A new gravity map of Mars

Using data from three orbiting NASA spacecraft scientists have created a new gravity map of Mars, showing the subtle variations in its gravitational field due to density differences within the planet.

The improved resolution of the new gravity map suggests a new explanation for how some features formed across the boundary that divides the relatively smooth northern lowlands from heavily cratered southern highlands. Also, the team confirmed that Mars has a liquid outer core of molten rock by analyzing tides in the Martian crust and mantle caused by the gravitational pull of the sun and the two moons of Mars. Finally, by observing how Mars’ gravity changed over 11 years – the period of an entire cycle of solar activity — the team inferred the massive amount of carbon dioxide that freezes out of the atmosphere onto a Martian polar ice cap when it experiences winter. They also observed how that mass moves between the south pole and the north pole with the change of season in each hemisphere.

Curiosity reaches Naukluft Plateau

The view from Naukluft

Apropos to my post yesterday on Curiosity’s journey on Mars, the rover this week reached the flat area the science team has dubbed Naukluff Plateau.

The Sol 1281 drive completed as planned, crossing the Murray/Stimson contact at the edge of the Naukluft plateau. Now that we have a better view of the plateau, we are ready to start driving across it. But first, ChemCam and Mastcam will observe targets “Orupembe” and “Witvlei” on the bedrock in front of the rover. Mastcam will also take pictures of the rocks in front of the rover and targets “Natab East” and “Natab West” on either side of the vehicle before the Sol 1282 drive. After the drive, in addition to the usual post-drive imaging, the Left Mastcam will acquire a full 360-degree panorama, as the view from the new location (near the left edge of the image above) is expected to be good. We are looking forward to seeing the new data!

The second link above leads to the rover’s daily update site. It was here that the science team reported an issue with the rover’s scoop back in early February. Since then, however, they have never revealed if the problem was solved. Nor have they used the scoop in any way since then. I now wonder if it is no longer operational and am considering pursuing that question a bit to find out.

Pinpointing Curiosity’s location in Gale Crater

Curiosity's traverse

The Curiosity science team recently released a new Mars Reconnaissance Orbiter image, showing Curiosity’s overall route since its landing on Mars in August 2012. I have posted a reduced version on the right.

Similarly, on the Curiosity website you can view this more detailed map of its traverse route. This map is updated regularly as Curiosity continues its climb up Mount Sharp.

Neither of these maps is to me very satisfying or useful, however. Neither shows the overall location of Curiosity within Gale Crater. Nor do they give one a sense of how far it is has come on its climb up the mountain. In fact, it is very unclear how close the rover actually is to the peak from either image.

Thus, I decided to do a little research to get some better context of Curiosity’s position and its overall journey.
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ExoMars blasts off

The European-Russian Mars orbiter/lander ExoMars was successfully launched on a Proton rocket this morning from Baikonur.

It will still take most of today for the rocket’s Briz-M upper stage to complete several additional engine burns to send the spacecraft on its path to Mars, but the most difficult part of the launch has now passed.

The article does a nice job of summing up Russia’s most recent track record in trying to send spacecraft to Mars, thus illustrating the significance of today’s success:

For Russian scientists, the launch marks the resumption of a cooperative effort with Europe to explore the Solar System, after the failure of the Phobos-Grunt mission in 2011.The launch of the ExoMars-2016 spacecraft will be Proton’s first “interplanetary” assignment in almost two decades. During its previous attempt in November 1996, Proton’s upper stage failed, sending the precious Mars-96 spacecraft to a fiery desmise in the Earth’s atmosphere and effectively stalling Russia’s planetary exploration program for a generation.

Further in the past, during the Soviet era, the Russians tried numerous times to either orbit or land on Mars. Every mission failed. If this mission successfully reaches Mars and lands it will mark the first time the Russians played a major role in a mission to Mars that actually reached its goal and worked.

ExoMars ready for launch

The European ExoMars Mars orbiter and lander mission, set for launch on March 14, is assembled on its Proton rocket and is ready for launch.

This European project was originally going to be in partnership with NASA, but the Obama administration pulled out of the deal. The Russians then offered to come in and provide a rocket for the mission.

NASA reschedules rather than cancels InSight

Forced to delay its launch because its primary instrument, built by the French, would not be ready for its 2016 launch, NASA has decided to go on with the InSight Mars mission, rescheduling it for a May 2018 launch, rather than cancelling it outright.

The seismometer, built by the French space agency CNES, will be repaired in time to make the 2018 launch window, said Jim Green, the head of NASA’s planetary sciences division in Washington DC. “That’s terrific news,” he told a planetary sciences advisory panel on 9 March. The Jet Propulsion Laboratory in Pasadena, California, will assume responsibility for building a new vacuum enclosure for the seismometer.

The last sentence above suggests that NASA has decided to take certain responsibilities from the French to make sure they get done right. It also means that the cost will be born by the NASA’s planetary program, cutting into other possible future missions.

Getting higher on Mount Sharp

Looking across Gale Crater

Cool image time! The above image, cropped and reduced slightly for presentation here, was taken by one of Curiosity’s navigation cameras on March 2. Though the science team has not captioned it, I think it is looking down from the heights that Curiosity has climbed and across the plains of Gale Crater to its rim in the far distance. The image itself appears to have been taken after the rover spent several days climbing up to what they have dubbed Naukluft Plateau.

Be sure to check out the full resolution image that can be found here.

Curiosity moves on, scoop still not working

Curiosity’s science team has finished its work at Namib Dune and has decided to move on, even though they are still analyzing an unspecified issue with the rover’s scoop instrument.

So far, in the week since they first had a problem while sifting sand from the dune, they have not described in any way what the problem is. All they have said is this:

Unfortunately, the CHIMRA behaved in an unexpected way during processing of the third scoop on Sol 1231, which prevented completion of the arm activities planned for last weekend.

The robot arm functions, and they used it yesterday to get some extreme close-ups of the sand, but it appears they cannot use the scoop at this time.

An issue with Curiosity’s scoop

The unit at the end of Curiosity’s robot arm that scoops up sand and processes it through sieves experienced “an anomaly” on January 25, causing a halt in arm operations.

The instrument has been scooping up sand from the sand dune that the rover has been studying recently. So far there has been no details at all about the “anomaly”, so it is unclear how serious the problem is. In the meantime the rover has been using its cameras and other instruments to do other observations.

Antarctic fungi survive Martian conditions on ISS

A European experiment on ISS has found that fungi from Antarctica can survive in a Mars-like environment.

For 18 months half of the Antarctic fungi were exposed to Mars-like conditions. More specifically, this is an atmosphere with 95% CO2, 1.6% argon, 0.15% oxygen, 2.7% nitrogen and 370 parts per million of H2O; and a pressure of 1,000 pascals. Through optical filters, samples were subjected to ultra-violet radiation as if on Mars (higher than 200 nanometres) and others to lower radiation, including separate control samples. “The most relevant outcome was that more than 60% of the cells of the endolithic communities studied remained intact after ‘exposure to Mars’, or rather, the stability of their cellular DNA was still high,” highlights Rosa de la Torre Noetzel from Spain’s National Institute of Aerospace Technology (INTA), co-researcher on the project.

Does this prove that life exists on Mars? Not at all (though I wouldn’t be surprised if we see news articles in the mainstream press over the next week suggesting exactly that). It does show us once again that life is resilient and could develop in many very extreme environments.

A river on Mars

A river on Mars

Cool image time! The science team for the high resolution camera on Mars Reconnaissance Orbiter this week released it monthly set of cool images. One of those images, which I have cropped and reduced to show it here, is of an ancient river on Mars, the formation process of which geologists still debate. As the scientists note,

The channel pattern, called “dendritic” because of its tree–like branching, begins at the top of the image and runs down over the rim of an ancient impact basin across the basin floor. The soil surface overlying these channels, and indeed the entire landscape, has been changed and reworked over the intervening millions of years, by the combined actions of wind and ice. Over time, the original channels become muted or even erased.

One thing I learned in writing an article for Astronomy about the rivers seen on Saturn’s moon Titan is that without plant life there is no known natural process to hold river banks in place. Instead, if the grade is shallow and not confined by bedrock cliffs, rivers will meander about randomly forming braided channels as there will be nothing on shore to hold the water within the same course. For example, on a lifeless Earth the water draining the central basin of the midwest United States would have flowed south across a wide scattered area covering the entire plains, rather than flowing within the courses of the Missouri and Mississippi rivers.

Thus, it is not surprising that this river on Mars appears muted or partly erased. It probably was never very clearly delineated in the first place.

InSight Mars mission suspended

Because of a serious technical problem with its prime instrument, NASA has decided that its InSight Mars lander will not make its March 2016 launch window and has suspended the mission.

NASA said the decision to delay follows unsuccessful attempts to repair a leak affecting the device, which requires a vacuum seal around its three main sensors to withstand the harsh conditions of the Martian environment. A leak discovered earlier this year, that prevented it from retaining vacuum conditions, was successfully repaired, and the mission team “was hopeful the most recent fix also would be successful.”

However, the instrument once again failed to hold a vacuum during testing on Monday in extreme cold temperature.

It is even possible that the mission will be cancelled entirely because of the problem.

Water unneeded to produce wet gullies on Mars

The uncertainty of science: New modeling suggests that the wet gullies seen on Mars can be produced by dry ice, not water.

The theory is not completely new, but Cedric Pilorget and François Forget, with the University of Paris-Sud, and Paris’ Pierre and Marie Curie University, respectively, flesh out the idea with some hard numbers. Their new computer model calculates seasonal changes and impacts of an underlying layer of regolith, a carbon dioxide ice layer and the carbon dioxide-dominated gas atmosphere above. The simulation can take into account a variety of latitudes, slopes and other parameters.

The scientists found that most of the gullies could be created in a process that does not require any liquid water.

French Mars’ instrument repair looks good

The head of France’s space agency announced today that repairs to their instrument for NASA’s InSight Mars lander will be completed in time to ship the instrument to the U.S. in time for the scheduled March launch.

Briefing reporters here at the COP21 United Nations Climate Change Conference, Jean-Yves Le Gall said the leak, which compromised the required high-precision vacuum chamber carrying InSight sensors, was caused by a defective weld that is applied to close off the tank.

The leak’s cause has been identified and a new weld performed, Le Gall said. Tests to confirm the new weld’s integrity are underway and, assuming no problems, will be completed in time to ship the instrument to the United States in the first week of January. It will then be integrated into the InSight lander in preparation for the March launch.

Curiosity heads for the dunes

Bagnold Dunes

The Curiosity science team has decided to send the rover towards some large active dunes, visible in its journey ahead up Mt. Sharp.

On its way to higher layers of the mountain where it is investigating how Mars’ environment changed billions of years ago, NASA’s Curiosity Mars rover will take advantage of a chance to study some modern Martian activity at mobile sand dunes.

In the next few days, the rover will get its first close-up look at these dark dunes, called the “Bagnold Dunes,” which skirt the northwestern flank of Mount Sharp. No Mars rover has previously visited a sand dune, as opposed to smaller sand ripples or drifts. One dune Curiosity will investigate is as tall as a two-story building and as broad as a football field. The Bagnold Dunes are active: Images from orbit indicate some of them are migrating as much as about 3 feet (1 meter) per Earth year. No active dunes have been visited anywhere in the solar system besides Earth.

In the image on the right the target dune is in the center beyond the dark ridge line in the foreground. It looks kind of like a pointed mesa. the dark sandy area on the center right just below the dark ridge line in the center of the image. (Newer images released today gave me a more correct idea of the dunes as shown in this image.) Click here to see the full image. The rover is presently about 200 yards from the first dune, and should reach it in the next few days.

China unveils model of planned 2020 Martian probe

The competition heats up: China today unveiled a one-third scale model of its planned Martian lander/rover, scheduled for launch in 2020.

If they succeed in putting a lander and rover on Mars, China will have clearly demonstrated the capability to do almost anything in space that the United States can do. The competition in the coming decades should thus be most interesting.

Posted from Tucson International Airport.

More evidence of giant flash floods on Mars

Mangala Valles

A newly released image from ESA’s Mars Express orbiter shows that catastrophic flooding — caused by ice melted from volcanic activity — created the Mangala Valles channels on Mars.

The perspective image on the right shows the topography of the region, with low points indicated in blue and high points by red. The channel along the right side of the image is Mangala Valles itself, though you can also see additional flood channels to the left of it passing around and through a large crater whose floor now stands above the surrounding terrain caused by the erosion of the rim plus the deposit of sediment inside the crater during the flooding.

I have a soft spot for Mangala Valles. When it was first photographed by the first orbiter missions to Mars in the early 1970s I was struck by its river-like appearance and striking topography. I therefore placed my Martian colony here in one of my efforts at science fiction writing. I figured it a good location for colonization, as there would likely be water and, by roofing over the deep canyon, a colony could be built relatively easily.

Better locations on Mars have since been found, but the location still intrigues me.

More confirmation from Curiosity of past lakes in Gale Crater

New data from Curiosity has now provided further confirmation that the deeper sedimentary layers seen in Gale Crater were likely formed far in the past by flowing water.

“Paradoxically, where there is a mountain today there was once a basin, and it was sometimes filled with water,” said John Grotzinger, the former project scientist for Mars Science Laboratory at the California Institute of Technology in Pasadena, and lead author of the new report. “We see evidence of about 250 feet (75 meters) of sedimentary fill, and based on mapping data from NASA’s Mars Reconnaissance Orbiter and images from Curiosity’s camera, it appears that the water-transported sedimentary deposition could have extended at least 500 to 650 feet (150 to 200) meters above the crater floor.”

Furthermore, the total thickness of sedimentary deposits in Gale Crater that indicate interaction with water could extend higher still, perhaps up to one-half mile (800 meters) above the crater floor.

Above 800 meters, Mount Sharp shows no evidence of hydrated strata, and that is the bulk of what forms Mount Sharp. Grotzinger suggests that perhaps this later segment of the crater’s history may have been dominated by dry, wind-driven deposits, as was once imagined for the lower part explored by Curiosity.

This was always the reason to go and climb Mount Sharp. As Curiosity heads uphill it begins to map out the geological history of Mars, first as a wet place with liquid water, then as a dry place in which the water is gone.

An avalanche on Mars, as it happens

Avalanche on Mars

Cool image time! In their routine monitoring for avalanches at the layered deposits at the Martian north pole, the Mars Reconnaissance Orbiter science team captured the avalanche on the right, as it happened.

This picture managed to capture a small avalanche in progress, right in the color strip. … The small white cloud in front of the brick red cliff is likely carbon dioxide frost dislodged from the layers above, caught in the act of cascading down the cliff. It is larger than it looks, more than 20 meters across, and (based on previous examples) it will likely kick up clouds of dust when it hits the ground.

They note that avalanches in this area of Mars are common in the spring when things are warming, and have been documented previously, but possibly not so dramatically.

Curiosity’s future path

Looking up Mt Sharp

Cool image time! The Curiosity science team has produced another panorama of Mount Sharp and the regions that the rover will soon traverse.

This composite image looking toward the higher regions of Mount Sharp was taken on September 9, 2015, by NASA’s Curiosity rover. In the foreground — about 2 miles (3 kilometers) from the rover — is a long ridge teeming with hematite, an iron oxide. Just beyond is an undulating plain rich in clay minerals. And just beyond that are a multitude of rounded buttes, all high in sulfate minerals. The changing mineralogy in these layers of Mount Sharp suggests a changing environment in early Mars, though all involve exposure to water billions of years ago. The Curiosity team hopes to be able to explore these diverse areas in the months and years ahead. Further back in the image are striking, light-toned cliffs in rock that may have formed in drier times and now is heavily eroded by winds.

They have adjusted the colors, adding blue, so that things look as they would on Earth, in order to help the geologists understand what they are looking at.

Be sure and click on the link. The full resolution image is quite amazing. Like mountains on Earth, from a distance things look a lot simpler than they do once you get there. The slopes of Mount Sharp are complex and rugged, and will be a big challenge for Curiosity to traverse.

Moreover, this rough terrain illustrates that the Martian surface has, like Earth, been significantly shaped by erosion. The surface we see here is not the surface produced by the impact that produced the crater. It has been reshaped and eroded over many eons by many later processes, including wind and water.

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