Mars Curiosity Rover

Mar’s Solar Conjuction — What Is It & What It Means

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Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
andrew.c.good@jpl.nasa.gov

Alana Johnson
NASA Headquarters, Washington
alana.r.johnson@nasa.gov

 

 

This animation illustrates Mars solar conjunction, a period when Mars is on the opposite side of the Sun from Earth. During this time, the Sun can interrupt radio transmissions to spacecraft on and around the Red Planet. Credit: NASA/JPL-Caltech

 

The daily chatter between antennas here on Earth and those on NASA spacecraft at Mars is about to get much quieter for a few weeks. 

That’s because Mars and Earth will be on opposite sides of the Sun, a period known as Mars solar conjunction. The Sun expels hot, ionized gas from its corona, which extends far into space. During solar conjunction, this gas can interfere with radio signals when engineers try to communicate with spacecraft at Mars, corrupting commands and resulting in unexpected behavior from our deep space explorers. 

 

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NASA’s Opportunity Rover Mission on Mars Comes to End

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DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.

Dwayne Brown / JoAnna Wendel
NASA Headquarters, Washington

 

Artist’s Concept of Rover on Mars. Image credit: NASA/JPL/Cornell University


One of the most successful and enduring feats of interplanetary exploration, NASA’s Opportunity rover mission is at an end after almost 15 years exploring the surface of Mars and helping lay the groundwork for NASA’s return to the Red Planet. 

The Opportunity rover stopped communicating with Earth when a severe Mars-wide dust storm blanketed its location in June 2018. After more than a thousand commands to restore contact, engineers in the Space Flight Operations Facility at NASA’s Jet Propulsion Laboratory (JPL) made their last attempt to revive Opportunity Tuesday, to no avail. The solar-powered rover’s final communication was received June 10.

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A Mixed-reality Trip to Mars

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Ceremonial_Ribbon_Cutting__Destiny_Mars.jpg
A ceremonial ribbon is cut for the opening of new “Destination: Mars” experience at the Kennedy Space Center visitor complex in Florida. From the left are Therrin Protze, chief operating officer of the visitor complex; center director Bob Cabana; Apollo 11 astronaut Buzz Aldrin; Kudo Tsunoda of Microsoft; and Jeff Norris of NASA’s Jet Propulsion Laboratory in Pasadena, California. Photo credit: NASA/Charles Babir

 

It’ll be years before the first astronauts leave the launch pad on Earth to journey to Mars. But starting Sept. 19, visitors to the Kennedy Space Center visitor complex in Florida will get a taste of what those astronauts will see when they touch down on the Red Planet.

“Destination: Mars,” a mixed-reality experience designed by NASA’s Jet Propulsion Laboratory, Pasadena, California, and Microsoft HoloLens, held a kick-off event for media at the Visitor Complex on Sept. 18. The experience uses real imagery taken by NASA’s Mars Curiosity rover to let users explore the Martian surface.

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NASA Awards Launch Services Contract for Mars 2020 Rover Mission

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The design of NASA’s Mars 2020 rover leverages many successful features of the agency’s Curiosity rover, which landed on Mars in 2012, but it adds new science instruments and a sampling system to carry out the new goals for the 2020 mission. Credits: NASA

 

NASA has selected United Launch Services LLC of Centennial, Colorado, to provide launch services for a mission that will address high-priority science goals for the agency’s Journey to Mars. 

Mars 2020 is targeted for launch in July 2020 aboard an Atlas V 541 rocket from Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida. The rover will conduct geological assessments of its landing site on Mars, determine the habitability of the environment, search for signs of ancient Martian life, and assess natural resources and hazards for future human explorers.

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Rewrite of Onboard Memory Planned for NASA Mars Orbiter

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This artist’s concept shows NASA’s Mars Reconnaissance Orbiter mission over the red planet. (NASA/JPL)


Mission Status Report

Tables stored in flash memory aboard NASA’s Mars Reconnaissance Orbiter (MRO) tell locations of Earth and the sun for the past 10 years, but not their locations next year. That needs to be changed. Carefully.
The long-lived orbiter relies on these tables to recover in the event of an unplanned computer shutdown. When the spacecraft computer reboots, it checks to see where it should position the antenna for communication and, even more critically, where it should position the solar arrays for power. Flash memory is “nonvolatile” — meaning that it retains information even while the power is off — so it works well for this backup role.

The tables were loaded before the spacecraft’s Aug. 12, 2005, launch and they cover location information through July 12, 2016. To be safe, the mission team plans to begin updating them next week. Doing so will require intentionally rebooting the onboard computer during a one-week suspension of MRO’s science observations and communication relay duty. Both of NASA’s active Mars rovers will use a different NASA Mars orbiter, Odyssey, for relaying their data to Earth while MRO is out of service.

Sixteen times since launch, MRO has experienced unplanned reboots that relied on the stored tables for recovery of the spacecraft. Managers anticipate that such events will continue to happen in coming years.

“Updating what’s in the memory is essential for spacecraft safety and for extending the mission,” said MRO Project Manager Dan Johnston at NASA’s Jet Propulsion Laboratory, Pasadena, California.

To update the location tables, engineers will rewrite the entire content of the nonvolatile memory on the spacecraft. The orbiter has two identical computers for redundancy, with only one of them active at a time. Each computer has its own nonvolatile memory unavailable to the other, so the rewrite needs to be done twice. The “Side B” computer has been active since an unplanned side swap in April 2015. The plan is to rewrite that computer’s nonvolatile memory starting on Nov. 2. The procedure for “Side A” will follow in early 2016.

The contents of each computer’s 256 megabytes of nonvolatile memory include backup copies of vital computer-operation files. “It’s the fundamental operating system of the spacecraft. That’s what adds risk,” Johnston said. “Just like with your home computer: If you mess with the operating system, the computer won’t work.”

Since MRO launched, the mission team has rewritten the nonvolatile memory just once, in 2009. The Side B rewrite next week will follow procedures similar to those used successfully in 2009, but with an added safeguard. After a partial rewrite, an intentional reboot will be commanded, to confirm that the newly recorded information is usable. If it is not, sufficient information from the 2009 rewrite would still be still available as backup for a successful reboot. After confirmation that the partial rewrite is successful, the rest of the memory contents will be replaced.

Though it is already in its fourth mission extension, MRO could remain a cornerstone of NASA’s Mars Exploration Program fleet for years to come. The longevity of the mission has given researchers tools to study seasonal and longer-term changes on Mars, including recently discovered seasonal activity of salty liquid water. Among other current activities, the orbiter is examining possible landing sites for future missions to Mars and relaying communications to Earth from Mars rovers.

JPL, a division of the California Institute of Technology in Pasadena, manages the MRO Project for NASA’s Science Mission Directorate, Washington. Lockheed Martin Space Systems in Denver built the orbiter and supports its operations. For more information about MRO, visit: http://www.nasa.gov/mor and http://mars.nasa.gov/mro and http://mars.nasa.gov/mroMission Status Report

NASA’s Curiosity Rover Inspects Unusual Bedrock (High-Silica ‘Lamoose’ Rock)

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A rock fragment dubbed “Lamoose” is shown in this picture taken by the Mars Hand Lens Imager (MAHLI) on NASA’s Curiosity rover. Like other nearby rocks in a portion of the “Marias Pass” area of Mt. Sharp, Mars, it has unusually high concentrations of silica. ( Image credit: NASA/JPL-Caltech/MSSS)

Fast Facts:

  • Rover examines geological contact zone near ‘Marias Pass’
  • Silica-rich rocks identified nearby with laser-firing instrument
  • Test of rover’s drill prepares for next use on Mars rock

Approaching the third anniversary of its landing on Mars, NASA’s Curiosity Mars rover has found a target unlike anything it has studied before — bedrock with surprisingly high levels of silica. Silica is a rock-forming compound containing silicon and oxygen, commonly found on Earth as quartz.

This area lies just downhill from a geological contact zone the rover has been studying near “Marias Pass” on lower Mount Sharp.

In fact, the Curiosity team decided to back up the rover 46 meters (151 feet) from the geological contact zone to investigate the high-silica target dubbed “Elk.” The decision was made after they analyzed data from two instruments, the laser-firing Chemistry & Camera (ChemCam) and Dynamic Albedo of Neutrons (DAN), which showed higher amounts of silicon and hydrogen, respectively. High levels of silica in the rock could indicate ideal conditions for preserving ancient organic material, if present, so the science team wants to take a closer look.

“One never knows what to expect on Mars, but the Elk target was interesting enough to go back and investigate,” said Roger Wiens, the principal investigator of the ChemCam instrument from the Los Alamos National Laboratory in New Mexico. ChemCam is coming up on its 1,000th target, having already fired its laser more than 260,000 times since Curiosity landed on Mars Aug. 6, 2012, Universal Time (evening of Aug. 5, Pacific Time).

In other news, an engineering test on the rover’s sample-collecting drill on July 18 is aiding analysis of intermittent short circuits in the drill’s percussion mechanism, in preparation for using the drill in the area where the rover has been working for the past two months. The latest test did not result in any short circuits, so the team plans to continue with more tests, performed on the science targets themselves.

Before Curiosity began further investigating the high-silica area, it was busy scrutinizing the geological contact zone near Marias Pass, where a pale mudstone meets darker sandstone.

 

A rock outcrop dubbed “Missoula,” near Marias Pass on Mars, is seen in this image mosaic taken by the Mars Hand Lens Imager on NASA’s Curiosity rover. Pale mudstone (bottom of outcrop) meets coarser sandstone (top) in this geological contact zone, which has piqued the interest of Mars scientists. (Image credit: NASA/JPL-Caltech/MSSS)

 

“We found an outcrop named Missoula where the two rock types came together, but it was quite small and close to the ground. We used the robotic arm to capture a dog’s-eye view with the MAHLI camera, getting our nose right in there,” said Ashwin Vasavada, the mission’s project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. MAHLI is short for Mars Hand Lens Imager.

The rover had reached this area after a steep climbed a 20-foot (6-meter) hill. Near the top of the climb, the ChemCam instrument fired its laser at the target Elk, and took a spectral reading of its composition.

“ChemCam acts like eyes and ears of the rover for nearby objects,” said Wiens.

The rover had moved on before analyzing the Elk data, so the rover performed a U-turn to get more data. Upon its return, the rover was able to study a similar target, “Lamoose,” up close with the MAHLI camera and the arm-mounted Alpha Particle X-ray Spectrometer (APXS).

Curiosity has been working on Mars since early August 2012. It reached the base of Mount Sharp last year after fruitfully investigating outcrops closer to its landing site and then trekking to the mountain. The main mission now is to look at successively higher layers of Mount Sharp.

The U.S. Department of Energy’s Los Alamos National Laboratory developed ChemCam in partnership with scientists and engineers funded by the French national space agency. Russia’s space agency provided Curiosity’s DAN instrument. JPL, a division of the California Institute of Technology in Pasadena, built the rover and manages the project for NASA’s Science Mission Directorate in Washington.

For more information about Curiosity, visit: http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl

You can also follow the mission on Facebook and Twitter at: http://www.facebook.com/marscuriosity and http://www.twitter.com/marscuriosity

Is Curiosity responsible for Mars methane readings?

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Written by Chuck Bednar (@BednarChuck)
May 28, 2015 – redOrbit.com

Is this little guy just detecting his own methane gas? (Credit: NASA)
 

(Chuck Bednar for redOrbit.com – @BednarChuck) One of the reasons the Curiosity rover was sent to Mars was to determine once and for all if the Red Planet was emitting methane, but could it have actually further muddled matters instead by giving off the chemical compound itself?

That’s the issue investigated by Johnny Bontemps of Astrobiology Magazine in a story published earlier this week by Discovery News. The gist of it is this: nearly five decades ago, Mariner 7 first purportedly detected methane near the south pole. While that turned out to be a false signal, orbiting spacecraft and Earth-based telescopes again detected methane in 2003 and 2004.

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NASA Mars Rover’s Weather Data Bolster Case for Brine

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Scene From ‘Artist’s Drive’ on Mars (Stereo) Curiosity View Ahead Through ‘Artist’s Drive’ (Stereo) Mars Weather-Station Tools on Rover’s Mast Curiosity View Ahead Through ‘Artist’s Drive’Scene From ‘Artist’s Drive’ on Mars The Rover Environmental Monitoring Station (REMS) on NASA’s Curiosity Mars rover includes temperature and humidity sensors mounted on the rover’s mast. One of the REMS booms extends to the left from the mast in this view. Credit: NASA/JPL-Caltech/MSSS

Martian weather and soil conditions that NASA’s Curiosity rover has measured, together with a type of salt found in Martian soil, could put liquid brine in the soil at night.

Perchlorate identified in Martian soil by the Curiosity mission, and previously by NASA’s Phoenix Mars Lander mission, has properties of absorbing water vapor from the atmosphere and lowering the freezing temperature of water. This has been proposed for years as a mechanism for possible existence of transient liquid brines at higher latitudes on modern Mars, despite the Red Planet’s cold and dry conditions.

New calculations were based on more than a full Mars year of temperature and humidity measurements by Curiosity. They indicate that conditions at the rover’s near-equatorial location were favorable for small quantities of brine to form during some nights throughout the year, drying out again after sunrise. Conditions should be even more favorable at higher latitudes, where colder temperatures and more water vapor can result in higher relative humidity more often.

“Liquid water is a requirement for life as we know it, and a target for Mars exploration missions,” said the report’s lead author, Javier Martin-Torres of the Spanish Research Council, Spain, and Lulea University of Technology, Sweden, and a member of Curiosity’s science team. “Conditions near the surface of present-day Mars are hardly favorable for microbial life as we know it, but the possibility for liquid brines on Mars has wider implications for habitability and geological water-related processes.”

Fast Facts:

  • Conditions that might produce liquid brine in Martian soil extend closer to the equator than expected
  • Perchlorate salt in soil can pull water molecules from the atmosphere and act as anti-freeze
  • Presence of brine would not make Curiosity’s vicinity favorable for microbes

The weather data in the report published today in Nature Geosciences come from the Cuirosity’s Rover Environmental Monitoring Station (REMS), which was provided by Spain and includes a relative-humidity sensor and a ground-temperature sensor. NASA’s Mars Science Laboratory Project is using Curiosity to investigate both ancient and modern environmental conditions in Mars’ Gale Crater region. The report also draws on measurements of hydrogen in the ground by the rover’s Dynamic Albedo of Neutrons (DAN) instrument, from Russia.

“We have not detected brines, but calculating the possibility that they might exist in Gale Crater during some nights testifies to the value of the round-the-clock and year-round measurements REMS is providing,” said Curiosity Project Scientist Ashwin Vasavada of NASA’s Jet Propulsion Laboratory, Pasadena, California, one of the new report’s co-authors.

Curiosity is the first mission to measure relative humidity in the Martian atmosphere close to the surface and ground temperature through all times of day and all seasons of the Martian year. Relative humidity depends on the temperature of the air, as well as the amount of water vapor in it. Curiosity’s measurements of relative humidity range from about five percent on summer afternoons to 100 percent on autumn and winter nights.

Air filling pores in the soil interacts with air just above the ground. When its relative humidity gets above a threshold level, salts can absorb enough water molecules to become dissolved in liquid, a process called deliquescence. Perchlorate salts are especially good at this. Since perchlorate has been identified both at near-polar and near-equatorial sites, it may be present in soils all over the planet.

Researchers using the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter have in recent years documented numerous sites on Mars where dark flows appear and extend on slopes during warm seasons. These features are called recurring slope lineae, or RSL. A leading hypothesis for how they occur involves brines formed by deliquesence.

“Gale Crater is one of the least likely places on Mars to have conditions for brines to form, compared to sites at higher latitudes or with more shading. So if brines can exist there, that strengthens the case they could form and persist even longer at many other locations, perhaps enough to explain RSL activity,” said HiRISE Principal Investigator Alfred McEwen of the University of Arizona, Tucson, also a co-author of the new report.

In the 12 months following its August 2012 landing, Curiosity found evidence for ancient streambeds and a lakebed environment more than 3 billion years ago that offered conditions favorable for microbial life. Now, the rover is examining a layered mountain inside Gale Crater for evidence about how ancient environmental conditions evolved. JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory and Mars Reconnaissance Projects for NASA’s Science Mission Directorate, Washington.

For more information about Curiosity, visit:

http://www.nasa.gov/msl

and

http://mars.jpl.nasa.gov/msl/

 

The Solar System and Beyond is Awash in Water

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NASA is exploring our solar system and beyond to understand the workings of the universe, searching for water and life among the stars. Image credit: NASA

As NASA missions explore our solar system and search for new worlds, they are finding water in surprising places. Water is but one piece of our search for habitable planets and life beyond Earth, yet it links many seemingly unrelated worlds in surprising ways. 

“NASA science activities have provided a wave of amazing findings related to water in recent years that inspire us to continue investigating our origins and the fascinating possibilities for other worlds, and life, in the universe,” said Ellen Stofan, chief scientist for the agency. “In our lifetime, we may very well finally answer whether we are alone in the solar system and beyond.”

The chemical elements in water, hydrogen and oxygen, are some of the most abundant elements in the universe. Astronomers see the signature of water in giant molecular clouds between the stars, in disks of material that represent newborn planetary systems, and in the atmospheres of giant planets orbiting other stars. 

There are several worlds thought to possess liquid water beneath their surfaces, and many more that have water in the form of ice or vapor. Water is found in primitive bodies like comets and asteroids, and dwarf planets like Ceres. The atmospheres and interiors of the four giant planets — Jupiter, Saturn, Uranus and Neptune — are thought to contain enormous quantities of the wet stuff, and their moons and rings have substantial water ice.

Perhaps the most surprising water worlds are the five icy moons of Jupiter and Saturn that show strong evidence of oceans beneath their surfaces: Ganymede, Europa and Callisto at Jupiter, and Enceladus and Titan at Saturn. 

Scientists using NASA’s Hubble Space Telescope recently provided powerful evidence that Ganymede has a saltwater, sub-surface ocean, likely sandwiched between two layers of ice. 

Europa and Enceladus are thought to have an ocean of liquid water beneath their surface in contact with mineral-rich rock, and may have the three ingredients needed for life as we know it: liquid water, essential chemical elements for biological processes, and sources of energy that could be used by living things. NASA’s Cassini mission has revealed Enceladus as an active world of icy geysers. Recent research suggests it may have hydrothermal activity on its ocean floor, an environment potentially suitable for living organisms. 

NASA spacecraft have also found signs of water in permanently shadowed craters on Mercury and our moon, which hold a record of icy impacts across the ages like cryogenic keepsakes.

While our solar system may seem drenched in some places, others seem to have lost large amounts of water. 

On Mars, NASA spacecraft have found clear evidence that the Red Planet had water on its surface for long periods in the distant past. NASA’s Curiosity Mars Rover discovered an ancient streambed that existed amidst conditions favorable for life as we know it.

More recently, NASA scientists using ground-based telescopes were able to estimate the amount of water Mars has lost over the eons. They concluded the planet once had enough liquid water to form an ocean occupying almost half of Mars’ northern hemisphere, in some regions reaching depths greater than a mile (1.6 kilometers). But where did the water go? 

It’s clear some of it is in the Martian polar ice caps and below the surface. We also think much of Mars’ early atmosphere was stripped away by the wind of charged particles that streams from the sun, causing the planet to dry out. NASA’s MAVEN mission is hard at work following this lead from its orbit around Mars. 

The story of how Mars dried out is intimately connected to how the Red Planet’s atmosphere interacts with the solar wind. Data from the agency’s solar missions — including STEREO, Solar Dynamics Observatory and the planned Solar Probe Plus — are vital to helping us better understand what happened.

Understanding the distribution of water in our solar system tells us a great deal about how the planets, moons, comets and other bodies formed 4.5 billion years ago from the disk of gas and dust that surrounded our sun. The space closer to the sun was hotter and drier than the space farther from the sun, which was cold enough for water to condense. The dividing line, called the “frost line,” sat around Jupiter’s present-day orbit. Even today, this is the approximate distance from the sun at which the ice on most comets begins to melt and become “active.” Their brilliant spray releases water ice, vapor, dust and other chemicals, which are thought to form the bedrock of most worlds of the frigid outer solar system.

Scientists think it was too hot in the solar system’s early days for water to condense into liquid or ice on the inner planets, so it had to be delivered — possibly by comets and water-bearing asteroids. NASA’s Dawn mission is currently studying Ceres, which is the largest body in the asteroid belt between Mars and Jupiter. Researchers think Ceres might have a water-rich composition similar to some of the bodies that brought water to the three rocky, inner planets, including Earth.

The amount of water in the giant planet Jupiter holds a critical missing piece to the puzzle of our solar system’s formation. Jupiter was likely the first planet to form, and it contains most of the material that wasn’t incorporated into the sun. The leading theories about its formation rest on the amount of water the planet soaked up. To help solve this mystery, NASA’s Juno mission will measure this important quantity beginning in mid-2016.

Looking further afield, observing other planetary systems as they form is like getting a glimpse of our own solar system’s baby pictures, and water is a big part of that story. For example, NASA’s Spitzer Space Telescope has observed signs of a hail of water-rich comets raining down on a young solar system, much like the bombardment planets in our solar system endured in their youth. 

With the study of exoplanets — planets that orbit other stars — we are closer than ever to finding out if other water-rich worlds like ours exist. In fact, our basic concept of what makes planets suitable for life is closely tied to water: Every star has a habitable zone, or a range of distances around it in which temperatures are neither too hot nor too cold for liquid water to exist. NASA’s planet-hunting Kepler mission was designed with this in mind. Kepler looks for planets in the habitable zone around many types of stars.

Recently verifying its thousandth exoplanet, Kepler data confirm that the most common planet sizes are worlds just slightly larger than Earth. Astronomers think many of those worlds could be entirely covered by deep oceans. Kepler’s successor, K2, continues to watch for dips in starlight to uncover new worlds. 

The agency’s upcoming TESS mission will search nearby, bright stars in the solar neighborhood for Earth- and super-Earth-sized exoplanets. Some of the planets TESS discovers may have water, and NASA’s next great space observatory, the James Webb Space Telescope, will examine the atmospheres of those special worlds in great detail. 

It’s easy to forget that the story of Earth’s water, from gentle rains to raging rivers, is intimately connected to the larger story of our solar system and beyond. But our water came from somewhere — every world in our solar system got its water from the same shared source. So it’s worth considering that the next glass of water you drink could easily have been part of a comet, or an ocean moon, or a long-vanished sea on the surface of Mars. And note that the night sky may be full of exoplanets formed by similar processes to our home world, where gentle waves wash against the shores of alien seas.

 

Curiosity Sniffs Out History of Martian Atmosphere

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A Sample Analysis at Mars (SAM) team member at NASA Goddard prepares the SAM testbed for an experiment. This test copy of the SAM suite of instruments is inside a chamber that, when closed, can model the pressure and temperature environment that SAM sees inside Curiosity on Mars.
 


NASA’s Curiosity rover is using a new experiment to better understand the history of the Martian atmosphere by analyzing xenon.

While NASA’s Curiosity rover concluded its detailed examination of the rock layers of the “Pahrump Hills” in Gale Crater on Mars this winter, some members of the rover team were busy analyzing the Martian atmosphere for xenon, a heavy noble gas.

Curiosity’s Sample Analysis at Mars (SAM) experiment analyzed xenon in the planet’s atmosphere. Since noble gases are chemically inert and do not react with other substances in the air or on the ground, they are excellent tracers of the history of the atmosphere. Xenon is present in the Martian atmosphere at a challengingly low quantity and can be directly measured only with on-site experiments such as SAM.

Xenon is a fundamental measurement to make on a planet such as Mars or Venus, since it provides essential information to understand the early history of these planets and why they turned out so differently from Earth,” said Melissa Trainer, one of the scientists analyzing the SAM data.

A planetary atmosphere is made up of different gases, which are in turn made up of variants of the same chemical element called isotopes. When a planet loses its atmosphere, that process can affect the ratios of remaining isotopes.

Measuring xenon tells us more about the history of the loss of the Martian atmosphere. The special characteristics of xenon – it exists naturally in nine different isotopes, ranging in atomic mass from 124 (with 70 neutrons per atom) to 136 (with 82 neutrons per atom) – allows us to learn more about the process by which the layers of atmosphere were stripped off of Mars than using measurements of other gases.

A process removing gas from the top of the atmosphere removes lighter isotopes more readily than heavier ones leaving a ratio higher in heavier isotopes than it was originally.

The SAM measurement of the ratios of the nine xenon isotopes traces a very early period in the history of Mars when a vigorous atmospheric escape process was pulling away even the heavy xenon gas. The lighter isotopes were escaping just a bit faster than the heavy isotopes.

Those escapes affected the ratio of isotopes in the atmosphere left behind, and the ratios today are a signature retained in the atmosphere for billions of years. This signature was first inferred several decades ago from isotope measurements on small amounts of Martian atmospheric gas trapped in rocks from Mars that made their way to Earth as meteorites.

“We are seeing a remarkably close match of the in-situ data to that from bits of atmosphere captured in some of the Martian meteorites,” said SAM Deputy Principal Investigator Pan Conrad.

SAM previously measured the ratio of two isotopes of a different noble gas, argon. The results pointed to continuous loss over time of much of the original atmosphere of Mars.

The xenon experiment required months of careful testing at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, using a close copy of the SAM instrument enclosed in a chamber that simulates the Mars environment. This testing was led by Goddard’s Charles Malespin, who developed and optimized the sequence of instructions for SAM to carry out on Mars.

“I’m gratified that we were able to successfully execute this run on Mars and demonstrate this new capability for Curiosity,” said Malespin.

NASA’s Mars Science Laboratory Project is using Curiosity to determine if life was possible on Mars and study major changes in Martian environmental conditions. NASA studies Mars to learn more about our own planet, and in preparation for future human missions to Mars. NASA’s Jet Propulsion Laboratory in Pasadena, California, a division of Caltech, manages the project for NASA’s Science Mission Directorate in Washington.

For more information about SAM, visit:

http://ssed.gsfc.nasa.gov/sam/

SAM experiment data are archived in the Planetary Data System, online at:

http://pds.nasa.gov/

For more information about Curiosity, visit:

http://www.nasa.gov/msl

You can follow the mission on Facebook and Twitter at:

http://www.facebook.com/marscuriosity

and

http://www.twitter.com/marscuriosity

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