Powering Saturn's Active Ocean Moon

Heat from friction could power hydrothermal activity on Saturn's moon Enceladus for billions of years if the moon has a highly porous core, according to a new modeling study by European and U.S. researchers working on NASA's Cassini mission.

The study, published today in the journal Nature Astronomy, helps resolve a question scientists have grappled with for a decade:Where does the energy to power the extraordinary geologic activity on Enceladus come from?

Cassini found that Enceladus sprays towering, geyser-like jets of water vapor and icy particles, including simple organics, from warm fractures near its south pole. Additional investigation revealed the moon has a global ocean beneath its icy crust,from which the jets are venting into space. Multiple lines of evidence from Cassini indicate that hydrothermal activity -- hot water interacting chemically with rock -- is taking place on the seafloor.

One of those lines was the detection of tiny rock grains inferred to be the product of hydrothermal chemistry taking place at temperatures of at least 194 degrees Fahrenheit (90 degrees Celsius). The amount of energy required to produce these temperatures is more than scientists think could be provided by decay of radioactive elements in the interior.

"Where Enceladus gets the sustained power to remain active has always been a bit of a mystery, but we've now considered in greater detail how the structure and composition of the moon's rocky core could play a key role in generating the necessary energy," said the study's lead author, Gaël Choblet from the University of Nantes in France.

Choblet and co-authors found that a loose, rocky core with 20 to 30 percent empty space would do the trick. Their simulations show that as Enceladus orbits Saturn, rocks in the porous core flex and rub together, generating heat. The loose interior also allows water from the ocean to percolate deep down, where it heats up, then rises, interacting chemically with the rocks. The models show this activity should be at a maximum at the moon's poles. Plumes of the warm, mineral-laden water gush from the seafloor and travel upward, thinning the moon's ice shell from beneath to only half a mile to 3 miles (1 to 5 kilometers) at the south pole. (The average global thickness of the ice is thought to be about 12 to 16 miles, or 20 to 25 kilometers.) And this same water is then expelled into space through fractures in the ice.

The study is the first to explain several key characteristics of Enceladus observed by Cassini: the global ocean, internal heating, thinner ice at the south pole, and hydrothermal activity. It doesn't explain why the north and south poles are so different though. Unlike the tortured, geologically fresh landscape of the south, Enceladus' northern extremes are heavily cratered and ancient. The authors note that if the ice shell was slightly thinner in the south to begin with, it would lead to runaway heating there over time.

The researchers estimate that, over time (between 25 and 250 million years), the entire volume of Enceladus' ocean passes through the moon's core. This is estimated to be an amount of water equal to two percent of the volume of Earth's oceans.

Flexing of Enceladus' icy crust due to the tidal pull of Saturn had previously been considered as a heat source, but models showed this would not produce enough sustained power. The ocean in Enceladus would have frozen within 30 million years. Although past studies modeled how tidal friction could generate heat in the moon's core, they made simpler assumptions or simulated the moon in only two dimensions. The new study ramped up the complexity of the model and simulated Enceladus in 3-D.

Although the Cassini science team had suspected for years that a porous core might play an important role in the mystery of Enceladus' warm interior, this study brings together several more recent lines of evidence in a very elegant way, according to NASA's Cassini Project Scientist Linda Spilker at theagency's Jet Propulsion Laboratory in Pasadena, California. "This powerful research makes use of newer details -- namely that the ocean is global and has hydrothermal activity -- that we just didn't have until the past couple of years. It's an insight that the mission needed time to build, one discovery upon another," she said.

Launched in 1997, the Cassini spacecraft orbited Saturn from 2004 to 2017. Cassini made numerous dramatic discoveries, including the surprising activity on Enceladus and liquid methane seas on Saturn's largest moon, Titan. Cassini ended its journey with a dramatic plunge into Saturn's atmosphere on Sept. 15, 2017, returning unique science data until it lost contact with Earth.

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. JPL designed, developed and assembled the Cassini orbiter.

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Virginia Students to Speak with NASA Astronauts on Space Station

NASA's Joe Acaba, Mark Vande Hei, and Randy Bresnik, during 52S Arrival,

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Astronomers Complete First International Asteroid Tracking Exercise

An international team of astronomers led by NASA scientists successfully completed the first global exercise using a real asteroid to test global response capabilities.

Planning for the so-called "TC4 Observation Campaign" started in April, under the sponsorship of NASA's Planetary Defense Coordination Office. The exercise commenced in earnest in late July, when the European Southern Observatory's Very Large Telescope recovered the asteroid. The finale was a close approach to Earth in mid-October. The goal: to recover, track and characterize a real asteroid as a potential impactor -- and to test the International Asteroid Warning Network for hazardous asteroid observations, modeling, prediction and communication.

The target of the exercise was asteroid 2012 TC4 -- a small asteroid originally estimated to be between 30 and 100 feet (10 and 30 meters) in size, which was known to be on a very close approach to Earth. On Oct. 12, TC4 safely passed Earth at a distance of only about 27,200 miles (43,780 kilometers) above Earth's surface. In the months leading up to the flyby, astronomers from the U.S., Canada, Colombia, Germany, Israel, Italy, Japan, the Netherlands, Russia and South Africa all tracked TC4 from ground- and space-based telescopes to study its orbit, shape, rotation and composition.

"This campaign was an excellent test of a real threat case. I learned that in many cases we are already well-prepared; communication and the openness of the community was fantastic," said Detlef Koschny, co-manager of the near-Earth object (NEO) segment in the European Space Agency (ESA)'s Space Situational Awareness program. "I personally was not prepared enough for the high response from the public and media -- I was positively surprised by that! It shows that what we are doing is relevant."

"The 2012 TC4 campaign was a superb opportunity for researchers to demonstrate willingness and readiness to participate in serious international cooperation in addressing the potential hazard to Earth posed by NEOs," said Boris Shustov, science director for the Institute of Astronomy at the Russian Academy of Sciences. "I am pleased to see how scientists from different countries effectively and enthusiastically worked together toward a common goal, and that the Russian-Ukrainian observatory in Terskol was able to contribute to the effort." Shustov added, "In the future I am confident that such international observing campaigns will become common practice."

Using the observations collected during the campaign, scientists at NASA's Center for Near-Earth Object Studies (CNEOS) at the Jet Propulsion Laboratory in Pasadena, California were able to precisely calculate TC4's orbit, predict its flyby distance on Oct. 12, and look for any possibility of a future impact. "The high-quality observations from optical and radar telescopes have enabled us to rule out any future impacts between the Earth and 2012 TC4," said Davide Farnocchia from CNEOS, who led the orbit determination effort. "These observations also help us understand subtle effects such as solar radiation pressure that can gently nudge the orbit of small asteroids."

A network of optical telescopes also worked together to study how fast TC4 rotates. Given that TC4 is small, astronomers expected it to be rotating fast, but were surprised when they found that TC4 was not only spinning once every 12 minutes, it was also tumbling. "The rotational campaign was a true international effort. We had astronomers from several countries working together as one team to study TC4's tumbling behavior," said Eileen Ryan, director of the Magdalena Ridge Observatory. Her team tracked TC4 for about 2 months using the 7.9-foot (2.4-meter) telescope in Socorro, New Mexico.

The observations that revealed the shape and confirmed the composition of the asteroid came from astronomers using NASA's Goldstone Deep Space Network antenna in California and the National Radio Astronomy Observatory's 330-foot (100-meter) Green Bank Telescope in West Virginia. "TC4 is a very elongated asteroid that's about 50 feet (15 meters) long and roughly 25 feet (8 meters) wide," said Marina Brozovic, a member of the asteroid radar team at JPL.

Finding out what TC4 is made of turned out to be more challenging. Due to adverse weather conditions, traditional NASA assets studying asteroid composition -- such as the NASA Infrared Telescope Facility (IRTF) at the Mauna Kea Observatory in Hawaii -- were unable to narrow down what TC4 was made of: either dark, carbon-rich or bright igneous material.

"Radar has the ability to identify asteroids with surfaces made of highly reflective rocky or metallic materials," said Lance Benner, who led the radar observations at JPL. "We were able to show that radar scattering properties are consistent with a bright rocky surface, similar to a particular class of meteorites that reflect as much as 50 percent of the light falling on them."

In addition to the observation campaign, NASA used this exercise to test communications between the many observers and also to test internal U.S. government messaging and communications up through the executive branch and across government agencies, as it would during an actual predicted impact emergency.

"We demonstrated that we could organize a large, worldwide observing campaign on a short timeline, and communicate results efficiently," said Vishnu Reddy of the University of Arizona's Lunar and Planetary Laboratory in Tucson, who led the observation campaign. Michael Kelley, TC4 exercise lead at NASA Headquarters in Washington added, "We are much better prepared today to deal with the threat of a potentially hazardous asteroid than we were before the TC4 campaign."

NASA's Planetary Defense Coordination Office administers the Near-Earth Object Observations Program and is responsible for finding, tracking and characterizing potentially hazardous asteroids and comets coming near Earth, issuing warnings about possible impacts, and assisting coordination of U.S. government response planning, should there be an actual impact threat.

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More Than 2.4 Million Names Are Going to Mars

Last month, NASA invited members of the public to send their names to Mars. And the public responded loud and clear.

More than 1.6 million people signed up to have their names etched on a microchip that will be carried on NASA's upcoming InSight mission, which launches in May of 2018.

NASA's Jet Propulsion Laboratory in Pasadena, California, reopened the opportunity after it proved successful in 2015. During that open call, nearly 827,000 names were collected for a microchip that now sits on top of the robotic InSight lander.

The grand total once a second microchip is added in early 2018 will be 2,429,807 names. Space enthusiasts who signed up this last round shared their downloadable "boarding passes" on social media, complete with the total number of flight miles they've collected by participating in engagement initiatives for other Mars missions.

InSight will be the first mission to look deep beneath the Martian surface, studying the planet's interior by listening for marsquakes. These quakes travel through geologic material at different speeds and give scientists a glimpse of the composition and structure of the planet's inside. The insights into how Mars formed will help us better understand how other rocky planets are created.

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Juno Aces Eighth Science Pass of Jupiter, Names New Project Manager

Data returned Tuesday, Oct. 31, indicate that NASA's Juno spacecraft successfully completed its eighth science flyby over Jupiter's mysterious cloud tops on Tuesday, Oct. 24. The confirmation was delayed by several days due to solar conjunction at Jupiter, which affected communications during the days prior to and after the flyby.

Solar conjunction is the period when the path of communication between Earth and Jupiter comes into close proximity with the Sun. During solar conjunction, no attempts are made to send new instructions or receive information from Juno, as it is impossible to predict what information might be corrupted due to interference from charged particles from the Sun. Instead, a transmission moratorium is put into place; engineers send instructions prior to the start of solar conjunction and store data on board for transmission back to Earth following the event.

"All the science collected during the flyby was carried in Juno's memory until yesterday, when Jupiter came out of solar conjunction," said the new Juno project manager, Ed Hirst, from NASA's Jet Propulsion Laboratory in Pasadena, California. "All science instruments and the spacecraft's JunoCam were operating, and the new data are now being transmitted to Earth and being delivered into the hands of our science team."

Hirst has worked on Juno since its preliminary design phase, through launch in 2011 and arrival at Jupiter in 2016. He previously worked on NASA's Galileo, Stardust and Genesis missions. Born in Guatemala City, Guatemala, he earned a B.S. in Aerospace Engineering from the University of Texas at Austin and joined JPL in 1993. Hirst succeeds Rick Nybakken, who was recently appointed deputy director for JPL's Office of Safety and Mission Success.

"We couldn't be happier for Rick and know he will continue to do great things to further NASA's leadership in space exploration," said Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio. "Similarly, we are pleased with Ed's promotion to project manager. He has been a critical part of Juno for many years and we know he'll hit the ground running."

Juno's next close flyby of Jupiter will occur on Dec. 16.

"There is no more exciting place to be than in orbit around Jupiter and no team I'd rather be with than the Juno team," said Hirst. "Our spacecraft is in great shape, and the team is looking forward to many more flybys of the solar system's largest planet."

Juno launched on Aug. 5, 2011, from Cape Canaveral, Florida, and arrived in orbit around Jupiter on July 4, 2016. During its mission of exploration, Juno soars low over the planet's cloud tops -- as close as about 2,100 miles (3,400 kilometers). During these flybys, Juno is probing beneath the obscuring cloud cover of Jupiter and studying its auroras to learn more about the planet's origins, structure, atmosphere and magnetosphere.

JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, for the Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. JPL is a division of Caltech in Pasadena, California.

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Overlooked Treasure: The First Evidence of Exoplanets

Briefings, NASA Television Coverage Set for Launch of NOAA Weather Satellite

Officials from the National Oceanic and Atmospheric Administration (NOAA) and NASA are preparing for the upcoming launch of the Joint Polar Satellite System-1 (JPSS-1), the first in a series of four highly advanced NOAA polar-orbiting satellites designed to improve the accuracy of weather forecasts out to seven days.

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New Greenland Maps Show More Glaciers at Risk

New maps of Greenland's coastal seafloor and bedrock beneath its massive ice sheet show that two to four times as many coastal glaciers are at risk of accelerated melting as previously thought.

Researchers at the University of California at Irvine (UCI), NASA and 30 other institutions have published the most comprehensive, accurate and high-resolution relief maps ever made of Greenland's bedrock and coastal seafloor. Among the many data sources incorporated into the new maps are data from NASA's Ocean Melting Greenland (OMG) campaign.

Lead author Mathieu Morlighem of UCI had demonstrated in an earlier paper that data from OMG's survey of the shape and depth, or bathymetry, of the seafloor in Greenland's fjords improved scientists' understanding not only of the coastline, but of the inland bedrock beneath glaciers that flow into the ocean. That's because the bathymetry where a glacier meets the ocean limits the possibilities for the shape of bedrock farther upstream.

A stretch of Greenland's coastline as created by BedMachine before and after the inclusion of new OMG data. Credit: UCI

The nearer to the shoreline, the more valuable the bathymetry data are for understanding on-shore topography, Morlighem said. "What made OMG unique compared to other campaigns is that they got right into the fjords, as close as possible to the glacier fronts. That's a big help for bedrock mapping." Additionally, the OMG campaign surveyed large sections of the Greenland coast for the first time ever. In fjords for which there are no data, it's difficult to estimate how deep the glaciers extend below sea level.

The OMG data are only one of many datasets Morlighem and his team used in the ice sheet mapper, which is named BedMachine. Another comprehensive source is NASA's Operation IceBridge airborne surveys. IceBridge measures the ice sheet thickness directly along a plane's flight path. This creates a set of long, narrow strips of data rather than a complete map of the ice sheet. Besides NASA, nearly 40 other international collaborators also contributed various types of survey data on different parts of Greenland.

No survey, not even OMG, covers every glacier on Greenland's long, convoluted coastline. To infer the bed topography in sparsely studied areas, BedMachine averages between existing data points using physical principles such as the conservation of mass.

The new maps reveal that two to four times more oceanfront glaciers extend deeper than 600 feet (200 meters) below sea level than earlier maps showed. That's bad news, because the top 600 feet of water around Greenland comes from the Arctic and is relatively cold. The water below it comes from farther south and is 6 to 8 degrees Fahrenheit (3 to 4 degrees Celsius) warmer than the water above. Deeper-seated glaciers are exposed to this warmer water, which melts them more rapidly.

Morlighem's team used the maps to refine their estimate of Greenland's total volume of ice and its potential to add to global sea level rise, if the ice were to melt completely -- which is not expected to occur within the next few hundred years. The new estimate is higher by 2.76 inches (7 centimeters) for a total of 24.34 feet (7.42 meters).

OMG Principal Investigator Josh Willis of JPL, who was not involved in producing the maps, said, "These results suggest that Greenland's ice is more threatened by changing climate than we had anticipated."

On Oct. 23, the five-year OMG campaign completed its second annual set of airborne surveys to measure, for the first time, the amount that warm water around the island is contributing to the loss of the Greenland ice sheet. Besides the one-time bathymetry survey, OMG is collecting annual measurements of the changing height of the ice sheet and the ocean temperature and salinity in more than 200 fjord locations. Morlighem looks forward to improving BedMachine's maps with data from the airborne surveys.

The maps and related research are in a paper titled "BedMachine v3: Complete bed topography and ocean bathymetry mapping of Greenland from multi-beam echo sounding combined with mass conservation" in Geophysical Research Letters.

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Martian Ridge Brings Out Rover's Color Talents

Color-discerning capabilities that NASA's Curiosity rover has been using on Mars since 2012 are proving particularly helpful on a mountainside ridge the rover is now climbing.

These capabilities go beyond the thousands of full-color images Curiosity takes every year: The rover can look at Mars with special filters helpful for identifying some minerals, and also with a spectrometer that sorts light into thousands of wavelengths, extending beyond visible-light colors into infrared and ultraviolet. These observations aid decisions about where to drive and investigations of chosen targets.

One of these methods for discerning targets' colors uses the Mast Camera (Mastcam); the other uses the Chemistry and Camera instrument (ChemCam).

Each of the Mastcam's two eyes -- one telephoto and one wider angle -- has several science filters that can be changed from one image to the next to assess how brightly a rock reflects light of specific colors. By design, some of the filters are for diagnostic wavelengths that certain minerals absorb, rather than reflect. Hematite, one iron-oxide mineral detectable with Mastcam's science filters, is a mineral of prime interest as the rover examines "Vera Rubin Ridge."

"We're in an area where this capability of Curiosity has a chance to shine," said Abigail Fraeman of NASA's Jet Propulsion Laboratory, Pasadena, California, who leads planning for the mission's investigation of Vera Rubin Ridge.

This ridge on lower Mount Sharp became a planned destination for Curiosity before the rover landed five years ago. Spectrometer observations from orbit revealed hematite here. Most hematite forms in the presence of water, and the mission focuses on clues about wet environments in Mars' ancient past. It found evidence during the first year after landing that some ancient Martian environments offered conditions favorable for life. As the mission continues, it is studying how those conditions varied and changed.

Curiosity's ChemCam is best known for zapping rocks with a laser to identify chemical elements in them, but it also can examine targets near and far without use of the laser. It does this by measuring sunlight reflected by the targets in thousands of wavelengths. Some patterns in this spectral data can identify hematite or other minerals.

"The colors of the rocks on the ridge are more interesting and more variable than what we saw earlier in Curiosity's traverse," said science team member Jeffrey Johnson of the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland. He uses both Mastcam and ChemCam data for analyzing rocks.

Hematite occurs at sufficiently small grain sizes in rocks found at this part of Mars to preferentially absorb some wavelengths of green light. This gives it a purplish tint in standard color images from Curiosity, due to more reflection of redder and bluer light than reflection of the green wavelengths. The additional color-discerning capabilities of Mastcam and ChemCam show hematite even more clearly.

Johnson said, "We're using these multi-spectral and hyper-spectral capabilities for examining rocks right in front of the rover and also for reconnaissance -- looking ahead to help with choosing where to drive for closer inspection."

For example, a false-color Sept. 12 panorama combining Mastcam images taken through three special filters provided a map of where hematite could be seen in a region a few days' drive away. The hematite is most apparent in zones around fractured bedrock. The team drove Curiosity to a site in that scene to check the possible link between fracture zones and hematite. Investigation with Mastcam, ChemCam and other tools, including a camera and brush on the rover's arm, revealed that hematite is also in bedrock farther from the fractures once an obscuring layer of tan dust is brushed away.The dust doesn't coat the fractured rock as thoroughly.

That finding suggests that dust and fractures cause the hematite to appear more patchy than it actually is. If the hematite is broadly distributed, its origin likely was early, rather than in a later period of fluids moving through fractures in the rock.

"As we approached the ridge and now as we're climbing it, we've been trying to tie what was detected from orbit to what we can learn on the ground," said Curiosity science team member Danika Wellington of Arizona State University, Tempe. "It's still very much a work in progress. The extent to which iron-bearing minerals here are oxidized relates to the history of interactions between water and rock."

The U.S. Department of Energy's Los Alamos National Laboratory in Los Alamos, New Mexico, developed ChemCam in partnership with scientists and engineers funded by the French national space agency (CNES). Mastcam was built by Malin Space Science Systems, San Diego. JPL, a division of Caltech in Pasadena, California, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington, and built the project's Curiosity rover. For more information about Curiosity, visit:

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NASA Estimates the Global Reach of Atmospheric Rivers

A recent study by NASA and several partners has estimated, for the first time, the global impact of atmospheric rivers on floods and droughts, as well as the number of people affected by these atmospheric phenomena.

Atmospheric rivers are relatively long, narrow, short-lived jets of air that transport water vapor across significant portions of Earth's mid-latitude oceans, onto the continents and into Earth's polar regions.

Previous studies recognized that atmospheric rivers can have profound effects on precipitation, floods and snowpack on land -- collectively known as hydrology -- but these studies were limited to very specific regions. The new study is a first attempt to determine how extensively atmospheric rivers affect global hydrology.

Like tropical cyclones, atmospheric rivers are a form of extreme weather that affects many areas of the globe. The new study conservatively estimates that, on average, at least 300 million people around the world are exposed to floods and droughts linked to atmospheric rivers each year. And while the percentage of Earth's population affected by atmospheric river storms is relatively small, their effects are quite significant.

The study authors found that globally, precipitation from atmospheric rivers contributes 22 percent of the total water that flows across Earth's land surfaces. In certain regions -- such as the west and east coasts of North America; Southeast Asia; and New Zealand -- that contribution can exceed 50 percent. These impacts come from just a handful of atmospheric river storms each year. Around the world, in places where their influence is strongest, atmospheric rivers make floods and droughts far more likely -- increasing the occurrence of floods by 80 percent in those areas, while their absence may increase the occurrence of droughts by up to 90 percent.

Earlier research on atmospheric rivers focused largely on two types of impacts from these systems. First, early studies in the 1990s noted that these storms are responsible for the vast majority of water vapor transported to Earth's higher latitudes, helping to shape the climate and water cycle of the polar regions. Second, most atmospheric river studies in the past decade have primarily focused on the impacts they bring to western North America and western Europe. The studies found that atmospheric rivers are responsible for most flooding events, as well as recoveries from drought, in these regions, and also that just a dozen or so storms drop 40 percent of California's annual water supply.

"This new work quantifies the potential impacts of atmospheric rivers on important freshwater quantities, such as snowpack, soil moisture and the occurrence of droughts and floods across the globe," said study co-author Duane Waliser, chief scientist of the Earth Science and Technology Directorate at NASA's Jet Propulsion Laboratory in Pasadena, California. "The findings provide added impetus for considering improvements to our observing and modeling systems that are used for forecasting atmospheric rivers."

For this research, the scientists used a database of atmospheric rivers (previously developed by the study co-authors) to model the amount of water these moisture-laden jets contribute to variations in stream flow, soil moisture and snowpack. Next, they identified regions where atmospheric rivers play a major role in influencing floods and droughts. They then calculated the number of people exposed to these hydrologic hazards due to atmospheric rivers.

"By incorporating demographic data into our study, we have found that, globally, a large number of people are exposed to hazards that stem from atmospheric rivers," said study lead author Homero Paltan. (Paltan is currently a graduate student at the University of Oxford in England, but began work on the study during a summer internship at JPL in 2016.) "They have a considerable impact that we're only beginning to understand and measure."

While many areas experience either drought or flooding as impacts of atmospheric rivers, Paltan said, in some places, rivers can bring both of these hazards. For example, people in the Iberian Peninsula (in Spain and Portugal), northern Iran, the Yellow River Valley in China, and areas of Australia and New Zealand might be exposed to droughts like the one California recently experienced. "Yet at the same time, in these and other areas around the globe, atmospheric rivers also represent a major source of flood risk."

The research was published online recently by the journal Geophysical Research Letters.

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Next Mars Rover Will Have 23 'Eyes'

When NASA's Mars Pathfinder touched down in 1997, it had five cameras: two on a mast that popped up from the lander, and three on NASA's first rover, Sojourner.

Since then, camera technology has taken a quantum leap. Photo sensors that were improved by the space program have become commercially ubiquitous. Cameras have shrunk in size, increased in quality and are now carried in every cellphone and laptop.

That same evolution has returned to space. NASA's Mars 2020 mission will have more "eyes" than any rover before it: a grand total of 23, to create sweeping panoramas, reveal obstacles, study the atmosphere, and assist science instruments. They will provide dramatic views during the rover's descent to Mars and be the first to capture images of a parachute as it opens on another planet. There will even be a camera inside the rover's body, which will study samples as they're stored and left on the surface for collection by a future mission.

All these cameras will be incorporated as the Mars 2020 rover is built at NASA's Jet Propulsion Laboratory in Pasadena, California. They represent a steady progression since Pathfinder: after that mission, the Spirit and Opportunity rovers were designed with 10 cameras each, including on their landers; Mars Science Laboratory's Curiosity rover has 17.

"Camera technology keeps improving," said Justin Maki of JPL, Mars 2020's imaging scientist and deputy principal investigator of the Mastcam-Z instrument. "Each successive mission is able to utilize these improvements, with better performance and lower cost."

That advantage represents a full circle of development, from NASA to the private sector and back. In the 1980s, JPL developed active-pixel sensors that used less power than earlier digital camera technology. These sensors were later commercialized by the Photobit Corporation, founded by former JPL researcher Eric Fossum, now at Dartmouth College, Hanover, New Hampshire.

20/20 Vision

The cameras on 2020 will include more color and 3-D imaging than on Curiosity, said Jim Bell of Arizona State University, Tempe, principal investigator for 2020's Mastcam-Z. The "Z" stands for "zoom," which will be added to an improved version of Curiosity's high-definition Mastcam, the rover's main eyes.

Mastcam-Z's stereoscopic cameras can support more 3-D images, which are ideal for examining geologic features and scouting potential samples from long distances away. Features like erosion and soil textures can be spotted at the length of a soccer field. Documenting details like these is important: They could reveal geologic clues and serve as "field notes" to contextualize samples for future scientists.

"Routinely using 3-D images at high resolution could pay off in a big way," Bell said. "They're useful for both long-range and near-field science targets."

Finally, in color

The Spirit, Opportunity and Curiosity rovers were all designed with engineering cameras for planning drives (Navcams) and avoiding hazards (Hazcams). These produced 1-megapixel images in black and white.

On the new rover, the engineering cameras have been upgraded to acquire high-resolution, 20-megapixel color images.

Their lenses will also have a wider field of view. That's critical for the 2020 mission, which will try to maximize the time spent doing science and collecting samples.

"Our previous Navcams would snap multiple pictures and stitch them together," said Colin McKinney of JPL, product delivery manager for the new engineering cameras. "With the wider field of view, we get the same perspective in one shot."

That means less time spent panning, snapping pictures and stitching. The cameras are also able to reduce motion blur, so they can take photos while the rover is on the move.

A Data Link to Mars

There's a challenge in all this upgrading: It means beaming more data through space.

"The limiting factor in most imaging systems is the telecommunications link," Maki said. "Cameras are capable of acquiring much more data than can be sent back to Earth."

To address that problem, rover cameras have gotten "smarter" over time -- especially regarding compression.

On Spirit and Opportunity, the compression was done using the onboard computer; on Curiosity, much of it was done using electronics built into the camera. That allows for more 3-D imaging, color, and even high-speed video.

NASA has also gotten better at using orbiting spacecraft as data relays. That concept was pioneered for rover missions with Spirit and Opportunity. The idea of using relays started as an experiment with NASA's Mars Odyssey orbiter, Bell said.

"We were expecting to do that mission on just tens of megabits each Mars day, or sol," he said. "When we got that first Odyssey overflight, and we had about 100 megabits per sol, we realized it was a whole new ballgame."

NASA plans to use existing spacecraft already in orbit at Mars -- the Mars Reconnaissance Orbiter, MAVEN, and the European Space Agency's Trace Gas Orbiter -- as relays for the Mars 2020 mission, which will support the cameras during the rover's first two years.

More information about Mars 2020's cameras is at:

http://ift.tt/2gQFEZ1

More information about the Mars 2020 mission is at:

http://ift.tt/2n3q2C4

News Media Contact

Andrew Good

Jet Propulsion Laboratory, Pasadena, Calif.

818-393-2433

andrew.c.good@jpl.nasa.gov

2017-282

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