Roughly 4.2 billion years ago, Mars was a much different place than it is today. It’s atmosphere was thicker and warmer and its surface much wetter. Unfortunately, the planet’s atmosphere was stripped away by solar wind over the next 500 million years, causing the surface to become so cold and dry that it makes Antarctica look balmy by comparison!
As a result, most of Mars’ water is currently locked away in its polar ice caps. But billions of years ago, water still flowed freely across the surface, forming ancient rivers and lakes. In fact, new research led by The University of Texas at Austin indicates that sometimes these lakes would fill so fast that they would overflow, causing massive floods that had a drastic impact on the surface.
Jezero crater is the landing spot for NASA’s upcoming 2020 rover. The crater is a rich geological site, and the 45 km wide (28 mile) impact crater contains at least five different types of rock that the rover will sample. Some of the landform features in the crater are 3.6 billion years old, making the site an ideal place to look for signs of ancient habitability.
In the summer of 2020, NASA’s Mars 2020rover will launch from Cape Canaveral and commence its journey towards the Red Planet. Once it arrives on the Martian surface, the rover will begin building on the foundation established by the Opportunity and Curiosityrovers. This will include collecting samples of Martian soil to learn more about the planet’s past and determine if life ever existed there (and still does).
Up until now, though, NASA has been uncertain as to where the rover will be landing. For the past few years, the choice has been narrowed down to three approved sites, with a fourth added earlier this year for good measure. And after three days of intense debate at the recent fourth Landing Site Workshop, scientists from NASA’s Mars Exploration Program held a non-binding vote that has brought them closer to selecting a landing site.
For some time, scientists have known that Mars was once a much warmer and wetter environment than it is today. However, between 4.2 and 3.7 billion years ago, its atmosphere was slowly stripped away, which turned the surface into the cold and desiccated place we know today. Even after multiple missions have confirmed the presence of ancient lake beds and rivers, there are still unanswered questions about how much water Mars once had.
One of the most important unanswered questions is whether or not large seas or an ocean ever existed in the northern lowlands. According to a new study by an international team of scientists, the Hypanis Valles ancient river system is actually the remains of a river delta. The presence of this geological feature is an indication that this river system once emptied into an ancient Martian sea in Mars’ northern hemisphere.
In July of 2020, the Mars 2020 rover – the latest from NASA’s Mars Exploration Program – will begin its long journey to the Red Planet. Hot on the heels of the Opportunity and Curiosity rovers, the Mars 2020 rover will attempt to answer some of the most pressing questions we have about Mars. Foremost among these is whether or not the planet had habitable conditions in the past, and whether or not microbial life existed there.
To this end, the Mars 2020 rover will obtain drill samples of Martian rock and set them aside in a cache. Future crewed missions may retrieve these samples and bring them back to Earth for analysis. However, in a recent announcement, NASA indicated that a piece of a Martian meteor will accompany the Mars 2020 rover back to Mars, which will be used to calibrate the rover’s high-precious laser scanner.
Ordinarily, these calibration targets involve pieces of rock, metal or glass, samples that are the result of a complex geological history. However, when addressing the SHERLOC’s calibration needs, JPL scientists came up with a rather innovative idea. For billions of years, Mars has experienced impacts that have sent pieces of its surface into orbit. In some cases, those pieces came to Earth in the form of meteorites, some of which have been identified.
While these meteorites are rare and not identical to the geologically diverse samples the Mars 2020 rover will collect, they are well-suited for target practice. As Luther Beegle of JPL, the principle investigator for SHERLOC, said in a recent NASA press statement:
“We’re studying things on such a fine scale that slight misalignments, caused by changes in temperature or even the rover settling into sand, can require us to correct our aim. By studying how the instrument sees a fixed target, we can understand how it will see a piece of the Martian surface.”
In this respect, the Mars 2020 rover is in good company. For example, Curiosity’s used its Chemistry and Camera (ChemCham) instrument – which relies on laser-induced breakdown spectroscopy (LIBS) – to determine the elemental compositions of rock and soil samples it has obtained. Similarly, the Opportunity rover’s Miniature Thermal Emission Spectrometer (Mini-TES) allowed this rover to detect the composition of rocks from a distance.
However, SHERLOC is unique in that it will be the first instrument deployed to Mars that uses Raman and fluorescence spectroscopy. Raman spectroscopy consists of subjecting materials to light in the visible, near infrared, or near ultraviolet range and measuring how the photons respond. Based on how their energy levels shift up or down, scientists are able to determine the presence of certain elements.
Fluorescence spectroscopy relies on ultraviolet lasers to excite the electrons in carbon-based compounds, which causes chemicals that are known to form in the presence of life (i.e. biosignatures) to glow. SHERLOC will also photograph the rocks it studies, which will allow the science team to map the chemical signatures it finds across the surface of Mars.
For their purposes, the SHERLOC team needed a sample that would be solid enough to withstand the intense vibrations caused by launch and landing. They also needed one that contained the right chemicals to test SHERLOC’s sensitivity to biosignatures. With the help of the Johnson Space Center and the Natural History Museum in London, they ultimately decided on a sample from the Sayh al Uhaymir 008 meteorite (aka. SaU008).
This meteorite, which was found in Oman in 1999, was more rugged that other samples and could be sliced without the rest of the meteorite flaking. As a result, SaU008 will be the first Martian meteorite sample that helps scientists look for past signs of life on Mars. It will also be the first Martian meteorite to have a piece of itself returned to the surface of Mars – though technically not the first to be sent back.
That honor goes to Zagami, a meteorite retrieved in Nigeria in 1962, which had a piece of itself sent back to Mars aboard the Mars Global Surveyor (MGS) in 1999. That mission ended in 2007, so this chunk has been floating around in orbit of Mars ever since. In addition, the team behind Mars 2020‘s SuperCam instrument will also be adding a Martian meteorite for their own calibration tests.
Along with bits of SaU008, the Mars 2020 payload will include samples of advanced materials. Aside from also being used to calibrate SHERLOC, these materials will be tested to see how they hold up to Martian weather and radiation. If they prove to be tough enough to survive on the Martian surface, these materials could be used in the manufacture of space suits, gloves and helmets for future astronauts.
As Marc Fries, a SHERLOC co-investigator and curator of extraterrestrial materials at Johnson Space Center, put it:
“The SHERLOC instrument is a valuable opportunity to prepare for human spaceflight as well as to perform fundamental scientific investigations of the Martian surface. It gives us a convenient way to test material that will keep future astronauts safe when they get to Mars.”
With every robotic mission sent to Mars, NASA and other space agencies are working towards the day when astronauts’ boots will finally touch down on the Red Planet. When the first crewed mission to Mars are conducted (currenty scheduled for the 2030s), they will be following in the tracks of some truly intrepid robotic explorers!
Over the past few decades, our ongoing studies of Mars have revealed some very fascinating things about the planet. In the 1960s and early 70s, the Mariner probes revealed that Mars was a dry, frigid planet that was most likely devoid of life. But as our understanding of the planet has deepened, it has come to be known that Mars once had a warmer, wetter environment that could have supported life.
This in turn has inspired multiple missions whose purpose it has been to find evidence of this past life. The key questions in this search, however, are where to look and what to look for? In a new study led by researchers from the University of Kansas, a team of international scientists recommended that future missions should look for vanadium. This rare element, they claim, could point the way towards fossilized evidence of life.
To be clear, finding signs of life on a planet like Mars is no easy task. As Craig Marshall indicated in a University of Kansas press release:
“You’ve got your work cut out if you’re looking at ancient sedimentary rock for microfossils here on Earth – and even more so on Mars. On Earth, the rocks have been here for 3.5 billion years, and tectonic collisions and realignments have put a lot of stress and pressure on rocks. Also, these rocks can get buried, and temperature increases with depth.”
In their paper, Marshall and his colleagues recommend that missions like NASA’s Mars 2020 rover, the ESA’s ExoMars 2020 rover, and other proposed surface missions could combine Raman spectroscopy with the search for vanadium to find evidence of fossilized life. On Earth, this element has been found in crude oils, asphalts, and black shales that have been formed by the slow decay of biological organic material.
In addition, paleontologists and astrobiologists have used Raman spectroscopy – a technique that reveals the cellular compositions of samples – on Mars for some time to search for signs of life. In this respect, the addition of vanadium would provide material that would act as a biosignature to confirm the existence of organic life in samples under study. As Marshall explained:
“People say, ‘If it looks like life and has a Raman signal of carbon, then we have life. But, of course, we know there can be carbonaceous materials made in other processes — like in hydrothermal vents — consistent with looking like microfossils that also have some carbon signal. People also make wonderful carbon structures artificially that look like microfossils — exactly the same. So, we’re at a juncture now where it’s really hard to tell if there’s life only based on morphology and Raman spectroscopy.”
This is not the first time that Marshall and his co-authors have advocated using vanadium to search for signs of life. Such was the subject of a presentation they made at the Astrobiology Science Conference in 2015. What’s more, Marshall and his team emphasize that it would be possible to perform this technique using instruments that are already part of NASA’s Mars 2020 mission.
Their proposed method also involves new technique known as X-ray fluorescence microscopy, which looks at elemental composition. To test this technique, the team examined thermally altered organic-walled microfossils which were once organic materials )called acritarchs). From their data, they confirmed that traces of vanadium are present within microfossils that were indisputably organic in origin.
“We tested acritarchs to do a proof-of-concept on a microfossil where there’s no shadow of a doubt that we’re looking at preserved ancient biology,” Marshall said. “The age of this microfossil we think is Devonian. These guys are aquatic microorganisms — they’re thought to be microalgae, a eukaryotic cell, more advanced than bacterial. We found the vanadium content you’d expect in cyanobacterial material.”
These microfossilized bit of life, they argue, are probably not very distinct from the kinds of life that could have existed on Mars billions of years ago. Other scientific research has also indicated that vanadium is the result of organic compounds (like chlorophyll) from living organisms undergoing a transformation process caused by heat and pressure (i.e. diagenetic alteration).
In other words, after living creatures die and become buried in sediment, vanadium forms in their remains as a result of being buried under more and more layers of rock – i.e. fossilization. Or, as Marshall explained it:
“Vanadium gets complexed in the chlorophyll molecule. Chlorophylls typically have magnesium at the center — under burial, vanadium replaces the magnesium. The chlorophyll molecule gets entangled within the carbonaceous material, thus preserving the vanadium. It’s like if you have a rope stored in your garage and before you put it away you wrap it so you can unravel it the next time you need it. But over time on the garage floor it becomes tangled, things get caught in it. Even when you shake that rope hard, things don’t come out. It’s a tangled mess. Similarly, if you look at carbonaceous material there’s a tangled mess of sheets of carbon and you’ve got the vanadium mixed in.”
At present, their research appears to have attracted the interesting of the European Space Agency. Howell Edwards, who also conducts research using Raman spectroscopy (and who’s work has been supported by an ARC grant), is part of the ESA’s Mars Explorer team, where he is responsible for instrumentation on the ExoMars 2020 rover. But, as Marshall indicated, the team also hopes that NASA will consider their study:
“Hopefully someone at NASA reads the paper. Interestingly enough, the scientist who is lead primary investigator for the X-ray spectrometer for the space probe, they call it the PIXL, was his first graduate student from Macquarie University, before his KU times. I think I’ll email her the paper and say, ‘This might be of interest.’”
The next decade is expected to be a very auspicious time for exploration missions to Mars. Multiple rovers will be exploring the surface, hoping to find the elusive evidence of life. These missions will also help pave the way for NASA’s crewed mission to Mars by the 2030s, which will see astronauts landing on the surface of the Red Planet for the first time in history.
If, in fact, these missions find evidence of life, it will have a profound effect on all future mission to Mars. It will also have an immeasurable impact on humanity’s perception of itself, knowing at long last that billions of years ago, life did not emerge on Earth alone!
NASA has always had its fingers in many different pies. This should come as no surprise, since the advancement of science and the exploration of the Universe requires a multi-faceted approach. So in addition to studying Earth and distant planets, the also study infectious diseases and medical treatments, and ensuring that food, water and vehicles are safe. But protecting Earth and other planets from contamination, that’s a rather special job!
For decades, this responsibility has fallen to the NASA Office of Planetary Protection, the head of which is known as the Planetary Protection Officer (PPO). Last month, NASA announced that it was looking for a new PPO, the person whose job it will be to ensure that future missions to other planets don’t contaminate them with microbes that have come along for the ride, and that return missions don’t bring extra-terrestrial microbes back to Earth.
Since the beginning of the Space Age, federal agencies have understood that any and all missions carried with them the risk of contamination. Aside from the possibility that robotic or crewed missions might transport Earth microbes to foreign planets (and thus disrupt any natural life cycles there), it was also understood that missions returning from other bodies could bring potentially harmful organisms back to Earth.
As such, the Office of Planetary Protection was established in 1967 to ensure that these risks were mitigated using proper safety and sterilization protocols. This was shortly after the United Nation’s Office of Outer Space Affairs (UNOOSA) drafted the Outer Space Treaty, which was signed by the United States, the United Kingdom, and the Soviet Union (as of 2017, 107 countries have become party to the treaty).
The goals of the Office of Planetary Protection are consistent with Article IX of the Outer Space Treaty; specifically, the part which states:
“States Parties to the Treaty shall pursue studies of outer space, including the Moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter and, where necessary, shall adopt appropriate measures for this purpose.”
For decades, these directives have been followed to ensure that missions to the Moon, Mars and the Outer Solar System did not threaten these extra-terrestrial environments. For example, after eight years studying Jupiter and its largest moons, the Galileo probe was deliberately crashed into Jupiter’s atmosphere to ensure that none of its moons (which could harbor life beneath their icy surfaces) were contaminated by Earth-based microbes.
The same procedure will be followed by the Juno mission, which is currently in orbit around Jupiter. Barring a possible mission extension, the probe is scheduled to be deorbited after conducting a total of 12 orbits of the gas giant. This will take place in July of 2018, at which point, the craft will burn up to avoid contaminating the Jovian moons of Europa, Ganymede and Callisto.
The same holds true for the Cassinispacecraft, which is currently passing between Saturn and its system of rings, as part of the mission’s Grand Finale. When this phase of its mission is complete – on September 15th, 2017 – the probe will be deorbited into Saturn’s atmosphere to prevent any microbes from reaching Enceladus, Titan, Dione, moons that may also support life in their interiors (or in Titan’s case, even on its surface!)
To be fair, the position of a Planetary Protection Officer is not unique to NASA. The European Space Agency (ESA), the Japanese Aerospace and Exploration Agency (JAXA) and other space agencies have similar positions. However, it is only within NASA and the ESA that it is considered to be a full-time job. The position is held for three years (with a possible extension to five) and is compensated to the tune of $124,406 to $187,000 per year.
The job, which can be applied for on USAJOBS.gov (and not through the Office of Planetary Protection), will remain open until August 18th, 2017. According to the posting, the PPO will be responsible for:
Leading planning and coordinating activities related to NASA mission planetary protection needs.
Leading independent evaluation of, and providing advice regarding, compliance by robotic and human spaceflight missions with NASA planetary protection policies, statutory requirements and international obligations.
Advising the Chief, SMA and other officials regarding the merit and implications of programmatic decisions involving risks to planetary protection objectives.
In coordination with relevant offices, leading interactions with COSPAR, National Academies, and advisory committees on planetary protection matters.
Recommending and leading the preparation of new or revised NASA standards and directives in accordance with established processes and guidelines.
What’s more, the fact that NASA is advertising the position is partly due to some recent changes to the role. As Catharine Conley*, NASA’s only planetary protection officer since 2014, indicated in a recent interview with Business Insider: “This new job ad is a result of relocating the position I currently hold to the Office of Safety and Mission Assurance, which is an independent technical authority within NASA.”
While the position has been undeniably important in the past, it is expected to become of even greater importance given NASA’s planned activities for the future. This includes NASA’s proposed “Journey to Mars“, a crewed mission which will see humans setting foot on the Red Planet sometime in the 2030s. And in just a few years time, the Mars 2020 rover is scheduled to begin searching the Martian surface for signs of life.
As part of this mission, the Mars 2020 rover will collect soil samples and place them in a cache to be retrieved by astronauts during the later crewed mission. Beyond Mars, NASA also hopes to conduct mission to Europa, Enceladus and Titan to look for signs of life. Each of these worlds have the necessary ingredients, which includes the prebiotic chemistry and geothermal energy necessary to support basic lifeforms.
Given that we intend to expand our horizons and explore increasingly exotic environments in the future – which could finally lead to the discovery of life beyond Earth – it only makes sense that the role of the Planetary Protection Officer become more prominent. If you think you’ve got the chops for it, and don’t mind a six-figure salary, be sure to apply soon!
*According to BI, Conley has not indicated if she will apply for the position again.
The Trump Administration has proposed a $19.1 Billion NASA budget request for Fiscal Year 2018, which amounts to a $0.5 Billion reduction compared to the recently enacted FY 2017 NASA Budget. Although it maintains many programs such as human spaceflight, planetary science and the Webb telescope, the budget also specifies significant cuts and terminations to NASA’s Earth Science and manned Asteroid redirect mission as well as the complete elimination of the Education Office.
Overall NASA’s FY 2018 budget is cut approximately 3%, or $560 million, for the upcoming fiscal year starting in October 2017 as part of the Trump Administration’s US Federal Budget proposal rolled out on May 23, and quite similar to the initial outline released in March.
The cuts to NASA are smaller compared to other Federal science agencies also absolutely vital to the health of US scientific research – such as the NIH, the NSF, the EPA, DOE and NIST which suffer unconscionable double digit slashes of 10 to 20% or more.
The highlights of NASA’s FY 2018 Budget were announced by NASA acting administrator Robert Lightfoot during a ‘State of NASA’ speech to agency employees held at NASA HQ, Washington, D.C. and broadcast to the public live on NASA TV.
Lightfoot’s message to NASA and space enthusiasts was upbeat overall.
“What this budget tells us to do is to keep going!” NASA acting administrator Robert Lightfoot said.
“Keep doing what we’ve been doing. It’s very important for us to maintain that course and move forward as an agency with all the great things we’re doing.”
“I want to reiterate how proud I am of all of you for your hard work – which is making a real difference around the world. NASA is leading the world in space exploration, and that is only possible through all of your efforts, every day.”
“We’re pleased by our top line number of $19.1 billion, which reflects the President’s confidence in our direction and the importance of everything we’ve been achieving.”
Thus Lightfoot’s vision for NASA has three great purposes – Discover, Explore, and Develop.
“NASA has a historic and enduring purpose. It can be summarized in three major strategic thrusts: Discover, Explore, and Develop. These correspond to our missions of scientific discovery, missions of exploration, and missions of new technology development in aeronautics and space systems.”
“We’ve had a horizon goal for some time now of reaching Mars, and this budget sustains that work and also provides the resources to keep exploring our solar system and look beyond it.”
Lightfoot also pointed to upcoming near term science missions- highlighting a pair of Mars landers – InSIGHT launching next year as well as the Mars 2020 rover. Also NASA’s next great astronomical observatory – the James Webb Space Telescope (JWST).
“In science, this budget supports approximately 100 missions: 40 missions currently preparing for launch & 60 operating missions.”
“The James Webb Space Telescope is built!” Lightfoot gleefully announced.
“It’s done testing at Goddard and now has moved to Johnson for tests to simulate the vacuum of space.”
JWST is the scientific successor to the Hubble Space Telescope and slated for launch in Oct. 2018. The budget maintains steady support for Webb.
The Planetary Sciences division receives excellent support with a $1.9 Billion budget request. It includes solid support for the two flagship missions – Mars 2020 and Europa Clipper as well as the two new Discovery class missions selected -Lucy and Psyche.
“The budget keeps us on track for the next selection for the New Frontiers program, and includes formulation of a mission to Jupiter’s moon Europa.”
“SLS and Orion are making great progress. They are far beyond concepts, and as I mentioned, components are being tested in multiple ways right now as we move toward the first flight of that integrated system.”
NASA is currently targeting the first integrated launch of SLS and Orion on the uncrewed Exploration Mission-1 (EM-1) for sometime in 2019.
NASA would have needed an additional $600 to $900 to upgrade EM-1 with humans.
Unfortunately Trump’s FY 2018 NASA budget calls for a slight reduction in development funding for both SLS and Orion – thus making a crewed EM-1 flight fiscally unviable.
The budget request does maintain full funding for both of NASA’s commercial crew vehicles planned to restore launching astronauts to low Earth orbit (LEO) and the ISS from US soil on US rockets – namely the crewed Dragon and CST-100 Starliner – currently under development by SpaceX and Boeing – thus ending our sole reliance on Russian Soyuz for manned launches.
“Working with commercial partners, NASA will fly astronauts from American soil on the first new crew transportation systems in a generation in the next couple of years.”
“We need commercial partners to succeed in low-Earth orbit, and we also need the SLS and Orion to take us deeper into space than ever before.”
However the Trump Administration has terminated NASA’s somewhat controversial plans for the Asteroid Redirect Mission (ARM) – initiated under the Obama Administration – to robotically retrieve a near Earth asteroid and redirect it to lunar orbit for a visit by a crewed Orion to gather unique asteroidal samples.
“While we are ending formulation of a mission to an asteroid, known as the Asteroid Redirect Mission, many of the central technologies in development for that mission will continue, as they constitute vital capabilities needed for future human deep space missions.”
Key among those vital capabilities to be retained and funded going forward is Solar Electric Propulsion (SEP).
“Solar electric propulsion (SEP) for our deep space missions is moving ahead as a key lynchpin.”
The Trump Administration’s well known dislike for Earth science and disdain of climate change has manifested itself in the form of the termination of 5 current and upcoming science missions.
NASA’s FY 2018 Earth Science budget suffers a $171 million cut to $1.8 Billion.
“While we are not proposing to move forward with Orbiting Carbon Observatory-3 (OCO-3), Plankton, Aerosol, Cloud, ocean Ecosystem (PACE), Climate Absolute Radiance and Refractivity Observatory Pathfinder (CLARREO PF), and the Radiation Budget Instrument (RBI), this budget still includes significant Earth Science efforts, including 18 Earth observing missions in space as well as airborne missions.”
The DSCOVR Earth-viewing instruments will also be shut down.
NASA’s Office of Education will also be terminated completely under the proposed FY 2018 budget and the $115 million of funding excised.
“While this budget no longer supports the formal Office of Education, NASA will continue to inspire the next generation through its missions and the many ways that our work excites and encourages discovery by learners and educators. Let me tell you, we are as committed to inspiring the next generation as ever.”
Congress will now have its say and a number of Senators, including Republicans says Trumps budget is DOA.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
For years now, scientists have understood that Mars was once a warmer, wetter place. Between terrain features that indicate the presence of rivers and lakes to mineral deposits that appeared to have dissolved in water, there is no shortage of evidence attesting to this “watery” past. However, just how warm and wet the climate was billions of years ago (and since) has been a subject of much debate.
According to a new study from an international team of scientists from the University of Nevada, Las Vegas (UNLV), it seems that Mars may have been a lot wetter than previous estimates gave it credit for. With the help of Berkeley Laboratory, they conducted simulations on a mineral that has been found in Martian meteorites. From this, they determined that Mars may have had a lot more water on its surface than previously thought.
When it comes to studying the Solar System, meteorites are sometimes the only physical evidence available to researchers. This includes Mars, where meteorites recovered from Earth’s surface have helped to shed light on the planet’s geological past and what kinds of processes have shaped its crust. For geoscientists, they are the best means of determining what Mars looked like eons ago.
Unfortunately for geoscientists, these meteorites have underdone changes as a result of the cataclysmic force that expelled them from Mars. As Dr. Christopher Adcock, an Assistant Research Professor at with the Dept. of Geoscience at UNLV and the lead author of the study, told Universe Today via email:
“Martian meteorites are pieces of Mars, basically they are our only samples of Mars on Earth until there is a sample return mission. Many of the discoveries we have made about Mars came from studying martian meteorites and wouldn’t be possible without them. Unfortunately, these meteorites have all experienced shock from being ejected of the Martian surface during impacts.”
Of the over 100 Martian meteorites that have been retrieved here on Earth, and range in age from between 4 billion years to 165 million years. They are also believed to have come from only a few regions on Mars, and were likely ejecta created from impact events. And in the course of examining them, scientists have noticed the presence of a calcium phosphate mineral known as merrillite.
As a member of the whitlockite group that is commonly found in Lunar and Martian meteorities, this mineral is known for being anhydrous (i.e. containing no water). As such, researchers have drawn the conclusion that the presence of this minerals indicates that Mars had an arid environment when these rocks were ejected. This is certainly consistent with what Mars looks like today – cold, icy and dry as a bone.
This consisted of placing the synthetic whitlockite sample inside a projectile, then using a helium gas gun to accelerate it up to speeds of 700 meters per second (2520 km/h or 1500 mph) into a metal plate – thus subjecting it to intense heat and pressure. The sample was then examined using the Berkeley Lab’s Advanced Light Source (ALS) and the Argonne National Laboratory’s Advanced Photon Source (APS) instruments.
“When we analyzed what came out of the capsule, we found a significant amount of the whitlockite had dehydrated to the mineral merrillite,” said Adcock. “Merrillite is found in many meteorites (including Martian). The means it is possible the rocks meteorites are made from originally started life with whitlockite in them in an environment with more water than previously thought. If true, it would indicate more water in the Martian past and the early Solar System.”
Not only does this find raise the “water budget” for Mars in the past, it also raises new questions about Mars’ habitability. In addition to being soluble in water, whitlockite also contains phosphorous – a crucial element for life here on Earth. Combined with recent evidence that shows that liquid water still exists on Mars’ surface – albeit intermittently – this raises new questions about whether or not Mars had life in the past (or even today).
But as Adcock explained, further experiments and evidence will be needed to determine if these results are indicative of a more watery past:
“As far as life goes, our results are very favorable for the possibility – but we need more data. Really we need a sample return mission or we need to go there in person – a human mission. Science is closing in on the answers to a number of big questions about our solar system, life elsewhere, and Mars. But it is difficult work when it all has to be done from far away.”
And sample returns are certainly on the horizon. NASA hopes to conduct the first step in this process with their Mars 2020 Rover, which will collect samples and leave them in a cache for future retrieval. The ESA’s ExoMars rover is expected to make the journey to Mars in the same year, and will also obtain samples as part of a sample-return mission to Earth.
These missions are scheduled to launch the summer of 2020, when the planets will be at their closest again. And with crewed missions to the surface planned for the following decade, we might see the first non-meteorite samples of Mars brought back to Earth for analysis.
For some time, scientists have suspected that life may have existed on Mars in the deep past. Owing to the presence of a thicker atmosphere and liquid water on its surface, it is entirely possible that the simplest of organisms might have begun to evolve there. And for those looking to make Mars a home for humanity someday, it is hoped that these conditions (i.e favorable to life) could be recreated again someday.
But as it turns out, there are some terrestrial organisms that could survive on Mars as it is today. According to a recent study by a team of researchers from the Arkansas Center for Space and Planetary Sciences (ACSPS) at the University of Arkansas, four species of methanogenic microorganisms have shown that they could withstand one of the most severe conditions on Mars, which is its low-pressure atmosphere.
To put it simply, Methanogens are ancient group of organisms that are classified as archaea, a species of microorganism that do not require oxygen and can therefore survive in what we consider to be “extreme environments”. On Earth, methanogens are common in wetlands, ocean environments, and even in the digestive tracts of animals, where they consume hydrogen and carbon dioxide to produce methane as a metabolic byproduct.
And as several NASA missions have shown, methane has also been found in the atmosphere of Mars. While the source of this methane has not yet been determined, it has been argued that it could be produced by methanogens living beneath the surface. As Rebecca Mickol, an astrobiologist at the ACSPS and the lead author of the study, explained:
“One of the exciting moments for me was the detection of methane in the Martian atmosphere. On Earth, most methane is produced biologically by past or present organisms. The same could possibly be true for Mars. Of course, there are a lot of possible alternatives to the methane on Mars and it is still considered controversial. But that just adds to the excitement.”
As part of the ongoing effort to understand the Martian environment, scientists have spent the past 20 years studying if four specific strains of methanogen – Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, Methanococcus maripaludis – can survive on Mars. While it is clear that they could endure the low-oxygen and radiation (if underground), there is still the matter of the extremely low air-pressure.
With help from the NASA Exobiology & Evolutionary Biology Program (part of NASA’s Astrobiology Program), which issued them a three-year grant back in 2012, Mickol and her team took a new approach to testing these methanogens. This included placing them in a series of test tubes and adding dirt and fluids to simulate underground aquifers. They then fed the samples hydrogen as a fuel source and deprived them of oxygen.
The next step was subjecting the microorganisms to pressure conditions analogues to Mars to see how they might hold up. For this, they relied on the Pegasus Chamber, an instrument operated by the ACSPS in their W.M. Keck Laboratory for Planetary Simulations. What they found was that the methanogens all survived exposure to pressures of 6 to 143 millibars for periods of between 3 and 21 days.
This study shows that certain species of microorganisms are not dependent on a the presence of a dense atmosphere for their survival. It also shows that these particular species of methanogens could withstand periodic contact with the Martian atmosphere. This all bodes well for the theories that Martian methane is being produced organically – possibly in subsurface, wet environments.
This is especially good news in light of evidence provided by NASA’s HiRISE instrument concerning Mars’ recurring slope lineae, which pointed towards a possible connection between liquid water columns on the surface and deeper levels in the subsurface. If this should prove to be the case, then organisms being transported in the water column would be able to withstand the changing pressures during transport.
The next step, according to Mickol is to see how these organisms can stand up to temperature. “Mars is very, very cold,” she said, “often getting down to -100ºC (-212ºF) at night, and sometimes, on the warmest day of the year, at noon, the temperature can rise above freezing. We’d run our experiments just above freezing, but the cold temperature would limit evaporation of the liquid media and it would create a more Mars-like environment.”
Scientists have suspected for some time that life may still be found on Mars, hiding in recesses and holes that we have yet to peek into. Research that confirms that it can indeed exist under Mars’ present (and severe) conditions is most helpful, in that it allows us to narrow down that search considerably.