The brightest spots on the dwarf planet Ceres gleam with mystery in new views delivered by NASA’s Dawn spacecraft. These closest-yet views of Occator crater, with a resolution of 450 feet (140 meters) per pixel, give scientists a deeper perspective on these very unusual features.
This image, made using images taken by NASA’s Dawn spacecraft, shows Occator crater on Ceres, home to a collection of intriguing bright spots. The bright spots are much brighter than the rest of Ceres’ surface, and tend to appear overexposed in most images. This view is a composite of two images of Occator: one using a short exposure that captures the detail in the bright spots, and one where the background surface is captured at normal exposure. The images were obtained by Dawn during the mission’s High Altitude Mapping Orbit (HAMO) phase, from which the spacecraft imaged the surface at a resolution of about 450 feet (140 meters) per pixel. Larger imageThe new up-close view of Occator crater from Dawn’s current vantage point reveals better-defined shapes of the brightest, central spot and features on the crater floor. Because these spots are so much brighter than the rest of Ceres’ surface, the Dawn team combined two different images into a single composite view — one properly exposed for the bright spots, and one for the surrounding surface.
Scientists also have produced animations that provide a virtual fly-around of the crater, including a colorful topographic map.
Dawn scientists note the rim of Occator crater is almost vertical in some places, where it rises steeply for 1 mile (nearly 2 kilometers).
Views from Dawn’s current orbit, taken at an altitude of 915 miles (1,470 kilometers), have about three times better resolution than the images the spacecraft delivered from its previous orbit in June, and nearly 10 times better than in the spacecraft’s first orbit at Ceres in April and May.
“Dawn has transformed what was so recently a few bright dots into a complex and beautiful, gleaming landscape,” said Marc Rayman, Dawn’s chief engineer and mission director based at NASA’s Jet Propulsion Laboratory, Pasadena, California. “Soon, the scientific analysis will reveal the geological and chemical nature of this mysterious and mesmerizing extraterrestrial scenery.”
The spacecraft has already completed two 11-day cycles of mapping the surface of Ceres from its current altitude, and began the third on Sept. 9. Dawn will map all of Ceres six times over the next two months. Each cycle consists of 14 orbits. By imaging Ceres at a slightly different angle in each mapping cycle, Dawn scientists will be able to assemble stereo views and construct 3-D maps.
Dawn is the first mission to visit a dwarf planet, and the first to orbit two distinct solar system targets. It orbited protoplanet Vesta for 14 months in 2011 and 2012, and arrived at Ceres on March 6, 2015.
Dawn’s 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: dawn.jpl.nasa.gov/mission
More information about Dawn is available at the following sites:
At Saturn, One of These Rings is not like the Others
Fast Facts: — A study suggests the particles in one section of Saturn’s rings are denser than elsewhere, possibly due to solid, icy cores.
— The findings could mean that particular ring is much younger than the rest.
When the sun set on Saturn’s rings in August 2009, scientists on NASA’s Cassini mission were watching closely. It was the equinox — one of two times in the Saturnian year when the sun illuminates the planet’s enormous ring system edge-on. The event provided an extraordinary opportunity for the orbiting Cassini spacecraft to observe short-lived changes in the rings that reveal details about their nature.
Like Earth, Saturn is tilted on its axis. Over the course of its 29-year-long orbit, the sun’s rays move from north to south over the planet and its rings, and back again. The changing sunlight causes the temperature of the rings — which are made of trillions of icy particles — to vary from season to season. During equinox, which lasted only a few days, unusual shadows and wavy structures appeared and, as they sat in twilight for this brief period, the rings began to cool.
In a recent study published in the journal Icarus, a team of Cassini scientists reported that one section of the rings appears to have been running a slight fever during equinox. The higher-than-expected temperature provided a unique window into the interior structure of ring particles not usually available to scientists.
“For the most part, we can’t learn much about what Saturn’s ring particles are like deeper than 1 millimeter below the surface. But the fact that one part of the rings didn’t cool as expected allowed us to model what they might be like on the inside,” said Ryuji Morishima of NASA’s Jet Propulsion Laboratory, Pasadena, California, who led the study.
The researchers examined data collected by Cassini’s Composite Infrared Spectrometer during the year around equinox. The instrument essentially took the rings’ temperature as they cooled. The scientists then compared the temperature data with computer models that attempt to describe the properties of ring particles on an individual scale.
What they found was puzzling. For most of the giant expanse of Saturn’s rings, the models correctly predicted how the rings cooled as they fell into darkness. But one large section — the outermost of the large, main rings, called the A ring — was much warmer than the models predicted. The temperature spike was especially prominent in the middle of the A ring.
To address this curiosity, Morishima and colleagues performed a detailed investigation of how ring particles with different structures would warm up and cool down during Saturn’s seasons. Previous studies based on Cassini data have shown Saturn’s icy ring particles are fluffy on the outside, like fresh snow. This outer material, called regolith, is created over time, as tiny impacts pulverize the surface of each particle. The team’s analysis suggested the best explanation for the A ring’s equinox temperatures was for the ring to be composed largely of particles roughly 3 feet (1 meter) wide made of mostly solid ice, with only a thin coating of regolith.
“A high concentration of dense, solid ice chunks in this one region of Saturn’s rings is unexpected,” said Morishima. “Ring particles usually spread out and become evenly distributed on a timescale of about 100 million years.”
The accumulation of dense ring particles in one place suggests that some process either placed the particles there in the recent geologic past or the particles are somehow being confined there. The researchers suggest a couple of possibilities to explain how this aggregation came to be. A moon may have existed at that location within the past hundred million years or so and was destroyed, perhaps by a giant impact. If so, debris from the breakup might not have had time to diffuse evenly throughout the ring. Alternatively, they posit that small, rubble-pile moonlets could be transporting the dense, icy particles as they migrate within the ring. The moonlets could disperse the icy chunks in the middle A ring as they break up there under the gravitational influence of Saturn and its larger moons.
“This particular result is fascinating because it suggests that the middle of Saturn’s A ring may be much younger than the rest of the rings,” said Linda Spilker, Cassini project scientist at JPL and a co-author of the study. “Other parts of the rings may be as old as Saturn itself.”
During its final series of close orbits to Saturn, Cassini will directly measure the mass of the planet’s main rings for the first time, using gravity science. Scientists will use the mass of the rings to place constraints on their age.
The Cassini-Huygens mission is a cooperative project of NASA, ESA and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington.
NASA has selected the potential next destination for the New Horizons mission to visit after its historic July 14 flyby of the Pluto system. The destination is a small Kuiper Belt object (KBO) known as 2014 MU69 that orbits nearly a billion miles beyond Pluto.
This remote KBO was one of two identified as potential destinations and the one recommended to NASA by the New Horizons team. Although NASA has selected 2014 MU69 as the target, as part of its normal review process the agency will conduct a detailed assessment before officially approving the mission extension to conduct additional science.
Artist’s impression of NASA’s New Horizons spacecraft encountering a Pluto-like object in the distant Kuiper Belt. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Steve Gribben). Larger image“Even as the New Horizon’s spacecraft speeds away from Pluto out into the Kuiper Belt, and the data from the exciting encounter with this new world is being streamed back to Earth, we are looking outward to the next destination for this intrepid explorer,” said John Grunsfeld, astronaut and chief of the NASA Science Mission Directorate at the agency headquarters in Washington. “While discussions whether to approve this extended mission will take place in the larger context of the planetary science portfolio, we expect it to be much less expensive than the prime mission while still providing new and exciting science.”
Like all NASA missions that have finished their main objective but seek to do more exploration, the New Horizons team must write a proposal to the agency to fund a KBO mission. That proposal – due in 2016 – will be evaluated by an independent team of experts before NASA can decide about the go-ahead.
Early target selection was important; the team needs to direct New Horizons toward the object this year in order to perform any extended mission with healthy fuel margins. New Horizons will perform a series of four maneuvers in late October and early November to set its course toward 2014 MU69 – nicknamed “PT1” (for “Potential Target 1”) – which it expects to reach on January 1, 2019. Any delays from those dates would cost precious fuel and add mission risk.
Path of NASA’s New Horizons spacecraft toward its next potential target, the Kuiper Belt object 2014 MU69, nicknamed “PT1” (for “Potential Target 1”) by the New Horizons team. Although NASA has selected 2014 MU69 as the target, as part of its normal review process the agency will conduct a detailed assessment before officially approving the mission extension to conduct additional science. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker). Larger image“2014 MU69 is a great choice because it is just the kind of ancient KBO, formed where it orbits now, that the Decadal Survey desired us to fly by,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado. “Moreover, this KBO costs less fuel to reach [than other candidate targets], leaving more fuel for the flyby, for ancillary science, and greater fuel reserves to protect against the unforeseen.”
New Horizons was originally designed to fly beyond the Pluto system and explore additional Kuiper Belt objects. The spacecraft carries extra hydrazine fuel for a KBO flyby; its communications system is designed to work from far beyond Pluto; its power system is designed to operate for many more years; and its scientific instruments were designed to operate in light levels much lower than it will experience during the 2014 MU69 flyby.
The 2003 National Academy of Sciences’ Planetary Decadal Survey (“New Frontiers in the Solar System”) strongly recommended that the first mission to the Kuiper Belt include flybys of Pluto and small KBOs, in order to sample the diversity of objects in that previously unexplored region of the solar system. The identification of PT1, which is in a completely different class of KBO than Pluto, potentially allows New Horizons to satisfy those goals.
But finding a suitable KBO flyby target was no easy task. Starting a search in 2011 using some of the largest ground-based telescopes on Earth, the New Horizons team found several dozen KBOs, but none were reachable within the fuel supply aboard the spacecraft.
The powerful Hubble Space Telescope came to the rescue in summer 2014, discovering five objects, since narrowed to two, within New Horizons’ flight path. Scientists estimate that PT1 is just under 30 miles (about 45 kilometers) across; that’s more than 10 times larger and 1,000 times more massive than typical comets, like the one the Rosetta mission is now orbiting, but only about 0.5 to 1 percent of the size (and about 1/10,000th the mass) of Pluto. As such, PT1 is thought to be like the building blocks of Kuiper Belt planets such as Pluto.
Unlike asteroids, KBOs have been heated only slightly by the Sun, and are thought to represent a well preserved, deep-freeze sample of what the outer solar system was like following its birth 4.6 billion years ago.
“There’s so much that we can learn from close-up spacecraft observations that we’ll never learn from Earth, as the Pluto flyby demonstrated so spectacularly,” said New Horizons science team member John Spencer, also of SwRI. “The detailed images and other data that New Horizons could obtain from a KBO flyby will revolutionize our understanding of the Kuiper Belt and KBOs.” The New Horizons spacecraft – currently 3 billion miles [4.9 billion kilometers] from Earth – is just starting to transmit the bulk of the images and other data, stored on its digital recorders, from its historic July encounter with the Pluto system. The spacecraft is healthy and operating normally.
New Horizons is part of NASA’s New Frontiers Program, managed by the agency’s Marshall Space Flight Center in Huntsville, Ala. The Johns Hopkins University Applied Physics Laboratory in Laurel, Md., designed, built, and operates the New Horizons spacecraft and manages the mission for NASA’s Science Mission Directorate. SwRI leads the science mission, payload operations, and encounter science planning.
This ESA Euronews video reports on various Euro space news and then focuses on Rosetta mission to Comet 67P/Churyumov-Gerasimenko, , including the study of organic molecules:
The Rosetta Mission has been writing a new chapter in what we know about the formation of life. The ESA teams involved are now preparing for the last part of this amazing journey.
Comet Churyumov-Gerasimenko has recently reached the perihelion – that’s the closest point to the Sun in its six and a half year orbit. It’s an important scientific step – as increasing solar energy warms the comet’s frozen ices, turning them to gas and dust. To stay safe, Rosetta has been forced to move further from the comet.
The Rosetta mission has been extended by nine months – until September next year. It’s hoped this will further boost the enormous amount of data that’s already been collected.
a dramatic outburst from Comet 67P/Churyumov-Gerasimenko, [it] was taken by Rosetta’s NAVCAM on 22 August 2015, about 336 km from the nucleus.
This single frame Rosetta navigation camera image of Comet 67P/Churyumov-Gerasimenko was taken on 22 August 2015 from a distance of 336 km from the comet centre. The image has a resolution of 28.6 m/pixel and measures 29.3 km across. The comet reached the closest point to the Sun along its 6.5-year orbit, or perihelion, on 13 August 2015. The comet’s activity, at its peak intensity around perihelion and in the weeks that follow, is clearly visible in the image, including a significant outburst. Larger imageMore about the image:
The image scale is 28.6 m/pixel and the image measures 29.3 km across. Although the activity is extraordinarily bright even in the original (below), the image above has been lightly enhanced to give a better view of the outline of the nucleus in the lower part of the image, as well as to show the full extent of the activity.
In this view, the comet is oriented with the large lobe up, revealing the Imhotep region as well as parts of Ash to the left, Aten at the centre (close to the edge and partly in shade), and Khepry to the right. The outburst seems to originate from a patch of the comet’s surface between Imhotep and Khepry.
The smaller lobe can be seen in the lower right part of the image, where indications of the ongoing activity over much of the comet can also be seen.
Comet 67P/C-G made its closest approach to the Sun, or perihelion, on 13 August 2015, just nine days before this image was taken. Based on observations made during previous passages of the comet through the inner solar system, scientists expect the activity to remain high for several weeks after perihelion, and the comet is likely to produce more of these sudden outbursts and peaks of activity.
The science instruments on Rosetta have also observed these outbursts and the teams are busy analysing the data to understand the nature of these events. These in-situ measurements are being complemented by astronomical observations from ground-based and near-Earth telescopes to try and understand the global impact of these events on the much larger coma of 67P/C-G
The closest-yet views of Ceres, delivered by NASA’s Dawn spacecraft, show the small world’s features in unprecedented detail, including Ceres’ tall, conical mountain; crater formation features and narrow, braided fractures.
NASA’s Dawn spacecraft spotted this tall, conical mountain on Ceres from a distance of 915 miles (1,470 kilometers). The mountain, located in the southern hemisphere, stands 4 miles (6 kilometers) high. Its perimeter is sharply defined, with almost no accumulated debris at the base of the brightly streaked slope with bright streaks. The image was taken on August 19, 2015. The resolution of the image is 450 feet (140 meters) per pixel. Full res jpeg.“Dawn is performing flawlessly in this new orbit as it conducts its ambitious exploration. The spacecraft’s view is now three times as sharp as in its previous mapping orbit, revealing exciting new details of this intriguing dwarf planet,” said Marc Rayman, Dawn’s chief engineer and mission director, based at NASA’s Jet Propulsion Laboratory, Pasadena, California.
At its current orbital altitude of 915 miles (1,470 kilometers), Dawn takes 11 days to capture and return images of Ceres’ whole surface. Each 11-day cycle consists of 14 orbits. Over the next two months, the spacecraft will map the entirety of Ceres six times.
NASA’s Dawn spacecraft took this image that shows a mountain ridge, near lower left, that lies in the center of Urvara crater on Ceres. Urvara is an Indian and Iranian deity of plants and fields. The crater’s diameter is 101 miles (163 kilometers). This view was acquired on August 19, 2015, from a distance of 915 miles (1,470 kilometers). The resolution of the image is 450 feet (140 meters) per pixel. Full res jpeg.The spacecraft is using its framing camera to extensively map the surface, enabling 3-D modeling. Every image from this orbit has a resolution of 450 feet (140 meters) per pixel, and covers less than 1 percent of the surface of Ceres.
At the same time, Dawn’s visible and infrared mapping spectrometer is collecting data that will give scientists a better understanding of the minerals found on Ceres’ surface.
NASA’s Dawn Spacecraft took this image of Gaue crater, the large crater on the bottom, on Ceres. Gaue is a Germanic goddess to whom offerings are made in harvesting rye. The center of this crater is sunken in. Its diameter is 84 kilometers (52 miles). The resolution of the image is 450 feet (140 meters) per pixel. The image was taken from a distance of 915 miles (1,470 kilometers) on August 18, 2015. Full res jpeg.Engineers and scientists will also refine their measurements of Ceres’ gravity field, which will help mission planners in designing Dawn’s next orbit — its lowest — as well as the journey to get there. In late October, Dawn will begin spiraling toward this final orbit, which will be at an altitude of 230 miles (375 kilometers).
Dawn is the first mission to visit a dwarf planet, and the first to orbit two distinct solar system targets. It orbited protoplanet Vesta for 14 months in 2011 and 2012, and arrived at Ceres on March 6, 2015.
This pair of images shows color-coded maps from NASA’s Dawn mission, revealing the highs and lows of topography on the surface of dwarf planet Ceres. The map at left is centered on terrain at 60 degrees east longitude; the map at right is centered on 240 degrees east longitude. The color scale extends about 5 miles (7.5 kilometers) below the surface in indigo to 5 miles (7.5 kilometers) above the surface in white. The topographic map was constructed from analyzing images from Dawn’s framing camera taken from varying sun and viewing angles. The map was combined with an image mosaic of Ceres and projected as an orthographic projection. The well-known bright spots in the center of Ceres northern hemisphere in the image at right retain their bright appearance, although they are color-coded in the same green elevation of the crater floor in which they sit. Full res jpeg.Dawn’s 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: dawn.jpl.nasa.gov/mission
More information about Dawn is available at the following sites:
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