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.
Perhaps the most important question we can possible ask is, “are we alone in the Universe?”.
And so far, the answer has been, “I don’t know”. I mean, it’s a huge Universe, with hundreds of billions of stars in the Milky Way, and now we learn there are trillions of galaxies in the Universe.
Is there life closer to home? What about in the Solar System? There are a few existing places we could look for life close to home. Really any place in the Solar System where there’s liquid water. Wherever we find water on Earth, we find life, so it make sense to search for places with liquid water in the Solar System.
I know, I know, life could take all kinds of wonderful forms. Enlightened beings of pure energy, living among us right now. Or maybe space whales on Titan that swim through lakes of ammonia. Beep boop silicon robot lifeforms that calculate the wasted potential of our lives.
Sure, we could search for those things, and we will. Later. We haven’t even got this basic problem done yet. Earth water life? Check! Other water life? No idea.
It turns out, water’s everywhere in the Solar System. In comets and asteroids, on the icy moons of Jupiter and Saturn, especially Europa or Enceladus. Or you could look for life on Mars.
Mars is similar to Earth in many ways, however, it’s smaller, has less gravity, a thinner atmosphere. And unfortunately, it’s bone dry. There are vast polar caps of water ice, but they’re frozen solid. There appears to be briny liquid water underneath the surface, and it occasionally spurts out onto the surface. Because it’s close and relatively easy to explore, it’s been the place scientists have gone looking for past or current life.
Researchers tried to answer the question with NASA’s twin Viking Landers, which touched down in 1976. The landers were both equipped with three biology experiments. The researchers weren’t kidding around, they were going to nail this question: is there life on Mars?
In the first experiment, they took soil samples from Mars, mixed in a liquid solution with organic and inorganic compounds, and then measured what chemicals were released. In a second experiment, they put Earth organic compounds into Martian soil, and saw carbon dioxide released. In the third experiment, they heated Martian soil and saw organic material come out of the soil.
Three experiments, and stuff happened in all three. Stuff! Pretty exciting, right? Unfortunately, there were equally plausible non-biological explanations for each of the results. The astrobiology community wasn’t convinced, and they still fight in brutal cage matches to this day. It was ambitious, but inconclusive. The worst kind of conclusive.
Researchers found more inconclusive evidence in 1994. Ugh, there’s that word again. They were studying a meteorite that fell in Antarctica, but came from Mars, based on gas samples taken from inside the rock.
They thought they found evidence of fossilized bacterial life inside the meteorite. But again, there were too many explanations for how the life could have gotten in there from here on Earth. Life found a way… to burrow into a rock from Mars.
NASA learned a powerful lesson from this experience. If they were going to prove life on Mars, they had to go about it carefully and conclusively, building up evidence that had no controversy.
The Spirit and Opportunity Rovers were an example of building up this case cautiously. They were sent to Mars in 2004 to find evidence of water. Not water today, but water in the ancient past. Old water Over the course of several years of exploration, both rovers turned up multiple lines of evidence there was water on the surface of Mars in the ancient past.
They found concretions, tiny pebbles containing iron-rich hematite that forms on Earth in water. They found the mineral gypsum; again, something that’s deposited by water on Earth.
NASA’s Curiosity Rover took this analysis to the next level, arriving in 2012 and searching for evidence that water was on Mars for vast periods of time; long enough for Martian life to evolve.
Once again, Curiosity found multiple lines of evidence that water acted on the surface of Mars. It found an ancient streambed near its landing site, and drilled into rock that showed the region was habitable for long periods of time.
In 2014, NASA turned the focus of its rovers from looking for evidence of water to searching for past evidence of life.
Curiosity found one of the most interesting targets: a strange strange rock formations while it was passing through an ancient riverbed on Mars. While it was examining the Gillespie Lake outcrop in Yellowknife Bay, it photographed sedimentary rock that looks very similar to deposits we see here on Earth. They’re caused by the fossilized mats of bacteria colonies that lived billions of years ago.
Not life today, but life when Mars was warmer and wetter. Still, fossilized life on Mars is better than no life at all. But there might still be life on Mars, right now, today. The best evidence is not on its surface, but in its atmosphere. Several spacecraft have detected trace amounts of methane in the Martian atmosphere.
Methane is a chemical that breaks down quickly in sunlight. If you farted on Mars, the methane from your farts would dissipate in a few hundred years. If spacecraft have detected this methane in the atmosphere, that means there’s some source replenishing those sneaky squeakers. It could be volcanic activity, but it might also be life. There could be microbes hanging on, in the last few places with liquid water, producing methane as a byproduct.
The European ExoMars orbiter just arrived at Mars, and its main job is sniff the Martian atmosphere and get to the bottom of this question.
Are there trace elements mixed in with the methane that means its volcanic in origin? Or did life create it? And if there’s life, where is it located? ExoMars should help us target a location for future study.
NASA is following up Curiosity with a twin rover designed to search for life. The Mars 2020 Rover will be a mobile astrobiology laboratory, capable of scooping up material from the surface of Mars and digesting it, scientifically speaking. It’ll search for the chemicals and structures produced by past life on Mars. It’ll also collect samples for a future sample return mission.
Even if we do discover if there’s life on Mars, it’s entirely possible that we and Martian life are actually related by a common ancestor, that split off billions of years ago. In fact, some astrobiologists think that Mars is a better place for life to have gotten started.
Not the dry husk of a Red Planet that we know today, but a much wetter, warmer version that we now know existed billions of years ago. When the surface of Mars was warm enough for liquid water to form oceans, lakes and rivers. And we now know it was like this for millions of years.
While Earth was still reeling from an early impact by the massive planet that crashed into it, forming the Moon, life on Mars could have gotten started early.
But how could we actually be related? The idea of Panspermia says that life could travel naturally from world to world in the Solar System, purely through the asteroid strikes that were regularly pounding everything in the early days.
Imagine an asteroid smashing into a world like Mars. In the lower gravity of Mars, debris from the impact could be launched into an escape trajectory, free to travel through the Solar System.
We know that bacteria can survive almost indefinitely, freeze dried, and protected from radiation within chunks of space rock. So it’s possible they could make the journey from Mars to Earth, crossing the orbit of our planet.
Even more amazingly, the meteorites that enter the Earth’s atmosphere would protect some of the bacterial inhabitants inside. As the Earth’s atmosphere is thick enough to slow down the descent of the space rocks, the tiny bacterialnauts could survive the entire journey from Mars, through space, to Earth.
If we do find life on Mars, how will we know it’s actually related to us? If Martian life has the similar DNA structure to Earth life, it’s probably related. In fact, we could probably trace the life back to determine the common ancestor, and even figure out when the tiny lifeforms make the journey.
If we do find life on Mars, which is related to us, that just means that life got around the Solar System. It doesn’t help us answer the bigger question about whether there’s life in the larger Universe. In fact, until we actually get a probe out to nearby stars, or receive signals from them, we might never know.
An even more amazing possibility is that it’s not related. That life on Mars arose completely independently. One clue that scientists will be looking for is the way the Martian life’s instructions are encoded. Here on Earth, all life follows “left-handed chirality” for the amino acid building blocks that make up DNA and RNA. But if right-handed amino acids are being used by Martian life, that would mean a completely independent origin of life.
Of course, if the life doesn’t use amino acids or DNA at all, then all bets are off. It’ll be truly alien, using a chemistry that we don’t understand at all.
There are many who believe that Mars isn’t the best place in the Solar System to search for life, that there are other places, like Europa or Enceladus, where there’s a vast amount of liquid water to be explored.
But Mars is close, it’s got a surface you can land on. We know there’s liquid water beneath the surface, and there was water there for a long time in the past. We’ve got the rovers, orbiters and landers on the planet and in the works to get to the bottom of this question. It’s an exciting time to be part of this search.
After four years on Mars, the Curiosity rover has made some pretty impressive discoveries. These have ranged from characterizing what Mars’ atmosphere was like billions of years ago to discovering organic molecules and methane there today. But arguably the biggest discovery Curiosity has made has been uncovering evidence of warm, flowing water on Mars’ surface.
Unfortunately, now faced with what could be signs of water directly in its path, NASA is forced to enact strict protocols. These signs take the form of dark streaks that have been observed along the sloping terrain of Aeolis Mons (aka. Mount Sharp), which the rover has been preparing to climb. In order to prevent contamination, the rover must avoid any contact with them, which could mean a serious diversion.
These sorts of dark streaks are known as recurring slope lineae (RSLs) because of their tendency to appear, fade away and reappear seasonally on steep slopes. The first RSLs were reported in 2011 by the Mars Reconnaissance Orbiter in a variety of locations, and are now seen as proof that water still periodically flows on Mars (albiet in the form of salt-water).
Since that time, a total of 452 possible RSLs have been observed, mostly in Mars’s southern mid-latitudes or near the equator (particularly in Mars’ Valles Marineris). They are generally a few meters wide, and appear to lengthen at the warmest times of the year, then fade during the colder times.
These seasonal flows of salt water are believed to have come from ice trapped about a meter below the surface. Ordinarily, such features would present an opportunity to conduct research. But doing so would cause the water source to be contaminated by Earth microbes aboard Curiosity. And right now, Curiosity has bigger fish to fry (so to speak).
During its planned climb, Curiosity was supposed to pass within a few kilometers of an RSL. However, if NASA determines that the risk is too high, the rover will have to alter its course. Unfortunately, that presents a major challenge, since there is currently only one clear route between Curiosity’s current location and its next destination.
But then again, Curiosity may not have to alter its course at all. Or it could find a route that lets it still accomplish its scientific goals, depending on the circumstances. As Ashwin R. Vasavada, the Project Scientist at the Mars Science Laboratory, told Universe Today via email:
“It may depend on the distance between the rover and a potentially sensitive region, for example. Based on that understanding, we’ll determine the right course of action. For example, it may be possible to achieve Curiosity’s science goals while maintaining a safe distance. Another possible outcome is that we determine that there are no Recurring Slope Lineae on Mount Sharp.”
For years, NASA scientists have been seeking to obtain samples from different locations around Mount Sharp. By studying the sedimentary deposits in the mountainside, the rover’s science team hopes to see how Mars’ environment changed over the past 3 billion years. As Vasavada explained:
“Curiosity’s science mission has focused on understanding whether the area around 5-km high Mount Sharp ever had conditions suitable for life. We’ve already found evidence for an ancient, 3-billion-year-old habitable environment out on the plains around the mountain, and in the lowest levels of the mountain.”
“The geology indicates that a series of lakes once was present in the basin of the crater, before the mountain took shape. Curiosity will continue climbing lower Mount Sharp to see how long these habitable conditions lasted. Every step higher we go, we encounter rocks that are a bit younger, but still around 3 billion years old.”
In the end, the job of determining the risk falls to NASA’s Planetary Protection Office. In addition to reviewing the current predicament, the issue of pre-mission safety standards is also likely to come up. Prior to its deployment to Mars, the Curiosity rover was only partially sterilized, and it is currently unknown how long Earth microbes could survive in the Martian atmosphere, or how far they could be carried in Mars’ atmosphere.
Answering these questions and coming up with new protocols that will address them in advance will come in handy for future missions – particularly the Mars 2020 Rover mission. In the course of its mission, which will include obtaining samples and leaving them behind for possible retrieval by a future crewed mission, the rover is likely to encounter several RSLs.
One of the Mars 2020 rover’s primary tasks will be finding evidence of microbial life, so ensuring that Earth microbes don’t get in the way will be of extreme importance. And with crewed missions on the horizon, knowing how we can prevent contaminating Mars with our own germs (of which there are many) is paramount!
On its currently project path, the Curiosity rover would not get closer than 2 km from the potential RSL (which it is currently 5 km from). And as Vasavada indicated, it is not known at the present time what alternate routes Curiosity could take, or if a diversion in the rover’s path will effect it’s overall mission.
“It’s unclear at this time,” he said. “But I’m optimistic that we can find a solution that protects Mars, allows us to accomplish our mission goals, and even gives us new insight into modern water on Mars, if it is there.”