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  • richardmitnick 3:07 pm on August 17, 2017 Permalink | Reply
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    From JPL: “Scientists Improve Brown Dwarf Weather Forecasts” 

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    JPL-Caltech

    August 17, 2017
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    This artist’s concept shows a brown dwarf with bands of clouds, thought to resemble those seen at Neptune and the other outer planets. Credit: NASA/JPL-Caltech

    Dim objects called brown dwarfs, less massive than the Sun but more massive than Jupiter, have powerful winds and clouds — specifically, hot patchy clouds made of iron droplets and silicate dust. Scientists recently realized these giant clouds can move and thicken or thin surprisingly rapidly, in less than an Earth day, but did not understand why.

    Now, researchers have a new model for explaining how clouds move and change shape in brown dwarfs, using insights from NASA’s Spitzer Space Telescope. Giant waves cause large-scale movement of particles in brown dwarfs’ atmospheres, changing the thickness of the silicate clouds, researchers report in the journal Science. The study also suggests these clouds are organized in bands confined to different latitudes, traveling with different speeds in different bands.

    “This is the first time we have seen atmospheric bands and waves in brown dwarfs,” said lead author Daniel Apai, associate professor of astronomy and planetary sciences at the University of Arizona in Tucson.

    Just as in Earth’s ocean, different types of waves can form in planetary atmospheres. For example, in Earth’s atmosphere, very long waves mix cold air from the polar regions to mid-latitudes, which often lead clouds to form or dissipate.

    The distribution and motions of the clouds on brown dwarfs in this study are more similar to those seen on Jupiter, Saturn, Uranus and Neptune. Neptune has cloud structures that follow banded paths too, but its clouds are made of ice. Observations of Neptune from NASA’s Kepler spacecraft, operating in its K2 mission, were important in this comparison between the planet and brown dwarfs.

    “The atmospheric winds of brown dwarfs seem to be more like Jupiter’s familiar regular pattern of belts and zones than the chaotic atmospheric boiling seen on the Sun and many other stars,” said study co-author Mark Marley at NASA’s Ames Research Center in California’s Silicon Valley.

    Brown dwarfs can be thought of as failed stars because they are too small to fuse chemical elements in their cores. They can also be thought of as “super planets” because they are more massive than Jupiter, yet have roughly the same diameter. Like gas giant planets, brown dwarfs are mostly made of hydrogen and helium, but they are often found apart from any planetary systems. In a 2014 study using Spitzer, scientists found that brown dwarfs commonly have atmospheric storms.

    Due to their similarity to giant exoplanets, brown dwarfs are windows into planetary systems beyond our own. It is easier to study brown dwarfs than planets because they often do not have a bright host star that obscures them.

    “It is likely the banded structure and large atmospheric waves we found in brown dwarfs will also be common in giant exoplanets,” Apai said.

    Using Spitzer, scientists monitored brightness changes in six brown dwarfs over more than a year, observing each of them rotate 32 times. As a brown dwarf rotates, its clouds move in and out of the hemisphere seen by the telescope, causing changes in the brightness of the brown dwarf. Scientists then analyzed these brightness variations to explore how silicate clouds are distributed in the brown dwarfs.

    Researchers had been expecting these brown dwarfs to have elliptical storms resembling Jupiter’s Great Red Spot, caused by high-pressure zones. The Great Red Spot has been present in Jupiter for hundreds of years and changes very slowly: Such “spots” could not explain the rapid changes in brightness that scientists saw while observing these brown dwarfs. The brightness levels of the brown dwarfs varied markedly just over the course of an Earth day.

    To make sense of the ups and downs of brightness, scientists had to rethink their assumptions about what was going on in the brown dwarf atmospheres. The best model to explain the variations involves large waves, propagating through the atmosphere with different periods. These waves would make the cloud structures rotate with different speeds in different bands.

    University of Arizona researcher Theodora Karalidi used a supercomputer and a new computer algorithm to create maps of how clouds travel on these brown dwarfs.

    “When the peaks of the two waves are offset, over the course of the day there are two points of maximum brightness,” Karalidi said. “When the waves are in sync, you get one large peak, making the brown dwarf twice as bright as with a single wave.”

    The results explain the puzzling behavior and brightness changes that researchers previously saw. The next step is to try to better understand what causes the waves that drive cloud behavior.

    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 5:20 am on August 17, 2017 Permalink | Reply
    Tags: , , NASA JPL - Caltech, NASA's Global Hawk autonomous aircraft, NASA-led Mission Studies Storm Intensification,   

    From JPL: “NASA-led Mission Studies Storm Intensification” 

    NASA JPL Banner

    JPL-Caltech

    August 16, 2017
    Alan Buis
    Jet Propulsion Laboratory, Pasadena, California
    818-354-0474
    alan.buis@jpl.nasa.gov

    Kate Squires
    NASA Armstrong Flight Research Center
    661-276-2020
    Kate.k.squires@nasa.gov

    Written by Kate Squires
    NASA Armstrong Flight Research Center

    1
    NASA’s Global Hawk being prepared at Armstrong to monitor and take scientific measurements of Hurricane Matthew in 2016. Credits: NASA Photo/Lauren Hughes.

    A group of NASA and National Oceanic and Atmospheric Administration (NOAA) scientists, including scientists from NASA’s Jet Propulsion Laboratory, Pasadena, California, are teaming up this month for an airborne mission focused on studying severe storm processes and intensification. The Hands-On Project Experience (HOPE) Eastern Pacific Origins and Characteristics of Hurricanes (EPOCH) field campaign will use NASA’s Global Hawk autonomous aircraft to study storms in the Northern Hemisphere to learn more about how storms intensify as they brew out over the ocean.

    The scope of the mission initially focused only on the East Pacific region, but was expanded to both the Gulf and Atlantic regions to give the science team broader opportunities for data collection.

    “Our key point of interest is still the Eastern Pacific, but if the team saw something developing off the East Coast that may have high impact to coastal communities, we would definitely recalibrate to send the aircraft to that area,” said Amber Emory, NASA’s principal investigator.

    Having a better understanding of storm intensification is an important goal of HOPE EPOCH. The data will help improve models that predict storm impact to coastal regions, where property damage and threat to human life can be high.

    NASA has led the campaign through integration of the HOPE EPOCH science payload onto the Global Hawk platform and maintained operational oversight for the six planned mission flights. NOAA’s role will be to incorporate data from dropsondes — devices dropped from aircraft to measure storm conditions — into NOAA National Weather Service operational models to improve storm track and intensity forecasts that will be provided to the public. NOAA first used the Global Hawk to study Hurricane Gaston in 2016.

    With the Global Hawk flying at altitudes of 60,000 feet (18,300 meters), the team will conduct six 24-hour-long flights, three of which are being supported and funded through a partnership with NOAA’s Unmanned Aircraft Systems program.

    NASA’s autonomous Global Hawk is operated from NASA’s Armstrong Flight Research Center at Edwards Air Force Base in California and was developed for the U.S. Air Force by Northrop Grumman. It is ideally suited for high-altitude, long-duration Earth science flights.

    The ability of the Global Hawk to autonomously fly long distances, remain aloft for extended periods of time and carry large payloads brings a new capability to the science community for measuring, monitoring and observing remote locations of Earth not feasible or practical with piloted aircraft or space satellites.

    The science payload consists of a variety of instruments that will measure different aspects of storm systems, including wind velocity, pressure, temperature, humidity, cloud moisture content and the overall structure of the storm system.

    Many of the science instruments have flown previously on the Global Hawk, including the High-Altitude MMIC Sounding Radiometer (HAMSR), a microwave sounder instrument that takes vertical profiles of temperature and humidity; and the Airborne Vertical Atmospheric Profiling System (AVAPS) dropsondes, which are released from the aircraft to profile temperature, humidity, pressure, wind speed and direction.

    New to the science payload is the ER-2 X-band Doppler Radar (EXRAD) instrument that observes vertical velocity of a storm system. EXRAD has one conically scanning beam as well as one nadir beam, which looks down directly underneath the aircraft. EXRAD now allows researchers to get direct retrievals of vertical velocities directly underneath the plane.

    The EXRAD instrument is managed and operated by NASA’s Goddard Space Flight Center in Greenbelt, Maryland; and the HAMSR instrument is managed by JPL. The National Center for Atmospheric Research developed the AVAPS dropsonde system, and the NOAA team will manage and operate the system for the HOPE EPOCH mission.

    Besides the scientific value that the HOPE EPOCH mission brings, the campaign also provides a unique opportunity for early-career scientists and project managers to gain professional development.

    HOPE is a cooperative workforce development program sponsored by the Academy of Program/Project & Engineering Leadership (APPEL) program and NASA’s Science Mission Directorate. The HOPE Training Program provides an opportunity for a team of early-entry NASA employees to propose, design, develop, build and launch a suborbital flight project over the course of 18 months. This opportunity enables participants to gain the knowledge and skills necessary to manage NASA’s future flight projects.

    Emory started as a NASA Pathways Intern in 2009. The HOPE EPOCH mission is particularly exciting for her, as some of her first science projects at NASA began with the Global Hawk program.

    The NASA Global Hawk had its first flights during the 2010 Genesis and Rapid Intensification Processes (GRIP) campaign. Incidentally, the first EPOCH science flight targeted Tropical Storm Franklin as it emerged from the Yucatan peninsula into the Gulf of Campeche along a track almost identical to that of Hurricane Karl in 2010, which was targeted during GRIP and where Emory played an important role.

    “It’s exciting to work with people who are so committed to making the mission successful,” Emory said. “Every mission has its own set of challenges, but when people come to the table with new ideas on how to solve those challenges, it makes for a very rewarding experience and we end up learning a lot from one another.”

    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 12:31 pm on August 11, 2017 Permalink | Reply
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    From JPL: “TRAPPIST-1 is Older Than Our Solar System” 

    NASA JPL Banner

    JPL-Caltech

    August 11, 2017
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    This illustration shows what the TRAPPIST-1 system might look like from a vantage point near planet TRAPPIST-1f (at right).

    The system has been revealed through observations from NASA’s Spitzer Space Telescope and the ground-based TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) telescope, as well as other ground-based observatories. The system was named for the TRAPPIST telescope.

    NASA/Spitzer Infrared Telescope

    ESO Belgian robotic Trappist-South National Telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    2
    This artist’s concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets’ diameters, masses and distances from the host star.

    If we want to know more about whether life could survive on a planet outside our solar system, it’s important to know the age of its star. Young stars have frequent releases of high-energy radiation called flares that can zap their planets’ surfaces. If the planets are newly formed, their orbits may also be unstable. On the other hand, planets orbiting older stars have survived the spate of youthful flares, but have also been exposed to the ravages of stellar radiation for a longer period of time.

    Scientists now have a good estimate for the age of one of the most intriguing planetary systems discovered to date — TRAPPIST-1, a system of seven Earth-size worlds orbiting an ultra-cool dwarf star about 40 light-years away. Researchers say in a new study that the TRAPPIST-1 star is quite old: between 5.4 and 9.8 billion years. This is up to twice as old as our own solar system, which formed some 4.5 billion years ago.

    The seven wonders of TRAPPIST-1 were revealed earlier this year in a NASA news conference, using a combination of results from the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile, NASA’s Spitzer Space Telescope, and other ground-based telescopes. Three of the TRAPPIST-1 planets reside in the star’s “habitable zone,” the orbital distance where a rocky planet with an atmosphere could have liquid water on its surface. All seven planets are likely tidally locked to their star, each with a perpetual dayside and nightside.

    At the time of its discovery, scientists believed the TRAPPIST-1 system had to be at least 500 million years old, since it takes stars of TRAPPIST-1’s low mass (roughly 8 percent that of the Sun) roughly that long to contract to its minimum size, just a bit larger than the planet Jupiter. However, even this lower age limit was uncertain; in theory, the star could be almost as old as the universe itself. Are the orbits of this compact system of planets stable? Might life have enough time to evolve on any of these worlds?

    “Our results really help constrain the evolution of the TRAPPIST-1 system, because the system has to have persisted for billions of years. This means the planets had to evolve together, otherwise the system would have fallen apart long ago,” said Adam Burgasser, an astronomer at the University of California, San Diego, and the paper’s first author. Burgasser teamed up with Eric Mamajek, deputy program scientist for NASA’s Exoplanet Exploration Program based at NASA’s Jet Propulsion Laboratory, Pasadena, California, to calculate TRAPPIST-1’s age. Their results will be published in The Astrophysical Journal.

    It is unclear what this older age means for the planets’ habitability. On the one hand, older stars flare less than younger stars, and Burgasser and Mamajek confirmed that TRAPPIST-1 is relatively quiet compared to other ultra-cool dwarf stars. On the other hand, since the planets are so close to the star, they have soaked up billions of years of high-energy radiation, which could have boiled off atmospheres and large amounts of water. In fact, the equivalent of an Earth ocean may have evaporated from each TRAPPIST-1 planet except for the two most distant from the host star: planets g and h. In our own solar system, Mars is an example of a planet that likely had liquid water on its surface in the past, but lost most of its water and atmosphere to the Sun’s high-energy radiation over billions of years.

    If we want to know more about whether life could survive on a planet outside our solar system, it’s important to know the age of its star. Young stars have frequent releases of high-energy radiation called flares that can zap their planets’ surfaces. If the planets are newly formed, their orbits may also be unstable. On the other hand, planets orbiting older stars have survived the spate of youthful flares, but have also been exposed to the ravages of stellar radiation for a longer period of time.

    Scientists now have a good estimate for the age of one of the most intriguing planetary systems discovered to date — TRAPPIST-1, a system of seven Earth-size worlds orbiting an ultra-cool dwarf star about 40 light-years away. Researchers say in a new study that the TRAPPIST-1 star is quite old: between 5.4 and 9.8 billion years. This is up to twice as old as our own solar system, which formed some 4.5 billion years ago.

    The seven wonders of TRAPPIST-1 were revealed earlier this year in a NASA news conference, using a combination of results from the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile, NASA’s Spitzer Space Telescope, and other ground-based telescopes. Three of the TRAPPIST-1 planets reside in the star’s “habitable zone,” the orbital distance where a rocky planet with an atmosphere could have liquid water on its surface. All seven planets are likely tidally locked to their star, each with a perpetual dayside and nightside.

    At the time of its discovery, scientists believed the TRAPPIST-1 system had to be at least 500 million years old, since it takes stars of TRAPPIST-1’s low mass (roughly 8 percent that of the Sun) roughly that long to contract to its minimum size, just a bit larger than the planet Jupiter. However, even this lower age limit was uncertain; in theory, the star could be almost as old as the universe itself. Are the orbits of this compact system of planets stable? Might life have enough time to evolve on any of these worlds?

    “Our results really help constrain the evolution of the TRAPPIST-1 system, because the system has to have persisted for billions of years. This means the planets had to evolve together, otherwise the system would have fallen apart long ago,” said Adam Burgasser, an astronomer at the University of California, San Diego, and the paper’s first author. Burgasser teamed up with Eric Mamajek, deputy program scientist for NASA’s Exoplanet Exploration Program based at NASA’s Jet Propulsion Laboratory, Pasadena, California, to calculate TRAPPIST-1’s age. Their results will be published in The Astrophysical Journal.

    It is unclear what this older age means for the planets’ habitability. On the one hand, older stars flare less than younger stars, and Burgasser and Mamajek confirmed that TRAPPIST-1 is relatively quiet compared to other ultra-cool dwarf stars. On the other hand, since the planets are so close to the star, they have soaked up billions of years of high-energy radiation, which could have boiled off atmospheres and large amounts of water. In fact, the equivalent of an Earth ocean may have evaporated from each TRAPPIST-1 planet except for the two most distant from the host star: planets g and h. In our own solar system, Mars is an example of a planet that likely had liquid water on its surface in the past, but lost most of its water and atmosphere to the Sun’s high-energy radiation over billions of years.

    However, old age does not necessarily mean that a planet’s atmosphere has been eroded. Given that the TRAPPIST-1 planets have lower densities than Earth, it is possible that large reservoirs of volatile molecules such as water could produce thick atmospheres that would shield the planetary surfaces from harmful radiation. A thick atmosphere could also help redistribute heat to the dark sides of these tidally locked planets, increasing habitable real estate. But this could also backfire in a “runaway greenhouse” process, in which the atmosphere becomes so thick the planet surface overheats – as on Venus.

    “If there is life on these planets, I would speculate that it has to be hardy life, because it has to be able to survive some potentially dire scenarios for billions of years,” Burgasser said.

    Fortunately, low-mass stars like TRAPPIST-1 have temperatures and brightnesses that remain relatively constant over trillions of years, punctuated by occasional magnetic flaring events. The lifetimes of tiny stars like TRAPPIST-1 are predicted to be much, much longer than the 13.7 billion-year age of the universe (the Sun, by comparison, has an expected lifetime of about 10 billion years).

    “Stars much more massive than the Sun consume their fuel quickly, brightening over millions of years and exploding as supernovae,” Mamajek said. “But TRAPPIST-1 is like a slow-burning candle that will shine for about 900 times longer than the current age of the universe.”

    Some of the clues Burgasser and Mamajek used to measure the age of TRAPPIST-1 included how fast the star is moving in its orbit around the Milky Way (speedier stars tend to be older), its atmosphere’s chemical composition, and how many flares TRAPPIST-1 had during observational periods. These variables all pointed to a star that is substantially older than our Sun.

    Future observations with NASA’s Hubble Space Telescope and upcoming James Webb Space Telescope may reveal whether these planets have atmospheres, and whether such atmospheres are like Earth’s.

    The seven planets of TRAPPIST-1 are all Earth-sized and terrestrial, according to research published in 2017 in the journal Nature. TRAPPIST-1 is an ultra-cool dwarf star in the constellation Aquarius, and its planets orbit very close to it.

    They are likely all tidally locked, meaning the same face of the planet is always pointed at the star, as the same side of our moon is always pointed at Earth. This creates a perpetual night side and perpetual day side on each planet.

    TRAPPIST-1b and c receive the most light from the star and would be the warmest. TRAPPIST-1e, f and g all orbit in the habitable zone, the area where liquid water is most likely to be detected. But any of the planets could potentially harbor liquid water, depending on their compositions.

    See the full article here .

    Please help promote STEM in your local schools.

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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 5:43 pm on July 31, 2017 Permalink | Reply
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    From JPL: “NASA’s Voyager Spacecraft Still Reaching for the Stars After 40 Years” 

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    JPL-Caltech

    July 31, 2017

    Dwayne Brown /
    Headquarters, Washington
    202-358-1726 /
    dwayne.c.brown@nasa.gov

    Laurie Cantillo
    Headquarters, Washington
    202-358-1077
    laura.l.cantillo@nasa.gov

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

    Jia-Rui Cook
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-0724
    jia-rui.c.cook@jpl.nasa.gov

    1
    An artist concept depicting one of the twin Voyager spacecraft. Humanity’s farthest and longest-lived spacecraft are celebrating 40 years in August and September 2017. Credits: NASA.

    Humanity’s farthest and longest-lived spacecraft, Voyager 1 and 2, achieve 40 years of operation and exploration this August and September. Despite their vast distance, they continue to communicate with NASA daily, still probing the final frontier.

    Their story has not only impacted generations of current and future scientists and engineers, but also Earth’s culture, including film, art and music. Each spacecraft carries a Golden Record of Earth sounds, pictures and messages.

    Voyager 1- The Interstellar Mission gold plated disc

    Since the spacecraft could last billions of years, these circular time capsules could one day be the only traces of human civilization.

    “I believe that few missions can ever match the achievements of the Voyager spacecraft during their four decades of exploration,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate (SMD) at NASA Headquarters. “They have educated us to the unknown wonders of the universe and truly inspired humanity to continue to explore our solar system and beyond.”

    The Voyagers have set numerous records in their unparalleled journeys. In 2012, Voyager 1, which launched on Sept. 5, 1977, became the only spacecraft to have entered interstellar space. Voyager 2, launched on Aug. 20, 1977, is the only spacecraft to have flown by all four outer planets – Jupiter, Saturn, Uranus and Neptune. Their numerous planetary encounters include discovering the first active volcanoes beyond Earth, on Jupiter’s moon Io; hints of a subsurface ocean on Jupiter’s moon Europa; the most Earth-like atmosphere in the solar system, on Saturn’s moon Titan; the jumbled-up, icy moon Miranda at Uranus; and icy-cold geysers on Neptune’s moon Triton.

    Though the spacecraft have left the planets far behind – and neither will come remotely close to another star for 40,000 years – the two probes still send back observations about conditions where our Sun’s influence diminishes and interstellar space begins.

    Voyager 1, now almost 13 billion miles from Earth, travels through interstellar space northward out of the plane of the planets. The probe has informed researchers that cosmic rays, atomic nuclei accelerated to nearly the speed of light, are as much as four times more abundant in interstellar space than in the vicinity of Earth. This means the heliosphere, the bubble-like volume containing our solar system’s planets and solar wind, effectively acts as a radiation shield for the planets. Voyager 1 also hinted that the magnetic field of the local interstellar medium is wrapped around the heliosphere.

    Voyager 2, now almost 11 billion miles from Earth, travels south and is expected to enter interstellar space in the next few years. The different locations of the two Voyagers allow scientists to compare right now two regions of space where the heliosphere interacts with the surrounding interstellar medium using instruments that measure charged particles, magnetic fields, low-frequency radio waves and solar wind plasma. Once Voyager 2 crosses into the interstellar medium, they will also be able to sample the medium from two different locations simultaneously.

    “None of us knew, when we launched 40 years ago, that anything would still be working, and continuing on this pioneering journey,” said Ed Stone, Voyager project scientist based at Caltech in Pasadena, California. “The most exciting thing they find in the next five years is likely to be something that we didn’t know was out there to be discovered.”

    The twin Voyagers have been cosmic overachievers, thanks to the foresight of mission designers. By preparing for the radiation environment at Jupiter, the harshest of all planets in our solar system, the spacecraft were well equipped for their subsequent journeys. Both Voyagers are equipped with long-lasting power supplies, as well as redundant systems that allow the spacecraft to switch to backup systems autonomously when necessary. Each Voyager carries three radioisotope thermoelectric generators, devices that use the heat energy generated from the decay of plutonium-238 – only half of it will be gone after 88 years.

    Space is almost empty, so the Voyagers are not at a significant level of risk of bombardment by large objects. However, Voyager 1’s interstellar space environment is not a complete void. It’s filled with clouds of dilute material remaining from stars that exploded as supernovae millions of years ago. This material doesn’t pose a danger to the spacecraft, but is a key part of the environment that the Voyager mission is helping scientists study and characterize.

    Because the Voyagers’ power decreases by four watts per year, engineers are learning how to operate the spacecraft under ever-tighter power constraints. And to maximize the Voyagers’ lifespans, they also have to consult documents written decade’s earlier describing commands and software, in addition to the expertise of former Voyager engineers.

    “The technology is many generations old, and it takes someone with 1970s design experience to understand how the spacecraft operate and what updates can be made to permit them to continue operating today and into the future,” said Suzanne Dodd, Voyager project manager based at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.

    Team members estimate they will have to turn off the last science instrument by 2030. However, even after the spacecraft go silent, they’ll continue on their trajectories at their present speed of more than 30,000 mph (48,280 kilometers per hour), completing an orbit within the Milky Way every 225 million years.

    The Voyager spacecraft were built by JPL, which continues to operate both. The Voyager missions are part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of SMD.

    For more information about the Voyager spacecraft, visit:

    https://www.nasa.gov/voyager

    and

    https://voyager.jpl.nasa.gov

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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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 2:06 pm on July 25, 2017 Permalink | Reply
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    From JPL: “Large, Distant Comets More Common Than Previously Thought” 

    NASA JPL Banner

    JPL-Caltech

    July 25, 2017
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    This illustration shows how scientists used data from NASA’s WISE spacecraft to determine the nucleus sizes of comets. They subtracted a model of how dust and gas behave in comets in order to obtain the core size. Credit: NASA/JPL-Caltech.

    2
    An animation of a comet. Credit: NASA/JPL-Caltech.

    Comets that take more than 200 years to make one revolution around the Sun are notoriously difficult to study. Because they spend most of their time far from our area of the solar system, many “long-period comets” will never approach the Sun in a person’s lifetime. In fact, those that travel inward from the Oort Cloud — a group of icy bodies beginning roughly 186 billion miles (300 billion kilometers) away from the Sun — can have periods of thousands or even millions of years.

    Oort Cloud NASA

    NASA’s WISE spacecraft, scanning the entire sky at infrared wavelengths, has delivered new insights about these distant wanderers.

    NASA/WISE Telescope

    Scientists found that there are about seven times more long-period comets measuring at least 0.6 miles (1 kilometer) across than had been predicted previously. They also found that long-period comets are on average up to twice as large as “Jupiter family comets,” whose orbits are shaped by Jupiter’s gravity and have periods of less than 20 years.

    Researchers also observed that in eight months, three to five times as many long-period comets passed by the Sun than had been predicted. The findings are published in The Astronomical Journal.

    “The number of comets speaks to the amount of material left over from the solar system’s formation,” said James Bauer, lead author of the study and now a research professor at the University of Maryland, College Park. “We now know that there are more relatively large chunks of ancient material coming from the Oort Cloud than we thought.”

    The Oort Cloud is too distant to be seen by current telescopes, but is thought to be a spherical distribution of small icy bodies at the outermost edge of the solar system. The density of comets within it is low, so the odds of comets colliding within it are rare. Long-period comets that WISE observed probably got kicked out of the Oort Cloud millions of years ago. The observations were carried out during the spacecraft’s primary mission before it was renamed NEOWISE and reactivated to target near-Earth objects (NEOs).

    “Our study is a rare look at objects perturbed out of the Oort Cloud,” said Amy Mainzer, study co-author based at NASA’s Jet Propulsion Laboratory, Pasadena, California, and principal investigator of the NEOWISE mission. “They are the most pristine examples of what the solar system was like when it formed.”

    Astronomers already had broader estimates of how many long-period and Jupiter family comets are in our solar system, but had no good way of measuring the sizes of long-period comets. That is because a comet has a “coma,” a cloud of gas and dust that appears hazy in images and obscures the cometary nucleus. But by using the WISE data showing the infrared glow of this coma, scientists were able to “subtract” the coma from the overall comet and estimate the nucleus sizes of these comets. The data came from 2010 WISE observations of 95 Jupiter family comets and 56 long-period comets.

    The results reinforce the idea that comets that pass by the Sun more often tend to be smaller than those spending much more time away from the Sun. That is because Jupiter family comets get more heat exposure, which causes volatile substances like water to sublimate and drag away other material from the comet’s surface as well.

    “Our results mean there’s an evolutionary difference between Jupiter family and long-period comets,” Bauer said.

    The existence of so many more long-period comets than predicted suggests that more of them have likely impacted planets, delivering icy materials from the outer reaches of the solar system.

    Researchers also found clustering in the orbits of the long-period comets they studied, suggesting there could have been larger bodies that broke apart to form these groups.

    The results will be important for assessing the likelihood of comets impacting our solar system’s planets, including Earth.

    “Comets travel much faster than asteroids, and some of them are very big,” Mainzer said. “Studies like this will help us define what kind of hazard long-period comets may pose.”

    NASA’s Jet Propulsion Laboratory in Pasadena, California, managed and operated WISE for NASA’s Science Mission Directorate in Washington. The NEOWISE project is funded by the Near Earth Object Observation Program, now part of NASA’s Planetary Defense Coordination Office. The spacecraft was put into hibernation mode in 2011 after twice scanned the entire sky, thereby completing its main objectives. In September 2013, WISE was reactivated, renamed NEOWISE and assigned a new mission to assist NASA’s efforts to identify potentially hazardous near-Earth objects.

    For more information on WISE, visit:

    https://www.nasa.gov/wise

    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 12:57 pm on July 25, 2017 Permalink | Reply
    Tags: , , , , , , NASA JPL - Caltech   

    From JPL: “A Final Farewell to LISA Pathfinder” 

    NASA JPL Banner

    JPL-Caltech

    July 24, 2017
    Andrew Good
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-393-2433
    andrew.c.good@jpl.nasa.gov

    1
    An artist’s concept of the European Space Agency’s LISA Pathfinder spacecraft, designed to pave the way for a mission detecting gravitational waves. NASA/JPL developed a thruster system on board.

    Official ESA/LISA Pathfinder image

    With the push of a button, final commands for the European Space Agency’s LISA Pathfinder mission were beamed to space on July 18, a final goodbye before the spacecraft was powered down.

    LISA Pathfinder had been directed into a parking orbit in April, keeping it out of Earth’s way. The final action this week switches it off completely after a successful 16 months of science measurements.

    While some spacecraft are flashy, never sitting still as they zip across the solar system, LISA Pathfinder was as steady as they come — literally.

    It housed a space-age motion detector so sensitive that it had to be protected against the force of photons from the Sun. That was made possible thanks to a system of thrusters that applied tiny reactive forces to the spacecraft, cancelling out the force of the Sun and allowing the spacecraft to stay within 10 nanometers of an ideal gravitational orbit.

    These requirements for Pathfinder were so challenging and unique that LISA Pathfinder flew two independent systems based on different designs – one provided by NASA and one by ESA – and ran tests with both during its 16-month mission.

    “We were trying to hold it as stable as the width of a DNA helix,” said John Ziemer, systems lead for the U.S. thruster system at NASA’s Jet Propulsion Laboratory in Pasadena, California. “And we went down from there to the width of part of a DNA helix.”

    JPL managed development of the thruster system, formally called the Space Technology 7 Disturbance Reduction System (ST7-DRS). The thrusters were developed by Busek Co., Inc., Natick, Massachusetts, with technical support from JPL. During the U.S. operations phase, Pathfinder was controlled using algorithims developed by ST7 team members at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. This control system took inputs from the European sensors and sent commands to the thrusters to precisely guide the spacecraft along its path.

    JPL finished primary mission experiments in the fall of 2016. In March and April of this year, they continued validating the algorithms used in stabilizing the spacecraft. They improved them through a number of tests.

    “The main goal for us was to show we can fly the spacecraft drag-free,” Ziemer said. “The main force on the spacecraft comes from the Sun, from photons with extremely tiny force that can subtly move the spacecraft.”

    So why build something this sensitive to begin with?

    LISA Pathfinder was just a starting point. The mission was led by ESA as a stepping-stone of sorts, proving the technology needed for an even more ambitious plan, the Laser Interferometer Space Antenna (LISA): a trio of spacecraft proposed to launch in 2034. With each spacecraft holding as still as possible, they would be able to detect the ripples sent out across space by the merging of black holes.

    ESA/eLISA the future of gravitational wave research

    These ripples, known as gravitational waves, have been a source of intense scientific interest in recent years. The ground-based Laser Interferometry Gravitational Wave Observatory detected gravitational waves for the first time in 2015.

    But there’s a bigger role for thrusters like the ones on LISA Pathfinder. Ziemer said the operation of super-steady thrusters could serve as an alternative to reaction wheels, the current standard for rotating and pointing spacecraft.

    “This kind of technology could be essential for space telescopes,” Ziemer said. “They could potentially hold them still enough to image exoplanets, or allow for formation flying of a series of spacecraft.”

    The thrusters are an enabling technology, opening up a magnitude of precision that simply wasn’t available before.

    The Pathfinder spacecraft was built by Airbus Defence and Space, Ltd., United Kingdom. Airbus Defence and Space, GmbH, Germany, is the payload architect for the LISA Technology Package.

    For more information about ST7-DRS, visit:

    http://www.jpl.nasa.gov/news/news.php?feature=4825

    [It was my understanding that this satellite would have a further mission in detecting NEO’s.]

    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 6:11 pm on July 11, 2017 Permalink | Reply
    Tags: A system of two closely orbiting stars may appear in images as a single point of light even from sophisticated observatories such as NASA's Kepler space telescope, , , , , Hidden Stars May Make Planets Appear Smaller, NASA JPL - Caltech   

    From JPL-Caltech: “Hidden Stars May Make Planets Appear Smaller” 

    NASA JPL Banner

    JPL-Caltech

    July 11, 2017
    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1
    This cartoon explains why the reported sizes of some exoplanets may need to be revised in cases where there is a second star in the system. Credit: NASA/JPL-Caltech

    In the search for planets similar to our own, an important point of comparison is the planet’s density. A low density tells scientists a planet is more likely to be gaseous like Jupiter, and a high density is associated with rocky planets like Earth. But a new study suggests some are less dense than previously thought because of a second, hidden star in their systems.

    As telescopes stare at particular patches of sky, they can’t always differentiate between one star and two. A system of two closely orbiting stars may appear in images as a single point of light, even from sophisticated observatories such as NASA’s Kepler space telescope.

    NASA/Kepler Telescope

    This can have significant consequences for determining the sizes of planets that orbit just one of these stars, says a forthcoming study in the Astronomical Journal by Elise Furlan of Caltech/IPAC-NExScI in Pasadena, California, and Steve Howell at NASA’s Ames Research Center in California’s Silicon Valley.

    “Our understanding of how many planets are small like Earth, and how many are big like Jupiter, may change as we gain more information about the stars they orbit,” Furlan said. “You really have to know the star well to get a good handle on the properties of its planets.”

    Some of the most well-studied planets outside our solar system — or exoplanets — are known to orbit lone stars. We know Kepler-186f, an Earth-size planet in the habitable zone of its star, orbits a star that has no companion (the habitable zone is the distance at which a rocky planet could support liquid water on its surface).

    2
    An artist’s depiction of Kepler 186f, shown as an Earth-like world, compared to the Earth. (PHL@ UPR Arecibo,NASA)

    TRAPPIST-1, the ultra-cool dwarf star that is home to seven Earth-size planets, does not have a companion either.

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

    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile interior

    ESO Belgian robotic Trappist-South National Telescope at Cerro La Silla, Chile

    That means there is no second star complicating the estimation of the planets’ diameters, and therefore their densities.

    But other stars have a nearby companion, high-resolution imaging has recently revealed. David Ciardi, chief scientist at the NASA Exoplanet Science Institute (NExScI) at Caltech, led a large-scale effort to follow up on stars that Kepler had studied using a variety of ground-based telescopes. This, combined with other research, has confirmed that many of the stars where Kepler found planets have binary companions. In some cases, the diameters of the planets orbiting these stars were calculated without taking the companion star into consideration. That means estimates for their sizes should be smaller, and their densities higher, than their true values.

    Previous studies determined that roughly half of all the sun-like stars in our sun’s neighborhood have a companion within 10,000 astronomical units (an astronomical unit is equal to the average distance between the sun and Earth, 93 million miles or 150 million kilometers). Based on this, about 15 percent of stars in the Kepler field could have a bright, close companion — meaning planets around these stars may be less dense than previously thought.

    The Transit Problem for Binaries

    When a telescope spots a planet crossing in front of its star — an event called a “transit” — astronomers measure the resulting apparent decrease in the star’s brightness.

    Planet transit. NASA/Ames

    The amount of light blocked during a transit depends on the size of the planet — the bigger the planet, the more light it blocks, and the greater the dimming that is observed. Scientists use this information to determine the radius — half the diameter — of the planet.

    If there are two stars in the system, the telescope measures the combined light of both stars. But a planet orbiting one of these stars will cause just one of them to dim. So, if you don’t know that there is a second star, you will underestimate the size of the planet.

    For example, if a telescope observes that a star dims by 5 percent, scientists would determine the transiting planet’s size relative to that one star. But if a second star adds its light, the planet must be larger to cause the same amount of dimming.

    If the planet orbits the brighter star in a binary pair, most of the light in the system comes from that star anyway, so the second star won’t have a big effect on the planet’s calculated size. But if the planet orbits the fainter star, the larger, primary star contributes more light to the system, and the correction to the calculated planet radius can be large — it could double, triple or increase even more. This will affect how the planet’s orbital distance is calculated, which could impact whether the planet is found to be in the habitable zone.

    If the stars are roughly equal in brightness, the “new” radius of the planet is about 40 percent larger than if the light were assumed to come from a single star. Because density is calculated using the cube of the radius, this would mean a nearly three-fold decrease in density. The impact of this correction is most significant for smaller planets because it means a planet that had once been considered rocky could, in fact, be gaseous.

    The New Study

    In the new study, Furlan and Howell focused on 50 planets in the Kepler observatory’s field of view whose masses and radii were previously estimated. These planets all orbit stars that have stellar companions within about 1,700 astronomical units. For 43 of the 50 planets, previous reports of their sizes did not take into account the contribution of light from a second star. That means a revision to their reported sizes is necessary.

    In most cases, the change to the planets’ reported sizes would be small. Previous research showed that 24 of the 50 planets orbit the bigger, brighter star in a binary pair. Moreover, Furlan and Howell determined that 11 of these planets would be too large to be planets if they orbited the fainter companion star. So, for 35 of the 50 planets, the published sizes will not change substantially.

    But for 15 of the planets, they could not determine whether they orbit the fainter or the brighter star in a binary pair. For five of the 15 planets, the stars in question are of roughly equal brightness, so their densities will decrease substantially regardless of which star they orbit.

    This effect of companion stars is important for scientists characterizing planets discovered by Kepler, which has found thousands of exoplanets. It will also be significant for NASA’s upcoming Transiting Exoplanet Survey Satellite (TESS) mission, which will look for small planets around nearby, bright stars and small, cool stars.

    NASA/TESS

    “In further studies, we want to make sure we are observing the type and size of planet we believe we are,” Howell said. “Correct planet sizes and densities are critical for future observations of high-value planets by NASA’s James Webb Space Telescope. In the big picture, knowing which planets are small and rocky will help us understand how likely we are to find planets the size of our own elsewhere in the galaxy.”

    For more information about exoplanets, visit:

    https://exoplanets.nasa.gov

    See the full article from JPL-Caltech here .
    See the full article from Caltech 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 2:36 pm on June 30, 2017 Permalink | Reply
    Tags: A new mission - to collect data along a series of very closely spaced ground tracks just 5 miles (8 kilometers) apart. The result will be a new high-resolution estimate of Earth's average sea surface , , , , NASA JPL - Caltech, U.S./European Ocean Surface Topography Mission (OSTM)/Jason-2 satellite   

    From JPL: “Veteran Ocean Satellite to Assume Added Role” 

    NASA JPL Banner

    JPL-Caltech

    Alan Buis
    Jet Propulsion Laboratory, Pasadena, California
    818-354-0474
    Alan.Buis@jpl.nasa.gov

    Pascale Bresson
    Centre National d’Etudes Spatiales, Paris
    011-33-0-1-44-76-75-39
    Pascale.bresson@cnes.fr

    Claudia Ritsert-Clark
    European Organisation for the Exploitation of Meteorological
    Satellites, Darmstadt, Germany
    011-49-6151-807-6050
    Claudia.RitsertClark@eumetsat.int

    John Leslie
    NOAA’s Satellite and Information Service, Silver Spring, Maryland
    301-713-0214
    John.leslie@noaa.gov

    U.S./European Ocean Surface Topography Mission (OSTM)/Jason-2 satellite in orbit.


    OSTM/Jason-2 will soon take on an additional role to help improve maps of Earth’s sea floor. Credit: NASA-JPL/Caltech

    A venerable U.S./European oceanography satellite mission with NASA participation that has expanded our knowledge of global sea level change, ocean currents and climate phenomena like El Niño and La Niña will take on an additional role next month: improving maps of Earth’s sea floor.

    The Ocean Surface Topography Mission (OSTM)/Jason-2 satellite, a partnership among NASA, the National Oceanic and Atmospheric Administration (NOAA), the French Space Agency Centre National d’Etudes Spatiales (CNES) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), marked its ninth year in orbit on June 20. Designed to fly three to five years, OSTM/Jason-2 has now completed more than 42,000 trips around our planet, contributing to a database of satellite altimetry that dates back to the launch of the U.S./French Topex/Poseidon satellite in 1992.

    Over the past nine years, OSTM/Jason-2 has precisely measured the height of 95 percent of the world’s ice-free ocean every 10 days. Since its launch in June 2008, it has measured a 1.6-inch (4-centimeter) increase in global mean sea level, which has been rising at a rate of about 0.12 inches (3 millimeters) a year since satellite altimetry records began in 1993. It has also tracked changes in regional sea level; monitored the speed and direction of ocean surface currents; enabled more accurate weather, ocean and climate forecasts; and observed multiple El Niño and La Niña events. Since October 2016, it has operated in a tandem mission with its successor, Jason-3, launched in January 2016, doubling coverage of the global ocean and improving data resolution for both missions.

    But as OSTM/Jason-2’s onboard systems age and key components begin to show signs of cumulative space radiation damage, it has become prudent to move the older satellite out of its current shared orbit with Jason-3. On June 20, Jason-2’s four mission partner agencies agreed to lower Jason-2’s orbit by 17 miles (27 kilometers) in early July, from 830 to 813 miles (1,336 to 1,309 kilometers), placing it in a new orbit with a long repeat period of just more than one year. The move is designed to safeguard the orbit for Jason-3 and its planned successor, Jason-CS/Sentinel-6, planned for launch in 2020.

    In its new orbit, OSTM/Jason-2 will also undertake a new science mission. The long-repeat orbit will allow OSTM/Jason-2 to collect data along a series of very closely spaced ground tracks just 5 miles (8 kilometers) apart. The result will be a new, high-resolution estimate of Earth’s average sea surface height.

    The shape of the sea surface is partly determined by underwater hills and valleys, which pull the water due to the force of gravity. Scientists will use these new OSTM/Jason-2 data to improve maps of the shape and depth of the sea floor, resolving many presently unknown seamounts (underwater mountains) and other geologic features on the ocean bottom. These new maps will permit advances in ocean modeling, tsunami wave forecasting, and naval operations support, and will boost understanding of the dynamics of the solid Earth.

    The data will also help prepare for the next generation of global satellite altimetry missions, including the NASA/CNES/Canadian Space Agency/UK Space Agency Surface Water and Ocean Topography (SWOT) mission, planned for launch in 2021; and Sentinel-3B, to be launched by the European Space Agency in early 2018.

    “It’s still too early for OSTM/Jason-2 to sail off into the sunset,” said OSTM/Jason-2 and Jason-3 Project Scientist Josh Willis of NASA’s Jet Propulsion Laboratory in Pasadena, California. “The ocean covers more than 71 percent of Earth’s surface, so improving our knowledge of the shape of the sea floor is like mapping a whole new world. These new data will also help pave the way for satellite altimetry missions that don’t need to follow traditional satellite ground tracks.”

    While OSTM/Jason-2 is leaving its old orbit, data from its new orbit will continue to be used by operational agencies to provide societal and strategic benefits ranging from deriving ocean currents and improving marine, fishery and naval operations; to assisting in forecasting the intensity of tropical hurricanes and cyclones by identifying regions of high thermal energy in the ocean.

    For more information, visit:

    https://sealevel.jpl.nasa.gov/

    and

    https://www.nasa.gov/ostm

    See the full article here .

    Please help promote STEM in your local schools.

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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 2:13 pm on June 30, 2017 Permalink | Reply
    Tags: Asteroids and comets, , , , , NASA JPL - Caltech,   

    From JPL: “How a Speck of Light Becomes an Asteroid” 

    NASA JPL Banner

    JPL-Caltech

    June 30, 2017
    DC Agle
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-393-9011
    agle@jpl.nasa.gov

    Guy Webster
    Jet Propulsion Laboratory, Pasadena, Calif
    818-354-6278
    guy.w.webster@jpl.nasa.gov

    Dwayne Brown
    NASA Headquarters, Washington
    202-358-1726
    dwayne.c.brown@nasa.gov

    Laurie Cantillo
    NASA Headquarters, Washington
    202-358-1077
    laura.l.cantillo@nasa.gov

    1
    In this sequence of four images taken during one night of observation by the Catalina Sky Survey near Tucson, Arizona, the speck of light that moves relative to the background stars is a small asteroid that was, at the time, about as far away as the moon. Image Credit: NASA/JPL-Caltech/CSS-Univ. of Arizona.

    On the first day of the year 1801, Italian astronomer Gioacchino Giuseppe Maria Ubaldo Nicolò Piazzi found a previously uncharted “tiny star” near the constellation of Taurus. The following night Piazzi again observed this newfound celestial object, discovering that the speck had changed its position relative to the nearby stars. Piazzi knew that real stars were so far away that they never wandered — that they always appeared in the sky as fixed in location relative to each other. Due to the movement of this new object, the astronomer to the king of the two Sicilies suspected he had discovered something much closer — something within our solar system. Piazzi made history’s first asteroid discovery. He named it after the Roman goddess for agriculture: Ceres.

    While astronomers of Piazzi’s era eventually understood there were many more small rocky bodies to be found, for decades after the Ceres discovery, asteroid detections were few and far between. Even a half-century after Ceres’ detection, there were only 15 known asteroids. But as time marched on, so did astronomers’ equipment, techniques and interest in hunting asteroids. By 1868 the number of known asteroids had reached 100. By 1923 it was 1,000. Today, it is more than half a million.

    As a nod to the importance of these objects, the United Nations has declared June 30 International Asteroid Day.

    Most asteroids are farther from the sun than Mars is — more than 1.5 times farther from the sun than Earth’s orbit is. Asteroids that come closer to the sun than about 1.3 times Earth’s distance from the sun are called near-Earth asteroids. The term “near” in near-Earth asteroid is actually a bit of a misnomer, since most of these bodies do not come close to Earth at all. As of this month, more than 16,000 of them are known. Near-Earth asteroids and comets that come within the neighborhood of Earth’s orbit are, together, classified as near-Earth objects, or NEOs.

    Thanks to new technology, better search techniques and a team of professional and dedicated amateur astronomers hunting for them, the number of known NEOs expands by about five every night of the year.

    Ever wonder how these small celestial objects are discovered?

    “Just as in Piazzi’s day, it usually starts with just a speck of light in an astronomer’s telescope,” said Paul Chodas, manager of the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Even with some of the most powerful optical telescopes on the planet tasked with hunting asteroids, they appear as mere specks of light in the sky because they are so small. When an astronomer finds a speck that is moving, that’s when the fun begins.”

    The Planetary Defense Coordination Office at NASA Headquarters in Washington is responsible for finding, tracking and characterizing potentially hazardous asteroids, issuing warnings about possible impacts, and coordinating U.S. government planning for response to an actual impact threat. Almost always, a new asteroid detection is courtesy of telescopes that are sponsored by NASA.

    The planetary defense office oversees the Near-Earth Object Observation Program, which in turn funds the Catalina Sky Survey in Arizona and the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) in Hawaii. Both projects upgraded their telescopes in 2015, significantly improving their asteroid and near-Earth object discovery rates.

    U Arizona Catalina Sky Survey, on Mount Lemmon, AR, USA

    Pan-STARRS1 located on Haleakala, Maui, HI, USA

    “Telescopes funded by outside institutions and even some amateurs are also involved with NEO discovery and do other important asteroid-related work,” said Chodas. “But, at present, Catalina and Pan-STARRS are our most powerful asteroid detection instruments. Between these two surveys, four telesopes in all, about 90 percent of all new NEO discoveries are made.”

    At the heart of each one of these survey telescopes is a hyper-upgraded version of the same kind of camera chip (called a CCD, or charge-coupled device) that is inside our cellphones. With the exception of nights that have too much rain or snow, or several nights surrounding a full moon (when moonlight can drown out the faint light of an asteroid), the dedicated observers of Catalina and Pan-STARRS open up their telescopes every night they can find a hole in the cloud cover and take 30-second exposure after 30-second exposure of the heavens above.

    Survey astronomers are on the lookout for points of light that move relative to the more distant and fixed background stars. To find them, they take three or more images of the same region of the sky (called a field), separated by several minutes. On a good night a survey will take several hundred photos of the sky.

    When survey astronomers find a point of light that appears to move across the same field in a series of images of the same region of the sky, they check it against the predicted positions of all the known objects in the catalog maintained by the NASA-sponsored Minor Planet Center (MPC) in Cambridge, Massachusetts. If the newfound, moving point of light does not match up with the predicted position and motion of an object in the MPC’s database of known asteroids and comets, there is a good chance it’s a new discovery — but there is more work to be done.

    Computers do much of this detection work, but a prudent astronomer also double checks the work, making sure the points of light are not some kind of reflection of a nearby star, or perhaps a faulty pixel on the CCD. If confident about the potential space-rock discovery, the astronomer ships the discovery’s coordinates (known as the “astrometry”) to the MPC’s NEO Confirmation Page, where it is given a temporary identifier — like YL9E0A0. The MPC also computes an initial (approximate) orbit for the still-to-be-confirmed NEO.

    CNEOS has a system called Scout, which actively monitors the MPC confirmation page, getting the data from each potential new asteroid discovery and automatically computing the possible range of future motions even before these objects have been confirmed as discoveries.

    “If our calculations indicate a new discovery could be coming close by Earth, we call in the reinforcements,” said Chodas. “NASA has a worldwide network of astronomers who perform follow-up observations. They take the latest astrometry and try to find the new speck of light, too. If they do find it, they measure its coordinates and send their follow-up astrometry back to the MPC, where it is added to a table of information about the object. This follow-up is extremely important. It really helps expand our understanding of a new discovery’s orbit.”

    Usually it takes two to three nights of observations for enough information to be collected on a new discovery for the MPC to verify that a speck of light is indeed a near-Earth object. When that transformation occurs, the MPC removes it from its confirmation page and replaces its temporary tag with a more permanent name, which always starts out with the year it was discovered and then an alphanumeric code indicating the half-month of discovery and the sequence within that half-month. The MPC then generates a Minor Planet Electronic Circular which contains all known astrometry and the preliminary orbit of the object. The MPC announces the new asteroid discovery in an email to those who are interested in that sort of thing.

    “We are interested all right,” said Chodas. “And we stay interested even after a discovery is announced, because we are in the asteroid- and comet-hunting game for the long run. The more information we get on a celestial object — new discovery or old — the more we refine our knowledge of its orbit.”

    All the new orbits are automatically picked up by a computer system at JPL called Sentry, where all asteroid and comet orbits, including those with future close-Earth approaches, are calculated and impact probabilities are assessed daily.

    “While NASA is leading the way in near-Earth object survey, we are not resting on our laurels,” said Lindley Johnson, NASA’s planetary defense officer. “New optical systems are coming on line, new computer programs are being created, and we are exploring new technologies both ground- and space-based that will further accelerate our discovery, characterization and orbital analysis of these potential threats.”

    See the full article here .

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  • richardmitnick 5:48 pm on June 29, 2017 Permalink | Reply
    Tags: A Seismic Detective Story, Earthquakes in Oklahoma, NASA JPL - Caltech, NASA-led Study Examines Geology of Oklahoma's Largest Earthquake, Oklahomans are no strangers to Mother Nature's whims, With Satellites   

    From JPL: “Sleuthing for Seismic Answers in the Sooner State” 

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    [THIS POST ID DEDICATED TO J.L.T. FOR HIS INTEREST IN AND LOVE FOR JPL]

    JPL-Caltech

    June 29, 2017
    Alan Buis
    Jet Propulsion Laboratory, Pasadena, California
    818-354-0474
    alan.buis@jpl.nasa.gov

    1
    Sleuthing for Seismic Answers in the Sooner State
    Radar measurements of Pawnee quake deformation based on before/after satellite data analysis. Red/pink areas moved west and up; blue areas moved east or down. Black lines are previously mapped faults; aftershocks are purple; magenta line is Sooner Lake Fault; water is grey; cyan line is Highway 412.Credit: Copernicus/NASA-JPL/Caltech/OGS

    2
    The inferred distribution of fault slip for the 2016 Pawnee quake. The maximum slip, 2 feet (60 cm), is near 7.5 miles (12 km) deep, shown in red; smaller slip amounts are yellow. Aftershocks are in cyan, with most shallower than 3 miles (5 km) deep. The main quake starting point is dark blue. Credit: NASA-JPL/Caltech/OGS

    NASA-led Study Examines Geology of Oklahoma’s Largest Earthquake

    Oklahomans are no strangers to Mother Nature’s whims. From tornadoes and floods to wildfires and winter storms, the state sees more than its share of natural hazards. But prior to 2009, “terra firma” in Oklahoma meant just that — earthquakes rarely shook the state.

    Then, after decades of seismic quiet where the state averaged less than two quakes of magnitude 3 or greater a year, Oklahoma suddenly saw a sharp uptick, to 20 such quakes in 2009. By 2013 there were 109 such quakes. Since then, the numbers have soared, reaching 903 in 2015 before dipping last year to 623. In the process, Oklahoma has surpassed California to become the most seismically active of the lower 48 U.S. states.

    In 2011, a magnitude 5.7 quake and two related magnitude 5.0 quakes struck near the Oklahoma town of Prague, causing damage and injuries. Then last Sept. 3, a magnitude 5.8 quake struck a few miles northwest of the city of Pawnee, population 2,200. That quake, which occurred on a previously unmapped fault, was the strongest ever measured by instruments in Oklahoma. It shook a large area of north-central Oklahoma and was felt throughout the Midwest and as far away as Phoenix and Pittsburgh.

    A Seismic Detective Story, With Satellites

    Even before NASA studied the Pawnee earthquake, studies published since late last year by the United States Geological Survey and other institutions suggested that the earthquake was human-induced due to increases in wastewater injection related to petroleum operations. Injection wells place fluids underground into porous geologic formations, which scientsts believe can sometimes enter buried faults that are ready to slip.

    To shed additional light on the source of the Pawnee quake, a team led by geophysicist Eric Fielding of NASA’s Jet Propulsion Laboratory in Pasadena, California, used enhanced seismic data and satellite image analysis to more accurately estimate the location and extent of the fault responsible for the quake, its hypocenter (the point below Earth’s surface where the quake began) and its aftershocks, and to measure how the fault moved. Results of their study were published recently in Seismological Research Letters.

    To help pinpoint which fault ruptured and where the main quake started, Fielding’s team updated the locations of earthquakes published in an Oklahoma Geological Survey catalog of aftershocks. The catalog included nearly 2,200 earthquakes of greater than magnitude 1.0 within about 31 miles (50 kilometers) of the Sept. 3 main shock.

    Around Pawnee, the main faults are oriented in a northeast or north direction. But most of the aftershocks to the Sept. 3 quake occurred along a line trending east-southeast from the epicenter. As reported in earlier studies and confirmed by Fielding’s team, this told scientists the main shock didn’t occur on a previously mapped fault, but on a new fault called the Sooner Lake Fault.

    To determine which parts of the fault slipped in the earthquake, Fielding’s team analyzed interferometric synthetic aperture radar (InSAR) data from the Copernicus and Sentinel-1B satellites operated by the European Space Agency and the McDonald, Dettweiler and Associates Ltd RADARSAT-2 satellite.

    ESA Sentinel-1B

    ESA/Sentinel 1

    CSA RADATSAT 2

    The team compared InSAR data from multiple satellite overpasses before and after the main shock to create images of ground deformation known as interferograms. The Pawnee earthquake is the first Oklahoma earthquake to be observed using radar satellite data.

    “Radar satellites allow us to study details of earthquakes on faults that were not previously mapped and don’t reach the surface,” Fielding said. “This allows us to learn more about the processes that cause earthquakes.”

    Interferograms created by the team from the InSAR data showed the ground deformed in a pattern consistent with slip along an east-to-southeast trending fault. The interferograms also showed the quake did not rupture Earth’s surface, consistent with field reports.

    Seeing the Unseeable: Creating Computer Models of a Buried Fault

    Fielding’s team next input the aftershock and InSAR data into a computer to create models of the fault’s likely location and of which parts of the fault slipped during the quake.

    Their preferred model of the Sooner Lake Fault calculates that it dips vertically and is 11 miles (18 kilometers) long and 9 miles (15 kilometers) wide. The model also calculates that the movement on the fault took place deeper than 1.4 miles (2.3 kilometers) beneath the surface, and that the parts that moved the most were located deeper than 2.8 miles (4.5 kilometers). These findings are consistent with a main fault rupture taking place in crystalline basement rock beneath more shallow sedimentary rock layers.

    Clues Point to a Human-Induced Quake

    The team’s results show the main shock began at a depth of about 2.8 miles (4.5 kilometers) below the surface and moved downward to a depth of at least 6.2 miles (10 kilometers) and perhaps as much as 8.7 miles (14 kilometers), into the basement rocks below the sedimentary layer. This downward rupture direction is unusual for natural earthquakes. The fault slipped horizontally about 2 feet (60 centimeters) at a depth of 7.5 miles (12 kilometers).

    “Our results showing a downward fault rupture are consistent with a human-induced earthquake resulting from wastewater injection, rather than a naturally caused quake,” said Fielding.

    Fielding said the research may help better manage induced seismicity. “By understanding how and where earthquakes are induced by wastewater injection, we may be able to mitigate their risk by identifying zones that should be avoided for injection,” he said.

    The NASA-ISRO SAR (NISAR) mission, planned for launch in 2021, may help scientists identify faults responsible for earthquakes and learn more about their causes, both natural and human-induced. It will provide frequent coverage of all land areas twice every 12 days.

    NASA ISRO SAR satellite

    Other institutions participating in the study included UCLA; the Canada Centre for Mapping and Earth Observation, Natural Resources Canada in Ottawa, Ontario; and the Oklahoma Geological Survey at the University of Oklahoma, Norman.

    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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