Updates Dawn Mission News

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NASA JPL / NASA:
NASA to Hold News Conference on Dawn Mission Results

May 7, 2012

PASADENA, Calif. -- NASA will host a news conference on Thursday, May 10, at 11 a.m. PDT (2 p.m. EDT) to present a new analysis of the giant asteroid Vesta using data from the agency's Dawn spacecraft.

The event will be held at NASA Headquarters in Washington, broadcast live on NASA Television and streamed on the agency's website. For NASA TV streaming video, downlink and scheduling information, visit: http://www.nasa.gov/ntv .

The event will also be streamed live on Ustream with a moderated chat available at: http://www.ustream.com/nasajpl2 . Questions may also be asked via Twitter using the hashtag #asknasa .


The panelists for the briefing are:

• Carol Raymond, Dawn deputy principal investigator, NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
• Harry McSween, chair, Dawn surface composition working group, University of Tennessee, Knoxville
• Vishnu Reddy, Dawn framing camera team member, Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, and the University of North Dakota, Grand Forks
• David O’Brien, Dawn participating scientist, Planetary Science Institute, Tucson, Ariz.
• Maria Cristina De Sanctis, Dawn co-investigator and visible and infrared mapping spectrometer team lead, Italian National Institute for Astrophysics, Rome

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NASA: MEDIA ADVISORY : M12-082 - NASA to Hold News Conference on Asteroid Mission Results

SPACE.com:

• NASA Probe Gets Extended Stay at Huge Asteroid Vesta
  
  
• NASA to Reveal New Vesta Discoveries by Asteroid Probe Thursday

 

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Universe Today: The Bright and Dark Side of Vesta’s Craters

Many types of craters are captured in this panorama of recent Dawn images​

 

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DLR: Vesta – a planet-like asteroid

 

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NASA / NASA JPL:
NASA Dawn Mission Reveals Secrets of Large Asteroid

May 10, 2012

PASADENA, Calif. - NASA's Dawn spacecraft has provided researchers with the first orbital analysis of the giant asteroid Vesta, yielding new insights into its creation and kinship with terrestrial planets and Earth's moon.

Vesta now has been revealed as a special fossil of the early solar system with a more varied, diverse surface than originally thought. Scientists have confirmed a variety of ways in which Vesta more closely resembles a small planet or Earth's moon than another asteroid. Results appear in today's edition of the journal Science.

Dawn's Virtual Flight over Vesta​

This video takes viewers on a virtual tour of Vesta's south polar basin, the "snowman" set of craters and a crater called Oppia. › Virtual flight video

"Dawn's visit to Vesta has confirmed our broad theories of this giant asteroid's history, while helping to fill in details it would have been impossible to know from afar," said Carol Raymond, deputy principal investigator at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Dawn's residence at Vesta of nearly a year has made the asteroid's planet-like qualities obvious and shown us our connection to that bright orb in our night sky."

Touring Vesta's Craters​

This video takes viewers on a virtual tour of Vesta's south polar basin, the "snowman" set of craters and a crater called Oppia. › Touring craters

Scientists now see Vesta as a layered, planetary building block with an iron core - the only one known to survive the earliest days of the solar system. The asteroid's geologic complexity can be attributed to a process that separated the asteroid into a crust, mantle and iron core with a radius of approximately 68 miles (110 kilometers) about 4.56 billion years ago. The terrestrial planets and Earth's moon formed in a similar way.

Dawn observed a pattern of minerals exposed by deep gashes created by space rock impacts, which may support the idea the asteroid once had a subsurface magma ocean. A magma ocean occurs when a body undergoes almost complete melting, leading to layered building blocks that can form planets. Other bodies with magma oceans ended up becoming parts of Earth and other planets.

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Mineral Diversity at Vesta's South Pole​

This image, made from data obtained by NASA's Dawn spacecraft, shows the mineral distribution in the southern hemisphere of the giant asteroid Vesta.

Image credit: NASA/JPL-Caltech/UCLA/INAF/MPS/DLR/IDA​

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Vesta in Perspective​

The giant asteroid Vesta is shown here as the smallest body among other similar bodies in the solar system: Mars, Mercury, Earth's moon and the dwarf planet Ceres. With Dawn's findings, Vesta is the only intact layered planetary building block with an iron core known to be remaining since the early days of the solar system.

Image credit: NASA/JPL-Caltech/UCLA​

Data also confirm a distinct group of meteorites found on Earth did, as theorized, originate from Vesta. The signatures of pyroxene, an iron- and magnesium-rich mineral, in those meteorites match those of rocks on Vesta's surface. These objects account for about 6 percent of all meteorites seen falling on Earth.

This makes the asteroid one of the largest single sources for Earth's meteorites. The finding also marks the first time a spacecraft has been able to visit the source of samples after they were identified on Earth.

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Vesta's Internal Structure​

This artist's concept shows the internal structure of the giant asteroid Vesta, based on data from NASA's Dawn mission.

Image credit: NASA/JPL-Caltech​

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South Pole Vistas​

Scientists with NASA's Dawn mission have created perspective views of the Rheasilvia impact basin on the giant asteroid Vesta. Rheasilvia is located in Vesta's southern hemisphere.

Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI​

Scientists now know Vesta's topography is quite steep and varied. Some craters on Vesta formed on very steep slopes and have nearly vertical sides, with landslides occurring more frequently than expected.

Another unexpected finding was that the asteroid's central peak in the Rheasilvia basin in the southern hemisphere is much higher and wider, relative to its crater size, than the central peaks of craters on bodies like our moon. Vesta also bears similarities to other low-gravity worlds like Saturn's small icy moons, and its surface has light and dark markings that don't match the predictable patterns on Earth's moon.

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Meteorites from Vesta​

This image shows three slices of a class of meteorites that fell to Earth that NASA's Dawn mission has confirmed as originating from the giant asteroid Vesta.

Image credit: University of Tennessee​

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Global Mineral Map of Vesta​

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This colorized map from NASA's Dawn mission shows the distribution of minerals across the surface of the giant asteroid Vesta.

Image credit: NASA/JPL-Caltech/UCLA/INAF/MPS/DLR/IDA​

"We know a lot about the moon and we're only coming up to speed now on Vesta," said Vishnu Reddy, a framing camera team member at the Max Planck Institute for Solar System Research in Germany and the University of North Dakota in Grand Forks. "Comparing the two gives us two storylines for how these fraternal twins evolved in the early solar system."

Dawn has revealed details of ongoing collisions that battered Vesta throughout its history. Dawn scientists now can date the two giant impacts that pounded Vesta's southern hemisphere and created the basin Veneneia approximately 2 billion years ago and the Rheasilvia basin about 1 billion years ago. Rheasilvia is the largest impact basin on Vesta.

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Crater Impacts on Vesta​

This graphic shows the global distribution of craters that hit the giant asteroid Vesta, based on data from NASA's Dawn mission.

Image Credit: NASA/JPL-Caltech/MPS/DLR/IDA/LSI​

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Vesta in the Infrared​

This global, colorized image of the giant asteroid Vesta from NASA's Dawn mission reveals how the minerals are distributed on the surface.

Image credit: NASA/JPL-Caltech/UCLA/INAF​

"The large impact basins on the moon are all quite old," said David O'Brien, a Dawn participating scientist from the Planetary Science Institute in Tucson, Ariz. "The fact that the largest impact on Vesta is so young was surprising."

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NASA Press Release: RELEASE : 12-153 - NASA Dawn Spacecraft Reveals Secrets of Large Asteroid

SPACE.com:

• Huge Asteroid Vesta Actually an Ancient Protoplanet
  
  
• Giant Asteroid Vesta's Planetary Chances Killed by Jupiter

Discovery News: Vesta is a Baby Planet, Not an Asteroid

Florida Today: Giant asteroid Vesta got one-two crater-carving punch

Universe Today: Fly Over Vesta’s Cratered Terrain with Dawn

 

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Aviation Week: NASA’s Dawn Uncovers New Secrets About Vesta

 

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The Planetary Society Blog: Dawn Journal: Riding gravitational currents to HAMO2

 

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NASA / NASA JPL:
Dawn Mission Video Shows Vesta's Coat of Many Colors

June 06, 2012

PASADENA, Calif. - A new video from NASA's Dawn mission reveals the dappled, variegated surface of the giant asteroid Vesta. The animation drapes high-resolution false color images over a 3-D model of the Vesta terrain constructed from Dawn's observations. This visualization enables a detailed view of the variation in the material properties of Vesta in the context of its topography.

The video is available online at: http://www.jpl.nasa.gov/video/index.cfm?id=1085.

The colors were chosen to highlight differences in surface composition that are too subtle for the human eye to see. Scientists are still analyzing what some of the colors mean for the composition of the surface. But it is clear that the orange material thrown out from some impact craters is different from the surrounding surface material. Green shows the relative abundance of iron. Parts of the huge impact basin known as Rheasilvia in Vesta's southern hemisphere, for instance, have areas with less iron than nearby areas.

Click on image for details​

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI​

Dawn has imaged the majority of the surface of Vesta with the framing camera to provide this 3-D map. While some areas in the north were in shadow at the time the images were obtained by the camera, Dawn expects to improve its coverage of Vesta's northern hemisphere with additional observations. Dawn's viewing geometry also prevented mapping of a portion of the mountain of the south pole.

The spacecraft is currently spiraling up from its lowest-altitude orbit into its final science orbit, where its average altitude will be about 420 miles (680 kilometers). Dawn is scheduled to leave Vesta around Aug. 26.

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Universe Today: Vesta’s Amazing Technicolor Surface

SPACE.com: NASA Video Reveals Huge Asteroid Vesta's Complex Surface

Discovery News: Protoplanet Vesta's Coat of Many Colors: Big Pic

 

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NASA / NASA JPL:
Dawn Easing into its Final Science Orbit

June 14, 2012

After successfully completing nearly five months scrutinizing the giant asteroid Vesta at its lowest orbit altitude, NASA's Dawn spacecraft will begin its final major science data-gathering phase at Vesta on June 15, at an average altitude of 420 miles (680 kilometers) above the surface.

Over the past six weeks, Dawn has been gently spiraling up from its lowest orbit - 130 miles, or 210 kilometers, above the surface - to the final planned science orbit, known as high-altitude mapping orbit 2. Observations obtained from this orbit will provide a companion set of data and images to those obtained during the first high-altitude mapping orbit phase, completed in October 2011. A key difference will be that the angle of sunlight hitting Vesta has changed, illuminating more of its northern region. The principal science observations planned in this new orbit will be obtained with the framing camera and the visible and infrared mapping spectrometer.

Following this final science data gathering phase, Dawn will then spend almost five weeks spiraling out from the giant asteroid to the point at which Vesta will lose its gravitational hold on the spacecraft. That departure day is expected to be around Aug. 26. Dawn will turn to view Vesta as it leaves and acquire more data. Then, Dawn will set its sights on the dwarf planet Ceres, and begin a two-and-a-half year journey to investigate the largest body in the main asteroid belt. Dawn will enter orbit around Ceres in 2015.

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The Planetary Society Blog: Dawn journal: seeing Vesta in a new light

 

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Universe Today: Dawn’s Vestan Endeavour Exceptionally Exciting near End of Year Long Super Science Survey

Location of Dawn in 23 minutes from this post's creation time.​

 

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The Planetary Society Blog: Pretty picture: Vesta's crater Aelia in high resolution

 

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NASA / NASA JPL:
Dawn Engineers Assess Reaction Wheel

August 13, 2012

Dawn Mission Status Report

PASADENA, Calif. -- Engineers working on NASA's Dawn spacecraft are assessing the status of a reaction wheel -- part of a system that helps the spacecraft point precisely -- after onboard software powered it off on Aug. 8. Dawn's mission is to study the geology and geochemistry of the giant asteroid Vesta and dwarf planet Ceres, the two most massive objects in the main asteroid belt. Dawn is now using its thrusters to point at Earth for communications. The rest of the spacecraft is otherwise healthy.

During a planned communications pass on Aug. 9, the team learned that the reaction wheel had been powered off. Telemetry data from the spacecraft suggest the wheel developed excessive friction, similar to the experience with another Dawn reaction wheel in June 2010. The Dawn team demonstrated during the cruise to Vesta in 2011 that, if necessary, they could complete the cruise to Ceres without the use of reaction wheels.

The spacecraft has been orbiting Vesta since July 15, 2011. Dawn concluded its primary science observations of Vesta on July 25, 2012, and has been spiraling slowly away from the giant asteroid using its ion propulsion system. Ion thrusting was halted to accommodate the reaction wheel investigation, which may briefly delay the escape from Vesta.

"The Vesta mission has been spectacularly successful, and we are looking forward to the exciting Ceres mission ahead of us," said Robert Mase, Dawn project manager, of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

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Aviation Week: NASA’s Dawn Mission Addresses Second Reaction Wheel Loss:

HOUSTON — The Dawn mission team at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., have slowed the probe’s scheduled Aug. 25 gravitational escape from Vesta until early September while controllers checked out high friction readings from a second spacecraft reaction wheel.

The condition is not expected to affect the second leg of its eight-year main belt asteroid mission to Ceres, or data collection at the dwarf planet.

The difficulty, which triggered a software shutdown of the spacecraft pointing device on Aug. 8, should not interfere with Dawn’s scheduled arrival at Ceres in February 2015, according to Marc Rayman, NASA’s Dawn chief engineer and mission director.

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The spacecraft will slip from Dawn’s gravitational clutch on Sept. 5, 11 days later than originally scheduled, Rayman told Aviation Week Aug. 15 via e-mail.

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[boogabooga]

They can't know for sure that this won't effect the mission.

 

[garyw]

Why not? They know the RCS prop levels, they already know the manevuers they want to perform and they know what they can cut/change to get the best out of the probe with the loss of the reaction wheels.
Yes, it's a bump in the road but it's not a major issue.

 

[SiberianTiger]

The spacecraft will slip from Dawn’s gravitational clutch

... from Vesta's?

 

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... from Vesta's?

There's a section you can leave a comment on the article. :lol:

Anyway, I'll update the quote, if Aviation Week does it too.

 

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DLR: Parting ways with Vesta

 

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NASA / NASA JPL:
NASA's Dawn Prepares for Trek Toward Dwarf Planet

August 30, 2012

PASADENA, Calif. - NASA's Dawn spacecraft is on track to become the first probe to orbit and study two distant solar system destinations, to help scientists answer questions about the formation of our solar system. The spacecraft is scheduled to leave the giant asteroid Vesta on Sept. 4 PDT (Sept. 5 EDT) to start its two-and-a-half-year journey to the dwarf planet Ceres.

Dawn began its 3-billion-mile (5-billion kilometer) odyssey to explore the two most massive objects in the main asteroid belt in 2007. Dawn arrived at Vesta in July 2011 and will reach Ceres in early 2015. Dawn's targets represent two icons of the asteroid belt that have been witness to much of our solar system's history.

To make its escape from Vesta, the spacecraft will spiral away as gently as it arrived, using a special, hyper-efficient system called ion propulsion. Dawn's ion propulsion system uses electricity to ionize xenon to generate thrust. The 12-inch-wide ion thrusters provide less power than conventional engines, but can maintain thrust for months at a time.

"Thrust is engaged, and we are now climbing away from Vesta atop a blue-green pillar of xenon ions," said Marc Rayman, Dawn's chief engineer and mission director, at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We are feeling somewhat wistful about concluding a fantastically productive and exciting exploration of Vesta, but now have our sights set on dwarf planet Ceres.

Dawn's orbit provided close-up views of Vesta, revealing unprecedented detail about the giant asteroid. The mission revealed that Vesta completely melted in the past, forming a layered body with an iron core. The spacecraft also revealed the scarring from titanic collisions Vesta suffered in its southern hemisphere, surviving not one but two colossal impacts in the last two billion years. Without Dawn, scientists would not have known about the dramatic troughs sculpted around Vesta, which are ripples from the two south polar impacts.

"We went to Vesta to fill in the blanks of our knowledge about the early history of our solar system," said Christopher Russell, Dawn's principal investigator, based at the University of California Los Angeles (UCLA). "Dawn has filled in those pages, and more, revealing to us how special Vesta is as a survivor from the earliest days of the solar system. We can now say with certainty that Vesta resembles a small planet more closely than a typical asteroid."

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SPACE.com: Dawn Spacecraft Leaving Huge Asteroid Vesta Next Week

 

[Cosmic Penguin]