Updates Dawn Mission News

[Andy44]

Looks almost like ruins of a base..... of course, it is just natural formations.

It's a forward SHADO outpost.

 

[Notebook]

http://www.bbc.co.uk/news/science-environment-31754585

It has been the big Solar System mystery of 2015 - what are the bright spots on Ceres, the largest object in the asteroid belt between Mars and Jupiter?

Scientists think they now have some answers.

They are places where impacts have excavated a briny layer of water-ice under the dwarf planet's surface, the researchers tell the journal Nature.

And the very brightest features are the youngest, freshest exposures.

 

[RGClark]

Other nice images:

New clues to Ceres' bright spots and origins.
December 9, 2015 by Elizabeth Landau

http://phys.org/news/2015-12-clues-ceres-bright.html


Bob Clark

 

[Ripley]

 

[Unstung]

JPL: "Bright Spots and Color Differences Revealed on Ceres"

"Occator Crater, measuring 57 miles (92 kilometers) across and 2.5 miles (4 kilometers) deep, contains the brightest area on Ceres."

"This global map shows the surface of Ceres in enhanced color, encompassing infrared wavelengths beyond human visual range."

"Ceres' Haulani Crater (21 miles, 34 kilometers wide) is shown in these views from the visible and infrared mapping spectrometer (VIR) aboard NASA's Dawn spacecraft."

"This map shows a portion of the northern hemisphere of Ceres with neutron counting data acquired by the gamma ray and neutron detector (GRaND) instrument aboard NASA's Dawn spacecraft."

"This colorized global map of Ceres was created from a clear-filter mosaic. Color was added to the map using spectral data from other observations of Ceres (calculated using a color transformation program)."

"The bright spots of Occator Crater are shown in enhanced color in this view from NASA's Dawn spacecraft."

"...the spacecraft's imaging coverage of dwarf planet Ceres during its low-altitude mapping orbit, 240 miles (385 kilometers) above the surface."
​

 

[Notebook]

BBC article:

http://www.bbc.co.uk/news/science-environment-35880029

 

[orb]

Spaceflight Now: NASA must decide soon on Dawn mission’s next act

 

[orb]

NASA: New Horizons Receives Mission Extension to Kuiper Belt, Dawn to Remain at Ceres:

{...}

NASA determined that the Dawn spacecraft should remain at the dwarf planet Ceres, rather than changing course to the main belt asteroid Adeona.

Green noted that NASA relies on the scientific assessment by the Senior Review Panel in making its decision on which extended mission option to approve. “The long-term monitoring of Ceres, particularly as it gets closer to perihelion – the part of its orbit with the shortest distance to the sun -- has the potential to provide more significant science discoveries than a flyby of Adeona,” he said.

{...}

 

[Unstung]

NASA had to decide by July 12 whether to send Dawn to the third asteroid due to hydrazine limitations. The mission scientists claimed that visiting another asteroid would be more scientifically valuable than staying at Ceres. Remaining would provide a relatively small gain in knowledge.

I was surprised that Dawn still could be sent to another asteroid. I think that NASA is concerned with the risk of doing so as the fuel margins appear very tight. The agency is playing it safe. If another issue arises with Dawn, it could prevent the chance of visiting a third asteroid. Then the extension would have been a waste of money.

The New Horizons extension is noteworthy on its own. Both missions will continue their work with no major disappointments.

 

[Nicholas Kang]

Dawn Discovers Evidence for Organic Material on Ceres

NASA:https://www.nasa.gov/feature/jpl/dawn-discovers-evidence-for-organic-material-on-ceres

Scientists using the spacecraft's visible and infrared mapping spectrometer (VIR) detected the material in and around a northern-hemisphere crater called Ernutet.

The VIR instrument was able to detect and map the locations of this material because of its special signature in near-infrared light.

The organic materials on Ceres are mainly located in an area covering approximately 400 square miles (about 1,000 square kilometers). The signature of organics is very clear on the floor of Ernutet Crater, on its southern rim and in an area just outside the crater to the southwest. Another large area with well-defined signatures is found across the northwest part of the crater rim and ejecta. There are other smaller organic-rich areas several miles (kilometers) west and east of the crater. Organics also were found in a very small area in Inamahari Crater, about 250 miles (400 kilometers) away from Ernutet.

In enhanced visible color images from Dawn's framing camera, the organic material is associated with areas that appear redder with respect to the rest of Ceres. The distinct nature of these regions stands out even in low-resolution image data from the visible and infrared mapping spectrometer.

This enhanced color composite image, made with data from the framing camera aboard NASA's Dawn spacecraft, shows the area around Ernutet Crater. The bright red portions appear redder with respect to the rest of Ceres.
Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

This enhanced color composite image from Dawn's visible and infrared mapping spectrometer shows the area around Ernutet Crater on Ceres. The instrument detected the evidence of organic materials in this area, as reported in a 2017 study in the journal Science. In this view, areas that appear pink with respect to the background appear to be rich in organics, and green areas are where organic material appears to be less abundant.Light with a wavelength of 2000 nanometers is shown in blue, 3400 nanometers is shown in green and 1700 nanometers is shown in red.
Credits: NASA/JPL-Caltech/UCLA/ASI/INAF

 

[Nicholas Kang]

Confirmed! Mission Extended!

NASA has authorized a second extension of the Dawn mission at Ceres, the largest object in the asteroid belt between Mars and Jupiter. During this extension, the spacecraft will descend to lower altitudes than ever before at the dwarf planet, which it has been orbiting since March 2015. The spacecraft will continue at Ceres for the remainder of its science investigation and will remain in a stable orbit indefinitely after its hydrazine fuel runs out.

The Dawn flight team is studying ways to maneuver Dawn into a new elliptical orbit, which may take the spacecraft to less than 120 miles (200 kilometers) from the surface of Ceres at closest approach. Previously, Dawn's lowest altitude was 240 miles (385 kilometers).

A priority of the second Ceres mission extension is collecting data with Dawn's gamma ray and neutron spectrometer, which measures the number and energy of gamma rays and neutrons. This information is important for understanding the composition of Ceres' uppermost layer and how much ice it contains.

The spacecraft also will take visible-light images of Ceres' surface geology with its camera, as well as measurements of Ceres’ mineralogy with its visible and infrared mapping spectrometer.

The extended mission at Ceres additionally allows Dawn to be in orbit while the dwarf planet goes through perihelion, its closest approach to the Sun, which will occur in April 2018. At closer proximity to the Sun, more ice on Ceres' surface may turn to water vapor, which may in turn contribute to the weak transient atmosphere detected by the European Space Agency's Herschel Space Observatory before Dawn's arrival. Building on Dawn’s findings, the team has hypothesized that water vapor may be produced in part from energetic particles from the Sun interacting with ice in Ceres’ shallow surface. Scientists will combine data from ground-based observatories with Dawn's observations to further study these phenomena as Ceres approaches perihelion.

The Dawn team is currently refining its plans for this next and final chapter of the mission. Because of its commitment to protect Ceres from Earthly contamination, Dawn will not land or crash into Ceres. Instead, it will carry out as much science as it can in its final planned orbit, where it will stay even after it can no longer communicate with Earth. Mission planners estimate the spacecraft can continue operating until the second half of 2018.

Source: NASA

 

[Nicholas Kang]

Some updates

This view from NASA’s Dawn mission shows where ice has been detected in the northern wall of Ceres’ Juling Crater, which is in almost permanent shadow.

Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/ASI/INAF​

Observations of Ceres have detected recent variations in its surface, revealing that the only dwarf planet in the inner solar system is a dynamic body that continues to evolve and change.

NASA’s Dawn mission has found recently exposed deposits that give us new information on the materials in the crust and how they are changing, according to two papers published March 14 in Science Advances that document the new findings.

Observations obtained by the visible and infrared mapping spectrometer (VIR) on the Dawn spacecraft previously found water ice in a dozen sites on Ceres. The new study revealed the abundance of ice on the northern wall of Juling Crater, a crater 12 miles (20 kilometers) in diameter. The new observations, conducted from April through October 2016, show an increase in the amount of ice on the crater wall.

This view from NASA’s Dawn mission shows the floor of Ceres’ Juling Crater. The crater floor shows evidence of the flow of ice and rock, similar to rock glaciers in Earth’s polar regions.

Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/ASI/INAF​

“This is the first direct detection of change on the surface of Ceres,” said Andrea Raponi of the Institute of Astrophysics and Planetary Science in Rome.

Raponi led the new study, which found changes in the amount of ice exposed on the dwarf planet. “The combination of Ceres moving closer to the sun in its orbit, along with seasonal change, triggers the release of water vapor from the subsurface, which then condenses on the cold crater wall. This causes an increase in the amount of exposed ice. The warming might also cause landslides on the crater walls that expose fresh ice patches.”

By combining chemical, geological and geophysical observations, the Dawn mission is producing a comprehensive view of Ceres. Previous data had shown Ceres has a crust about 25 miles (40 kilometers) thick and rich in water, salts and, possibly, organics.

This view from NASA’s Dawn mission shows Ceres’ tallest mountain, Ahuna Mons, 2.5 miles (4 kilometers) high and 11 miles (17 kilometers) wide. This is one of the few sites on Ceres at which a significant amount of sodium carbonate has been found, shown in green and red colors in the lower right image.

Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/ASI/INAF​

In a second study, VIR observations also reveal new information about the variability of Ceres’ crust, and suggest recent surface changes, in the form of newly exposed material.

Dawn previously found carbonates, common on the planet’s surface, that formed within an ocean. Sodium carbonates, for example, dominate the bright regions in Occator Crater, and material of similar composition has been found at Oxo Crater and Ahuna Mons.

This study, led by Giacomo Carrozzo of the Institute of Astrophysics and Planetary Science, identified 12 sites rich in sodium carbonates and examined in detail several areas of a few square miles that show where water is present as part of the carbonate structure. The study marks the first time hydrated carbonate has been found on the surface of Ceres, or any other planetary body besides Earth, giving us new information about the dwarf planet’s chemical evolution.

Water ice is not stable on the surface of Ceres over long time periods unless it is hidden in shadows, as in the case of Juling. Similarly, hydrated carbonate would dehydrate, although over a longer timescale of a few million years.

“This implies that the sites rich in hydrated carbonates have been exposed due to recent activity on the surface,” Carrozzo said.

The great diversity of material, ice and carbonates, exposed via impacts, landslides and cryovolcanism suggests Ceres’ crust is not uniform in composition. These heterogeneities were either produced during the freezing of Ceres’ original ocean – which formed the crust – or later on as a consequence of large impacts or cryovolcanic intrusions.

“Changes in the abundance of water ice on a short timescale, as well as the presence of hydrated sodium carbonates, are further evidence that Ceres is a geologically and chemically active body,” said Cristina De Sanctis, VIR team leader at the Institute of Astrophysics and Planetary Science.

 

[Nicholas Kang]

One of the first images returned by Dawn in more than a year, as Dawn moves to its lowest-ever and final orbit around Ceres. Dawn captured this view on May 16, 2018 from an altitude of about 270 miles (440 kilometers).
Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA​

NASA’s Dawn spacecraft is maneuvering to its lowest-ever orbit for a close-up examination of the inner solar system’s only dwarf planet.

In early June, Dawn will reach its new, final orbit above Ceres. Soon after, it will begin collecting images and other science data from an unprecedented vantage point. This orbit will be less than 30 miles (50 kilometers) above the surface of Ceres -- 10 times closer than the spacecraft has ever been.

Dawn will collect gamma ray and neutron spectra, which help scientists understand variations in the chemical makeup of Ceres’ uppermost layer. That very low orbit also will garner some of Dawn’s closest images yet.

The transfer from Dawn’s previous orbit to its final one is not as simple as making a lane change. Dawn’s operations team worked for months to plot the course for this second extended mission of the veteran spacecraft, which is propelled by an ion engine. Engineers mapped out more than 45,000 possible trajectories before devising a plan that will allow the best science observations.

More detailed information about Dawn’s planned orbit is in Marc Rayman’s Dawn Journal. Rayman is Dawn’s mission director and chief engineer.

Source: NASA

 

[mahdavi3d]

Jet Propulsion Laboratory : Dawn's Latest Orbit Reveals Dramatic New Views of Occator Crater

{...}
The flight team maneuvered the spacecraft into an orbit that dives 22 miles (35 kilometers) above the surface of Ceres and viewed Occator Crater, site of the famous bright deposits, and other intriguing regions. In more than three years of orbiting Ceres, Dawn's lowest altitude before this month was 240 miles (385 kilometers), so the data from this current orbit bring the dwarf planet into much sharper focus.

These low orbits have revealed unprecedented details of the relationships between bright and dark materials in the region of Vinalia Faculae. Dawn's visible and infrared mapping spectrometer had previously found the bright deposits to be made of sodium carbonate, a material commonly found in evaporite deposits on Earth. Last week Dawn fired its ion engine, possibly for the final time, to fly nearer Cerealia Facula, the large deposit of sodium carbonate in the center of Occator Crater.
{...}

This mosaic of a prominent mound located on the western side of Cerealia Facula was obtained by NASA's Dawn spacecraft on June 22, 2018 from an altitude of about 21 miles (34 kilometers). Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

This close-up image of the Vinalia Faculae in Occator Crater was obtained by NASA's Dawn spacecraft on June 14, 2018 from an altitude of about 24 miles (39 kilometers). Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA​

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[IronRain]

I just find these views so stunning.

 

[Unstung]

NASA: "Dusk for Dawn: Mission of Many Firsts to Gather More Data in Home Stretch"

There are some new images of Occator Crater from around periapsis, just 34 kilometers above the surface as previously reported.

Of course, Dawn will observe Ceres until the end and researchers will continue to study the data.

[...]

Although the Dawn mission is winding down, the science is not. Besides the high-resolution images, the spacecraft is collecting gamma ray and neutron spectra, infrared and visible spectra, and gravity data. The observations focus on the area around Occator and Urvara craters, with the main goal of understanding the evolution of Ceres, and testing for possible ongoing geology.

“The new images of Occator Crater and the surrounding areas have exceeded expectations, revealing beautiful, alien landscapes,” said Carol Raymond of JPL, principal investigator of the Dawn mission. “Ceres’ unique surface appears to be shaped by impacts into its volatile-rich crust, resulting in intriguing, complex geology, as we can see in the new high-resolution mosaics of Cerealia Facula and Vinalia Faculae.”

The first results of this mission phase, which started in early June, are being presented this week at the Committee on SPAce Research (COSPAR) meeting in Pasadena. Raymond and JPL scientist Jennifer Scully will offer new information on the relationships between bright and dark materials on the floor of Occator Crater, which show impact processes, landslides and cryovolcanism.

Dawn scientists are using new high-resolution data from Dawn to test and refine hypotheses about Occator crater’s formation and evolution. “Observations, modeling and laboratory studies helped us conclude that the bright spots are either formed by impacts interacting with the crust, or that a reservoir of briny melt contributed to their formation,” said Scully.

The new images so far support the hypothesis that exposure of subsurface material in that region is ongoing, and that it is geologically active, feeding from a deep reservoir. Eleonora Ammannito of the Italian Space Agency, deputy lead for the Dawn visible and infrared mapping spectrometer, will present updated maps at the conference showing the distribution of briny materials across Ceres’ surface.

Also at COSPAR, Dawn flight team member Dan Grebow of JPL will describe Dawn’s final orbit, designed to abide by NASA’s planetary protection protocols.

[...]

 

[Nicholas Kang]

Ending soon

She's coming to an end...

NASA’s Dawn mission is drawing to a close after 11 years of breaking new ground in planetary science, gathering breathtaking imagery, and performing unprecedented feats of spacecraft engineering.

Dawn’s mission was extended several times as it explored Ceres and Vesta, which when combined, make up 45 percent of the mass of the main asteroid belt. Now, the spacecraft is about to run out of a key fuel, hydrazine. When that happens, most likely between September and October, Dawn will lose its ability to communicate with Earth. It will remain in a silent orbit around Ceres for decades.

Interestingly, she will be orbiting Ceres for another few decades.

Nearing the End

Dawn has continued to gather high-resolution images, gamma ray and neutron spectra, infrared spectra and gravity data at Ceres. Nearly once a day, it will swoop over Ceres about 22 miles (35 kilometers) from its surface -- only about three times the altitude of a passenger jet -- gathering valuable data until it expends the last of the hydrazine that feeds thrusters controlling its orientation.

Because Ceres has conditions of interest to scientists who study chemistry that leads to the development of life, NASA follows strict planetary protection protocols for the disposal of the Dawn spacecraft. Unlike Cassini, which deliberately plunged into Saturn’s atmosphere to protect the system from contamination -- Dawn will remain in orbit around Ceres, which has no atmosphere.

Engineers designed Dawn’s final orbit to ensure it will not crash for at least 20 years -- and likely decades longer.

Rayman, who led the team that flew Dawn throughout the mission and into its final orbit, likes to think of Dawn’s end this way: as “an inert, celestial monument to human creativity and ingenuity.”

Links: Mission Toolkit, Media Reel, Vesta Trek, Archived Science Chat

 

[Urwumpe]

And the next probe is pining for the fjords.

NASA's Dawn spacecraft has gone silent, ending a historic mission that studied time capsules from the solar system's earliest chapter.

https://www.jpl.nasa.gov/news/news.php?feature=7275