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Freitag, 21. April 2017 - 07:45 Uhr

Raumfahrt - NASA Mars Rover 2020 Mission-Update-2

12.01.2017

Seeking Signs of Life and More: NASA's Mars 2020 Mission 

The next Mars rover will be able to land near rugged terrain, giving scientists access to diverse landscapes. It will also cache core samples, a first step in the quest to return samples to Earth.

By  and K. H. Williford 

NASA recently confirmed that it plans to fly to Mars in 2020, sending the fifth in a series of increasingly ambitious rovers to investigate the Red Planet. The specific landing site hasn’t been chosen yet, but the Mars 2020 mission will explore one of several possible paleoenvironments older than 3.5 billion years that might once have been conducive to microbial life.

The rover will assess the geology of the landing site and analyze surface targets for signs of ancient life using imaging, organic and inorganic geochemistry, and mineralogy. Notably, the rover, also called Mars 2020, will also be the first to select, collect, and cache a suite of samples from another planet for possible future return to Earth, fulfilling the vision of the most recent planetary science decadal survey to take the first step toward Mars Sample Return [National Research Council, 2011].

A Shift in Strategy

 

Previous rovers used sophisticated analytic instruments and prepared rock and soil specimens for analysis on board the rover itself. Mars 2020, however, will be the first rover tasked with detailed exploration of the surface to support the collection of a large, high-value sample suite designated for possible later study in laboratories back on Earth.

 

Conceptually, Mars 2020 marks a transition from missions in which sampling guided exploration to one where exploration guides sampling. In other words, the rover’s scientific instruments will observe the surrounding terrain and provide the critical context for choosing where samples will be collected. Ultimately, this context will also be used to interpret the samples. This evolution is familiar on Earth, where initial field observations and limited sampling in the service of geologic mapping lead to hypotheses that are eventually tested through focused sample collection and laboratory analysis.

Instruments on Board

The Mars 2020 rover has new scientific instruments and a sampling and caching system for possible sample return to Earth.
Fig. 1. The Mars 2020 rover closely follows the design of Curiosity, but it has new scientific instruments and a sampling and caching system for the drilling and storage of samples for possible return to Earth. Credit: NASA/JPL-Caltech

The architecture of this mission closely follows the highly successful Mars Science Laboratory (MSL) and its Curiosity rover, but Mars 2020 will be modified with new scientific instruments and capabilities that allow more intensive and efficient use of the rover (Figure 1).

Two instruments will be mounted on the rover mast: Mastcam-Z, a high-resolution, color stereo zoom camera, and SuperCam, a multifaceted instrument that collects spectroscopic data using visible–near-infrared (Vis-NIR), Raman, and laser-induced breakdown spectroscopy (LIBS) techniques. SuperCam will analyze data from rock and regolith materials that may be several meters away from the rover to characterize their texture, mineralogy, and chemistry.

Two instruments on the robotic arm will permit researchers to study rock surfaces with unprecedented spatial resolution (features as small as about 100 micrometers). The Planetary Instrument for X-ray Lithochemistry (PIXL) will use X-ray fluorescence to map elemental composition, whereas Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) will use deep-UV Raman and fluorescence spectroscopy to map the molecular chemistry of organic matter and select mineral classes. SHERLOC also includes a high-resolution color microscopic imager.

The rover will be able to assess subsurface geologic structure using a ground-penetrating radar instrument called Radar Imager for Mars’ Subsurface Experiment (RIMFAX). The rover will characterize environmental conditions, including temperature, humidity, and winds, using the Mars Environmental Dynamics Analyzer (MEDA) instrument. The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) will demonstrate a critical technology for human exploration of Mars by converting carbon dioxide in the atmosphere to oxygen as a potential source of rocket propellant.

Rover Hits the Ground Running

 

In addition to the new scientific instruments, Mars 2020 builds on the innovative MSL “sky crane” entry, descent, and landing system. The sky crane lowers the rover to the surface from a rocket-powered descent stage rather than using air bags to provide a soft landing. New onboard navigational capabilities will enable the rover to land closer to regions with abundant rock outcroppings, which are scientifically desirable but potentially hazardous for landing. The rover will also have stronger wheels to reduce the puncture problems that plague the Curiosity rover.

 

New onboard software provides the rover with more autonomy for driving and for science investigations. New Earth-based tools and practices will enable the operations team to assess results and develop the next planning cycle over a much shorter timeline.

Studying the Samples

Mars 2020 will carry an entirely new subsystem to collect and prepare samples. As studies of lunar samples returned by the Apollo missions demonstrated, specimens brought back from Mars would be analyzed for an extraordinary diversity of purposes. Notable examples include igneous and sedimentary petrology, geochemistry, geochronology, and astrobiology.

Samples brought back to Earth would also help researchers assess hazards associated with possible human exploration of Mars. And, of course, the samples would be analyzed for the presence of current life on Mars.

Readying samples for such study creates demanding requirements on this subsystem (Table 1). These requirements and their implementation are informed by previous studies [e.g., McLennan et al., 2012; Summons et al., 2014], as well as by the mission’s Returned Sample Science Board. Notable among these requirements are capabilities to ensure that contamination from Earth, brought over by the spacecraft,  is limited to less than 10 parts per billion of total organic carbon and statistically less than one viable Earth organism in each of the returned samples.

Table 1. Requirements for the Samples to Be Prepared for Caching by the Mars 2020 Mission
Category Requirement
Number of samples at least 31
Sample mass, each 10- to 15-gram cylindrical cores
Contamination limits  
        Inorganic limits on 21 key geochemical elements based on Martian meteorite concentrations
        Organic <10 parts per billion total organic carbon

 

<1 part per billion of 10 critical marker compounds

        Biologic less than one viable Earth organism per sample
Drilling and storage temperature <60°C at all times, including during depot on Mars surface
Individual sample tube sealing  hermetic (to prevent volatile loss as well as contamination)
Sample disaggregation  maintain large pieces during drilling, storage, and possible Earth return to retain petrologic context

 

 

Coring, Sealing, and Storing

Sample tubes are mounted in a drill bit, and sample core material is introduced directly into the tube through an opening.
Fig. 2. (a) Sample tubes will be coated with titanium nitride (gold color) to limit organic molecule adsorption and with aluminum oxide (white) to reduce solar heating during residence on Mars’s surface. The tube is mounted within a rotary-percussive drill bit, and sample core material is introduced directly into the tube through an opening (located at the top in the orientation shown here). Features at the bottom of the tube are used for robotic tube manipulation. (b) Samples are cylindrical cores, typically 7.5 centimeters in length. Samples frequently break into fragments during drilling, as illustrated by this basalt test core. Both images are at the scale indicated. Credit: NASA/JPL-Caltech

The rover will carry a rack of about 40 sample tubes, each capable of holding a single core of rock or regolith measuring about 7.5 cubic centimeters and weighing about 10–15 grams (Figure 2). To collect a sample, the rover will withdraw a clean tube from the tube silo and insert it into a reusable coring drill bit. This assembly will then be inserted into the drill mechanism on the robotic arm and placed on the target.

The drill bit will use rotary motion with or without percussion to penetrate the rock and to force the core into the sample tube. After the core is broken off from the surrounding rock, the drill bit will be returned to storage. The sample and tube will be handed off to an assembly that carries the tubes through a series of stations: The sample will be photographed, the sample volume will be confirmed, and a cap will be inserted that provides a hermetic metal-on-metal seal that prevents contamination and loss of volatile components.

As a quality assurance check, the rover will carry and process multiple blank sample tubes. If the sample tubes pick up any Earth-sourced elemental, organic, or biologic contamination during the mission and possible Earth return, the blank samples will indicate the presence and nature of this contamination.

Mars 2020 has adopted an approach to caching in which sample tubes are filled and stored on board the rover. When the rover obtains an adequate number of samples, it will deposit them as a cache in a “depot” on the Martian surface for possible return to Earth.

The depot’s location will be carefully selected to prevent blowing sand and dust from obscuring the individual tubes. Then, a vehicle from a possible follow-on element of the Mars Sample Return campaign could easily locate and pick up the samples. The tubes are designed to survive at least a decade after being deposited on the surface and another decade in space on the potential return journey.

Making Preparations

Mars 2020 is currently under development at the Jet Propulsion Laboratory in Pasadena, Calif. The mission has a 2-month launch window in midsummer 2020, followed by landing in February 2021. Mars 2020 has a prime mission of at least 1 Mars year (just under 2 Earth years).

Eight potential landing sites are now being considered. Scientists have hypothesized that environments at these sites range from ancient rivers, lakes, and deltas to extensive hydrothermal systems, similar to hot springs found on Earth.

Over the next few years, the landing site list will be honed down to a single site and a backup site that meet scientific desires and engineering constraints. We highly encourage the continued involvement of the broad scientific community, including scientists who may someday analyze the returned samples, in site selection. The next Mars 2020 landing site workshop is scheduled for 8–10 February 2017.

Acknowledgment

This project is being developed at the Jet Propulsion Laboratory, California Institute of Technology, for NASA.

Quelle: EOS

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Update: 31.01.2017

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Quelle: ESA

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Update: 12.02.2017

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Scientists Shortlist Three Landing Sites for Mars 2020

Three potential landing sites for NASA's next Mars rover
Three potential landing sites for NASA's next Mars rover.
Credits: NASA
Three potential landing sites for NASA's next Mars rover
 

Participants in a landing site workshop for NASA’s upcoming Mars 2020 mission have recommended three locations on the Red Planet for further evaluation. The three potential landing sites for NASA’s next Mars rover include Northeast Syrtis (a very ancient portion of Mars’ surface), Jezero crater, (once home to an ancient Martian lake), and Columbia Hills (potentially home to an ancient hot spring, explored by NASA’s Spirit rover).

 

More information on the landing sites can be found at:

 

http://mars.nasa.gov/mars2020/mission/timeline/prelaunch/landing-site-se...

 

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. It will also prepare a collection of samples for possible return to Earth by a future mission.

 

NASA's Jet Propulsion Laboratory will build and manage operations of the Mars 2020 rover for the NASA Science Mission Directorate at the agency's headquarters in Washington.

Quelle: NASA

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Update: 29.03.2017

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ExoMars: Rover scientists to study Mawrth Vallis option

Artwork: ExoMars roverImage copyrightESA
Image captionArtwork: The ExoMars rover would land on the Red Planet in early 2021

Europe is going to investigate a second site on Mars as a possible destination to send its 2021 rover.

Scientists spent two days considering the options and plumped in the end for Mawrth Vallis - an area rich in clay minerals that must have formed during prolonged rock interactions with water.

Mawrth joins Oxia Planum, which was selected for study in 2015.

The European Space Agency's ExoMars rover will carry a suite of instruments to search for past or present life.

It will use a drill to bore up to 2m into the ground, to find samples for analysis that have not been sterilised by the planet's harsh environment.

The launch of the robot from Earth was due to take place in 2018 but this has now been pushed back by two years because of hold-ups in the preparation of hardware.

Mawrth VallisImage copyrightBJÖRN SCHREINER - FU BERLIN
Image captionMawrth Vallis is an ancient terrain that shows clear evidence of past water activity

Although disappointing, the delay has at least allowed scientists to consider in detail a wider selection of potential landing sites.

Engineering constraints, including the angle of approach to the Red Planet, meant that only Oxia Planum was really suitable for a mission launched in 2018 (the cruise to Mars takes eight months).

A launch in July 2020 (and touch-down in March 2021) brought back into play two sites of interest that had originally lost out to Oxia.

Mawrth Vallis has long interested scientists. The terrain is ancient and there is a feeling that if life has ever existed on Mars, this might be the kind of area that would retain evidence of its presence.

Aram Dorsum was the other candidate on the table during the two days of discussions at Esa's technical centre in Noordwijk in the Netherlands. Aram contains a large channel. The sedimentary rocks around this channel may well be the consequence of flood deposits. 

But in the end, the Noordwijk meeting voted in favour of Mawrth, and this was then endorsed by the ExoMars Landing Site Selection Working Group (LSSWG). 

Oxia Planum
Image copyrightESA/DLR/FU BERLIN/NASA/MGS/MOLA
Image captionOxia Planum was the only option for a 2018 launch, but is also still a 2020 possibility

Technically, Oxia Planum - another clay-rich location - was back in competition, but it remains in play and will now be subjected - as ExoMars project scientist Jorge Vago put it - to "excruciating investigation", along with Mawrth.

"In Oxia and Mawrth, we will be investigating areas of Mars where the deposits are so ancient they record what the conditions were during the very early history of the planet - more than four billion years ago," Dr Vago told BBC News. 

"No other mission has landed on a site this old. So, I think the mineral variety and the age of the landing site contributed to the preference of the people who voted for Mawrth Vallis."

Picture analysts need to identify a swathe of ground roughly 120km by 20km (the ellipse of error expected with the rover's landing system) at both locations that is largely free from fissures, excessive slopes and large boulders.

These are the hazards that could kill the rover before its surface mission has even begun.

Assuming that can be done for both Oxia Planum and Mawrth Vallis, a final decision on where to send the robot can be made on the science imperatives alone.

This downselection to the one preferred destination is not expected to be made until the year before launch.

Map
Image captionThe site selection process started in 2015 with four equatorial candidates

Quelle: BBC

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Update: 21.04.2017

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A false color image highlights the complex geology of the Northeast Syrtis Major region on Mars.NASA/JPL/University of Arizona

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Researchers produce detailed map of potential Mars rover landing site

Mineral deposits in a region called Northeast Syrtis Major suggest a plethora of once-habitable environments. By mapping those deposits in the region’s larger geological context, Brown researchers may help set the stage for a future rover mission.

PROVIDENCE, R.I. [Brown University] — Brown University researchers have published the most detailed geological history to date for a region of Mars known as Northeast Syrtis Major, a spot high on NASA’s list of potential landing sites for its next Mars rover to be launched in 2020.

The region is home to a striking mineral diversity, including deposits that indicate a variety of past environments that could have hosted life. Using the highest resolution images available from NASA’s Mars Reconnaissance Orbiter, the study maps the extent of those key mineral deposits across the surface and places them within the region’s larger geological context.

“When we look at this in high resolution, we can see complicated geomorphic patterns and a diversity of minerals at the surface that I think is unlike anything we’ve ever seen on Mars,” said Mike Bramble, a Ph.D. student at Brown who led the study, which is published in the journal Icarus. “Within a few kilometers, there’s a huge spectrum of things you can see and they change very quickly.”

If NASA ultimately decides to land at Northeast Syrtis, the work would help in providing a roadmap for the rover’s journey.

“This is a foundational paper for considering this part of the planet as a potential landing site for the Mars2020 rover,” said Jack Mustard, a professor in Brown’s Department of Earth, Environmental and Planetary Sciences and a coauthor on the paper. “This represents an exceptional amount of work on Mike’s part, really going into the key morphologic and spectroscopic datasets we need in order to understand what this region can tell us about the history of Mars if we explore it with a rover.”

Past habitable environments

Northeast Syrtis sits between two giant Martian landforms—an impact crater 2,000 kilometers in diameter called the Isidis Basin, and a large volcano called Syrtis Major. The impact basin formed about 3.96 billion years ago, while lava flow from the volcano came later, about 3.7 billion years ago. Northeast Syrtis preserves the geological activity that occurred in the 250 million years between those two events. Billions of years of erosion, mostly from winds howling across the region into the Isidis lowlands, have exposed that history on the surface.

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A detailed map shows the the various geologic units exposed at Northeast Syrtis.
Credit: Mike Bramble/Mustard Lab

Within Northeast Syrtis are the mineral signatures of four distinct types of watery and potentially habitable past environments. Those minerals had been detected by prior research, but the new map shows in detail how they are distributed within the region’s larger geological context. That helps constrain the mechanisms that may have formed them, and shows when they formed relative to each other.

The lowest and the oldest layer exposed at Northeast Syrtis has the kind of clay minerals formed when rocks interact with water that has a fairly neutral pH. Next in the sequence are rocks containing kaolinite, a mineral formed by water percolating through soil. The next layer up contains spots where the mineral olivine has been altered to carbonate—an aqueous reaction that, on Earth, is known to provide chemical energy for bacterial colonies. The upper layers contain sulfate minerals, another sign of a watery, potentially life-sustaining environment.

Understanding the relative timing of these environments is critical, Mustard says. They occurred around the transition between the Noachian and Hesperian epochs—a time of profound environmental change on Mars.   

“We know that these environments existed near this major pivot point in Mars history, and in mapping their context we know what came first, what came next and what came last,” Mustard said. “So now if we’re able to go there with a rover, we can sample rock on either side of that pivot point, which could help us understand the changes that occurred at that time, and test different hypotheses for the possibility of past life.”

And finding signs of past life is the primary mission of the Mars2020 rover. NASA has held three workshops in which scientists debated the merits of various landing targets for the rover. Mustard and Bramble have led the charge for Northeast Syrtis, which has come out near the top of the list at each workshop. Last February, NASA announced that the site is one of the final three under consideration.

Mustard and Bramble hope this latest work might inform NASA’s decision, and ultimately help in planning the Mars2020 mission.

“As we turn our eyes to the next target for in situ exploration on the martian surface,” the researchers conclude, “no location offers better access of the gamut of geological processes active at Mars than Northeast Syrtis Major.”

Quelle: Brown University

 


Tags: NASA Mars Rover 2020 Mission 

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