NASA Mars Curiosity Rover: Leaving Landing 'Safe Zone'

This image taken on June 27, 2014 by NASA's Mars Reconnaissance Orbiter shows NASA's Curiosity Mars rover on the rover's landing-ellipse boundary, which is superimposed on the image. 

The ellipse measures approximately 4 miles wide by 12 miles long.

Credit: NASA /JPL-Caltech /Univ. of Arizona

NASA's Curiosity Mars rover has entered a new realm on the Red Planet.

The 1-ton Curiosity rover has now cruised out of its landing ellipse, the area, about 4 miles wide by 12 miles long (7 by 20 kilometers), regarded as safe ground for its August 2012 touchdown within Mars' huge Gale Crater, NASA officials said.

Indeed, a photo taken by the space agency's Mars Reconnaissance Orbiter on June 27 shows Curiosity right on this boundary, which encloses a region of relatively flat and smooth terrain.



Curiosity landed with the aid of a rocket-powered sky crane, which lowered the six-wheeled robot down softly on cables before flying off to crash-land intentionally a safe distance away.

This system, which had never been used before at Mars, allowed Curiosity to land with much more precision than previous Red Planet missions had been able to achieve.

For example, NASA's twin Spirit and Opportunity rovers landed inside an ellipse measuring 93 miles by 12 miles (150 by 20 km) in January 2004, and the ellipse for the agency's two Viking landers, which touched down on Mars in 1976, spanned 174 miles by 62 miles (280 by 100 km).

Curiosity's $2.5 billion mission, officially known as the Mars Science Laboratory (MSL), seeks to determine if Mars has ever been capable of supporting microbial life.

The rover team has already achieved this goal, announcing last year that an area near Curiosity's landing site called Yellowknife Bay was a habitable lake-and-stream system billions of years ago.

NASA MSL: Apparent Mystery of Mars 'doughnut' rock solved

NASA image shows before-and-after of the same patch of ground in front of NASA's Mars Exploration Rover Opportunity 13 days apart documenting the arrival of a bright rock onto the scene, on January 22, 2014

NASA scientists were finally able to explain the origin of the mysterious rock shaped like a jelly doughnut that appeared near the rover Opportunity in early January.

The small, round object suddenly popped up in pictures taken 12 days apart by the US space agency's decade-old Opportunity rover.

On December 26, 2013, it was not there. On January 8, it was. But what is it?

The explanation is somewhat prosaic: the 1.5 inches (four centimeters) wide, white-rimmed, red-centered rock, dubbed Pinnacle Island, is a piece of a larger rock that was broken and moved by Opportunity's wheel in early January.

"Once we moved Opportunity a short distance, after inspecting Pinnacle Island, we could see directly uphill an overturned rock that has the same unusual appearance," said Opportunity Deputy Principal Investigator Ray Arvidson of Washington University in St. Louis on Friday.

"We drove over it. We can see the track. That's where Pinnacle Island came from."

However, the rock is unusual and scientifically significant.

A close examination with Opportunity's spectrometer showed "high levels of elements such as manganese and sulphur, suggesting these water-soluble ingredients were concentrated in the rock by the action of water," NASA said.

This image taken by the panoramic camera on Opportunity shows the rover's Moessbauer spectrometer (circular device in center).

"This may have happened just beneath the surface relatively recently," Arvidson said, "or it may have happened deeper below ground longer ago and then, by serendipity, erosion stripped away material above it and made it accessible to our wheels."

Opportunity is one of two Mars Exploration Rovers. Its companion, Spirit, stopped communicating with Earth in 2010.

Both have lived long beyond their planned 90-day missions and have made important discoveries about water on Mars and environments that might have supported microbial life in the distant past.

NASA Mars Rover: Terramechanics research keeps rovers rolling

The Curiosity rover, which lifted off Nov. 26, 2011, will arrive at the Red Planet in August 2012. 

The rover, shown here during testing inside the Spacecraft Assembly Facility at the Jet Propulsion Laboratory in California, is about the size of a Mini Cooper and weighs roughly five times as much as the Spirit and Opportunity rovers.

In May 2009, the Mars rover Spirit cracked through a crusty layer of Martian topsoil, sinking into softer underlying sand. 

The unexpected sand trap permanently mired the vehicle, despite months of remote maneuvering by NASA engineers to attempt to free the rover.

The mission mishap may have been prevented, says MIT's Karl Iagnemma, by a better understanding of terramechanics—the interaction between vehicles and deformable terrain.

Iagnemma says scientists have a pretty good understanding of how soils interact with vehicles that weigh more than 2,000 pounds. But for smaller, lighter vehicles like the Mars rovers, the situation is murkier.

"There's a lot of knowledge in civil engineering about how soils will react when subjected to heavy loads," says Iagnemma, who is a principal research scientist in the Department of Mechanical Engineering.

"When you take lightweight vehicles and granular soils of varying composition, it's a very complex modeling process."

Karl Iagnemma

Now Iagnemma and researchers from Washington University in St. Louis and the Jet Propulsion Laboratory (JPL) in Pasadena, Calif., have developed a model called Artemis that accurately simulates rover mobility over various types of soil and terrain.

The model works much like a video game: A user plugs in commands to, for example, move the simulated rover forward a certain distance—instructions similar to those that NASA engineers give to rovers on Mars.

The simulation then predicts how the rover will move, based on the underlying soil properties, vehicle characteristics and a terrain's incline.

The team tested the model against observations in the field, including actual drive paths from previous Mars rovers, and found that the simulations behaved much like actual rovers in various terrains.



The researchers also performed experiments in the lab, rolling a replica of a Mars rover's wheel over Martian-like sand. The tests established relationships between wheel dynamics and soil properties—information that the team used to further refine the model.

Carmine Senatore

"Once you have a model you trust that is really representative of how the rover behaves, it can help mission planners make path plans in a safer way," says team member Carmine Senatore, who is a research scientist at MIT.

"It could say that this path looks shorter and faster, but if the soil is not what we expected, it may be much more dangerous, so it's better to go another way."

Senatore, Iagnemma, Raymond Arvidson of Washington University, and collaborators will outline the details of the model in a paper to appear in the Journal of Field Robotics.

Beach Sand and Cake Flour
For the most part, the terrain over which Mars rovers travel—including the most recent Curiosity mission—is relatively benign, consisting mostly of flat, firm surfaces.

But occasionally, rovers encounter more challenging environments, such as steep dunes covered in fine, loose soil.

"Think about the difference between beach sand, which you can walk on and even play volleyball on, and cake flour," Iagnemma says. "The reason [for that difference] goes down to the microscale of the material."

To know how much work is required for a rover to get over a dune, Iagnemma says one needs to understand the properties of an environment's soil.

To develop its model, the team estimated soil properties on Mars based on a variety of data sources, including measurements of the planet by orbiting sensors and images from the rovers themselves, as well as data on the amount of torque required to drive a wheel through a particular type of terrain.

The team coupled Martian soil data with properties of the rover, such as its size and weight, and developed a model to predict the likelihood and extent to which a rover may sink into a given terrain.

Iagnemma and Senatore refined the model with experiments in the lab. The researchers set up a bed of both coarse and fine soil, similar to sediment that has been observed on Mars. They built a straight track overhead, and attached a spare wheel from the Mars rover Opportunity.

Powering the wheel with a motor, the team observed the wheel's performance, noting how much the wheel sank into the soil, and the amount of torque needed to overcome sinking.

"Sometimes in a car you end up doing things like rocking it back and forth," Iagnemma says. "There's limited strategies for a Mars rover because it's not a very dynamic vehicle, and moves very slowly. So we have to be more creative and develop strategies to get out."

More information: Paper: onlinelibrary.wiley.com/journal/10.1002/(ISSN)1556-4967

NASA Mars Rovers: Opportunity Continues to Cover New Ground

While many obsessed over speculation that NASA’s newest Mars rover, Curiosity, had dug up signs of life, but it had not, it is the agency’s older, smaller jalopy, Opportunity, that has been exploring a more intriguing plot of Martian real estate. 

“This is our first glimpse ever at conditions on ancient Mars that clearly show us a chemistry that would have been suitable for life,” Steven W. Squyres, the principal investigator for Opportunity, said at a news conference last week at a meeting of the American Geophysical Union. 

Opportunity could be sitting on rocks chock-full of organic molecules but the rover and the scientists back on Earth would never know. Unlike Curiosity, Opportunity is not carrying instruments that can detect those kinds of molecules. 

But the scientists are not complaining. Everything from Opportunity over the past eight years has been a bonus for a mission that was to have ended long ago. 

Opportunity landed on Mars in January 2004, for what was supposed to be a three-month mission. Yet the rover continues operating in good condition. 

Its twin rover, Spirit, died in 2010, stuck in a sand trap and unable to point its solar arrays in the correct direction to survive winter, outliving its planned lifetime by almost six years.

Last year, Opportunity arrived at a 14-mile-wide crater named Endeavour, where NASA’s Mars Reconnaissance Orbiter has spotted clays from above. Clays generally form in the presence of water.

On Sol 3146 (Nov. 29, 2012), Opportunity using the Rock Abrasion Tool (RAT) performed a grind of the surface target "Sandcherry."

This was followed with an image mosaic collected by the Microscopic Imager (MI) and then a placement of the Alpha Particle X-ray Spectrometer (APXS) for an overnight integration. 

On Sol 3151 (Dec. 4, 2012), the rover moved just 9 inches (23 centimeters) to reach some new surface targets.

The clay signal pointed to a hill, which the scientists named after Jacob Matijevic, an engineer on the rover team who died this year.

As Opportunity approached, “We started seeing things that looked really, really different,” Dr. Squyres said. 

The most common rock there was light-coloured, fine-grained, very soft, and nothing like any that Opportunity had come across before.

“It is right in the sweet spot of where the clay signature is present,” Dr. Squyres said. “It has got to be the clay-bearing stuff.”

But when the rover looked at the elements in the rock, it was the same mix of elements in a typical Martian rock. “What’s unusual is that it’s not unusual,” Dr. Squyres said. “This puzzled us at first. I was expecting something dramatic and instead what you see here kind of looks like average Mars.”

Another instrument could have identified minerals in the rock, but the radioactive cobalt it relies on has long decayed away.

If Curiosity were at the Endeavour crater, its instruments could directly look for the carbon-based molecules known as organics that are the building blocks of life. 

Unfortunately, Curiosity, which landed in August, is more than 5,000 miles away exploring a different crater where clays have also been spotted from orbit  and it is still months away from reaching Matijevic.

NASA Mars Spirit Lander and Bonneville Crater in Colour

Near the lower left corner of this view is the three-petal lander platform that NASA's Mars Exploration Rover Spirit drove off in January 2004.

The lander is still bright, but with a reddish colour, probably due to accumulation of Martian dust.

› See labeled version

The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter recorded this view on Jan. 29, 2012, providing the first image from orbit to show Spirit's lander platform in colour.

The view covers an area about 2,000 feet (about 600 meters) wide, dominated by Bonneveille Crater. North is up. A bright spot on the northern edge of Bonneville Crater is a remnant of Spirit's heat shield.

Spirit spent most of its six-year working life in a range of hills about two miles east of its landing site.

An image of the lander platform taken by Spirit's Panoramic Camera (Pancam) after the rover had driven off is at http://photojournal.jpl.nasa.gov/catalog/PIA05117.

The bright heat shield remnant can be seen in a panorama the same camera took of Bonneville Crater, at http://photojournal.jpl.nasa.gov/jpeg/PIA05591.jpg .

This image is one product from HiRISE observation ESP_025815_1655. Other products from the same observation can be found at http://hirise.lpl.arizona.edu/ESP_025815_1655 .

Image credit: NASA/JPL-Caltech/Univ. of Arizona

NASA’s Mars Rover: Farewell Spirit, you served us well

NASA’s Spirit rover looks like it is going to fade away due to the harsh Martian winter.

The space agency said it has ended attempts to gain contact with the Spirit rover.

According to NASA, the Spirit rover last communicated on March 22, 2010. NASA said it will make one final attempt to day.

The hope was that the Spirit may reawaken once it got more solar energy. It appears that components were damaged without its heaters.

NASA statement:

Engineers’ assessments in recent months have shown a very low probability for recovering communications with Spirit.

Communications assets that have been used by the Spirit mission in the past, including NASA’s Deep Space Network of antennas on Earth, plus two NASA Mars orbiters that can relay communications, now are needed to prepare for NASA’s Mars Science Laboratory mission. MSL is scheduled to launch later this year.

Spirit landed in early 2004 amid much fanfare. The rover was designed to last three months. Spirit’s twin, Opportunity, continues to explore Mars.

The Future
NASA is planning to launch a new rover called Curiosity in November.

Spirit has returned a ton of data to NASA about Mars, including photos, soil samples, thermal readings and other items.

Meanwhile, NASA has captured Spirit’s entire project log via an update page. The last year has been disappointing, but Spirit had an extended life and notched up a lot of small victories.

NASA Trapped Mars Rover Finds Evidence of Subsurface Water

The ground where NASA's Mars Exploration Rover Spirit became stuck last year holds evidence that water, perhaps as snow melt, trickled into the subsurface fairly recently and on a continuing basis.

Stratified soil layers with different compositions close to the surface led the rover science team to propose that thin films of water may have entered the ground from frost or snow.

The seepage could have happened during cyclical climate changes during periods when Mars tilted farther on its axis.

The water may have moved down into the sand, carrying soluble minerals deeper than less-soluble ones. Spin-axis tilt varies over timescales of hundreds of thousands of years.

The relatively insoluble minerals near the surface include what is thought to be hematite, silica and gypsum. Ferric sulfates, which are more soluble, appear to have been dissolved and carried down by water. None of these minerals is exposed at the surface, which is covered by wind-blown sand and dust.

"The lack of exposures at the surface indicates the preferential dissolution of ferric sulfates must be a relatively recent and ongoing process since wind has been systematically stripping soil and altering landscapes in the region Spirit has been examining," said Ray Arvidson of Washington University in St. Louis, deputy principal investigator for the twin rovers Spirit and Opportunity.

Analysis of these findings appears in a report in the Journal of Geophysical Research published by Arvidson and 36 co-authors about Spirit's operations from late 2007 until just before the rover stopped communicating in March.

The twin Mars rovers finished their three-month prime missions in April 2004, then kept exploring in bonus missions. One of Spirit's six wheels quit working in 2006.

In April 2009, Spirit's left wheels broke through a crust at a site called "Troy" and churned into soft sand. A second wheel stopped working seven months later. Spirit could not obtain a position slanting its solar panels toward the sun for the winter, as it had for previous winters. Engineers anticipated it would enter a low-power, silent hibernation mode, and the rover stopped communicating March 22. Spring begins next month at Spirit's site, and NASA is using the Deep Space Network and the Mars Odyssey orbiter to listen if the rover reawakens.

Researchers took advantage of Spirit's months at Troy last year to examine in great detail soil layers the wheels had exposed, and also neighboring surfaces. Spirit made 13 inches of progress in its last 10 backward drives before energy levels fell too low for further driving in February. Those drives exposed a new area of soil for possible examination if Spirit does awaken and its robotic arm is still usable.

"With insufficient solar energy during the winter, Spirit goes into a deep-sleep hibernation mode where all rover systems are turned off, including the radio and survival heaters," said John Callas, project manager for Spirit and Opportunity at NASA's Jet Propulsion Laboratory, in Pasadena, Calif. "All available solar array energy goes into charging the batteries and keeping the mission clock running."

NASA MARS: Stranded Rover Spirit reveals interesting discovery

A topographic map of Spirit's surroundings at Troy. Spirit is straddling the edge of a small crater. Sulfate materials are located in the crater (from the middle of the rover and extending to the left).

The topo map was generated from stereo images taken by Spirit's navigation camera when it was approaching the area in April 7, 2009.

Welcome to "Troy" - Mars style. NASA's robotic rover Spirit is bogged down on the Red Planet in a place the rover team named after the ancient city of Troy. So why aren't scientists lamenting?

"The rover's spinning wheels have broken through a crust, and we've found something supremely interesting in the disturbed soil," says Ray Arvidson of the Washington University in St. Louis.

Spirit, like its twin rover Opportunity, has roamed the Red Planet for nearly 6 years. During that time, the rover has had some close calls and come out fighting from each. In fact, it's been driving backwards since one of its wheels jammed in 2006. From the beginning, the rovers' motto has been "follow the water."

Both rovers have been searching Mars for minerals formed in the presence of H2O. Mars appears dry today, but minerals can provide clues that water was once there.

"It's been easy for Opportunity to find such minerals," explains Arvidson. "Opportunity landed in an ancient lake bed. Spirit has had to work much harder. Spirit landed in basaltic plains formed by lava flows chewed up by repeated meteoroid impacts. There's been little evidence of anything that was ever very wet."

But when Spirit reached an area of Mars called the "Columbia Hills," the whole complexion of the mission changed. "Spirit came across iron hydroxide, a mineral that forms in the presence of water. That alerted us to the change. We started coming across more and more rocks formed in the presence of water." Then Spirit got stuck in a patch of loose soil on the edge of a small crater. Heavy sigh. Stuck again.

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