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  • richardmitnick 9:51 am on April 27, 2017 Permalink | Reply
    Tags: Joint Japan Aerospace Exploration Agency NASA Hinode satellite, NASA JPL - Caltech, Scientists Propose Mechanism to Describe Solar Eruptions of All Sizes, SDO - NASA’s Solar Dynamics Observatory, ,   

    From Goddard: “Scientists Propose Mechanism to Describe Solar Eruptions of All Sizes” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    April 26, 2017
    Lina Tran
    kathalina.k.tran@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    1
    A long filament erupted on the sun on Aug. 31, 2012, shown here in imagery captured by NASA’s Solar Dynamics Observatory. Credit: NASA’s Goddard Space Flight Center/SDO
    From long, tapered jets to massive explosions of solar material and energy, eruptions on the sun come in many shapes and sizes. Since they erupt at such vastly different scales, jets and the massive clouds — called coronal mass ejections, or CMEs — were previously thought to be driven by different processes.

    Scientists from Durham University in the United Kingdom and NASA now propose that a universal mechanism can explain the whole spectrum of solar eruptions. They used 3-D computer simulations to demonstrate that a variety of eruptions can theoretically be thought of as the same kind of event, only in different sizes and manifested in different ways. Their work is summarized in a paper published in Nature on April 26, 2017.


    Follow the evolution of a jet eruption in this video, which uses a 3-D computer simulation of the breakout model to demonstrate how a filament forms, gains energy and erupts from the sun.
    Credits: NASA’s Goddard Space Flight Center/ARMS/Genna Duberstein, producer

    The study was motivated by high-resolution observations of filaments from NASA’s Solar Dynamics Observatory, or SDO, and the joint Japan Aerospace Exploration Agency/NASA Hinode satellite.

    NASA/SDO

    JAXA/HINODE spacecraft

    Filaments are dark, serpentine structures that are suspended above the sun’s surface and consist of dense, cold solar material. The onset of CME eruptions had long been known to be associated with filaments, but improved observations have recently shown that jets have similar filament-like structures before eruption too. So the scientists set out to see if they could get their computer simulations to link filaments to jet eruptions as well.

    “In CMEs, filaments are large, and when they become unstable, they erupt,” said Peter Wyper, a solar physicist at Durham University and the lead author of the study. “Recent observations have shown the same thing may be happening in smaller events such as coronal jets. Our theoretical model shows the jet can essentially be described as a mini-CME.”

    Solar scientists can use computer models like this to help round out their understanding of the observations they see through space telescopes. The models can be used to test different theories, essentially creating simulated experiments that cannot, of course, be performed on an actual star in real life.

    The scientists call their proposed mechanism for how these filaments lead to eruptions the breakout model, for the way the stressed filament pushes relentlessly at — and ultimately breaks through — its magnetic restraints into space. They previously used this model to describe CMEs; in this study, the scientists adapted the model to smaller events and were able to reproduce jets in the computer simulations that match the SDO and Hinode observations. Such simulations provide additional confirmation to support the observations that first suggested coronal jets and CMEs are caused in the same way.

    “The breakout model unifies our picture of what’s going on at the sun,” said Richard DeVore, a co-author of the study and solar physicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Within a unified context, we can advance understanding of how these eruptions are started, how to predict them and how to better understand their consequences.”

    The key for understanding a solar eruption, according to Wyper, is recognizing how the filament system loses equilibrium, which triggers eruption. In the breakout model, the culprit is magnetic reconnection — a process in which magnetic field lines come together and explosively realign into a new configuration.

    NASA Magnetic reconnection, Credit: M. Aschwanden et al. (LMSAL), TRACE, NASA

    In stable conditions, loops of magnetic field lines hold the filament down and suppress eruption. But the filament naturally wants to expand outward, which stresses its magnetic surroundings over time and eventually initiates magnetic reconnection. The process explosively releases the energy stored in the filament, which breaks out from the sun’s surface and is ejected into space.

    Exactly which kind of eruption occurs depends on the initial strength and configuration of the magnetic field lines containing the filament. In a CME, field lines form closed loops completely surrounding the filament, so a bubble-shaped cloud ultimately bursts from the sun. In jets, nearby fields lines stream freely from the surface into interplanetary space, so solar material from the filament flows out along those reconnected lines away from the sun.

    “Now we have the possibility to explain a continuum of eruptions through the same process,” Wyper said. “With this mechanism, we can understand the similarities between small jets and massive CMEs, and infer eruptions anywhere in between.”

    Confirming this theoretical mechanism will require high-resolution observations of the magnetic field and plasma flows in the solar atmosphere, especially around the sun’s poles where many jets originate — and that’s data that currently are not available. For now, scientists look to upcoming missions such as NASA’s Solar Probe Plus and the joint ESA (European Space Agency)/NASA Solar Orbiter, which will acquire novel measurements of the sun’s atmosphere and magnetic fields emanating from solar eruptions.

    NASA/SPP Solar Probe Plus

    NASA/ESA Solar Orbiter

    See the full article here.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.


    NASA/Goddard Campus

     
  • richardmitnick 8:33 am on April 27, 2017 Permalink | Reply
    Tags: , NASA JPL - Caltech, Tsunami science   

    From JPL-Caltech: “NASA Study Challenges Long-held Tsunami Formation Theory” 

    NASA JPL Banner

    JPL-Caltech

    April 26, 2017
    News Media Contact
    Alan Buis
    Jet Propulsion Laboratory, Pasadena, California
    818-354-0474
    Alan.buis@jpl.nasa.gov

    Written by Samson Reiny
    NASA Earth Science News Team

    1
    Photo taken March 11, 2011, by Sadatsugu Tomizawa and released via Jiji Press on March 21, 2011, showing tsunami waves hitting the coast of Minamisoma in Fukushima prefecture, Japan. Credit: Sadatsugu Tomizawa CC BY-NC-ND 2.0

    Fast Facts:

    › Conventional theory holds that vertical seafloor movement creates nearly all of the energy that generates tsunamis.

    › A new study shows that horizontal seafloor movement also creates energy for tsunamis.

    › The finding further validates a GPS-based approach for detecting a tsunami’s size and strength for early warnings.

    A new NASA study is challenging a long-held theory that tsunamis form and acquire their energy mostly from vertical movement of the seafloor.

    An undisputed fact was that most tsunamis result from a massive shifting of the seafloor — usually from the subduction, or sliding, of one tectonic plate under another during an earthquake.

    The tectonic plates of the world were mapped in 1996, USGS.

    Experiments conducted in wave tanks in the 1970s demonstrated that vertical uplift of the tank bottom could generate tsunami-like waves. In the following decade, Japanese scientists simulated horizontal seafloor displacements in a wave tank and observed that the resulting energy was negligible. This led to the current widely held view that vertical movement of the seafloor is the primary factor in tsunami generation.

    In 2007, Tony Song, an oceanographer at NASA’s Jet Propulsion Laboratory in Pasadena, California, cast doubt on that theory after analyzing the powerful 2004 Sumatra earthquake in the Indian Ocean. Seismograph and GPS data showed that the vertical uplift of the seafloor did not produce enough energy to create a tsunami that powerful. But formulations by Song and his colleagues showed that once energy from the horizontal movement of the seafloor was factored in, all of the tsunami’s energy was accounted for. Those results matched tsunami data collected from a trio of satellites -the NASA/Centre National d’Etudes Spatiales (CNES) Jason, the U.S. Navy’s Geosat Follow-on and the European Space Agency’s Environmental Satellite.

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    NASA/Centre National d’Etudes Spatiales (CNES) Jason

    3
    Artist’s view of the GFO spacecraft (image credit: US Navy)

    4
    Artist’s conception of Sentinel-1, an environment-monitoring satellite from the European Space Agency. Credit: ESA/ATG medialab

    Further research by Song on the 2004 Sumatra earthquake, using satellite data from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE) mission, also backed up his claim that the amount of energy created by the vertical uplift of the seafloor alone was insufficient for a tsunami of that size.

    5
    NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE)

    “I had all this evidence that contradicted the conventional theory, but I needed more proof,” Song said.

    His search for more proof rested on physics — namely, the fact that horizontal seafloor movement creates kinetic energy, which is proportional to the depth of the ocean and the speed of the seafloor’s movement. After critically evaluating the wave tank experiments of the 1980s, Song found that the tanks used did not accurately represent either of these two variables. They were too shallow to reproduce the actual ratio between ocean depth and seafloor movement that exists in a tsunami, and the wall in the tank that simulated the horizontal seafloor movement moved too slowly to replicate the actual speed at which a tectonic plate moves during an earthquake.

    “I began to consider that those two misrepresentations were responsible for the long-accepted but misleading conclusion that horizontal movement produces only a small amount of kinetic energy,” Song said.

    Building a Better Wave Tank

    To put his theory to the test, Song and researchers from Oregon State University in Corvallis simulated the 2004 Sumatra and 2011 Tohoku earthquakes at the university’s Wave Research Laboratory by using both directly measured and satellite observations as reference. Like the experiments of the 1980s, they mimicked horizontal land displacement in two different tanks by moving a vertical wall in the tank against water, but they used a piston-powered wave maker capable of generating faster speeds. They also better accounted for the ratio of how deep the water is to the amount of horizontal displacement in actual tsunamis.

    The new experiments illustrated that horizontal seafloor displacement contributed more than half the energy that generated the 2004 and 2011 tsunamis.

    “From this study, we’ve demonstrated that we need to look at not only the vertical but also the horizontal movement of the seafloor to derive the total energy transferred to the ocean and predict a tsunami,” said Solomon Yim, a professor of civil and construction engineering at Oregon State University and a co-author on the study.

    The finding further validates an approach developed by Song and his colleagues that uses GPS technology to detect a tsunami’s size and strength for early warnings.

    The JPL-managed Global Differential Global Positioning System (GDGPS) is a very accurate real-time GPS processing system that can measure seafloor movement during an earthquake. As the land shifts, ground receiver stations nearer to the epicenter also shift. The stations can detect their movement every second through real-time communication with a constellation of satellites to estimate the amount and direction of horizontal and vertical land displacement that took place in the ocean. They developed computer models to incorporate that data with ocean floor topography and other information to calculate the size and direction of a tsunami.

    “By identifying the important role of the horizontal motion of the seafloor, our GPS approach directly estimates the energy transferred by an earthquake to the ocean,” Song said. “Our goal is to detect a tsunami’s size before it even forms, for early warnings.”

    The study is published in Journal of Geophysical Research — Oceans

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 11:55 am on April 26, 2017 Permalink | Reply
    Tags: NASA JPL - Caltech, , New planet OGLE-2016-BLG-1195Lb found   

    From Spitzer: “Iceball’ Planet Discovered Through Microlensing” 

    NASA Spitzer Telescope

    Spitzer

    04.26.17
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1

    Scientists have discovered a new planet with the mass of Earth, orbiting its star at the same distance that we orbit our sun. The planet is likely far too cold to be habitable for life as we know it, however, because its star is so faint. But the discovery adds to scientists’ understanding of the types of planetary systems that exist beyond our own.

    “This ‘iceball’ planet is the lowest-mass planet ever found through microlensing,” said Yossi Shvartzvald, a NASA postdoctoral fellow based at NASA’s Jet Propulsion Laboratory, Pasadena, California, and lead author of a study published in the Astrophysical Journal Letters.

    Gravitational microlensing, S. Liebes, Physical Review B, 133 (1964): 835

    Microlensing is a technique that facilitates the discovery of distant objects by using background stars as flashlights. When a star crosses precisely in front of a bright star in the background, the gravity of the foreground star focuses the light of the background star, making it appear brighter. A planet orbiting the foreground object may cause an additional blip in the star’s brightness. In this case, the blip only lasted a few hours. This technique has found the most distant known exoplanets from Earth, and can detect low-mass planets that are substantially farther from their stars than Earth is from our sun.

    The newly discovered planet, called OGLE-2016-BLG-1195Lb, aids scientists in their quest to figure out the distribution of planets in our galaxy. An open question is whether there is a difference in the frequency of planets in the Milky Way’s central bulge compared to its disk, the pancake-like region surrounding the bulge. OGLE-2016-BLG-1195Lb is located in the disk, as are two planets previously detected through microlensing by NASA’s Spitzer Space Telescope.

    “Although we only have a handful of planetary systems with well-determined distances that are this far outside our solar system, the lack of Spitzer detections in the bulge suggests that planets may be less common toward the center of our galaxy than in the disk,” said Geoff Bryden, astronomer at JPL and co-author of the study.

    For the new study, researchers were alerted to the initial microlensing event by the ground-based Optical Gravitational Lensing Experiment (OGLE) survey, managed by the University of Warsaw in Poland. Study authors used the Korea Microlensing Telescope Network (KMTNet), operated by the Korea Astronomy and Space Science Institute, and Spitzer, to track the event from Earth and space.

    3
    KMTNet-CTIO

    1.3 meter OGLE Warsaw Telescope at the Las Campanas Observatory in Chile

    KMTNet consists of three wide-field telescopes: one in Chile, one in Australia, and one in South Africa. When scientists from the Spitzer team received the OGLE alert, they realized the potential for a planetary discovery. The microlensing event alert was only a couple of hours before Spitzer’s targets for the week were to be finalized, but it made the cut.

    With both KMTNet and Spitzer observing the event, scientists had two vantage points from which to study the objects involved, as though two eyes separated by a great distance were viewing it. Having data from these two perspectives allowed them to detect the planet with KMTNet and calculate the mass of the star and the planet using Spitzer data.

    “We are able to know details about this planet because of the synergy between KMTNet and Spitzer,” said Andrew Gould, professor emeritus of astronomy at Ohio State University, Columbus, and study co-author.

    Although OGLE-2016-BLG-1195Lb is about the same mass as Earth, and the same distance from its host star as our planet is from our sun, the similarities may end there.

    OGLE-2016-BLG-1195Lb is nearly 13,000 light-years away and orbits a star so small, scientists aren’t sure if it’s a star at all. It could be a brown dwarf, a star-like object whose core is not hot enough to generate energy through nuclear fusion. This particular star is only 7.8 percent the mass of our sun, right on the border between being a star and not.

    Alternatively, it could be an ultra-cool dwarf star much like TRAPPIST-1, which Spitzer and ground-based telescopes recently revealed to host seven Earth-size planets.

    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets (NASA).

    Those seven planets all huddle closely around TRAPPIST-1, even closer than Mercury orbits our sun, and they all have potential for liquid water. But OGLE-2016-BLG-1195Lb, at the sun-Earth distance from a very faint star, would be extremely cold — likely even colder than Pluto is in our own solar system, such that any surface water would be frozen. A planet would need to orbit much closer to the tiny, faint star to receive enough light to maintain liquid water on its surface.

    Ground-based telescopes available today are not able to find smaller planets than this one using the microlensing method. A highly sensitive space telescope would be needed to spot smaller bodies in microlensing events. NASA’s upcoming Wide Field Infrared Survey Telescope (WFIRST), planned for launch in the mid-2020s, will have this capability.

    NASA/WFIRST

    “One of the problems with estimating how many planets like this are out there is that we have reached the lower limit of planet masses that we can currently detect with microlensing,” Shvartzvald said. “WFIRST will be able to change that.”

    JPL manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit:

    http://spitzer.caltech.edu

    http://www.nasa.gov/spitzer

    See the full article here .

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    The Spitzer Space Telescope is a NASA mission managed by the Jet Propulsion Laboratory located on the campus of the California Institute of Technology and part of NASA’s Infrared Processing and Analysis Center.

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  • richardmitnick 3:17 pm on April 20, 2017 Permalink | Reply
    Tags: , Detecting Life in the Driest Place on Earth, NASA JPL - Caltech   

    From JPL-Caltech: “Detecting Life in the Driest Place on Earth” 

    NASA JPL Banner

    JPL-Caltech

    April 20, 2017
    Andrew Good
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-393-2433
    andrew.c.good@jpl.nasa.gov

    1
    Chile’s Atacama Desert is the driest place on Earth — and a ready analog for Mars’ rugged, arid terrain. Image Credit: NASA/JPL-Caltech

    2
    The Chemical Laptop, a life-detecting device designed for other planets, was recently tested in Chile’s Atacama Desert. Image Credit: NASA/JPL-Caltech

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    This automated extractor uses water, high pressure and high temperature to release amino acids trapped inside of soil samples. Image Credit: NASA/JPL-Caltech

    4
    The JPL team that recently tested life-detecting devices in Chile’s Atacama Desert, from left to right: Peter Willis, Jessica Creamer, Fernanda Mora, Eric Tavares Da Costa and Florian Kehl. Image Credit: NASA/JPL-Caltech

    Few places are as hostile to life as Chile’s Atacama Desert. It’s the driest place on Earth, and only the hardiest microbes survive there. Its rocky landscape has lain undisturbed for eons, exposed to extreme temperatures and radiation from the sun.

    If you can find life here, you might be able to find it in an even harsher environment — like the surface of Mars. That’s why a team of researchers from NASA and several universities visited the Atacama in February. They spent 10 days testing devices that could one day be used to search for signs of life on other worlds. That group included a team from NASA’s Jet Propulsion Laboratory in Pasadena, California, working on a portable chemistry lab called the Chemical Laptop.

    With just a small water sample, the Laptop can check for amino acids, the organic molecules that are widespread in our solar system and considered the building blocks of all life as we know it. Liquid-based analysis techniques have been shown to be orders of magnitude more sensitive than gas-based methods for the same kinds of samples. But when you scoop up a sample from Mars, the amino acids you’re looking for will be trapped inside of or chemically bonded to minerals.

    To break down those bonds, JPL has designed another piece of technology, a subcritical water extractor that would act as the “front end” for the Laptop. This extractor uses water to release the amino acids from a soil sample, leaving them ready to be analyzed by the Chemical Laptop.

    “These two pieces of technology work together so that we can search for biosignatures in solid samples on rocky or icy worlds,” said Peter Willis of JPL, the project’s principal investigator. “The Atacama served as a proving ground to see how this technology would work on an arid planet like Mars.”

    To find life, just add water

    Willis’ team revisited an Atacama site he first went to in 2005. At that time, the extractor he used was manually operated; in February, the team used an automated extractor designed by Florian Kehl, a postdoctoral researcher at JPL.

    The extractor ingests soil and regolith samples and mixes them with water. Then, it subjects the samples to high pressure and temperature to get the organics out.

    “At high temperatures, water has the ability to dissolve the organic compounds from the soil,” Kehl said. “Think of a tea bag: in cold water, not much happens. But when you add hot water, the tea releases an entire bouquet of molecules that gives the water a particular flavor, color and smell.”

    To remove the amino acids from those minerals, the water has to get much hotter than your ordinary cup of tea: Kehl said the extractor is currently able to reach temperatures as high as 392 degrees Fahrenheit (200 degrees Celsius).

    Liquid samples would be more readily available on ocean worlds like Jupiter’s moon Europa, Kehl said. There, the extractor might still be necessary, as amino acids could be bonded to minerals mixed into the ice. They also may be present as part of larger molecules, which the extractor could break into smaller building blocks before analyzing them with the Chemical Laptop. Once the extractor has prepared its samples, the Laptop can do its work.

    NASA’s own tricorder

    The Chemical Laptop checks liquid samples for a set of 17 amino acids — what the team refers to as “the Signature 17.” By looking at the types, amounts and geometries of these amino acids in a sample, it’s possible to infer the presence of life.

    “All these molecules ‘like’ being in water,” said Fernanda Mora of JPL, the Chemical Laptop’s lead scientist. “They dissolve in water and they don’t evaporate easily, so they’re much easier to detect in water.”

    The Laptop mixes liquid samples with a fluorescent dye, which attaches to amino acids and makes it possible to detect them when illuminated by a laser.

    Then, the sample is injected onto a separation microchip. A voltage is applied between the two ends of the channel, causing the amino acids to move at different speeds towards the end, where the laser is shining. Amino acids can be identified by how quickly they move through the channel. As the molecules pass through the laser, they emit light that is used to quantify how much of each amino acid is present.

    “The idea is to automate and miniaturize all the steps you would do manually in a chemistry lab on Earth,” Mora said. “That way, we can do the same analyses on another world simply by sending commands with a computer.”

    The near-term goal is to integrate the extractor and Chemical Laptop into a single, automated device. It would be tested during future field campaigns to the Atacama Desert with a team of researchers led by Brian Glass of NASA’s Ames Research Center in Mountain View, California.

    “These are some of the hardest samples to analyze you can get on the planet,” Mora said of the team’s work in the Atacama. She added that in the future, the team wants to test this technology in icy environments like Antarctica. Those could serve as analogs to Europa and other ocean worlds, where liquid samples would be more readily plentiful.

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 7:07 am on April 20, 2017 Permalink | Reply
    Tags: , , , , , , NASA JPL - Caltech, NASA Radar Spots Relatively Large Asteroid Prior to Flyby   

    From JPL-Caltech: “NASA Radar Spots Relatively Large Asteroid Prior to Flyby” 

    NASA JPL Banner

    JPL-Caltech

    April 18, 2017
    DC Agle
    Jet Propulsion Laboratory, Pasadena, California
    818-393-9011
    agle@jpl.nasa.gov


    This movie of asteroid 2014 JO25 was generated using radar data collected by NASA’s Goldstone Solar System Radar in California’s Mojave Desert.
    Credits: NASA/JPL-Caltech/GSSR

    Radar images of asteroid 2014 JO25 were obtained in the early morning hours on Tuesday, with NASA’s 70-meter (230-foot) antenna at the Goldstone Deep Space Communications Complex in California.

    NASA DSCC Goldstone Antenna California in the Mojave Desert, USA

    The images reveal a peanut-shaped asteroid that rotates about once every five hours. The images have resolutions as fine as 25 feet (7.5 meters) per pixel.

    Asteroid 2014 JO25 was discovered in May 2014 by astronomers at the Catalina Sky Survey near Tucson, Arizona — a project of NASA’s Near-Earth Objects Observations Program in collaboration with the University of Arizona. The asteroid will fly safely past Earth on Wednesday at a distance of about 1.1 million miles (1.8 million kilometers), or about 4.6 times the distance from Earth to the moon. The encounter is the closest the object will have come to Earth in 400 years and will be its closest approach for at least the next 500 years.
    “The asteroid has a contact binary structure – two lobes connected by a neck-like region,” said Shantanu Naidu, a scientist from NASA’s Jet Propulsion Laboratory in Pasadena, California, who led the Goldstone observations. “The images show flat facets, concavities and angular topography.”

    The largest of the asteroid’s two lobes is estimated to be 2,000 feet (620 meters) across. Radar observations of the asteroid also have been conducted at the National Science Foundation’s Arecibo Observatory in Puerto Rico. Additional radar observations are being conducted at both Goldstone and Arecibo on April 19 20, and 21, and could provide images with even higher resolution.

    Radar has been used to observe hundreds of asteroids. When these small, natural remnants of the formation of the solar system pass relatively close to Earth, deep space radar is a powerful technique for studying their sizes, shapes, rotation, surface features, and roughness, and for more precise determination of their orbital path.

    1
    This composite of 30 images of asteroid 2014 JO25 was generated with radar data collected using NASA’s Goldstone Solar System Radar in California’s Mojave Desert.
    Credits: NASA/JPL-Caltech/GSSR

    NASA’s Jet Propulsion Laboratory, Pasadena, California, manages and operates NASA’s Deep Space Network, including the Goldstone Solar System Radar, and hosts the Center for Near-Earth Object Studies for NASA’s Near-Earth Object Observations Program within the agency’s Science Mission Directorate.

    More information about asteroids and near-Earth objects can be found at:

    http://cneos.jpl.nasa.gov

    http://www.jpl.nasa.gov/asteroidwatch

    For more information about NASA’s Planetary Defense Coordination Office, visit:

    http://www.nasa.gov/planetarydefense

    For asteroid and comet news and updates, follow AsteroidWatch on Twitter:

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 3:17 pm on April 19, 2017 Permalink | Reply
    Tags: , , , , NASA JPL - Caltech, Nine Ways Cassini-Huygens Matters,   

    From JPL-Caltech: “Nine Ways Cassini-Huygens Matters” 

    NASA JPL Banner

    JPL-Caltech

    4.19.17
    No writer credit

    NASA’s Cassini spacecraft and ESA’s Huygens probe expanded our understanding of the kinds of worlds where life might exist.

    NASA/ESA/ASI Cassini Spacecraft

    With discoveries at Saturn’s moons Enceladus and Titan, Cassini and Huygens made exploring “ocean worlds” a major focus of planetary science. Insights from the mission also help us look for potentially habitable planets — and moons — beyond our solar system.

    Life as we know it is thought to be possible in stable environments that offer liquid water, essential chemical elements, and a source of energy (from sunlight or chemical reactions). Before Cassini launched in 1997, it wasn’t clear that any place in the icy outer solar system (that is, beyond Mars) might have this mix of ingredients. By the next year, NASA’s Galileo mission revealed that Jupiter’s moon Europa likely has a global ocean that could be habitable. Since its 2004 arrival at Saturn, Cassini has shown that Europa isn’t an oddball: Potentially habitable ocean worlds exist even in the Saturn system — 10 times farther from the sun than Earth.

    When the Cassini mission started, scientists presumed Enceladus was too small to generate and hold onto the heat required to maintain subsurface reservoirs of liquid water. Cassini’s discovery of intense geologic activity near the moon’s unexpectedly warm south pole — complete with towering jets of icy spray — sent shockwaves through the space science community. After over a decade of investigation, the mission eventually determined that Enceladus hosts a global liquid water ocean, with salts and simple organic molecules, and likely even hydrothermal vents on its seafloor. Thanks to Cassini, Enceladus is now one of the most promising places in our solar system to search for present-day life beyond Earth.

    Saturn’s largest moon, Titan, offered tantalizing hints that it, too, could help us understand whether life could have evolved elsewhere. Cassini and ESA’s Huygens probe (which landed on Titan’s surface) found clear evidence for a global ocean of water beneath Titan’s thick, icy crust and an atmosphere teeming with prebiotic chemicals. Based on modeling studies, some researchers think Titan, too, may have hydrothermal chemistry in its ocean that could provide energy for life. On its frigid surface, which hosts vast seas of liquid hydrocarbons, scientists wonder, could Titan be home to exotic forms of life “as we don’t know it”?

    At Saturn’s largest moon, Titan, Cassini and Huygens showed us one of the most Earth-like worlds we’ve ever encountered, with weather, climate and geology that provide new ways to understand our home planet.

    Titan is 10 times farther from the sun than Earth and much colder, but Cassini showed it to be the only other place in our solar system with stable liquid on its surface and a kind of “hydrological” cycle involving methane rather than water.

    Flowing liquid hydrocarbons at Titan make for eerily Earthlike landscapes — they carve branching channels and steep canyons into rock-hard ice; they settle into lakes and seas with gently sloping shorelines and sheltered bays; they tumble water-ice “rocks” into rounded pebble shapes like those in earthly rivers.

    Titan’s landscape also shares other similarities with Earth. Large, arid swaths of dunes gird the moon’s equatorial regions. Composed of organic materials that settle out of Titan’s thick, hazy atmosphere, these dunelands are sculpted by winds in ways similar to dunes in places like Namibia and the Sahara. Scientists have also spotted volcano-like mounds that, if indeed volcanic in nature, would erupt slushy lavas made of water rather than molten rock.

    From its perch in space, Cassini has been watching Titan’s climate cycle play out over the years, with seasonal changes bringing bright, feathery methane rain clouds that dump precipitation on the landscape. Huygens saw clear evidence of a landscape that experiences intermittent but heavy floods, not unlike places in the American desert southwest.

    Titan’s smoggy atmosphere resembles an extreme version of the skies above Los Angeles on a day with poor air quality. And, more importantly, Titan’s atmosphere is thought to be similar to early Earth’s before life developed here. Titan provides perhaps the best stage in the solar system to watch the organic chemistry that led to the origin of life on Earth billions of years ago. Titan can also be considered a possible analog for the future Earth. Its methane cycle gives us a hint of what Earth’s water cycle might look like in the far future as the increasingly brighter-burning sun changes the stability of water in our oceans and atmosphere. The seas at Titan’s poles might be remnants of larger bodies of liquid that once covered much more of the moon’s surface.​

    Cassini is, in a sense, a time machine. It has given us a portal to see the physical processes that likely shaped the development of our solar system, as well as planetary systems around other stars.

    Cassini has provided a brief glimpse into deep time in the Saturn system. The rings, for example, are a natural laboratory for processes that form planets — a mini solar system, if you will. They show us how objects clump together and break apart. And in the ripples we can read the history of impacts into the rings. We also see “propeller” features that obey the same physical processes that form planets.

    Moons in the Saturn system are also time capsules preserving histories of bombardment and other forces at play over time. At Titan, in particular, we have access to the kinds of complex carbon chemistry that might have taken place on Earth in its “prebiotic” days. During the Cassini mission’s finale, data about the planet’s interior and the mass of the rings will provide a powerful insights about their formation and evolution.

    The length of Cassini’s mission has enabled us to observe weather and seasonal changes, improving our understanding of similar processes at Earth, and potentially those at planets around other stars.

    While other missions flew past Saturn or trained telescopes periodically from afar, Cassini has had a front-row seat for approximately 13 years — nearly half a Saturn year (northern winter to the start of northern summer) — to epic changes unfolding before its very eyes.

    This long-lived robotic observing platform, bristling with science instruments, provided an unparalleled glimpse into what happens as weather and climate conditions on the planet and Titan respond to the seasons — sometimes rather abruptly. Among the most amazing changes Cassini captured: the eruption of a once-every-30-years storm (one of the most powerful ever seen in the solar system), methane rainstorms at Titan and the appearance and disappearance of features such as the “magic island.”

    Over a longer span of years, the color of Saturn’s northern hemisphere shifted as the ring shadows retreated southward — changing from the surprisingly bluish tones seen upon arrival to the hazy, golden hues most observers are familiar with. On Titan, Cassini witnessed a vortex filled with complex organic chemicals forming over its south pole, and saw sunlight glinting off of the lakes in its northern hemisphere as the sun rose over them.

    The spacecraft’s patient eyes also were rewarded with new views of Saturn’s north pole as winter ended there and the sun rose once more. Cassini’s infrared sensors measured temperatures across the rings as the sun set on one side and rose on the other, revealing new details about the structure of ring particles. It used the onset of wintry darkness at the south pole of Enceladus to obtain an unambiguous reading of the amount of heat coming out of the moon’s interior. And it saw the mysterious ring features called spokes (wedge-shaped features in the rings that rotate along with the rings like the spokes in a wheel) appear and disappear — apparently a seasonal phenomenon.

    Cassini revealed Saturn’s moons to be unique worlds with their own stories to tell.

    Planet-size Titan and diminutive Enceladus stood out in Cassini’s in-depth survey of Saturn’s moons. But the mission showed that every moon in the Saturn system is a unique character with its own mysteries, and many of Saturn’s satellites are related in surprising ways.

    For example, Cassini data enabled scientists to confirm earlier suspicions that Phoebe is likely an object from the outer solar system beyond Neptune, captured by Saturn’s gravity long ago. Phoebe also turns out to be key to the two-toned appearance of the moon Iapetus: As Phoebe sheds its dark dust, it coats the leading side of Iapetus and causes ice to heat up and migrate to the moon’s opposite side.

    Cassini also gave scientists a better understanding of why Hyperion looks like a giant sponge or wasp’s nest tumbling through space. Researchers determined that the moon’s density is so low that impacts tend to compress its surface rather than blasting it out, and the material that is launched into space tends to escape for good, thanks to Hyperion’s low gravity.

    Cassini found that Enceladus is not only active, but that its geologic activity is creating Saturn’s E ring and spray-painting the surfaces of several of the other moons with its highly reflective ice particles.

    The mission also followed up on a mystery from the early 1980s when NASA’s Voyager spacecraft flew by the Saturn system and saw bright wispy terrains on Dione. Cassini found that the features were in fact a vast network of canyons. Cassini also detected hints of a faint atmosphere that might have been outgassed from the moon’s interior.

    And Cassini watched closely over many years how Prometheus interacts with Saturn’s F ring to create features like “streamers,” “plumes” and “drapes.”

    Cassini showed us the complexity of Saturn’s rings and the dramatic processes operating within them.

    Although Cassini scientists are still working on determining the exact origin of Saturn’s main system of rings — and hope to collect data that will answer this question as its mission draws to a close — they have learned along the way that there are in fact, many ways to form rings around a planet.

    There is a diffuse ring that is created out of the bits of water ice jetted out by the moon Enceladus (the E ring). There are rings that were created because of the material thrown off when meteorites hit moons (such as the G ring and the two rings discovered by Cassini in images from 2006 — the Janus-Epimetheus ring and the Pallene ring). There are rings controlled by interactions with moons, like the F ring, which is regularly perturbed by Prometheus, and the narrow ringlets that share the Encke Gap with Pan.

    In addition to the rings’ origins, Cassini’s close-up examination has also revealed propeller-shaped features that mark the locations of hidden moonlets. The processes involved in the formation of such objects are thought to be similar to how planets form in disks around young stars.

    Cassini also helped explain Saturn’s “spokes,” first spotted during the Voyager flybys of the early 1980s. Cassini scientists figured out that they are made of tiny ice particles that are lifted above the surface of the rings by an electrostatic charge, the way a statically-charged balloon held over a person’s head will lift hairs. Their charge appears to be related to the angle of sunlight striking the rings — a seasonal effect.

    The changing angle of the sun also showed scientists an array of vertical structures in the rings, including fluffy peaks of material as high as the Rocky Mountains at the outer edges of the A and B rings. The vertical structures and the shadows they cast also revealed wavy patterns in the parts of the rings that resemble a miniature Milky Way, giving scientists insight into the way galaxies form.

    Some of Cassini’s best discoveries were serendipitous. What Cassini found at Saturn prompted scientists to rethink their understanding of the solar system.

    You can only get to know a planet so well with remote and sporadic observations. To truly understand the dynamics of a place as complicated and interesting as Saturn, you have to go there and stay to explore.

    Towering jets of ice and water vapor pouring out of a moon as tiny as Enceladus were a huge surprise (explaining why Voyager flybys in the early 1980s saw that the moon had a young surface), as was the later finding that the moon has an ocean under its icy crust. Scientists also had not expected to find Saturn’s magnetosphere — the region around the planet strongly influenced by Saturn’s magnetic field — to be filled with an electrically excited gas, or plasma, of oxygen. It turned out this was another surprise from Enceladus, as the water vapor from its plume is broken apart by sunlight and the liberated oxygen spreads out through Saturn’s magnetic bubble. Cassini detected this oxygen on approach to Saturn, but its origin was perplexing at first.

    No one knew for sure what kind of environment ESA’s Huygens probe would find when it came to rest on Titan’s surface, so Huygens was built either to land on hard ground or float, if need be. Cassini later showed scientists that most of the moon’s lakes and seas were near the north pole, and most of the moon’s landscape was more like the Arizona desert. Cassini also observed a surprisingly rich variety of complex, organic chemicals forming in Titan’s atmosphere.

    Another unexpected finding — which endures as a mystery — is the irregularity of Saturn’s day (how long the planet takes to make one rotation on its axis). At Jupiter, a beacon-like burst of radio waves known as “kilometric radiation” beams out with clock-like regularity once a day. But Saturn’s kilometric radiation isn’t consistent. It’s somewhere between 10.6 and 10.8 hours. That might not seem like a big discrepancy, but for such a fundamental property as the planet’s rotation period, it’s frustratingly imprecise for scientists. They hope to settle the score by the time the mission ends by flying Cassini close enough to the planet to tease out the true answer from the magnetic field.

    Cassini represents a staggering achievement of human and technical complexity, finding innovative ways to use the spacecraft and its instruments, and paving the way for future missions to explore our solar system.

    The Cassini-Huygens mission is an international collaboration involving three space agencies, with 19 countries contributing hardware to the flight system. The Cassini spacecraft carries 12 instruments, Huygens carried six more, and scientists from 26 nations are participating in the investigations. Among the many pioneering technologies of the mission are new solid-state data recorders with no moving parts that have since replaced tape recorders, solid-state power switches (space-based versions of circuit breakers), and advanced solid-state electronics. The spacecraft has over 9 miles (14 kilometers) of cabling and 22,000 connections.

    Cassini was able explore the entire Saturn system in a way inconceivable with conventional propulsion. Building on the techniques used by the Galileo mission to Jupiter, Cassini mission planners designed flybys of the moon Titan to utilize the moon’s gravity to navigate around the Saturn system and maximize the science return of the mission. Titan became, in a way, Cassini’s virtual “gas station” since the spacecraft couldn’t possibly have brought enough fuel for a tour this long and complex. Each of Cassini’s 127 targeted Titan flybys changed the spacecraft’s velocity (on average) by as much as the entire Saturn orbit insertion burn. The exquisite optimization techniques developed during Cassini will enable planning for future exploration that can use similar approachs. Chief among these opportunities is NASA’s planned mission to explore Jupiter’s moon Europa using multiple flybys, known as the Europa Clipper.

    Cassini has required an extremely complex schedule for determining which instrument’s observations can be made at any given moment. Cassini’s intricate observation sequences, often timed to fractions of a second, are frequently planned many months or years before they are executed by the spacecraft. The collaboration between multiple teams with often differing objectives has become an exemplary model for future missions.

    Over the course of almost 20 years in space, Cassini also showed that you can teach an old dog new tricks, as the mission team found new ways to use its instruments and engineering systems that their designers had not foreseen. These include using the radar instrument to plumb the depths of Titan’s seas; tasting the plume of Enceladus with instruments meant to sample Titan’s atmosphere; scanning the rings with a radar originally designed to bounce signals off of Titan’s surface; and having the Deep Space Network’s highly accurate frequency reference fill in for the radio science instrument’s lost ultra-stable onboard frequency reference. In a unique collaboration, the attitude control and navigation teams joined with the instrument teams to develop a consolidated model of Titan’s atmosphere. Cassini will finish its mission repurposing the instruments that sniffed Titan’s atmosphere and Enceladus’ plume once more, this time to sample the Saturn atmosphere itself.

    The mission has also had some rather surprising earthly benefits. A Cassini resource exchange, created prior to launch to help team members trade and effectively share power, mass, data rates and budget, has become a model for how to manage other types of international collaboration, including carbon trading.

    When Cassini plunges into Saturn’s atmosphere, it will have spent nearly every last drop of fuel it’s carrying, a fitting end to a spacecraft that pushed itself to the limit…and in many ways, beyond.

    Cassini revealed the beauty of Saturn, its rings and moons, inspiring our sense of wonder and enriching our sense of place in the cosmos.

    Earthlings have cast their gaze upward at Saturn since ancient times, but it was Cassini’s decade-plus odyssey in orbit there that revealed the true splendor of what is arguably the most photogenic planet in our solar system.

    The mission returned stunning views of complex, swirling features in Saturn’s atmosphere, draped by the graceful ring shadows that slowly shift with the seasons.

    The spacecraft also revealed the bewildering variety of Saturn’s moons and helped us see each one as a unique world in its own right. One has a noticeable ridge around its equator and a two-toned color pattern (Iapetus); one looks like the “Death Star” from Star Wars (Mimas); one looks like a sponge (Hyperion); another looks like a flying saucer (Atlas); another looks like a potato (Prometheus); another looks like a ravioli (Pan).

    Cassini has shown us icy ringscapes that are at once magnificent in their sheer physical extent and exquisitely delicate in their expression of the subtle harmonies of gravity. These ringscapes mesmerize with the myriad designs embossed in them — the changing pattern of thick and thin, ruffles that stand as high as the Rocky Mountains, icy waves generated by small moons interacting with the rings, and “streamers” and “mini-jets” created in the ribbon-thin F ring by interactions with Prometheus.

    The views that have been perhaps the most awe-inspiring are panoramic scenes that encompass the entire Saturn system, including those with the planet and rings backlit, and the tiny glow of our far-off, blue home planet visible far across the gulf of outer space.

    2
    Cassini carries 12 science instruments to collect a wide range of information about the Saturnian environment. These sophisticated devices take images across the infrared, visible and ultraviolet light spectra, detect dust particles, and characterize Saturn’s plasma environment and magnetosphere.

    3
    The Cassini-Huygens spacecraft during vibration and thermal testing in 1996.

    Cassini-Huygens is one of the most ambitious missions ever launched into space. Loaded with an array of powerful instruments and cameras, the spacecraft is capable of taking accurate measurements and detailed images in a variety of atmospheric conditions and light spectra.

    The spacecraft was launched with two elements: the Cassini orbiter and the Huygens probe. Cassini-Huygens reached Saturn and its moons in July 2004, beaming home valuable data that has transformed our understand of the Saturnian system. Huygens entered the murky atmosphere of Titan, Saturn’s biggest moon, and descended via parachute onto its surface – the most distant spacecraft landing to date.

    Cassini-Huygens is a three-axis stabilized spacecraft equipped for 27 diverse science investigations. The Cassini orbiter has 12 instruments and the Huygens probe had six. Equipped to thoroughly investigate all the important elements that the Saturn system may uncover, many of the instruments have multiple functions. The spacecraft communicates through one high-gain and two-low gain antennas. It is only in the event of a power failure or other such emergency situation, however, that the spacecraft communicates through one of its low-gain antennas.

    Three Radioisotope Thermoelectric Generators – commonly referred to as RTGs – provide power for the spacecraft, including the instruments, computers, and radio transmitters on board, attitude thrusters, and reaction wheels.

    In some ways, the Cassini spacecraft has senses better than our own. For example, Cassini can “see” in wavelengths of light and energy that the human eye cannot. The instruments on the spacecraft can “feel” things about magnetic fields and tiny dust particles that no human hand could detect.

    The science instruments can be classified in a way that can be compared to the way human senses operate. Your eyes and ears are “remote sensing” devices because you can receive information from remote objects without being in direct contact with them. Your senses of touch and taste are “direct sensing” devices. Your nose can be construed as either a remote or direct sensing device. You can certainly smell the apple pie across the room without having your nose in direct contact with it, but the molecules carrying the scent do have to make direct contact with your sinuses. Cassini’s instruments can be classified as remote and microwave remote sensing instruments, and fields and particles instruments – these are all designed to record significant data and take a variety of close-up measurements.

    The remote sensing instruments on the Cassini Spacecraft can calculate measurements from a great distance. This set includes both optical and microwave sensing instruments including cameras, spectrometers, radar and radio.

    The fields and particles instruments take “in situ” (on site) direct sensing measurements of the environment around the spacecraft. These instruments measure magnetic fields, mass, electrical charges and densities of atomic particles. They also measure the quantity and composition of dust particles, the strengths of plasma (electrically charged gas), and radio waves.

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 2:46 pm on April 19, 2017 Permalink | Reply
    Tags: Cassini - End of Life, NASA JPL - Caltech, The Grand Finale Toolkit   

    From JPL- Caltech: “The Grand Finale Toolkit” Cassini’s End of Life 

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    JPL-Caltech

    NASA/ESA/ASI Cassini Spacecraft

    1
    Artist’s concept of Cassini diving between Saturn and its innermost ring.

    After almost 20 years in space, NASA’s Cassini spacecraft begins the final chapter of its remarkable story of exploration: its Grand Finale.

    Between April and September 2017, Cassini will undertake a daring set of orbits that is, in many ways, like a whole new mission. Following a final close flyby of Saturn’s moon Titan, Cassini will leap over the planet’s icy rings and begin a series of 22 weekly dives between the planet and the rings.

    No other mission has ever explored this unique region. What we learn from these final orbits will help to improve our understanding of how giant planets – and planetary systems everywhere – form and evolve.

    On the final orbit, Cassini will plunge into Saturn’s atmosphere, sending back new and unique science to the very end. After losing contact with Earth, the spacecraft will burn up like a meteor, becoming part of the planet itself.

    Daring exploration

    Cassini’s Grand Finale is about so much more than the spacecraft’s final dive into Saturn. That dramatic event is the capstone of six months of daring exploration and scientific discovery. (And those six months are the thrilling final chapter in a historic 20-year journey.)

    At times, the spacecraft will skirt the very inner edge of the rings; at other times, it will skim the outer edges of the atmosphere. While the mission team is confident the risks are well understood, there could still be surprises. It’s the kind of bold adventure that could only be undertaken at the end of the mission.

    Unique science

    As Cassini plunges past Saturn, the spacecraft will collect some incredibly rich and valuable information that was too risky to obtain earlier in the mission:

    The spacecraft will make detailed maps of Saturn’s gravity and magnetic fields, revealing how the planet is arranged internally, and possibly helping to solve the irksome mystery of just how fast Saturn is rotating.
    The final dives will vastly improve our knowledge of how much material is in the rings, bringing us closer to understanding their origins.
    Cassini’s particle detectors will sample icy ring particles being funneled into the atmosphere by Saturn’s magnetic field.
    Its cameras will take amazing, ultra-close images of Saturn’s rings and clouds.

    Discoveries to the end

    Cassini’s final images will have been sent to Earth several hours before its final plunge, but even as the spacecraft makes its fateful dive into the planet’s atmosphere, it will be sending home new data in real time. Key measurements will come from its mass spectrometer, which will sample Saturn’s atmosphere, telling us about its composition until contact is lost.

    While it’s always sad when a mission comes to an end, Cassini’s finale plunge is a truly spectacular end for one of the most scientifically rich voyages yet undertaken in our solar system. From its launch in 1997 to the unique Grand Finale science of 2017, the Cassini-Huygens mission has racked up a remarkable list of achievements.

    Why End the Mission?

    By 2017, Cassini will have spent 13 years in orbit around Saturn, following a seven-year journey from Earth. The spacecraft is running low on the rocket fuel used for adjusting its course. If left unchecked, this situation would eventually prevent mission operators from controlling the course of the spacecraft.

    Two moons of Saturn, Enceladus and Titan, have captured news headlines over the past decade as Cassini data revealed their potential to contain habitable – or at least “prebiotic” – environments.

    In order to avoid the unlikely possibility of Cassini someday colliding with one of these moons, NASA has chosen to safely dispose of the spacecraft in the atmosphere of Saturn. This will ensure that Cassini cannot contaminate any future studies of habitability and potential life on those moons.

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 2:23 pm on April 19, 2017 Permalink | Reply
    Tags: NASA JPL - Caltech, NASA/ESA/ASI Cassini Spacecraft, ,   

    From JPL-Caltech: “Cassini Heads Toward Final Close Encounter with Titan” 

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    JPL-Caltech

    April 19, 2017
    Preston Dyches
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-394-7013
    preston.dyches@jpl.nasa.gov

    1
    Cassini will make its final close flyby of Saturn’s moon Titan on April 21 (PDT), using its radar to reveal the moon’s surface lakes and seas one last time. Credit: NASA/JPL-Caltech

    NASA’s Cassini spacecraft will make its final close flyby of Saturn’s haze-enshrouded moon Titan this weekend. The flyby marks the mission’s final opportunity for up-close observations of the lakes and seas of liquid hydrocarbons that spread across the moon’s northern polar region, and the last chance to use its powerful radar to pierce the haze and make detailed images of the surface.

    Closest approach to Titan is planned for 11:08 p.m. PDT on April 21 (2:08 a.m. EDT April 22). During the encounter, Cassini will pass as close as 608 miles (979 kilometers) above Titan’s surface at a speed of about 13,000 mph (21,000 kph).

    The flyby is also the gateway to Cassini’s Grand Finale — a final set of 22 orbits that pass between the planet and its rings, ending with a plunge into Saturn on Sept. 15 that will end the mission. During the close pass on April 21, Titan’s gravity will bend Cassini’s orbit around Saturn, shrinking it slightly, so that instead of passing just outside the rings, the spacecraft will begin its finale dives which pass just inside the rings.

    The flyby is Cassini’s 127th targeted encounter with Titan. A targeted flyby is one for which the spacecraft uses its rocket engine or thrusters to accurately aim toward the encounter.

    Cassini’s radar instrument will look for changes in Titan’s methane lakes and seas, and attempt for the first (and last) time to study the depth and composition of Titan’s smaller lakes. The radar instrument will also search a final time for Titan’s “magic island,” a mysterious feature in one of the moon’s seas that changed in appearance over the course of several flybys. Scientists hope to gain additional insights to help them determine whether the feature is waves, bubbles, floating debris, or something else entirely.

    More information about Cassini’s final Titan flyby is available at:

    https://go.nasa.gov/2nFHaTo

    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.

    More information about Cassini:

    http://www.nasa.gov/cassini

    http://saturn.jpl.nasa.gov

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 9:41 am on April 19, 2017 Permalink | Reply
    Tags: 'Space Fabric' Links Fashion and Engineering, 4-D printing, Additive manufacturing, , NASA JPL - Caltech   

    From JPL-Caltech: “‘Space Fabric’ Links Fashion and Engineering” 

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    JPL-Caltech

    April 18, 2017
    Written by Elizabeth Landau

    Andrew Good
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-393-2433
    andrew.c.good@jpl.nasa.gov

    1
    This metallic “space fabric” was created using 3-D printed techniques that add different functionality to each side of the material.
    Credits: NASA/JPL-Caltech

    Raul Polit-Casillas grew up around fabrics. His mother is a fashion designer in Spain, and, at a young age, he was intrigued by how materials are used for design.

    Now, as a systems engineer at NASA’s Jet Propulsion Laboratory in Pasadena, California, he is still very much in the world of textiles. He and his colleagues are designing advanced woven metal fabrics for use in space.

    These fabrics could potentially be useful for large antennas and other deployable devices, because the material is foldable and its shape can change quickly. The fabrics could also eventually be used to shield a spacecraft from meteorites, for astronaut spacesuits, or for capturing objects on the surface of another planet. One potential use might be for an icy moon like Jupiter’s Europa, where these fabrics could insulate the spacecraft. At the same time, this flexible material could fold over uneven terrain, creating “feet” that won’t melt the ice under them.

    The prototypes that Polit-Casillas and colleagues have created look like chain mail, with small silver squares strung together. But these fabrics were not sewn by hand; instead, they were “printed,” created in one piece with advanced technologies.

    A technique called additive manufacturing, otherwise known as 3-D printing on an industrial scale, is necessary to make such fabrics. Unlike traditional manufacturing techniques, in which parts are welded together, additive manufacturing deposits material in layers to build up the desired object. This reduces the cost and increases the ability to create unique materials.

    “We call it ‘4-D printing’ because we can print both the geometry and the function of these materials,” said Polit-Casillas. “If 20th Century manufacturing was driven by mass production, then this is the mass production of functions.”

    Fabricating spacecraft designs can be complex and costly, said Andrew Shapiro-Scharlotta of JPL, whose office funds research for early-stage technologies like the space fabric. He said that adding multiple functions to a material at different stages of development could make the whole process cheaper. It could also open the door to new designs.

    “We are just scratching the surface of what’s possible,” Shapiro-Scharlotta said. “The use of organic and non-linear shapes at no additional costs to fabrication will lead to more efficient mechanical designs.”

    The space fabrics have four essential functions: reflectivity, passive heat management, foldability and tensile strength. One side of the fabric reflects light, while the other absorbs it, acting as a means of thermal control. It can fold in many different ways and adapt to shapes while still being able to sustain the force of pulling on it.

    The JPL team not only wants to try out these fabrics in space someday, they want to be able to manufacture them in space, too.

    Separate from his space fabric research, Polit-Casillas co-founded JPL’s Atelier, a workshop that does rapid prototyping of advanced concepts and systems. They use additive manufacturing to mix metals and polymers, creating composites with a range of functionality.

    In the distant future, Polit-Casillas said, astronauts might be able to print materials as they’re needed — and even recycle old materials, breaking them down and reusing them. Conservation is critical when you’re trapped in space with just the resources you take with you.

    But it would also be critical to think about new forms. Print a single plate of aluminum, and it has limited functionality. Print the same plate using a heat-radiating design, and suddenly it’s more useful. Spacecraft housing could have different functionality on its outsides and insides, becoming more than just structural.

    “I can program new functions into the material I’m printing,” Polit-Casillas said. “That also reduces the amount of time spent on integration and testing. You can print, test and destroy material as many times as you want.”

    This kind of design-based thinking could revolutionize the way spacecraft are engineered. Instead of having to assemble something with dozens of parts, all of which create potential points of failure, the spacecraft of the future could be created “whole cloth” — and with added function, as well.

    See the full article here .

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    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 8:17 am on April 8, 2017 Permalink | Reply
    Tags: , , , , Ceres' Temporary Atmosphere Linked to Solar Activity, , NASA JPL - Caltech   

    From JPL-Caltech: “Ceres’ Temporary Atmosphere Linked to Solar Activity” 

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    JPL-Caltech

    April 6, 2017
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, CA
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    NASA’s Dawn spacecraft determined the hydrogen content of the upper yard, or meter, of Ceres’ surface. Blue indicates where hydrogen content is higher, near the poles, while red indicates lower content at lower latitudes. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

    NASA Dawn Spacescraft

    Scientists have long thought that Ceres may have a very weak, transient atmosphere, but mysteries lingered about its origin and why it’s not always present. Now, researchers suggest that this temporary atmosphere appears to be related to the behavior of the sun, rather than Ceres’ proximity to the sun. The study was conducted by scientists from NASA’s Dawn mission and others who previously identified water vapor at Ceres using other observatories.

    “We think the occurrence of Ceres’ transient atmosphere is the product of solar activity,” said Michaela Villarreal, lead author of the new study in the Astrophysical Journal Letters and researcher at the University of California, Los Angeles.

    Ceres is the largest object in the asteroid belt that lies between Mars and Jupiter. When energetic particles from the sun hit exposed ice and ice near the surface of the dwarf planet, it transfers energy to the water molecules as they collide. This frees the water molecules from the ground, allowing them to escape and create a tenuous atmosphere that may last for a week or so.

    “Our results also have implications for other airless, water-rich bodies of the solar system, including the polar regions of the moon and some asteroids,” said Chris Russell, principal investigator of the Dawn mission, also at UCLA. “Atmospheric releases might be expected from their surfaces, too, when solar activity erupts.”

    Before Dawn arrived in orbit at Ceres in 2015, evidence for an atmosphere had been detected by some observatories at certain times, but not others, suggesting that it is a transient phenomenon. In 1991, the International Ultraviolet Explorer satellite detected hydroxyl emission from Ceres, but not in 1990. Then, in 2007, the European Southern Observatory’s Very Large Telescope searched for a hydroxide emission, but came up empty.

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    The European Space Agency’s Herschel Space Observatory detected water in the possible weak atmosphere, or “exosphere,” of Ceres on three occasions, but did not on a fourth attempt.

    ESA/Herschel spacecraft

    As Dawn began its thorough study of Ceres in March 2015, scientists found ample evidence for water in the form of ice. The spacecraft’s gamma ray and neutron detector (GRaND) has found that the uppermost surface is rich in hydrogen, which is consistent with broad expanses of water ice. This ice is nearer to the surface at higher latitudes, where temperatures are lower, a 2016 study published in the journal Science found. Ice has been detected directly at the small bright crater called Oxo and in at least one of the craters that are persistently in shadow in the northern hemisphere. Other research has suggested that persistently shadowed craters are likely to harbor ice. Additionally, the shapes of craters and other features are consistent with significant water-ice content in the crust.

    Because of this evidence for abundant ice, many scientists think that Ceres’ exosphere is created in a process similar to what occurs on comets, even though they are much smaller. In that model, the closer Ceres gets to the sun, the more water vapor is released because of ice sublimating near or at the surface.

    But the new study suggests comet-like behavior may not explain the mix of detections and non-detections of a weak atmosphere.

    “Sublimation probably is present, but we don’t think it’s significant enough to produce the amount of exosphere that we’re seeing,” Villarreal said.

    Villarreal and colleagues showed that past detections of the transient atmosphere coincided with higher concentrations of energetic protons from the sun. Non-detections coincided with lower concentrations of these particles. What’s more, the best detections of Ceres’ atmosphere did not occur at its closest approach to the sun. This suggests that solar activity, rather than Ceres’ proximity to the sun, is a more important factor in generating an exosphere.

    The research began with a 2016 Science study led by Chris Russell. The study, using GRaND data, suggested that, during a six-day period in 2015, Ceres had accelerated electrons from the solar wind to very high energies.

    In its orbital path, Ceres is currently getting closer to the sun. But the sun is now in a particularly quiet period, expected to last for several more years. Since their results indicate Ceres’ exosphere is related to solar activity, study authors are predicting that the dwarf planet will have little to no atmosphere for some time. However, they recommend that other observatories monitor Ceres for future emissions.

    Dawn is now in its extended mission and studying Ceres in a highly elliptical orbit. Engineers are maneuvering the spacecraft to a different orbital plane so that Ceres can be viewed in a new geometry. The primary science objective is to measure cosmic rays to help determine which chemical elements lie near the surface of Ceres. As a bonus, in late April, the sun will be directly behind Dawn, when the spacecraft is at an altitude of about 12,300 miles (20,000 kilometers). Ceres will appear brighter than before in that configuration, and perhaps reveal more secrets about its composition and history.

    The Dawn mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit:

    http://dawn.jpl.nasa.gov/mission

    More information about Dawn is available at the following sites:

    http://www.nasa.gov/dawn

    http://dawn.jpl.nasa.gov

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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