What Will Curiosity Come Up With Next?
NASA’s Mars rover Curiosity’s discovery of organic compounds in the ground and plumes of methane in the air opens two potentially related investigations into whether or not the planet most like Earth in the solar system also hosted life.
NASA's Mars rover Curiosity's discovery of organic compounds in the ground and plumes of methane in the air opens two potentially related investigations into whether or not the planet most like Earth in the solar system also hosted life.
The methane spikes, announced by scientists at a press conference Tuesday, may be the easier issue for rover scientists to tackle since it is basically a waiting game to see if the plumes reoccur.
Between late November 2013 and late January 2014, samples of the atmosphere collected and analyzed by Curiosity showed a 10-fold increase in concentrations of methane, a gas which on Earth is strongly tied to life.
When the next sample was taken two months later, the gas was gone, a mystery in and of itself since methane gas should last for 300 years in the Martian atmosphere.
The rover, which is now exploring the base Mount Sharp, a three-mile high mound of sediment rising from the floor of its Gale Crater landing site, will continuously sniff the air for methane, said lead scientist John Grotzinger, with the California Institute of Technology in Pasadena.
If higher concentrations are detected, the rover's onboard chemistry lab will attempt to enrich the samples by scrubbing away atmospheric carbon dioxide, leaving more methane for analysis. Detailed studies of how quickly the methane dissipates could provide clues about its origin and what causes its periodic release. For now, scientists suspect the methane burp came from somewhere in or near Gale Crater.
If a very large burst of methane was detected, scientists could attempt to chemically analyze its isotopic composition, which again might provide insight into whether it was produced by past or present day microbes, or if it is a byproduct of geochemical processes, such as meteorite impacts or hydrated mineral transformations.
The emissions show that "Mars is currently active and that the subsurface is communicating with the atmosphere," Curiosity participating scientist Sushil Atreya, with the University of Michigan at Ann Arbor, said at the American Geophysical Union press conference.
The scientists had news about ancient Mars too, revealing – after 18 months of analysis – that chlorobenzene organics were detected in samples drilled out from an ancient mudstone called Cumberland.
"We knew we were on to something but it's hard to know for sure that it wasn't a false positive until you've analyzed more rocks," Grotzinger said. "You don't want to get faked out if it was contamination from the instrument."
Finding more organics and bigger molecules is tricky since the same process that turns sediment into rock tends to destroy organics. Plus, Mars' surface is continuously blasted by deadly cosmic rays; its soil is extremely oxidizing (hence the planet's reddish hue from the breakdown of iron) and it is loaded with perchlorates, which can release chlorine molecules that combine with organics and transform them.
The Curiosity science team has been developing hunt strategies, which will continue to be tested as the rover explores Mount Sharp.
"We may never get lucky again, we may never find more organics but ... maybe we will and we can get smart at learning how to explore for these materials," Grotzinger said.
Like the methane, scientists have no idea if the organic compounds found in the rock sample were remnants of a carbon-rich and fortuitously preserved bit of meteorite or cosmic dust speck, or were produced by some type of living organism.
Grotzinger said the chance that Curiosity will be able to differentiate between biotic and abiotic organic compounds is slim.
If the quantity of organics was high enough it's possible that Curiosity, also known as the Mars Science Lab, or MSL, could assess their molecular structure, giving scientists a clue about whether they were produced by life or not.
More likely, it will be up to NASA's next Mars rover, slated to launch in 2020, to find the right samples and cache them for a future return to Earth.
"Hopefully, the legacy of the MSL mission will be to leave behind for the 2020 mission a blueprint for how to go about the deliberate search" for organics, Grotzinger said.
NASA's Mars rover Curiosity drilled into this rock target, "Cumberland," during the 279th Martian day, or sol, of the rover's work on Mars (May 19, 2013) and collected a powdered sample of material from the rock's interior.
NASA's rover Curiosity has begun drilling operations for the third time on Mars. Currently located at a geologically interesting location nicknamed "The Kimberley," the one-ton rover also took the opportunity to photograph itself and the surrounding landscape in some stunning Martian "selfies." In this scene, Curiosity appears to be leaning its "head" -- a suite of instruments including the Chemcam (the laser "eye") and Mastcam cameras -- to the side, capturing the 5 kilometer-high Aeolis Mons (a.k.a. "Mount Sharp") on the horizon. The self portrait has been stitched together
from a series of raw photographs (taken on sol 613, April 28, of the mission) by Curiosity's robotic arm-mounted Mars Hand Lens Imager (MAHLI) instrument.
In this scene, Curiosity appears to be concentrating hard on a rock of interest -- dubbed "Windjana" by mission scientists after a gorge in Western Australia -- that it has cleaned with its robotic arm-mounted Dust Abrasion Tool. A grey circular patch can be seen on the otherwise rusty rock's surface where the tool has scrubbed away any surface dust ready for analysis and drilling. This beautiful selfie was created
, after assembling a collection of photos from the rover's Mars Hand Lens Imager (MAHLI) on sol 613 (April 28) of the mission. Curiosity's selfies not only produce some breathtaking scenes, they are also used by mission engineers to keep tabs on the condition of the rover the more time it is exposed to the harsh Martian environment.
Curiosity used its Mastcam to photograph this closeup of its Rock Abrasion Tool. The instrument spins the wire-bristle brush over rock surfaces to remove layers of dust that has accumulated.
After brushing, a grey circle of rock beneath the ruddy Mars dust is exposed for further analysis. In this photo by Curiosity's Mars Hand Lens Imager (MAHLI), the texture of Mars dust is obvious and fine cracks or seams in "Windjana" can be seen. "In the brushed spot, we can see that the rock is fine-grained, its true color is much grayer than the surface dust, and some portions of the rock are harder than others, creating the interesting bumpy textures,"
, Curiosity science team member, of the California Institute of Technology, Pasadena. "All of these traits reinforce our interest in drilling here in order understand the chemistry of the fluids that bound these grains together to form the rock."
On April 29, Curiosity used its drill to bore a 2 centimeter hole into Windjana. This is only the third rock Curiosity has drilled into since landing on the red planet on Aug. 5, 2012. The grey color obviously extends deeper into the rock than just on its surface, and the powder created can provide a pristine rock sample for further analysis, helping mission scientists understand how the rock formed and under what environmental conditions.
The first two drilled rocks were located in Yellowknife Bay, approximately 4 kilometers from The Kimberley. Those rocks were determined to be mudstone slabs formed through water action and sediment, providing compelling evidence that the interior of Gale Crater used to play host to a lakebed and may have provided a habitable environment for ancient microbial life. This new drilling operation will provide more clues as to how rock formed in the region, revealing more tantalizing clues as to the past habitability of the red planet.