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A recent paper published in PNAS reported SAM’s discovery of some interesting carbon from samples at Gale crater. Carbon is a necessary element for life as we know it and its isotopes can tell us about ancient processes. Carbon has two stable isotopes: 12C, which makes up the majority of all carbon, and 13C, which represents the remaining carbon. The superscript numbers are based on the number of protons and neutrons in the atomic nucleus, where 12C has 6 protons and 6 neutrons while 13C has 6 protons and 7 neutrons. The relative amounts of 13C and 12C can help reveal chemical and biological processes. SAM can analyze carbon and its isotopes from samples to help piece together the history of carbon on Mars.

SAM analyzed two dozen solid samples collected from Mars and found some intriguing isotopic signatures. These samples were heated to a high temperature (~850 ºC), which resulted in the decomposition of sample components and the corresponding release of gases such as carbon dioxide (CO2), water (H2O), and methane (CH4). The gases were sent to the tunable laser spectrometer, which can determine their abundances and isotopes. The team found that 10 of these 24 samples from 6 unique locations released methane whose carbon had much less 13C than 12C compared to an Earth standard (in other words, they were depleted in 13C relative to the standard). These highly depleted values were all at least 70 parts per thousand (‰) less than the standard (i.e., < -70‰). For comparison, the CO2 in the modern Martian atmosphere has an overabundance of 13C compared to the Earth standard by +46‰. Interestingly, in addition to the highly depleted carbon isotopes, the team found broad associations with evidence for reduced sulfur (like the mineral pyrite, a.k.a. fool’s gold), isotopes of sulfur that were also low compared to a standard, and sample sites that may have been connected by an ancient surface. The anomalous carbon isotope values are shown below in Figure 1.

shows anomalous carbon isotope values and sample sites with strongly depleted 13C values

Figure 1. From House et al. (2022) showing sample sites with strongly depleted 13C values.

What could be causing such highly depleted values? The team put forward three hypotheses (summarized in Figure 2, below) that all fit the data, but none of them can be accepted or rejected without additional data and analysis. Let’s dig into each of these hypotheses a bit.

  1. Biologically-produced methane reacted with ultraviolet (UV) radiation in the atmosphere and deposited as organic molecules onto the paleosurface. Life on Earth has a preference for the lighter isotope of carbon, 12C. Methane can be produced by some microbes on Earth and tends to be depleted in 13C. If Martian microbes were present and produced methane, it could have interacted with ultraviolet radiation to produce organic molecules (carbon-containing compounds) that were deposited. Similarly, microbes on Earth can have metabolisms that result in depleted sulfur isotopes and reduced sulfur. While microbes could, in principle, explain the carbon and sulfur isotope depletions, other evidence is needed before accepting a biological explanation. Such an explanation would have required a complex network of microorganisms and there has been no evidence that such communities were present on Mars, unlike on Earth where such evidence is abundant in the rock record.
  2. Atmospheric CO2 reacted with ultraviolet radiation and sulfur dioxide (SO2) to form isotopically depleted organics. Some studies have shown that ultraviolet light can form carbon monoxide (CO) from CO2 with carbon depleted in 13C concentrating in the CO in certain conditions. If this happened on Mars, CO may have undergone further reactions to form more complex organic molecules (including some containing sulfur) that were deposited onto the proposed ancient surface, perhaps shortly after a volcanic eruption. It is not yet clear, however, that ultraviolet radiation in the Martian atmosphere would produce 13C-depleted CO. While this explanation is plausible, more research about the isotopic effects of radiation under Martian conditions needs to be conducted.
  3. Mars passed through a giant molecular cloud (GMC), which may have deposited isotopically depleted dust onto an ancient Martian surface. Our solar system passes through a giant molecular cloud approximately every 100 million years. The dust in these clouds can contain carbon that is highly depleted in 13C (down to -260‰) that could explain the values seen in some of the samples on Mars. This dust may have caused a cooling event that allowed for the formation of glaciers. The dust then could have been concentrated on glaciers that later melted to deposit the carbon on an ancient surface. This hypothesis, while it explains the carbon isotope data, may be too reliant on a rare event, and there is not currently strong evidence for glaciers associated with the proposed ancient surface. More research is needed to definitively rule this hypothesis in or out.
summary of hypotheses outlined above

Figure 2. From House et al. (2022) summarizing the three hypotheses above. In blue: methane produced by microbes is released to the atmosphere, reacts with UV light, and falls to the surface as organic molecules. In orange: gases from a volcanic eruption go through a series of reactions with UV light to eventually deposit organics to the surface. In gray: Mars passes through a giant molecular cloud that deposits dust onto the Martian surface.

All of these hypotheses could reasonably fit the data; however, more work needs to be done before we can land on an explanation. The rover will have the opportunity to return to the proposed paleosurface and we hope to look for more clues!

Author: Gregory Wong

Rafael Navarro-González in his home office in Mexico City. Credit: Luz Fabiola Aceves de Navarro

NASA announced today that the MSL team named a hill along Curiosity rover's path on Mars in honor of a recently deceased mission scientist Rafael Navarro-González, a co-investigator on the Sample Analysis at Mars (SAM). A craggy hump that stretches 450 feet (120 meters) tall, “Rafael Navarro mountain” is located on Mount Sharp in northwest Gale Crater.

Navarro-González was an award-winning scientist and a leading astrobiologist in Mexico; he died on Jan. 28, 2021, from complications related to COVID-19. His many accomplishments included leading the team that identified ancient organic compounds on Mars and identifying the role of volcanic lightning in the origin of life on Earth. Navarro-González was a researcher at Nuclear Sciences Institute at the National Autonomous University of Mexico in Mexico City.

Read the full NASA press release here.

His children, Rafael and Karina Navarro Aceves, shared the following about their father:

We are truly honored to have a prominent hill named after our dad; it’s his and our dream come true to see this happen. Ever since our parents met, their dreams merged together and they became a beautiful team, working very hard for 36 years. My dad was an accomplished scientist, but above all, a great human being who managed to balance work and family. Our mom, Faby, would always tell him that his name one day would be on Mars, and now that is coming true. We all believe that there must be a party in heaven.

As for our dad’s story, he comes from a family of hard working people. He became inspired to be academically prepared and to be a great scientist when the Apollo missions landed on the Moon, and he became fascinated with space, as well as the origins of life. He went to public school, which meant he needed to take English lessons in his free time just so he could achieve his goal of studying abroad; he worked really hard for it.

While studying for his bachelor’s in biology at the National Autonomous University of Mexico, he met Dr. Cyril Andrew Ponnamperuma, who invited him to earn his Ph.D. at the University of Maryland, College Park.

Our parents met in November 1983 and it was love at first sight. Our dad left in August 1984 to begin his first semester of his graduate program in Maryland. He returned in December of that year to marry our mom, achieving one of his goals: meeting someone he could spend the rest of his life with and have a family with.

As soon as our dad finished his postdoctoral research, he was approached by the Mexican government, which was working to bring back exceptional scientists from abroad. The government helped him establish his own state-of-the-art lab at the National Autonomous University of Mexico, so our family relocated back to Mexico City in the early 1990s. But our dad continued to travel worldwide in order to continue doing his field research.

He became interested in Mars while working with NASA scientists in the Atacama Desert in Chile. He joined the Curiosity mission in 2002 while working at the University of Paris, fulfilling another dream of being part of something so great. He was the only Mexico-based scientist on the Curiosity team.

Our dad is a true inspiration to kids and people worldwide. He proves that if you set your mind to a goal, you can achieve anything. He always tried to serve all levels of education when he gave conferences and lectures, from speaking to his granddaughter’s kindergarten class to giving university lectures. He always thought that if even just one person in the audience became a scientist, he would have fulfilled his mission.

Rafael Navarro-González and his wife, Fabiola Aceves de Navarro, in Washington, D.C., in 2014. Credit: Navarro-González family

Regarding our mom, Faby, well, since our parents met they truly became a team, as she helped him through all these years to fulfill his dreams. Mom is a dentist by training, but she gave up everything for our family. Our parents worked very hard, but my mom’s job was sometimes harder because it was 24/7; she always took care of us and made our lives easier. We have always done everything to support our dad’s work, including moving around the world (College Park, Maryland, 1984-1989 and 1991-1992; Boston, Massachusetts, 1997-1998; Paris, France, 2002-2003; and Pasadena, California, late 2013).

Our mom always traveled with our dad to scientific conferences, and sometimes we traveled to conferences as a family. We would do it without questions because we knew that the most important thing was to be together, and that what we were doing helped our dad to truly move towards any goal he had in his mind. We are very grateful that we had this opportunity to be together and to have many beautiful memories.

The SAM team provided several progress reports at the AGU virtual fall meeting including posters and presentations on discoveries in the Clay Unit and the wet chemistry experiments conducted on drilled samples. Links to these posters or presentations are below.

Jennifer Eigenbrode

Sample Chemistry Revealed by TMAH-Evolved Gas Analysis: Results from the First In Situ Thermochemolysis Experiment at Gale Crater, Mars

Amy Mcadam

Constraints on the Depositional and Diagenetic History of the Glen Torridon Clay-Bearing Unit from the Mars Science Laboratory Sample Analysis at Mars Instrument Suite

Brad Sutter

Geochemical Processes Along the Glen Torridon/Greenheugh Pediment, Unconformity, Gale Crater, Mars: Results from the Sample Analysis at Mars Instrument

Amy Williams

Results from the First TMAH Wet Chemistry Experiment at Gale Crater, Mars

Last weekend, Stephanie A. Getty and SAM Principal Investigator Paul R. Mahaffy of NASA’s Solar System Exploration Division talked with the Chemical & Engineering News team at the American Chemical Society meeting in Orlando, Florida. Check out their interview discussing what recent missions have taught us about the red planet, and what we hope to learn from future missions.

Author: Andrea Jones

The Curiosity rover has been on the Red Planet for more than 2,000 Martian days now, and the SAM team is involved in the tactical operations every day. The responsibility of the SAM Payload Downlink Leads (PDLs) and Payload Uplink Leads (PULs) is to check the health assessment of the instrument, to deliver science data, and plan the next experiments on Mars–all on a daily basis.

NASA Goddard recently hosted 2 days of refresher and training for the SAM PDLs and PULs, who came in from California, Houston, and France. This refresher session proved to be a good way to review the procedures for the downlink and the uplink of data, and get the team up to speed on the new features and changes in the MSL tactical shifts. Some of these PDLs and PULs are new to SAM team and they were able to benefit from the experience of other PDLs and PULs present since the beginning of the mission. Training sessions like this one allow the SAM team to continue to train the next set of PULs and PDLs in anticipation for the next 2,000 sols on Mars!

Attendees at the SAM refresher and training 2-day session.

Author: Samuel Teinturier

On the 19th of December, 2017, Sol 1909 on Mars, the SAM team successfully performed the first wet chemistry derivatization experiments on another planet. The target was the Ogunquit Beach (OG) dune sample collected by Curiosity. A photo of the Ogunquit Beach, located within Mars' Gale Crater, is shown Figure 1. It was taken by "Mastcam," one of Curiosity's cameras, and shows some of the active sand dunes present on Mars.

Figure 1. Part of a 360-degree panorama of 'Ogunquit Beach' acquired by the Curiosity rover on March 24th and March 25th, 2017, during the 1647th sol of the Mars Science Laboratory Mission.

Figure 1. Part of a 360-degree panorama of "Ogunquit Beach" acquired by the Curiosity rover on March 24th and March 25th, 2017, during the 1647th sol of the Mars Science Laboratory Mission. Image and legend credit: NASA/JPL-Caltech/MSSS.

Among the 74 cups carried within the Sample Manipulation System of the SAM instrument, nine contain chemicals in a liquid form (Fig. 2). Seven of these reagent cups are filled with N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) and two are filled with Tetramethylammonium hydroxide (TMAH). These cups are dedicated to performing wet chemistry experiments, also called derivatization experiments, on the solid samples of soil and rocks collected by Curiosity.

Figure 2. (Left) The Carousel of SAM, called the "Sample Manipulation System," and its 74 cups, are dedicated to receiving solid samples collected by the Curiosity rover. (Left and right) Nine of these cups are made of metal and contain liquid chemical products: MTBSTFA and TMAH. The two TMAH cups were not installed on the Carousel at the time of the photo, so only the seven MTBSTFA metal cups are shown.

Figure 2. (Left) The Carousel of SAM, called the "Sample Manipulation System," and its 74 cups, are dedicated to receiving solid samples collected by the Curiosity rover. (Left and right) Nine of these cups are made of metal and contain liquid chemical products: MTBSTFA and TMAH. The two TMAH cups were not installed on the Carousel at the time of the photo, so only the seven MTBSTFA metal cups are shown.

Searching for organic molecules on Mars is one of the major goals of SAM. But some molecules of high astrobiological interest—such as amino acids and carboxylic acids—are not directly analyzable by the GCMS of SAM. They are potentially present on Mars, but they are not easily volatized, or turned into a gas. So to analyze these molecules with SAM, we need to help them transform into volatile molecules. To do so, we perform a chemical reaction before analysis in one of the SAM cups containing a liquid reagent (Fig. 2). The cup is first punctured to liberate the liquid from the foil cap (Fig. 2) with two puncture needles. The robotized arm of the rover then drops the solid sample (up to ~150 mg) in the cup containing the liquid reagent. The derivatization reaction occurs as the sample is heated in contact with the chemical reagent (MTBSTFA or TMAH). Molecules present in the sample become more volatile, more heat-resistant, and more separable, making them far more amenable to analysis with the SAM GCMS. An example of MTBSTFA derivatization on an amino acid is shown Figure 3.

Figure 3. (Top) Cartoon simplifying a derivatization reaction with MTBSFTA (courtesy of Arnaud Buch): The caterpillar represents a non-volatile molecule reacting with MTBSTFA. This reaction gives "wings" to the caterpillar to become a "butterfly," a volatile molecule directly analyzable by GMCS. (Bottom) An example of reaction between and amino acid and MTSBTFA: the labile hydrogen of the amino acid is replaced by a silyl group, producing a volatile amino acid amenable to analysis by GCMS.

Figure 3. (Top) Cartoon simplifying a derivatization reaction with MTBSFTA (courtesy of Arnaud Buch): The caterpillar represents a non-volatile molecule reacting with MTBSTFA. This reaction gives "wings" to the caterpillar to become a "butterfly," a volatile molecule directly analyzable by GMCS. (Bottom) An example of reaction between and amino acid and MTSBTFA: the labile hydrogen of the amino acid is replaced by a silyl group, producing a volatile amino acid amenable to analysis by GCMS.

The SAM team decided to perform its first wet chemistry experiment by adding ~45 mg of the Ogunquit Beach dune sample to one of the MTBSTFA cups. The initial results appear extremely rich and interesting, but these complex data require careful analysis, and data analysis by team members is still ongoing. The detection of many peaks related to the MTBSTFA chemical reagent confirm that the wet chemistry experiment on Mars was successful, marking a major milestone in Mars exploration. Laboratory experiments and comparison with previous SAM data are now underway to identify the derivatized compounds detected. The next step will be to perform wet chemistry experiments on drilled clay samples that Curiosity will collect in the coming months as these phyllosilicate-rich minerals are known to preserve organic matter exceptionally well.

Author: Maëva Millan

A large portion of the SAM team visited New Orleans in this week for the annual Fall Meeting of the American Geophysical Union (AGU). SAM science was presented in over a dozen talks and posters at the largest gathering of Earth and Space Scientists in the world!

During the AGU meeting, three members of the SAM team presented overview "flash" talks on the hyperwall stage, part of the large NASA booth. Presenting on the hyperwall in the exhibit hall setting is very different from standing on a stage in a large conference auditorium. For one, you really have to talk loud so people can hear you (especially over announcements for beignets…). Since you are right in the middle of the booth, it helps to be immune to distractions such as the audience coming and going right in front of you, or computer problems for which there is no time to fix. Plus giving a lot of context or scientific background in under 10 minutes is always a challenge, especially for a successful mission and instrument with over 5 years of data on Mars.

Despite these challenges, the SAM team prevailed, with successful talks on several aspects of the Mars Science Laboratory mission discoveries. There was good attendance at the NASA booth for these presentations. Audience participation included some probing questions on the SAM/TLS methane measurements from NASA’s Planetary Science Division Director Dr. Jim Green.

Dr. Melissa Trainer kicked off the series of talks with 'uriosity and the Four Seasons', detailing SAM's atmospheric measurements.
Dr. Melissa Trainer kicked off the series of talks with "Curiosity and the Four Seasons", detailing SAM’s atmospheric measurements.

Dr. Amy McAdam described the types of minerals detected by SAM in Exploring Gale Crater's Record of Martian Environmental History.
Dr. Amy McAdam described the types of minerals detected by SAM in "Exploring Gale Crater's Record of Martian Environmental History".

Dr. James Lewis finished off the session with 'Detecting Organic Molecules on Mars', explaining the methods and findings of one of SAM's most ambitious measurement goals on Mars.
Dr. James Lewis finished off the session with "Detecting Organic Molecules on Mars"”, explaining the methods and findings of one of SAM's most ambitious measurement goals on Mars.

Author: Melissa Trainer

Scientists and engineers from the SAM team – including SAM Principal Investigator Paul Mahaffy and SAM Deputy Principal Investigator Charles Malespin – hosted an Ask Me Anything (AMA) event through Reddit last Friday, in honor of the 5th anniversary of Curiosity's spectacular landing in Gale Crater on Mars. They answered lots of questions from the public about the science and mission adventures since August 2012, careers at NASA, looking forward towards what’s next for Curiosity and NASA’s planetary exploration, and so much more.

Check out the questions and answers, archived here: https://www.reddit.com/r/science/comments/6rkf5x/nasa_ama_were_a_group_of_nasa_scientists_and/

Image of Curiosity’s descent to the martian surface, captured by the high resolution camera HiRISE onboard NASA’s Mars Reconnaissance Orbiter. Image credit: NASA/JPL/University of Arizona.
Image of Curiosity’s descent to the martian surface, captured by the high resolution camera HiRISE onboard NASA’s Mars Reconnaissance Orbiter. Image credit: NASA/JPL/University of Arizona.

Author: Andrea Jones

Two weeks ago, a few SAM team members joined part of the MSL team on a field trip to see the Sudbury Impact Crater and associated rocks in Sudbury, Ontario. This geology trip was filled with lots of roadside stops, fun hikes, and great views! The group learned about the formation of the Sudbury Crater and the deformation the impact caused in the preexisting rock. Exploring an impact crater on Earth gives scientists the opportunity to make comparisons between what we observe here and what we have seen or might see at Gale Crater on Mars with the Curiosity rover.

The rock types and features the group saw on this field trip are just some examples of what helps geologists to identify different geologic processes and events that are now preserved in the rock record. Stops included a road cut along the Trans Canadian Trail in Sudbury, ON where lots of shatter cones were preserved. Shatter cones are features formed in a rock from a high speed comet or meteorite impact. These particular shatter cones formed 1.85 billion years ago when the comet that formed the Sudbury Crater hit the Earth. The group also looked at rocks that formed during the Great Oxidation Event, a time in Earth’s history when oxygen began to accumulate in the atmosphere. The Gordon Lake Formation has diagenetic reduction spots that are light green in color, which represent iron reduction. This unit and the relevant features are a key piece of evidence in determining that the Great Oxidation Event took place during this time period, about 2.3 billion years ago.

Group photo of the MSL team members on the field trip at Horne Lake.
Group photo of the MSL team members on the field trip at Horne Lake.

Shatter cones that formed in the metasedimentary rocks 1.85 billion years ago. In this image, multiple shatter cones are visible, the apexes of the cones point toward the bottom left of the frame.
Shatter cones that formed in the metasedimentary rocks 1.85 billion years ago. In this image, multiple shatter cones are visible, the apexes of the cones point toward the bottom left of the frame.

The Gordon Lake Formation is made up of tan colored laminated sandstones, purple and green colored siltstones, and chert. These sediments were deposited in a tidal flat type of environment, before the formation of Sudbury Crater, about 2.3 billion years ago.
The Gordon Lake Formation is made up of tan colored laminated sandstones, purple and green colored siltstones, and chert. These sediments were deposited in a tidal flat type of environment, before the formation of Sudbury Crater, about 2.3 billion years ago.

Author: Christine Knudson

Operating a car-sized rover on another planet unsurprisingly requires a huge number of scientists and engineers. The Curiosity team are spread over many institutions, both within America and overseas, and as a result, day-to-day mission activities are typically coordinated through teleconferences and emails. However, every six months we get together to meet face to face and present mission updates, scientific results and plan for the future. This year our summer meeting was held in Montreal and in addition to the routine there was a lot of interesting data to discuss and exciting upcoming scientific campaigns to consider.

The day before the entire rover team got together, the SAM team met at a hotel in downtown Montreal to discuss laboratory work and simulations we've been carrying out to aid our interpretations of data returned from Mars. Given the broad capabilities of SAM, the presentations were extremely wide ranging and we continue to push as hard as we can to get our data published so we can share it with the public! One of the team's most recent papers, published in the Journal of Geophysical Research: Planets, summarizes SAM data from Yellowknife Bay to the Namib Dune; you can read the abstract here.

The Canadian Space Agency then very kindly hosted 130 members of the rover team for two days of presentations. Brad Sutter and Doug Archer gave an update on SAM results from the Bagnold Dunes campaign and James Lewis and Amy McAdam gave a summary of SAM laboratory activities. Further details for the exciting science planned at Vera Rubin Ridge and the clay and sulfate deposits beyond were outlined. We also got to tour the Canada Arm training facilities used by astronauts on the International Space Station as well as the rover labs and Mars yard. Almost exactly five years after landing, Curiosity continues to do really exciting science and is approaching some of the most interesting and puzzling regions of Gale Crater identified from orbit. Stay tuned!

Curiosity rover team in Canada
The Curiosity rover team at the Canadian Space Agency in Montréal

Author: James Lewis

During the month of March, Ryan Danell participated in two career days at North Carolina elementary schools in Wilmington and Winterville, speaking with 5th and 3rd graders respectively. Topics included why NASA is interested in Mars, what the Curiosity rover is and what it is doing on Mars, and how mass spectrometry, and specifically SAM, can help with those goals. Ryan also discussed how ExoMars and its instrument MOMA will augment Curiosity's results once this rover arrives on Mars. Students also heard about some of the other broad topics NASA works on and had many questions about what it is like to work at NASA, as well as what kind of careers are available in the space agency.

Ryan Danell speaks to elementary school students

Author: Ryan Danell

As Curiosity makes its way up the lower slopes of Mount Sharp, one of its primary goals is to continue the hunt for organic molecules that might tell us whether life ever existed on Mars. The materials we have scooped and drilled from the surface are complicated mixtures of many different minerals and, as proven by SAM, some of these samples also host organic matter. When rock powders are heated inside SAM's ovens, a portion of the inorganic and organic phases are desorbed or broken down by the high temperatures. The resulting gases are sent to SAM's analytical instruments. The data collected can reveal much about a sample’s chemistry, which is why heating experiments were also used on earlier missions, such as the Phoenix and Viking landers.

The "Confidence Hills" drill hole within the "Pahrump Hills" outcrop, the first hole drilled into the base of Mount Sharp by NASA’s Curiosity rover. Credit: NASA/JPL-Caltech/MSSS
The "Confidence Hills" drill hole within the "Pahrump Hills" outcrop, the first hole drilled into the base of Mount Sharp by NASA’s Curiosity rover. Credit: NASA/JPL-Caltech/MSSS

Many of the minerals we have analysed in Gale Crater have turned out to be poorly crystalline or present at low abundances, making them very challenging to investigate. If any of these minerals break down during heating, they may release gases such as water, oxygen, or carbon dioxide at distinctive temperatures that enable their identification. For example, SAM data identified that perchlorate salts are present in Gale Crater because of their signature release of oxygen and chlorine at low temperatures. Perchlorates can therefore oxidise and chlorinate organic molecules during SAM experiments, obscuring their signals. When we make interpretations about organic matter on Mars, the influence of perchlorates on our analyses cannot be ignored.

"Confidence Hills" drill powder in the Curiosity rover's scoop. The SAM instrument suite analyzes powder from drilled samples, such as this one. Credit: NASA/JPL-Caltech/MSSS
"Confidence Hills" drill powder in the Curiosity rover's scoop. The SAM instrument suite analyzes powder from drilled samples, such as this one. Credit: NASA/JPL-Caltech/MSSS

In addition to perchlorates, Curiosity has sampled many iron and sulfur minerals that thermally decompose during SAM heating runs. To understand whether these minerals might help or hinder our search for organic molecules, we are conducting SAM-like laboratory experiments here on Earth. The results are helping us understand how minerals and organic matter interact when heated. Previous research has suggested that some minerals on Mars may lock organic molecules into their structure and protect them from perchlorate oxidation. If an organic-containing mineral is sampled that decomposes above the range of perchlorates, we may get a clearer signal for organic matter. Further interpretations about the origin of this organic matter (whether from meteorites or indigenous Mars processes) may then be possible!

Author: James Lewis

The picture below is a view looking into the 74 cups on SAM when it was on Earth in the NASA cleanroom, and the cups were clean and empty. As I write this blog, 29 of the white-colored quartz cups have been filled with Martian sand or powdered rock material from our drill campaigns. Close your eyes and imagine looking now and seeing 29 dark cups randomly scattered around the two rings – dark because they contain ashes of the sand or powdered sample left over from some very hot (1000°C or 1832°F) experiments on Mars.

Some of SAM's cups are filled with a calibrant material – material of a very-well-known composition, brought from Earth, that allows scientists to make sure the SAM instruments are functioning properly. One of the cups containing solid calibrant material (a metal cup on the inner ring, on the left side of this picture) was punctured and analyzed on Mars. The analysis confirmed that all SAM instruments are performing as they should – SAM is 'nominal" as we say in "NASA-speak".

We still have 30 empty quartz cups ready to receive sample on Mars – enough for another four years (two martian years) of experiments, at the rate we are currently analyzing samples. We will use the two additional solid calibration cups on the inner ring to continue monitoring the performance of our "inner" oven, and we can calibrate our "outer" oven three times.

The nine metal cups at the top of this picture are for wet chemistry experiments. We have not used them yet – stay tuned for more exciting news as we continue to collect and analyze samples, and do our first wet chemistry experiments on Mars!

To summarize, right now SAM has 29 cups filled + 30 cups empty + 1 calibration cup used + 5 calibration cups ready + 9 wet chemistry cups ready = 74 cups total. It has 30 cups used and 44 cups ready for future, exciting SAM analysis on Mars!

cups on the sam instrument

Author: Benny Prats

Benny Prats is an Aerospace Engineer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. He has worked on SAM since 2007, helping design, build, and test many parts of SAM and SAM’s duplicate (the SAM “Test-bed”, kept at NASA Goddard, on which experiments can be tested before they are done on Mars). Since Curiosity landed in 2012, Benny has helped create the software programs that send commands to SAM on Mars, receive SAM data from Mars, evaluate experiment performance, and keep track of SAM’s health. Benny also works on the ExoMars project. He likes to volunteer at schools and NASA outreach events to share the excitement of engineering, exploration, and Mars missions.

SAM is an international instrument suite developed between the United States and France. The gas chromatograph, also known as the SAM-GC or GCMS (gas chromatograph mass spectrometer), was developed by the "Frenchies" of the SAM team belonging to a consortium of three laboratories (LATMOS, LGPM and LISA) located near Paris. Outreach activities are an important part of science and all SAM-GC team members are involved in bringing information about the Mars Science Laboratory (MSL) and SAM to the French people. One big step in this activity was done last year with the set-up and inauguration of an exhibition at LATMOS presenting the scientific context of the MSL mission, the Curiosity rover with all her instruments, with a particular highlight on SAM and the results coming from the GCMS–for example, the first detection ever of Martian organics.

This exhibition presents a number of different materials: a full size SAM model (see picture below), posters, an MSL rover model, and an artifact of the instrument development: an engineering model that was produced to test the SAM-GC concept and structure. This exhibition leads visitors through the development process of the SAM instrument suite, the rover landing at Mars, and the route she is traveling in Gale crater (over 12 km to date and more to come in the future!). Important results are also presented. Note that this exhibition was conceived to be movable in the Paris area (and beyond) in order to give the possibility to touch the wider public as much as possible.

You can visit this exhibition during dedicated outreach events, such as the "Fête de la science": a science fair occurring every year in October. It was successfully launched last autumn during the last fair, gathering more than 300 people who were fascinated by this amazing mission and instrument. Scientists will guide you through the mission adventure and you will have the opportunity to directly ask them your questions. Visit our websites and twitter accounts for more information on our laboratories and how you can visit this exhibition.

laboratories website :
LATMOS : http://www.latmos.ipsl.fr/index.php/en/
LISA : http://www.lisa.univ-paris12.fr/en
LGPM : http://www.lgpm.ecp.fr/

Twitter account:
LATMOS: https://twitter.com/latmos_ipsl

SAM exhibit
SAM exhibit

Author: Jean-Yves Bonnet and the SAM-GC team

The SAM instrument suite is the result of collaboration between NASA, a number of university partners, and international partners. The French Space Agency supported the development of SAM’s Gas Chromatograph, and several French scientists are part of the SAM science team. This blog entry was contributed by Maëva Millan, a Ph.D. student in France who is supporting SAM laboratory research.

The SAM instrument contributes to the Curiosity’s scientific goal to characterize the potential past or present habitability of Mars. The first three soil and rocks samples collected by Curiosity were partly delivered to SAM and analyzed with the Gas Chromatograph-Mass spectrometer (GCMS) during the first martian year of the Mars Science Laboratory (MSL) mission. Analyzing the GCMS runs, SAM scientists reported the detection of chlorinated organic compounds above instrument background levels in the Cumberland drill hole sample, leading to the first time detection of organic materials in a Mars sample – ever. A very important result! Some of these compounds originate from reactions between oxychlorine salts, widely spread at Mars’ surface, with organic carbon preserved in the rocks.

Before claiming identification of these chemical species, a lot of hard laboratory work was done. In particular, laboratory experiments on spare part

Gas chromatography (GC) coupled with mass spectrometry (MS) allows the physical separation of the compounds, and their identification, by combining structural information (mass) given by the MS and the time it takes for different chemical species to move through the GC (retention time). SAM GCMS signatures are often complex. Information from both the GC and MS are required to ensure the identification.

This is the reason why the French GC team carefully determines the retention times of a wide range of organic molecules, which have been detected on Mars. This method allowed the clear identifications of all chlorohydrocarbons present in martian solid samples, such the chlorobenzene and the dichloroalkanes.

Laboratory measurements are also used to predict the retention times of molecules that may have been delivered to the surface of Mars by meteorites, or involved in prebiotic chemistry and possible indicators of life. Compiling a database of this information will allow us to know where to look for these types of molecules in SAM analyses, and be able to identify them if they are present. The laboratory calibrations are of primary importance because they are the only way to ensure that we understand the data SAM returned from Mars.

Graph comparing laboratory data with data from Mars.

Author: Maëva Millan

Florence Tan, shown in photo from MarsFest 2013 SAM scientists, educators, and one of SAM’s lead engineers (Florence Tan, shown in photo from MarsFest 2013) are preparing for our trip to Death Valley this week to support Death Valley’s Celestial Centennial/MarsFest Symposium. The festival will take place April 8–10. We will have a SAM booth in the festival Expo with SAM engineering components, visuals of SAM science highlights, and hands-on demonstrations. We will help lead family–friendly programing highlighting connections between Death Valley National Park and Mars, and how NASA is preparing for the Journey to Mars. And, we will support the Friday and Saturday evening programs.

If you are in the area, come by and see us – and check out the full program of events!


Author: Andrea Jones

MarsFest 2016 poster The SAM Team will support the Celestial Centennial and MarsFest Symposium in Death Valley National Park this April, a celebration of 100 years of the National Park Service and the rich heritage of Mars science and exploration research in the Death Valley. Join us for a weekend of field trips to other-wordly sites here on Earth, presentations by NASA scientists, hands-on activities for kids, and evening programs designed for space enthusiasts and full family engagement.

The initial event announcement is posted here:

Look for more information on Death Valley’s website:

Author: Andrea Jones

SAM scientist Jennifer Eigenbrode was invited to speak during the prestigious Edison Talks event during Chicago Ideas Week ("Our premier, invitation-only event, Edison Talks is a specially curated day of mind-bending speakers, provocative performances and unique experiences. At Edison Talks, CIW features extraordinary presenters sharing stories and ideas designed to shift the way you experience the world.").

Watch her presentation and an interview – given during the Chicago Ideas Week segment, "Genius: A Peek Inside the World's Most Brilliant Minds" – here:


Author: Andrea Jones

The combination of the SAM pyrolysis and gas chromatograph mass spectrometer (GCMS) systems led to the first detection and identification of organic molecules indigenous to a martian sample. At the Cumberland drill hole in the Yellowknife Bay formation, SAM scientists reported the discovery of chlorobenzene (a six carbon ring with a chlorine atom) and chlorinated two to four-carbon chains (dichloroalkanes). These organic molecules are thought to be products of reaction between perchlorates or other oxychlorine salts and more complex organic material preserved in surface rocks over geological timescales. The origin of the organic material remains unknown and may be exogenous (from meteorites or interplanetary dust particles), or internal to Mars from hydrothermal activity or even biological activity. This detection opens up the habitability of Gale Crater to another level where the building blocks of life were present on the red planet at the time liquid water was flowing and at the time life appeared on the Earth. These measurements represent the first detection on Mars of indigenous organic compounds in surface rocks and addressed a long standing objective of the Mars exploration program.

Graph showing chlorobenzene amounts in 4 locations on Mars.

The Freissinet et al. ": Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars" paper which made the cover of the Journal of Geophysical Research: Planets journal is available in open access here: http://onlinelibrary.wiley.com/doi/10.1002/2014JE004737/full.

Author: Caroline Freissinet

NASA recently unveiled two new online tools that allow users to participate in the journey to Mars. Mars Trek is a free, Web-based application that provides high-quality, detailed visualizations of the planet using real data from 50 years of NASA exploration and allowing astronomers, citizen scientists and students to study the Red Planet's features. Experience Curiosity allows viewers to journey along with the rover, including the SAM instrument suite, on its expedition within Gale Crater. The program simulates Mars in 3-D based on actual data from Curiosity and NASA's Mars Reconnaissance Orbiter (MRO), giving users first-hand experience in a day in the life of a Mars rover. More details are available in this NASA press release.

Author: Lora Bleacher

In celebration of Curiosity’s 3rd anniversary of a successful landing on Mars, a Chilean journalist interviewed team members, including Ashwin Vasavada, Curiosity’s Project Scientist, and SAM’s Principal Investigator, Paul Mahaffy, to discuss the mission’s achievements and the challenges that still lie ahead. You can read about it here – in Spanish!

English updates are also available: You can watch a video, download a poster, send a postcard, and see top science discoveries on the Curiosity website, created in honor of this occasion.

Author: Andrea Jones

While we are studying everything we can about the rocks on the surface of Mars, SAM is busy making sure we also learn as much as we can about the atmosphere of Mars!

The inert gases are special because they don’t react with other chemical elements the way some other familiar elements like carbon, oxygen, sulfur, sodium, hydrogen, and silicon, do. That’s why the inert gases are also called noble. These noble gases are helium, neon, argon, krypton, xenon, and radon.

The noble gases are released from the interiors of planets. Over time, some of the gases inside planets escape into the atmosphere, and some of the atmospheric gases escape into space.

The noble gases have stable isotopes (varieties of the same element but with a different number of neutrons in their nuclei), which are useful in tracking evidence of processes that have affected planets over time. Scientists measure the amount of each stable isotope present in a planet’s atmosphere for a number of noble gases, and compare the ratios of these isotopes to each other and to values typical of the solar wind, primitive meteorites, meteorite samples from planets like Mars, and the atmospheres of Earth and Mars. The ratios of noble gas stable isotopes are different in each of these different environments which tells us something about where they came from and some of the processes that have affected them over time.

The noble gases krypton and xenon have lots of isotopes—krypton has six and xenon has nine! They are really big atoms, so they don’t get included in the formation of minerals and they are not very mobile. And now SAM has measured all the stable isotopes of these trace species in the atmosphere of Mars! This is important because it is the most precise measurement ever made of these gases directly in the martian atmosphere. It required a technological feat that has not previously been done on another planet.

Usually, gases flow directly through SAM’s measurement chamber and we measure them as they move. But in a special experiment called static mass spectrometry, SAM was able to hold gases inside its measurement chamber, accumulating enough gas pressure that there were sufficient atoms of the noble gas stable isotopes to count them before the gases were released.

What do these krypton and xenon measurements tell us? They help us better understand the evolution of the Mars atmosphere. Even though Mars has roughly the same total amount of xenon in its atmosphere as Earth does, for example, the ratios of the xenon isotopes in Mars’s atmosphere are different than the xenon isotope ratios in Earth’s atmosphere. The xenon and krypton isotope ratio measurements help us to infer is that Mars lost most of its original atmosphere pretty early in its evolution – a very important discovery.

Three years on Mars, breathing in and breathing out, and SAM is still learning new things about the martian atmosphere.

Author: Pan Conrad

Astrobiology Magazine made a list of the Top 10 astrobiology stories of 2014. Three of the ten stories featured results from the Mars Science Laboratory Curiosity rover, and their number one story of the year is the first definitive discovery of organic molecules on the surface of Mars: a discovery made by the SAM team using data from their powerful instrument suite.

The full article, with links to publications and video footage describing the discovery, is available here: http://www.astrobio.net/news-exclusive/48291/

Author: Andrea Jones

SAM results were highlighted in a press conference held today at the American Geophysical Union Fall Meeting in San Francisco, California. SAM detected a sharp increase and then decrease in the amount of methane (an organic chemical) in the atmosphere surrounding the Curiosity rover, and also detected different martian organic chemicals in powder drilled from a rock in Gale Crater - the first definitive detection of organics on the surface of Mars.

The press release is available here: http://www.jpl.nasa.gov/news/news.php?feature=4413

The Webster et al. and Mahaffy et al. Science Express papers, which describe these results in more detail, are accessible here: http://mars.jpl.nasa.gov/msl/mission/science/researchpapers/

Author: Andrea Jones

SAM and SAM scientist Danny Glavin are featured in the New York Times science article Mars Rover Finds Stronger Potential for Life by Marc Kaufman. The article includes a fantastic interactive that highlights Curiositys's activities and the path it's traveled since it touched down on Mars.

Read about it at: http://www.nytimes.com/2014/12/09/science/-stronger-signs-of-life-on-mars.html?_r=0

Author: Andrea Jones

This mosaic, taken with the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter, shows the planned route (in yellow) of NASA's Curiosity rover from "Pahrump Hills" at the base of Mount Sharp, through the "Murray Formation," and south to the hematite ridge further up the flank of Mount Sharp. Go here for more information about the image. Image Credit: NASA/JPL-Caltech

Three weeks ago, Curiosity fulfilled one of the mission's long-term goals when she arrived at Pahrump Hills, the base of Mount Sharp in Gale Crater. The suite of minerals in the three kilometer high mountain, first identified by satellites in orbit around Mars, told us that something every interesting happened in Gale Crater a long time ago.

Three distinct sets of rock units became clear from orbit: the first appears to be composed of clay-bearing rocks, the second forms a resistant hematite-bearing ridge, and the third contains sulfate-bearing rocks. Clay-bearing units, such as this one, suggest the presence of a lot of water at one time on Mars, while the sulfate-rich rocks suggest a time of "drying-out". This interesting suite of rock units may record a significant climatic change on Mars, from the time Mars was wet to the arid environments we're familiar with today - and Curiosity is starting to learn about it from the ground up!

Curiosity drove though sandy, interconnected valleys to arrive at Pahrump Hills. Her view from the ground is providing us with more information about the rocks we first saw from orbit. The rocks exposed at the very bottom of Mount Sharp are called the Murray Formation. The Pahrump Hills site (found at the edge of where the Murray Formation is exposed at the surface) includes a very soft rock unit, believed to be a fine-grained rock like a mudstone. It has morphologically interesting features in the shallow subsurface that form dendrites and clusters. These features were likely formed by fluids that moved through the Martian mudstone a long time ago. The science team hopes to learn about the composition of these fluids and the surrounding rock by analyzing samples of the rocks with the rover's internal instruments, CheMin and SAM. Curiosity drilled 6.7 centimeters into the soft rock of Pahrump Hills, and the next step is to ensure the drill powder is safe to deliver to the internal instruments. Once this is confirmed, the SAM team will get our first taste of Mount Sharp rocks!

Curiosity completed its primary mission after one Mars year (two Earth years) of surface operations. It has now begun its extended mission. SAM will continue to play a vital role in this second phase of Curiosity's mission, providing chemical and isotopic analyses that help the rover's science team understand what's in the clay-, sulfate-, and hematite-bearing rock units, how they formed in Mount Sharp, and what those rocks can tell us about the ancient environments and climatic evolution of Gale Crater - and Mars. Like a good field geologist, we're starting from the ground up at Pahrump Hills!

To see Curiosity's route from landing to Pahrump Hills, go here.

Author: Amy Williams

Paul Mahaffy is the 2014 winner of the John C. Lindsay Memorial Award, a highly prestigious award for scientists at NASA's Goddard Space Flight Center. Dr. Mahaffy will deliver the John C. Lindsay Memorial Lecture, "Chlorinated Organics in a Gale Crater Mudstone and the Imprint of an Ancient Fluvial Environment in 3 Billion Year Old Water Found in a 4 Billion Year Old Martian Rock," as part of Goddard's colloquium series on Wednesday, October 1 at 3:30pm.

The abstract is available here: http://scicolloq.gsfc.nasa.gov/Mahaffy_Lindsay.html

Information about attending or streaming the presentation is available here: http://scicolloq.gsfc.nasa.gov.

Author: Andrea Jones

The SAM team recently made a shiny, new updated fact sheet. Find an overview of SAM and how it analyzes rock, soil, and atmospheric samples with its three powerful instruments here!

Author: Andrea Jones

Check it out! A video featuring MarsFest in Death Valley National Park. The SAM Team will support the third annual MarsFest at the end of this week!


Author: Andrea Jones

Planetary scientists have long studied terrestrial analogs to help them better understand the environments they observe or expect to encounter on other bodies in the Solar System. Death Valley National Park encompasses some of the most extreme environments on Earth, some of which share many similarities with Martian environments. For decades, planetary scientists and engineers have visited the Park to conduct research and test instruments.

MarsFest is a festival that invites the public to celebrate this scientific heritage and the connections between Death Valley and planetary science and exploration. It is a collaborative effort between NASA, the National Park Service, and the SETI Institute. The SAM E/PO Team helps organize and run the festival. This year, I will give a talk about the importance of planetary analog sites, as well as an overview of the Curiosity mission and science highlights so far (particularly featuring SAM) during a Curiosity Hour at the Death Valley Visitor Center.

The third annual MarsFest will take place March 28-30, 2014. It will include field trips to other-worldly sites led by planetary scientists, as well as talks about planetary science and exploration. For more information, visit: http://www.seti.org/seti-institute/marsfest-2014

Hope to see you there!

Author: Andrea Jones

A collection of SAM science results as of mid December 2013 are compiled on the Spaceflight 101 website.


Author: Paul Mahaffy

SAM has many different types of experiments it can run, but one of the more exciting results (for me) came from an experiment we ran on the Cumberland mudstone Curiosity drilled. On Earth, we can use a set of techniques to help determine the age of rocks. This had never been done before on another planet. But now, with SAM, we were able to apply similar techniques to obtain a formation age for a rock on Mars - for the very first time. The technique we used was potassium-argon dating (K-Ar), which measures how much argon gas a rock contains. Over time atoms of potassium-40 (an isotope of potassium which is radioactive) decay into the stable isotope argon-40. If we use the potassium measured from the APXS instrument on Curiosity, coupled with the amount of argon-40 SAM measures in a sample, we can calculate the age of the rock. Simple, right?

It turns out that running this experiment is not as simple as it seemed. On Earth, we have access to state-of-the-art laboratories where rock samples can be analyzed with several different instruments. Unfortunately, we have not been able to bring any rock samples from Mars back to Earth yet, so we had to design the experiment to work with the state-of-the-art laboratory we have on Mars: SAM! The rock age-dating experiment was developed and tested for many months on Earth using the SAM testbed, which is an identical running instrument we keep here at NASA Goddard Space Flight Center. In the procedure for the experiment, a powdered rock sample is heated to 1000 C to release all the gases within the sample, and the evolved gases are 'cleaned' up to remove all the gases we do not need for our analysis.

Once we got all the settings and experimental parameters correct and optimized, we ran the experiment on Mars - and got some amazing results! We measured a rock's age using the K-Ar dating technique, and obtained an age of 4.21 billion years. This measured age is similar to what we had predicted the age of the rock would be before the experiment. This may not seem like an exciting result, since the measured age of the rock matched our prediction, but it proved that the technique worked and that we could apply it to other rock samples as Curiosity climbs Mt. Sharp. The experiment worked!

For the full details, see the published paper in the journal Science.

Author: Charles Malespin