News from Mars: Laser-Blasting and Soil Sampling

mars_lifeAs the exploration of Mars goes on, the small army of robotic rovers, satellites and orbiters continue to provide us with information, photographs and discoveries that remind us of how great a mystery the Red Planet truly is. For instance, in the past month, two major stories have been announced concerning the nature of Martian soil, its ancient history, and some of the more exciting moments in it’s exploration.

For example, Curiosity made news as its high resolution camera caught an image of sparks being generated as it zapped a Martian rock. In it’s lifetime, the rover has used its million watt Chemistry and Camera (ChemCam) laser to zap over 600 rock or soil targets as part of its mission. However, this was the first time that the rover team was able to get the arm-mounted Mars Hand Lens Imager (MAHLI) to capture the action as it occurred.

Curiosity-Laser-BeamThe ChemCam laser is used to determine the composition of Martian rocks and soils at a distance of up to 8 meters (25 feet). By hitting targets with several high-energy pulses, it is able to yield preliminary data for the scientists and engineers back at Earth to help them decide if a target warrants a closer investigation and, in rare cases, sampling and drilling activities.

ChemCam works through a process called laser-induced breakdown spectroscopy. The laser hits a target with pulses to generate sparks, whose spectra provide information about which chemical elements are in the target. Successive laser shots are fired in sequence to gradually blast away thin layers of material. Each shot exposes a slightly deeper layer for examination by the ChemCam spectrometer.

Mars_novarockAs Curiosity fired deeper into the target rock – named “Nova” – it showed an increasing concentration of aluminum as the sequential laser blasts penetrated through the uninteresting dust on the rock’s surface. Silicon and sodium were also detected. As Sylvestre Maurice, ChemCam’s Deputy Principal Investigator at the Research Institute in Astrophysics and Planetology, said in a statement:

This is so exciting! The ChemCam laser has fired more than 150,000 times on Mars, but this is the first time we see the plasma plume that is created… Each time the laser hits a target, the plasma light is caught and analyzed by ChemCam’s spectrometers. What the new images add is confirmation that the size and shape of the spark are what we anticipated under Martian conditions.

During it’s first year on Mars, Curiosity has already accomplished its primary objective of discovering a habitable zone on Mars that contains the minerals necessary to support microbial life billions of years ago when Mars was wetter and warmer. Currently, the rover is driving swiftly to the base of Mount Sharp at the center of Gale Crater, where it hopes to find more.

Mars_soilIn that same vein, according to new geological information obtained by Curiosty’s images and soil examinations, samples that were pulled out of a crater that is estimated to be some 3.7 billion years old contain more evidence that Mars was once much warmer and wetter. These findings were announced in a recent paper published in the online edition of Geology by University of Oregon geologist Gregory Retallack.

Unlike Earth, the Martian landscape is littered with loose rocks from impacts or layered by catastrophic floods. However, recent images from Curiosity from the Gale Crater reveal Earth-like soil profiles with cracked surfaces lined with sulfate, ellipsoidal hollows and concentrations of sulfate comparable with soils in Antarctica’s McMurdo Dry Valleys and Chile’s Atacama Desert.

mars-180-degrees-panorama_croppedRetallack, the paper’s lone author, studied mineral and chemical data published by researchers closely tied with the Curiosity mission. As a professor of geological sciences and co-director of paleontology research at the UO Museum of Natural and Cultural History, he internationally known as an expert on the recognition of paleosols – ancient fossilized soils contained in rocks.

As he explains in the paper:

The pictures were the first clue, but then all the data really nailed it. The key to this discovery has been the superb chemical and mineral analytical capability of the Curiosity Rover, which is an order of magnitude improvement over earlier generations of rovers. The new data show clear chemical weathering trends, and clay accumulation at the expense of the mineral olivine, as expected in soils on Earth. Phosphorus depletion within the profiles is especially tantalizing, because it attributed to microbial activity on Earth.

dryvalleysThe ancient soils do not prove that Mars once contained life, but they do add to growing evidence that an early, wetter and warmer Mars was more habitable than the planet has been in the past 3 billion years. Surface cracks in the deeply buried soils suggest typical soil clods. Vesicular hollows, or rounded holes, and sulfate concentrations, he said, are both features of desert soils on Earth.

Since Curiosity is currently on its way to Mount Sharp, future missions will be needed to fully explore these features. But as Retallack explained, the parallels with Earth are quite exciting:

None of these features is seen in younger surface soils of Mars. The exploration of Mars, like that of other planetary bodies, commonly turns up unexpected discoveries, but it is equally unexpected to discover such familiar ground.

The newly discovered soils indicate that more benign and habitable soil condition existed on Mars than previously expected. What’s more, their dating to 3.7 billion years ago places them within a transition period when the planet went from an early, benign water cycle to the acidic and arid Mars of today. This is especially important since major changes were taking place on Earth at around the same time.

Living-Mars.2Roughly 3.5 billion years ago, life on Earth is believed to have emerged and began diversifying. But some scientists have theorized that potential evidence that might indicate that life existed on Earth earlier may have been destroyed by tectonic activity, which did not occur on Mars. Basically, it may offer some credence to the theory that while flourished on Earth, it originated on Mars.

One person who supports this theory is Steven Benner of the Westheimer Institute of Science and Technology in Florida.  In the past, he has speculated that life is more likely to have originated on a soil planet like Mars than a water planet like Earth. In an email interview with Science Daily, Benner wrote that Retallack’s paper:

[S]hows not only soils that might be direct products of an early Martian life, but also the wet-dry cycles that many models require for the emergence of life.

So in addition to shedding light on the mysteries of Mars, Curiosity has also been pivotal in addressing some major questions which only increase the mystery of our own existence. Did life as we know it originate on Mars but flourish on Earth? Are there still some remnants of this microbial “Eden” being preserved deep within the soil and rocks? And could life exist there again some day?

All good questions that will no doubt keep robotic rovers, orbiters, landers, and even manned missions busy for many decades to come! In the meantime, check out the video from NASA’s Jet Propulsion Laboratory of Curiosity’s spark-generating laser blast being caught on tape:


Sources:
universetoday.com, sciencedaily.com

NASA’s 3D Printed Moon Base

ESA_moonbaseSounds like the title of a funky children’s story, doesn’t it? But in fact, it’s actually part of NASA’s plan for building a Lunar base that could one day support inhabitants and make humanity a truly interplanetary species. My thanks to Raven Lunatick for once again beating me to the punch! While I don’t consider myself the jealous type, knowing that my friends and colleagues are in the know before I am on stuff like this always gets me!

In any case, people may recall that back in January of 2013, the European Space Agency announced that it could be possible to build a Lunar Base using 3D printing technology and moon dust. Teaming up with the architecture firm Foster + Partners, they were able to demonstrate that one could fashion entire structures cheaply and quite easily using only regolith, inflatable frames, and 3D printing technology.

sinterhab2_1And now, it seems that NASA is on board with the idea and is coming up with its own plans for a Lunar base. Much like the ESA’s planned habitat, NASA’s would be located in the Shackleton Crater near the Moon’s south pole, where sunlight (and thus solar energy) is nearly constant due to the Moon’s inclination on the crater’s rim. What’s more, NASA”s plan would also rely on the combination of lunar dust and 3D printing for the sake of construction.

However, the two plans differ in some key respects. For one, NASA’s plan – which goes by the name of SisterHab – is far more ambitious. As a joint research project between space architects Tomas Rousek, Katarina Eriksson and Ondrej Doule and scientists from Nasa’s Jet Propulsion Laboratory (JPL), SinterHab is so-named because it involves sintering lunar dust: heating it up with microwaves to the point where the dust fuses to become a solid, ceramic-like block.

This would mean that bonding agents would not have to be flown to the Moon, which is called for in the ESA’s plan. What’s more, the NASA base would be constructed by a series of giant spider robots designed by JPL Robotics. The prototype version of this mechanical spider is known as the Athlete rover, which despite being a half-size variant of the real thing has already been successfully tested on Earth.

athlete_robotEach one of these robots is human-controlled, has six 8.2m legs with wheels at the end, and comes with a detachable habitable capsule mounted at the top. Each limb has a different function, depending on what the controller is looking to do. For example, it has tools for digging and scooping up soil samples, manipulators for poking around in the soil, and will have a microwave 3D printer mounted on one of the legs for the sake of building the base. It also has 48 3D cameras that stream video to its operator or a remote controlling station.

The immediate advantages to NASA’s plan are pretty clear. Sintering is quite cheap, in terms of power as well as materials, and current estimates claim that an Athlete rover should be able to construct a habitation “bubble” in only two weeks. Another benefit of the process is that astronauts could use it on the surface of the Moon surrounding their base, binding dust and stopping it from clogging their equipment. Moon dust is extremely abrasive, made up of tiny, jagged morcels rather than finely eroded spheres.

sinterhab3Since it was first proposed in 2010 at the International Aeronautical Congress, the concept of SinterHab has been continually refined and updated. In the end, a base built on its specifications will look like a rocky mass of bubbles connected together, with cladding added later. The equilibrium and symmetry afforded in this design not only ensures that grouping will be easy, but will also guarantee the structural integrity and longevity of the structures.

As engineers have known for quite some time, there’s just something about domes and bubble-like structures that were made to last. Ever been to St. Peter’s Basilica in Rome, or the Blue Mosque in Istanbul? Ever looked at a centuries old building with Onion Dome and felt awed by their natural beauty? Well, there’s a  reason they’re still standing! Knowing that we can expect similar beauty and engineering brilliance down the road gives me comfort.

In the meantime, have a gander at the gallery for the proposed SinterHab base, and be sure to check out this video of the Athlete rover in action:

Source: Wired.co.uk, robotics.jpl.nasa.gov