a renewal of global interest in space exploration, are at the top of the agenda for the 2,000 space scientists, astronauts, satellite manufacturers and launchers who gathered in Hyderabad.

NASA is due to start sending a series of robotic missions to the moon starting next year to prepare for future spaceflights and do research on the effects of extended space travel on human beings.