The idea that Mars could have supported life at one time is the subject of ongoing debate. Image credit: NASA
Mars is currently home to a small army robotic rovers, satellites and orbiters, all of which are busy at work trying to unravel the deeper mysteries of Earth’s neighbor. These include whether or not the planet ever had liquid water on its surface, what the atmosphere once looked like, and – most importantly of all – if it ever supported life.
And while much has been learned about Martian water and its atmosphere, the all-important question of life remains unanswered. Until such time as organic molecules – considered to be the holy grail for missions like Curiosity – are found, scientists must look elsewhere to find evidence of Martian life.
According to a recent paper submitted by an international team of scientists, that evidence may have arrived on Earth three and a half years ago aboard a meteorite that fell in the Moroccan desert. Believed to have broken away from Mars 700,000 years ago, so-called Tissint meteorite has internal features that researchers say appear to be organic materials.
The paper appeared in the scientific journal Meteoritics and Planetary Sciences. In it, the research team – which includes scientists from the Swiss Federal Institute of Technology in Lausanne (EPFL) – indicate organic carbon is located inside fissures in the rock. All indications are the meteorite is Martian in origin.
“So far, there is no other theory that we find more compelling,” says Philippe Gillet, director of EPFL’s Earth and Planetary Sciences Laboratory. He and his colleagues from China, Japan and Germany performed a detailed analysis of organic carbon traces from a Martian meteorite, and have concluded that they have a very probable biological origin.
Artist’s conception of an fragment as it blasts off from Mars as a result of a meteor impact. Credit: The Planetary Society
The scientists argue that carbon could have been deposited into the fissures of the rock when it was still on Mars by the infiltration of fluid that was rich in organic matter.
If this sounds familiar, you may recall a previous Martian meteorite named ALH84001, found in the Allen Hills region in Antarctica. In 1996 NASA researchers announced they had found evidence within ALH84001 that strongly suggested primitive life may have existed on Mars more than 3.6 billion years ago. While subsequent studies of the now famous Allen Hills Meteorite shot down theories that the Mars rock held fossilized alien life, both sides continue to debate the issue.
This new research on the Tissint meteorite will likely be reviewed and rebutted, as well.
The researchers say the meteorite was likely ejected from Mars after an asteroid crashed on its surface, and fell to Earth on July 18, 2011, and fell in Morocco in view of several eyewitnesses.
Upon examination, the alien rock was found to have small fissures that were filled with carbon-containing matter. Several research teams have already shown that this component is organic in nature, but they are still debating where the carbon came from.
Chemical, microscopic and isotope analysis of the carbon material led the researchers to several possible explanations of its origin. They established characteristics that unequivocally excluded a terrestrial origin, and showed that the carbon content were deposited in the Tissint’s fissures before it left Mars.
This research challenges research proposed in 2012 that asserted that the carbon traces originated through the high-temperature crystallization of magma. According to the new study, a more likely explanation is that liquids containing organic compounds of biological origin infiltrated Tissint’s “mother” rock at low temperatures, near the Martian surface.
A piece of the Tissint meteorite that landed on Earth on July 18th, 2011. Credit: EPFL/Alain Herzog
These conclusions are supported by several intrinsic properties of the meteorite’s carbon, e.g. its ratio of carbon-13 to carbon-12. This was found to be significantly lower than the ratio of carbon-13 in the CO2 of Mars’s atmosphere, previously measured by the Phoenix and Curiosity rovers.
Moreover, the difference between these ratios corresponds perfectly with what is observed on Earth between a piece of coal – which is biological in origin – and the carbon in the atmosphere.
The researchers note that this organic matter could also have been brought to Mars when very primitive meteorites – carbonated chondrites – fell on it. However, they consider this scenario unlikely because such meteorites contain very low concentrations of organic matter.
“Insisting on certainty is unwise, particularly on such a sensitive topic,” warns Gillet. “I’m completely open to the possibility that other studies might contradict our findings. However, our conclusions are such that they will rekindle the debate as to the possible existence of biological activity on Mars – at least in the past.”
Be sure to check out these videos from EPFL News, which include an interview with Philippe Gillet, EPFL and co-author of the study:
And this video explaining the history of the Tissint meteor:
Credit: NASA/MRO/Rendering: James Dickson, Brown University
Though the surface of Mars is a dry, dessicated and bitterly cold place today, it is strongly believed that the planet once had rivers, streams, lakes, and flowing water on its surface. Thanks to a combination of spacecraft imagery, remote sensing techniques and surface investigations from landers and rovers, ample evidence has been assembled to support this theory.
However, it is hard to reconcile this view with the latest climate models of Mars which suggest that it should have been a perennially cold and icy place. But according to a new study, the presence of warm, flowing water may have been an episodic occurrence, something that happened for decades or centuries when the planet was warmed sufficiently by volcanic eruptions and greenhouse gases.
The study, which was conducted by scientists from Brown University and Israel’s Weizmann Institute of Science, suggests that warmth and water flow on ancient Mars were probably episodic, related to brief periods of volcanic activity that spewed tons of greenhouse-inducing sulfur dioxide gas into the atmosphere.
The work combines the effect of volcanism with the latest climate models of early Mars and suggests that periods of temperatures warm enough for water to flow likely lasted for only tens or hundreds of years at a time.
The notion that Mars had surface water predates the space age by centuries. Long before Percival Lowell observed what he thought were “canals” on the Martian surface in 1877, the polar ice caps and dark spots on the surface were being observed by astronomers who thought that they were indications of liquid water.
Curiosity found evidence of an ancient, flowing stream on Mars at a few sites, including the “Hottah” rock outcrop pictured here. Credit: NASA/JPL
But with all that’s been learned about Mars in recent years, the mystery of the planet’s ancient water has only deepened. The latest generation of climate models for early Mars suggests that the atmosphere was too thin to heat the planet enough for water to flow. Billions of years ago, the sun was also much dimmer than it is today, which further complicates this picture of a warmer early Mars.
“These new climate models that predict a cold and ice-covered world have been difficult to reconcile with the abundant evidence that water flowed across the surface to form streams and lakes,” said James W. Head, professor of earth, environmental and planetary sciences at Brown University and co-author of the new paper with Weizmann’s Itay Halevy. “This new analysis provides a mechanism for episodic periods of heating and melting of snow and ice that could have each lasted decades to centuries.”
Halevy and Head explored the idea that heating may have been linked to periodic volcanism. Many of the geological features that suggest water was flowing on the Martian surface have been dated to 3.7 billion years ago, a time when massive volcanoes are thought to have been active.
And whereas on Earth, widespread volcanism has often led to global dimming rather than warming – on account of sulfuric acid particles reflecting the sun’s rays – Head and Halevy think the effects may have been different in Mars’ dusty atmosphere.
To test this theory, they created a model of how sulfuric acid might react with the widespread dust in the Martian atmosphere. The work suggests that those sulfuric acid particles would have glommed onto dust particles and reduced their ability to reflect the sun’s rays. Meanwhile, sulfur dioxide gas would have produced enough greenhouse effect to warm the Martian equatorial region so that water could flow.
Image of the McMurdo Dry Valleys, Antarctica, acquired by Landsat 7’s Enhanced Thematic Mapper plus (ETM+) instrument. Credit: NASA/EO
Head has been doing fieldwork for years in Antarctica and thinks the climate on early Mars may have been very similar to what he has observed in the cold, desert-like.
“The average yearly temperature in the Antarctic Dry Valleys is way below freezing, but peak summer daytime temperatures can exceed the melting point of water, forming transient streams, which then refreeze,” Head said. “In a similar manner, we find that volcanism can bring the temperature on early Mars above the melting point for decades to centuries, causing episodic periods of stream and lake formation.”
As that early active volcanism on Mars ceased, so did the possibility of warmer temperatures and flowing water.
According to Head, this theory might also help in the ongoing search for signs that Mars once hosted life. If it ever did exist, this new research may offer clues as to where the fossilized remnants ended up.
“Life in Antarctica, in the form of algal mats, is very resistant to extremely cold and dry conditions and simply waits for the episodic infusion of water to ‘bloom’ and develop,” he said. “Thus, the ancient and currently dry and barren river and lake floors on Mars may harbor the remnants of similar primitive life, if it ever occurred on Mars.”
Artist's concept of the proposed "ExoLance" instrument that Explore Mars would have burrow beneath the Red Planet's surface for life. Credit: ExoLance/Indiegogo/YouTube (screenshot)
Not-for-profit group Explore Mars has a new IndieGoGo campaign that could see an instrument, ExoLance, head to the Red Planet to burrow for subsurface life. The first stage will be to raise money to build the prototype and then test it, within 12-14 months of finishing the fundraising.
No launch date for this mission has been announced, but the group says that will be determined after testing is finished and a launch provider can be found.
“Explore Mars has devised a simple system capable of being delivered to the Martian surface to detect microorganisms living on or under the surface,” the campaign page states.
“ExoLance leverages a delivery system that was originally designed for military purposes. As each small, lightweight penetrator probe (“arrow”) impacts the surface, it leaves behind a radio transmitter at the surface to communicate with an orbiter, and then kinetically burrows to emplace a life-detection experiment one to two meters below the surface. ExoLance combines the experiments of the 1970s Viking landers and the Curiosity rover with bunker-busting weapons technology.”
The project aims to raise $250,000, but there will be milestone goals available all the way up to $1 million.
An artist's conception of the European Space Agency's ExoMars rover, scheduled to launch in 2018. Credit: ESA
Signs of life on the Martian surface would still be visible even after bacteria were zapped with a potentially fatal dose of radiation, according to new research — if life ever existed there, of course.
Using “model” bacteria expected to resemble what microbes could look like on the Red Planet, the research team used a Raman spectrometer — an instrument type that the ExoMars rover will carry in 2018 — to see how the signal from the bacteria change as they get exposed to more and more radiation.
The bottom line is the study authors believe the European Space Agency rover’s instrument would be capable of seeing bacteria on Mars — from the past or the present — if the bacteria were there in the first place.
Readings from the NASA Mars Curiosity rover recently found that humans on the surface of Mars would have a higher risk of cancer due to the increased radiation level on the surface. Mars does not have a global magnetic field to deflect radiation from solar flares, nor a thick atmosphere to shelter the surface.
The new study still found the signature of life in these model microbes at 15,000 Gray of radiation, which is thousands of times higher than the radiation dose that would kill a human. At 10 times more, or 150,000 Gray, the signature is erased.
ExoMars 2016 Mission to the Red Planet. It consists of two spacecraft – the Trace Gas Orbiter (TGO) and the Entry, Descent and Landing Demonstrator Module (EDM) which will land. Credit: ESA
“What we’ve been able to show is how the tell-tale signature of life is erased as the energetic radiation smashes up the cells’ molecules,” stated Lewis Dartnell, an astrobiology researcher at the University of Leicester who led the study.
Specifically, the spectrometer detected carotenoid molecules, which can be used to protect a microorganism against difficult conditions in the environment. The research teams stated that these cartenoids have been proposed as “good biosignatures of life” on Mars.
This image shows a river that sprang from a past glacier from an unnamed crater in Mars’ middle latitudes. Credit: NASA/JPL/MSSS
“In this study we’ve used a bacterium with unrivaled resistance to radiation as a model for the type of bacteria we might find signs of on Mars. What we want to explore now is how other signs of life might be distorted or degraded by irradiation,” Dartnell added. “This is crucial work for understanding what signs to look for to detect remnants of ancient life on Mars that has been exposed to the bombardment of cosmic radiation for very long periods of time.”
Many scientists believe flowing water existed on the planet, though, based on rock findings from three NASA rovers and the appearance of channels, streams and perhaps even oceans as spotted by orbiting satellites. Some scientists say the atmosphere of Mars was much thicker in the past, but it then dissipated for reasons that are still being investigated. Water, however, does not necessarily point to life.
View of Mars from Viking 2 lander, September 1976. (NASA/JPL-Caltech)
[/caption]
The Curiosity rover is currently on its way to Mars, scheduled to make a dramatic landing within Gale Crater in mid-August and begin its hunt for the geologic signatures of a watery, life-friendly past. Solid evidence that large volumes of water existed on Mars at some point would be a major step forward in the search for life on the Red Planet.
But… has it already been found? Some scientists say yes.
Researchers from universities in Los Angeles, California, Tempe, Arizona and Siena, Italy have published a paper in the International Journal of Aeronautical and Space Sciences (IJASS) citing the results of their work with data obtained by NASA’s Viking mission.
The twin Viking 1 and 2 landers launched in August and September of 1975 and successfully landed on Mars in July and September of the following year. Their principal mission was to search for life, which they did by digging into the ruddy Martian soil looking for signs of respiration — a signal of biological activity.
A six-inch-deep trench in the Martian soil dug by Viking 1 in February 1977. The goal was to reach a foot below the surface for sampling.
The results, although promising, were inconclusive.
Now, 35 years later, one team of researchers claims that the Viking landers did indeed detect life, and the data’s been there all along.
“Active soils exhibited rapid, substantial gas release,” the team’s report states. “The gas was probably CO2 and, possibly, other radiocarbon-containing gases.”
By applying mathematical complexities to the Viking data for deeper analysis, the researchers found that the Martian samples behaved differently than a non-biological control group.
“Control responses that exhibit relatively low initial order rapidly devolve into near-random noise, while the active experiments exhibit higher initial order which decays only slowly,” the paper states. “This suggests a robust biological response.”
While some critics of the findings claim that such a process of identifying life has not yet been perfected — not even here on Earth — the results are certainly intriguing… enough to bolster support for further investigation into Viking data and perhaps re-evaluate the historic mission’s “inconclusive” findings.
Computer-generated perspective of the Tractus Catene pit chains. Credit: ESA/DLR/FU Berlin (G. Neukum)
[/caption]
Recent images from ESA’s Mars Express spacecraft reveal long rows of crater-like depressions lining the flanks of ancient Martian volcanoes located in the planet’s vast Tharsis region. Rather than being the result of impact events, these “pit chains” were likely caused by underground lava flows — and could be a prime location for look for life.
Like similar features found on Earth, lava tubes on Mars are the result of rivers of magma that carved channels beneath the surface. When these channels empty out, a hollow tube is left. If the roof of a particularly large tube is near the surface the roof can eventually collapse, creating a surface depression… or, in some cases, opening up to the surface entirely.
Even though volcanism on Mars isn’t currently active — the last eruptions probably took place at least over a million years ago — the features left by volcanic activity are still very much present today and likely well-preserved beneath the Martian surface.
Shielded from harsh solar and cosmic radiation, the interior of such lava tubes could provide a safe haven for microbial life — especially if groundwater had found its way inside at some point.
Even though the surface of Mars can receive 250 times the radiation levels found on Earth, the layers of soil and rock surrounding the tubes can provide adequate protection for life, whether it be ancient Martian microbes or future explorers from Earth.
A wider image of the Tractus Catena region showing the large shield volcano Ascraeus Mons. Credits: ESA/DLR/FU Berlin (G. Neukum)
Of course, water and protection from radiation aren’t the only factors necessary for life. There also needs to be some source of heat. Fortunately, the pit chains imaged by Mars Express happen to be within one of the most volcano-laden areas of the Red Planet, a region called the Arcadia quadrangle. Within this area exist some of the largest volcanoes on Mars — and the Tractus Catena pits are located right in the middle of them.
If a heat source were ever to have been beneath the surface of Mars, there would be a good chance it would have been here.
And if our own planet is any measure of such things, where there’s heat and water there is often some form of life — however extreme the conditions may be.
“I’d like to see us land ON a volcano,” Dr. Tracy Gregg, a volcanologist with the University of Buffalo, had once told Universe Today back in 2004. “Right on the flanks. Often the best place to look for evidence of life on any planet is near volcanoes.”
“That may sound counterintuitive, but think about Yellowstone National Park , which really is nothing but a huge volcano,” Gregg elaborated. “Even when the weather in Wyoming is 20 below zero, all the geysers, which are fed by volcanic heat, are swarming with bacteria and all kinds of happy little things cruising around in the water. So, since we think that the necessary ingredients for life on Earth were water and heat, we are looking for the same things on Mars.”
As far as any remaining geothermal activity still happening beneath the Martian surface?
“I strongly suspect there are still molten (or at least mushy) magma bodies beneath the huge Tharsis volcanoes,” Gregg had said. (Read the full article here.)
On Earth, lava tubes, caves and underground spaces of all kinds harbor life, often specialized forms that are found no place else. Could this be (or have once been) the case on Mars as well? Only future exploration will tell. Until then, places like Tractus Catena will remain on scientists’ short list of places to look.
Microbes have been found flourishing beneath the surface of the Atacama Desert. (Parro et al./CAB/SINC)
[/caption]
Researchers from the Center of Astrobiology (CAB) in Spain and the Catholic University of the North in Chile have found an “oasis” of microorganisms living two meters beneath the arid soil of the Atacama, proving that even on the driest place on Earth, life finds a way.
Chile’s Atacama Desert receives on average less than .01 cm (.004 inches) of rain per year. In some locations rain has not fallen for over 400 years. But even in this harsh environment there is moisture… just enough, at least, for rock salts and other compounds that can absorb any traces of water to support microbial life beneath the surface.
Using a device called SOLID (Signs Of LIfe Detection) developed by CAB, the researchers were able to identify the presence of microorganisms living on thin films of water within the salty subsurface soil.
Even the substrate itself is able to absorb moisture from the air, concentrating it into films only a few microns thick around the salt crystals. This gives the microorganisms everything they need to survive and flourish — two to three meters underground.
SOLID's array of life-detector modules. (CAB)
At that depth, there is no sunlight and no oxygen, but there is life.
And even when researchers dug to a depth of five meters (a little over 16 feet) and took samples back to a lab, they were able to not only locate microorganisms but also revive them with the addition of a little water.
Of course, the implications for finding life — or at least the remains of its past existence — on Mars is evident. Mars has been shown to have saline deposits in many regions, and the salt is what helps water remain liquid, longer.
“The high concentration of salt has a double effect: it absorbs water between the crystals and lowers the freezing point, so that they can have thin films of water (in brine) at temperatures several degrees below zero, up to minus 20 C,” said Victor Parro, researcher from the Center of Astrobiology (INTA-CSIC, Spain) and coordinator of the study. This is within the temperature range of many regions of Mars, and also anything located several meters below the surface would be well protected from UV radiation from the Sun.
“If there are similar microbes on Mars or remains in similar conditions to the ones we have found in Atacama, we could detect them with instruments like SOLID,” Parro said.
The development of a new version of the SOLID instrument is currently underway for ESA’s ExoMars program.
Opportunity discovers Water related mineral vein at Endeavour Crater - November 2011. Opportunity rover discovered Gypsum at the Homestake mineral vein, while exploring around the base of Cape York ridge at the rim of Endeavour Crater. The vein is composed of calcium sulfate and indicates the ancient flow of liquid water at this spot on Mars. Opportunity drove North (ahead) from here in search of a sunny winter haven. Credit: NASA/JPL/Cornell/Kenneth Kremer/Marco Di Lorenzo
[/caption]
NASA’s long lived Opportunity rover has discovered the most scientifically compelling evidence yet for the flow of liquid water on ancient Mars. The startling revelation comes in the form of a bright vein of the mineral gypsum located at the foothills of an enormous crater named Endeavour, where the intrepid robot is currently traversing. See our mosaic above, illustrating the exact spot.
Update: ‘Homestake’ Opportunity Mosaic above has just been published on Astronomy Picture of the Day (APOD) – 12 Dec 2011 (by Ken Kremer and Marco Di Lorenzo)
Researchers trumpeted the significant water finding this week (Dec. 7) at the annual winter meeting of the American Geophysical Union (AGU) in San Francisco.
“This gypsum vein is the single most powerful piece of evidence for liquid water at Mars that has been discovered by the Opportunity rover,” announced Steve Squyres of Cornell University, Ithaca, N.Y., Principal Investigator for Opportunity, at an AGU press conference.
The light-toned vein is apparently composed of the mineral gypsum and was deposited as a result of precipitation from percolating pools of liquid water which flowed on the surface and subsurface of ancient Mars, billions of years ago. Liquid water is an essential prerequisite for life as we know it.
“This tells a slam-dunk story that water flowed through underground fractures in the rock,” said Squyres. “This stuff is a fairly pure chemical deposit that formed in place right where we see it. That can’t be said for other gypsum seen on Mars or for other water-related minerals Opportunity has found. It’s not uncommon on Earth, but on Mars, it’s the kind of thing that makes geologists jump out of their chairs.”
'Homestake' Vein in Color and Close-up
This color view of a mineral vein called "Homestake" was taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity. The vein is about the width of a thumb and about 18 inches (45 centimeters) long. Opportunity examined it in November 2011 and found it to be rich in calcium and sulfur, possibly the calcium-sulfate mineral gypsum.
The light-toned vein is informally named “Homestake”, and was examined up close by Opportunity’s cameras and science instruments for several weeks this past month in November 2011, as the rover was driving northwards along the western edge of a ridge dubbed ‘Cape York’ – which is a low lying segment of the eroded rim of Endeavour Crater.
Veins are a geologic indication of the past flow of liquid water
Opportunity just arrived at the rim of the 14 mile (22 kilometere) wide Endeavour Crater in mid-August 2011 following an epic three year trek across treacherous dune fields from her prior investigative target at the ½ mile wide Victoria Crater.
“It’s like a whole new mission since we arrived at Cape York,” said Squyres.
‘Homestake’ is a very bright linear feature.
“The ‘Homestake’ vein is about 1 centimeter wide and 40 to 50 centimeters long,” Squyres elaborated. “It’s about the width of a human thumb.”
Opportunity's Approach to 'Homestake'
This view from the front hazard-avoidance camera on NASA's Mars Exploration Rover Opportunity shows the rover's arm's shadow falling near a bright mineral vein informally named Homestake. The vein is about the width of a thumb and about 18 inches (45 centimeters) long. Opportunity examined it in November 2011 and found it to be rich in calcium and sulfur, possibly the calcium-sulfate mineral gypsum. Opportunity took this image on Sol 2763 on Mars (Nov. 7, 2011). Credit: NASA/JPL-Caltech
Homestake protrudes slightly above the surrounding ground and bedrock and appears to be part of a system of mineral veins running inside an apron (or Bench) that in turn encircles the entire ridge dubbed Cape York.
In another first, no other veins like these have been seen by Opportunity throughout her entire 20 miles (33 kilometers) and nearly eight year long Martian journey across the cratered, pockmarked plains of Meridiani Planum, said Squyres.
The veins have also not been seen in the higher ground around the rim at Endeavour crater.
“We want to understand why these veins are in the apron but not out on the plains,” said the mission’s deputy principal investigator, Ray Arvidson, of Washington University in St. Louis. “The answer may be that rising groundwater coming from the ancient crust moved through material adjacent to Cape York and deposited gypsum, because this material would be relatively insoluble compared with either magnesium or iron sulfates.”
Opportunity was tasked to engage her Microscopic Imager and Alpha Particle X-ray Spectrometer (APXS) mounted on the terminus of the rover’s arm as well as multiple filters of the mast mounted Panoramic Camera to examine ‘Homestake’.
“The APXS spectrometer shows ’Homestake’ is chock full of Calcium and Sulfur,” Squyres gushed.
Microscopic Close-up View of 'Homestake' Vein
This close-up view of a mineral vein called Homestake comes from the microscopic imager on Opportunity. The vein is about the width of a thumb and about 18 inches (45 centimeters) long. Opportunity examined it in November 2011 and found it to be rich in calcium and sulfur, possibly the calcium-sulfate mineral gypsum. Homestake is near the edge of the "Cape York" segment of the western rim of Endeavour Crater. This view blends three exposures taken by the microscopic imager during the 2,765th and 2,766th Martian days, or sols, of Opportunity's career on Mars (Nov. 3 and 4, 2011). Credit: NASA/JPL-Caltech/Cornell/USGS
The measurements of composition with the APXS show that the ratio points to it being relatively pure calcium sulfate, Squyres explained. “One type of calcium sulfate is gypsum.”
Calcium sulfate can have varying amounts of water bound into the minerals crystal structure.
The rover science team believes that this form of gypsum discovered by Opportunity is the dihydrate; CaSO4•2H2O. On Earth, gypsum is used for making drywall and plaster of Paris.
The gypsum was formed in the exact spot where Opportunity found it – unlike the sulfate minerals previously discovered which were moved around by the wind and other environmental and geologic forces.
“There was a fracture in the rock, water flowed through it, gypsum was precipitated from the water. End of story,” Squyres noted. “There’s no ambiguity about this, and this is what makes it so cool.”
At Homestake we are seeing the evidence of the ground waters that flowed through the ancient Noachian rocks and the precipitation of the gypsum, which is the least soluble of the sulfates, and the other magnesium and iron sulfates which Opportunity has been driving on for the last 8 years.
Opportunity Traverse Map 2004 to 2011
Traverse map showing the 8 Year Journey of Opportunity from Eagle Crater landing site Sol 1 (Jan. 24, 2004) to Sol 2775 (November 2011). Map shows rover location around Homestake water related mineral on Sol 2763 (November 2011) at Cape York ridge at Endeavour Crater rim. Endeavour Crater is 14 miles or 22 kilometers in diameter. Opportunity has driven more than 21 miles (34 km).
Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Kenneth Kremer
“Here, both the chemistry, mineralogy, and the morphology just scream water,” Squyres exclaimed. “This is more solid than anything else that we’ve seen in the whole mission.”
It’s inconceivable that the vein is something else beside gypsum, said Squyres.
As Opportunity drove from the plains of Meridiani onto the rim of Endeavour Crater and Cape York, it crossed a geologic boundary and arrived at a much different and older region of ancient Mars.
The evidence for flowing liquid water at Endeavour crater is even more powerful than the silica deposits found by Spirit around the Home Plate volcanic feature at Gusev Crater a few years ago.
“We will look for more of these veins in the [Martian] springtime,” said Squyres.
If a bigger, fatter vein can be found, then Opportunity will be directed to grind into it with her still well functioning Rock Abrasion Tool, or RAT.
Homestake was crunched with the wheels – driving back and forth over the vein – to break it up and expose the interior. Opportunity did a triple crunch over Homestake, said Arvidson.
Homestake was found near the northern tip of Cape York, while Opportunity was scouting out a “Winter Haven” location to spend the approaching Martian winter.
Arvidson emphasized that the team wants Opportunity to be positioned on a northerly tilted slope to catch the maximum amount of the sun’s rays to keep the rover powered up for continuing science activities throughout the fast approaching Martian winter.
“Martian winter in the southern hemisphere starts on March 29, 2012. But, Solar power levels already begin dropping dramatically months before Martian winter starts,” said Alfonso Herrera to Universe Today, Herrera is a Mars rover mission manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
“Opportunity is in excellent health,” said Bruce Banerdt, the Project Scientist for the Mars rover mission at JPL.
“This has been a very exciting time. We’ll head back south in the springtime and have a whole bunch of things to do with a very capable robot,” Squyres concluded.
'Botany Bay' and 'Cape York' with Vertical Exaggeration
This graphic combines a perspective view of the "Botany Bay" and "Cape York" areas of the rim of Endeavour Crater on Mars, and an inset with mapping-spectrometer data. Major features are labeled. In the perspective view, the landscape's vertical dimension is exaggerated five-fold compared with horizontal dimensions. NASA's Mars Exploration Rover Opportunity examined targets in the Cape York area during the second half of 2011. The perspective view was generated by producing an elevation map from a stereo pair of images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter, then draping one of the HiRISE images over the elevation model. The inset presents data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on the Mars Reconnaissance Orbiter. In this CRISM observation, taken on March 29, 2011 Thermal inertia estimates from observations by the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter indicate that Botany Bay is a region with extensive outcrop exposures. Credit: NASA/JPL-Caltech/UA/JHUAPL
Meanwhile, NASA’s next leap in exploring potential Martian habitats for life – the car sized Curiosity Mars Science Lab rover – is speeding towards the Red Planet.
Read Ken’s continuing features about Opportunity starting here:
This image of the Centauri-Hellas Montes region was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at a portion of a trough in the Nili Fossae region of Mars is shown in enhanced color in this image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/Univ. of Arizona
[/caption]
What does a more than three billion year old sandstone formation in Western Australia have in common with Mars? The Aussie stones contain the oldest living microbial record of life on Earth – and it might be the basis of fossil discovery on Mars. The early Archaean rocks are providing geologists with microfossil evidence that early life might have been utilizing sulpher – instead of oxygen – for their ecosystems.
“At last we have good solid evidence for life over 3.4 billion years ago. It confirms there were bacteria at this time, living without oxygen,” said co-researcher Professor Martin Brasier at Oxford University, UK. “Such bacteria are still common today. Sulphur bacteria are found in smelly ditches, soil, hot springs, hydrothermal vents – anywhere where there’s little free oxygen and they can live off organic matter,” he explained.
But providing morphological evidence for these sulphur-metabolizing bacteria hasn’t been as easy as just digging up some stones. The first detection came in 2007 at Strelley Pool, a now arid area which may have once been an estuary or shallow water region. Associated with micrometre-sized pyrite crystals, these microstructures show all the right ingredients for early life properties, such as hollow cell lumens and carbonaceous cell walls enriched in nitrogen. Spheroidal and ellipsoidal forms are good indicators of bacterial formations and tubular sheaths point to multiple cell growth. They also display pyrite content, but there’s no “fool’s gold” here in these light isotopes… it’s a metabolic by-products of the cells.
“Life likes lighter isotopes, so if you have a light signature in these minerals then it looks biological,” said lead author Dr David Wacey from the University of Western Australia. “There are ways to get the same signature without biology, but that generally requires very high temperatures. So when you put together the light isotope signature with the fact the pyrite is right next to the microfossils – just a couple of microns away – then it really does look like there was a whole sulphur ecosystem there,” he reported to BBC News.
So what does this discovery have to do with Mars? In its northern hemisphere is a region called Nili Fossae which photographically bears a strong resemblance to Australia’s Pilbara region – home to Strelley Pool. With a huge amount of clay minerals documented, Nili Fossae just might be the ideal place for US space agency’s Curiosity-Mars Science Laboratory rover mission to begin a search for early Martian life forms. But don’t get too excited just yet… The study on a remote planet is going to prove even more difficult than here on Earth.
“Some of the instruments we used can fill a whole room, but some of them can be miniaturised,” said Dr Wacey. “A rover could narrow down the targets but then you’d really have to bring samples back to Earth to study them in detail.”
Spirit’s last panoramic from Mars was taken during February 2010 before her death. Featured on Astronomy Picture of the Day (APOD) on 30 May 2011. Spirit’s final panoramic picture show from Mars was snapped on Sol 2175 in February 2010 before entering hibernation mode in March 2010 just prior to the onset of her 4th Martian winter. Spirit was just 500 feet from her next science target - dubbed Von Braun – center of the mosaic. The Columbia Hills form the backdrop to the mosaic from Spirits final resting place. Spirit never awoke. NASA ceased all communications attempts with Spirit on May 25, 2011. Credit: Mosaic by Marco De Lorenzo and Ken Kremer, images NASA/JPL/Cornell University.
[/caption]
Scientists leading NASA’s Mars rover team have selected “Spirit Point” as the name for the spot where the “Opportunity” Mars rover will arrive at her next destination – Endeavour Crater. The site was named in honor of the death of the “Spirit” Mars Exploration Rover, which NASA recently declared has ceased all communications with Earth.
Spirit’s passing comes after more than six highly productive years roving the surface of the red planet as humankind’s surrogate. NASA concluded the last attempt to communicate with Spirit in a transmission on May 25, 2011.
“First landfall at Endeavour will be at the southern end of Cape York [at Spirit Point],” Steve Squyres told me. Squyres of Cornell University, Ithaca, N.Y., is principal investigator for the rovers. Read tributes from the Spirit rover science team below.
In memory of Spirit, the last panorama she snapped on Sol 2175 in February 2010 was featured on Astronomy Picture of the Day (APOD) on May 30, 2011 and is the lead image here. The photo mosaic was created by Marco Di Lorenzo and Ken Kremer and shows some of the last scenes that Spirit ever photographed.
Spirit approaches von Braun mound in April 2009
This mosaic of images was collected on Sol 1869 in April 2009 as Spirit approached a mysterious circular volcanic mound known as Von Braun, at left. Foreground at center, left ahead shows where Spirit became stuck in a concealed sand trap of slippery, water related sulfate minerals lying adjacent to the eroded volcanic plateau named Home Plate. Columbia Hills in the background.
Mosaic Credit: Kenneth Kremer/Marco Di Lorenzo/NASA/JPL/Cornell
Endeavour’s massive rim consists of a series of ridges. Cape York is a 400 foot wide (120 meters) rim fragment at the western edge of Endeavour. Opportunity should reach “Spirit Point” before the end of this year, 2011.
“Spirit Point” was chosen as the site at Endeavour to commemorate the scientific achievements of Opportunity’s twin sister “Spirit”. Endeavour Crater was determined to be Opportunity’s long term destination nearly three ago after she departed the environs of Victoria crater.
“The Initial exploration plan will be decided when we get closer. The [science] priorities will depend on what we find,” Squyres added.
Since August 2008, the blistering pace of Opportunity’s long overland trek of about 11 miles (18 kilometers) has brought the golf cart sized robot to within about 2 miles (3 kilometers) of the rim of the humongous Endeavour crater – some 14 miles (22 kilometers) in diameter. Endeavour is more than 20 times wider than Victoria crater and by far the largest feature the Opportunity will ever explore – see route maps below.
This oblique view with moderate vertical exaggeration shows the portion of the rim of Endeavour crater given the informal name "Spirit Point." This is the location where the team operating NASA's Mars Exploration Rover Opportunity plans to drive the rover to its arrival at the Endeavour rim. As of mid-June 2011, Opportunity was about 2 miles away from the rim of Endeavour. Credit: NASA/JPL-Caltech/Univ. of Arizona
“Spirit achieved far more than we ever could have hoped when we designed her,” according to Squyres in a NASA statement. “This name will be a reminder that we need to keep pushing as hard as we can to make new discoveries with Opportunity. The exploration of Spirit Point is the next major goal for us to strive for.”
The imaging team of Marco Di Lorenzo and Ken Kremer created a series of Spirit photomosaics from publically available images to illustrate the location and hazardous nature of Spirits final resting place – which fortuitously turned out to be a scientific goldmine revealing new insights into the flow of liquid water on Mars billions of years ago.
Mosaic of microscopic images of Spirit’s underbelly on Sol 1925 in June 2009
Mosaic shows predicament of being stuck at Troy with wheels buried in the sulfate-rich Martian soil. This false color mosaic has been enhanced and stretched to bring out additional details about the surrounding terrain and embedded wheels and distinctly shows a pointy rock perhaps in contact with the underbelly.
Mosaic Credit: Marco Di Lorenzo/ Kenneth Kremer/NASA/JPL/Cornell
The western rim of Endeavour possesses geological deposits far older than any Opportunity has investigated before and which may feature environmental conditions that were more conducive to the potential formation of ancient Martian life forms.
Spirits last transmissions to Earth took place in March 2010, before she entered hibernation mode due to ebbing solar power and succumbed to the likely damaging effects of her 4th Martian winter.
Spirit was closing in on her next science target, a mysterious volcanic feature named Von Braun, when she became mired in a sand trap named “Troy” on the outskirts of the eroded volcano named “Home Plate, just about 500 feet away. See our mosaics.
Spirit embedded at sand trap in February 2010 on Sol 2174
Numerous attempts by the rover team failed to extricate Spirit from the sand trap at Troy in which she became mired in May 2009 on the western edge of Home Plate. Mosaic shows last robotic arm maneuver before hibernation and above bright toned soil containing hydrated sulfates. Mosaic Credit: Marco Di Lorenzo/ Kenneth Kremer/ NASA/JPL/Cornell
Unable to escape and absent of sufficient power to run critical survival heaters, Spirit experienced temperatures colder than ever before that probably crippled fragile electronics components and connections and prevented further communications – although no one knows for sure.
NASA’s twin rovers Spirit and Opportunity have been exploring the Martian terrain on opposite sides of the red planet since the dynamic duo successfully landed over 7 years ago in January 2004.
Both robots were expected to last just three months but have accumulated a vast bonus time of exploration and discovery in numerous extended mission phases.
*** Several top members of the rover science team kindly provided me some comments (below) to sum up Spirits achievements and legacy and what’s ahead for Opportunity at Endeavour.
Ray Arvidson of Washington University, St Louis, Deputy Principal Investigator for the rovers:
“Spirit’s last communication with Earth was in March 2010 as the southern hemisphere winter season began to set in, the sun was low on the horizon, and the rover presumably stopped communicating to use all available solar power to charge the batteries.
Von Braun was one of the two destinations Spirit was traveling to when the rover became embedded in soft sands in the valley to the west of Home Plate.
Von Braun is a conically-shaped hill to the south of Home Plate, Inner Basin, Columbia Hills. Goddard is an oval-shaped shallow depression to the west of von Braun and was the second area to be visited by Spirit. Both von Braun and Goddard are suspected to be volcanic features.
Spirit is the brightest spot in this image taken on 31 March 2011 from Mars orbit. Spirit is gleaming in the sun beside Home Plate inside Gusev Crater. The solar panels are not covered by an optically thick layer of dust. Spirit last communicated on 22 March 2010. Credit: NASA/JPL/UA
During Spirit’s six year and two month mission the vehicle acquired remote sensing and in-situ observations that conclusively demonstrated that the ancient Columbia Hills in Gusev Crater expose materials that have been altered in water-related environments, including ground water corrosion and generation of sulfate and opaline minerals in volcanic steam vents and perhaps hydrothermal pools.
Together with its sister rover, Opportunity, the Mars Exploration Rover Mission, was designed to “follow the water” and return data that would allow us to test the hypothesis that water was at and near the surface during previous epochs.
Opportunity is still exploring the evidence in Meridiani for ancient shallow lakes and is on the way to outcrops on the rim of Endeavour crater, a ~20 km wide crater that exposes the old Noachian crust that shows evidence from orbital data for hydrated clay minerals.
These two rovers have performed far beyond expectations, unveiled the early, wet history of Mars, and have made an enormous scientific return on investment.”
Steve Squyres of Cornell University, Ithaca, N.Y., Principal Investigator for the rovers:
“Our best hope for hearing from Spirit was last fall. When that didn’t happen, we began a long, careful process of trying every possible approach to re-establishing contact. But it slowly became clear that it was unlikely, and I personally got used to the idea that Spirit’s mission was probably over several months ago.
Once that right front wheel failed, Spirit’s days were numbered in that kind of terrain. It wouldn’t have made any difference if we had tried to move Spirit sooner. We were very lucky to have survived as long as we did.
One of the lessons learned is to try to keep the wheels from failing.
It’s very sad to lose Spirit. But two things have softened the blow. First we’ve had a long time to get used to the idea. Second, even though Spirit is dead, she died an honorable death. If we’d lost her early in the mission, before she accomplished so much, it would have been much harder. But she accomplished so much more than any of us expected, the sadness is very much tempered with satisfaction and pride.
The big scientific accomplishments are the silica deposits at Home Plate, the carbonates at Comanche, and all the evidence for hydrothermal systems and explosive volcanism. What we’ve learned is that early Mars at Spirit’s site was a hot, violent place, with hot springs, steam vents, and volcanic explosions. It was extraordinarily different from the Mars of today.
Opportunity is heading at high speed for the rim of Endeavour Crater. First landfall will be at the southern end of Cape York. She should be there in not too many more months.
It hasn’t yet been decided where Opportunity will attempt to climb up Endeavour… we’ll see when we get there.
The phyllosilicates are a high priority, but the top priority depends on what we find.
The yellow line on this map shows where NASA's Mars Rover Opportunity has driven from the place where it landed in January 2004 -- inside Eagle crater, at the upper left end of the track -- to a point about 2.2 miles (3.5 kilometers) away from reaching the rim of Endeavour crater. Credit: NASA/JPL-Caltech/MSSS
I hope Spirits legacy will be the inspiration that people, especially kids, will take away from Spirit’s mission. I have had long, thoughtful conversations about Spirit with kids who have had a rover on Mars as long as they can remember. And my fondest hope for Spirit is that somewhere there are kids who will look at what we did with her, and say to themselves “well, that’s pretty cool… but I bet when I grow up I can do better. That’s what we need for the future of space exploration.
Spirit existed, and did what she did, because of the extraordinary team of engineers and scientists who worked so hard to make it possible. It’s a team that I’m incredibly proud to have been a small part of. Working with them has been quite literally the adventure of a lifetime.”
Jim Bell of Arizona State University, lead scientist for the rovers Pancam stereo panoramic camera:
“It is with a bittersweet sense of both sadness and pride that NASA announced the official end of the mission for the Mars Exploration Rover Spirit.
The Spirit team has seen the end coming since communications were lost with the rover in March 2010. Mission engineers made heroic efforts to reestablish contact. In the end Spirit was conquered by the extremely cold Martian winter and its two broken wheels, which prevented its dusty solar panels from pointing toward the Sun.
But what a mission! Designed to last 90 days, Spirit kept going for more than six years, with the team driving the rover almost 5 miles (8 km) across rocky volcanic plains, climbing rugged ancient hills, and scurrying past giant sand-dune fields. It eventually spent most of the mission near the region known as Home Plate, which is full of layered, hydrated minerals.
Data from the rover enabled dozens of scientific discoveries, but three stand out to me as most important:
Hydrated sulfate and high-silica soils in the Columbia Hills and around Home Plate.
These minerals, and the environment in which they occur (Home Plate is a circular-shaped, finely layered plateau that may be the eroded remains of a volcanic cone or other hydrothermal deposit), tell us that at some point in the past history of Gusev there was liquid water and there were heat sources — two key ingredients needed to consider the area habitable for life as we know it.
Carbonate minerals in some of the rocks within the Columbia Hills.
Carbonates were expected on Mars, if indeed the climate was warmer and wetter in the past. However, their detection has been elusive so far. Indeed, the Spirit team had to work hard to uncover the signature of carbonates years after the rover made the measurements. As the analysis continues the results for Mars in general could be profound.
An incredible diversity of rock types, from all over Mars, that Spirit was able to sample in Gusev crater.
Some of the rocks appear to be from local volcanic lava flows or ash deposits. But others have likely been flung in to the area over time by distant impacts or volcanoes, and a few even appear to be meteorites, flung in from outer space. Spirit’s instruments provided the team with the ability to recognize this amazing diversity, and thus to learn much more about Mars in general, not just Gusev in particular.
Spirit also helped us test an experiment: If we put all the rover’s images out on the Web for everyone in the world to see, in near real-time, would people follow along? They did!
I wonder if, maybe 10 or 15 years from now, I’ll meet some young colleagues who were turned on to space exploration by being able to check out the latest Spirit images from Mars from their classroom, or living room, every day when they were a kid. That would be extremely satisfying — and a great testament to the power of openly sharing data from space exploration missions like Spirit’s.
Meanwhile, Opportunity continues to rove on to city-size Endeavour crater, where orbital measurements have identified, for the first time in either rover’s mission, the signatures of clay minerals in the crater’s rim. Clays are also formed in water, but in less acidic, perhaps more life-friendly water than the sulfates that Opportunity has been mapping thus far.”
Rob Manning, Jet Propulsion laboratory, Pasadena, CA., Mars Rover Spacecraft System Engineering team lead
“Although Opportunity has proven her endurance, Spirit was the one we struggled with the hardest to get what she earned. Suffering from late repair and modification, a blown fuse in her power system and with possibly damaged circuits, she was very late getting out the door and onto the pad in Florida.
Unlike Opportunity, whose Hematite-laden Meridiani destination had been established long before launch, Spirit was launched with a great deal of uncertainty on where she would find herself on Mars. Would it be the flat and safe plains of Elysium? Would the intriguing but rough ancient Gusev crater with what appears to have been an ancient river flowing into a giant but now dry lake?
If Opportunity failed to get on her way to Mars, would her destination become Meridiani? Would Spirit have also been as lucky to find herself bouncing into a tiny rock-outcropped crater as Opportunity had?
Only after the successful launch of Opportunity followed by further successful rocket and airbag tests to confirm that the landing system design would work in the rougher terrain inside Gusev crater allowed us to seal her fate and her permanent home.
She would go Gusev and test the Gusev lake hypothesis. Sadly the surface of Gusev where she came to rest revealed a meteor impact-tilled lake of ancient lava. Any signs of ancient water lake beds and other fantastic discoveries would have to wait until she surmounted many more obstacles including summiting a formidable hill her designers never intended her to attempt.
Spirit, her designers, her builders, her testers, her handlers and I have a lot to be thankful for.
That NASA, the congress and the public were willing to trust us with this daunting feat is perhaps a statement about the persistent spirit of discovery that remains in all of us.
I think that Spirit is alive and well.”
Map mosaic shows 7 Year and 30 Kilometer Long Journey of Opportunity approaching Endeavour Crater. Opportunity is being targeted to Spirit Point on the rim of Endeavour Crater, to honor her now dead sister. Photo mosaic of Santa Maria crater at top right was featured on Astronomy Picture of the Day on 29 January 2011. Mosaic shows Opportunity self portrait at the rim of Santa Maria where she investigated signatures of hydrated mineral deposits.
Mosaic Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Kenneth Kremer
