Taking Tarpeia's Temperature

This colorized image from NASA’s Dawn mission shows temperature variations at Tarpeia Crater, near the south pole of the giant asteroid Vesta. Obtained by the visible and infrared mapping spectrometer, data show the warmest areas in white, measuring about minus 10 degrees Fahrenheit (minus 23 degrees Celsius). The dark areas are the coldest, with temperatures at or below minus 150 degrees Fahrenheit (minus 100 degrees Celsius).

The variations in the red shading indicate the intensity of the emitted light in the 5-micron wavelength, which is indicative of the surface temperature.

The visible and infrared mapping spectrometer obtained the images during Dawn’s low-altitude mapping orbit (130 miles or 210 kilometers in altitude) on Feb. 5, 2012.

Image Credit: NASA/JPL-Caltech/UCLA/INAF

NASA Dawn Spacecraft Reveals Secrets of Giant Asteroid Vesta

Dwayne Brown

Headquarters, Washington

202-358-1726

dwayne.c.brown@nasa.gov

 

Jia-Rui C. Cook

Jet Propulsion Laboratory, Pasadena, Calif.

818-354-0850

jccook@jpl.nasa.gov

WASHINGTON -- Findings from NASA's Dawn spacecraft reveal new details about the giant asteroid Vesta, including its varied surface composition, sharp temperature changes and clues to its internal structure. The findings were presented today at the European Geosciences Union meeting in Vienna, Austria and will help scientists better understand the early solar system and processes that dominated its formation.

Spacecraft images, taken 420 miles (680 kilometers) and 130 miles (210 kilometers) above the surface of the asteroid, show a variety of surface mineral and rock patterns. Coded false-color images help scientists better understand Vesta's composition and enable them to identify material that was once molten below the asteroid's surface.

Researchers also see breccias, which are rocks fused during impacts from space debris. Many of the materials seen by Dawn are composed of iron- and magnesium-rich minerals, which often are found in Earth's volcanic rocks. Images also reveal smooth pond-like deposits, which might have formed as fine dust created during impacts settled into low regions.

"Dawn now enables us to study the variety of rock mixtures making up Vesta's surface in great detail," said Harald Hiesinger, a Dawn participating scientist at Münster University in Germany. "The images suggest an amazing variety of processes that paint Vesta's surface."

At the Tarpeia crater near the south pole of the asteroid, Dawn revealed bands of minerals that appear as brilliant layers on the crater's steep slopes. The exposed layering allows scientists to see farther back into the geological history of the giant asteroid.

The layers closer to the surface bear evidence of contamination from space rocks bombarding Vesta's surface. Layers below preserve more of their original characteristics. Frequent landslides on the slopes of the craters also have revealed other hidden mineral patterns.

"These results from Dawn suggest Vesta's 'skin' is constantly renewing," said Maria Cristina De Sanctis, lead of the visible and infrared mapping spectrometer team based at Italy's National Institute for Astrophysics in Rome.

Dawn has given scientists a near 3-D view into Vesta's internal structure. By making ultrasensitive measurements of the asteroid's gravitational tug on the spacecraft, Dawn can detect unusual densities within its outer layers. Data now show an anomalous area near Vesta's south pole, suggesting denser material from a lower layer of Vesta has been exposed by the impact that created a feature called the Rheasilvia basin. The lighter, younger layers coating other parts of Vesta's surface have been blasted away in the basin.

Dawn obtained the highest-resolution surface temperature maps of any asteroid visited by a spacecraft. Data reveal temperatures can vary from as warm as -10 degrees Fahrenheit (-23 degrees Celsius) in the sunniest spots to as cold as -150 degrees Fahrenheit (-100 degrees Celsius) in the shadows. This is the lowest temperature measurable by Dawn. These findings show the surface responds quickly to illumination with no mitigating effect of an atmosphere.

"After more than nine months at Vesta, Dawn's suite of instruments has enabled us to peel back the layers of mystery that have surrounded this giant asteroid since humankind first saw it as just a bright spot in the night sky," said Carol Raymond, Dawn deputy principal investigator at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "We are closing in on the giant asteroid's secrets."

Launched in 2007, Dawn began its exploration of the approximately 330-mile- (530-kilometer-) wide asteroid in mid-2011. The spacecraft's next assignment will be to study the dwarf planet Ceres in 2015. These two icons of the asteroid belt have been witness to much of our solar system's history.

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, Ala. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. in Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team.

To view the new images and for more information about Dawn, visit http://www.nasa.gov/dawn.

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NASA's Dawn Sees New Surface Features on Giant Asteroid Vesta

Dwayne Brown

Headquarters, Washington

 

Jia-Rui C. Cook

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- NASA's Dawn spacecraft has revealed unexpected details on the surface of the giant asteroid Vesta. New images and data highlight the diversity of Vesta's surface and reveal unusual geologic features, some of which were never previously seen on asteroids.

Vesta is one of the brightest objects in the solar system and the only asteroid in the so-called main belt between Mars and Jupiter visible to the naked eye from Earth. Dawn found that some areas on Vesta can be nearly twice as bright as others, revealing clues about the asteroid's history.

"Our analysis finds this bright material originates from Vesta and has undergone little change since the formation of Vesta over 4 billion years ago," said Jian-Yang Li, a Dawn participating scientist at the University of Maryland, College Park. "We're eager to learn more about what minerals make up this material and how the present Vesta surface came to be."

Bright areas appear everywhere on Vesta but are most predominant in and around craters. The areas vary from several hundred feet to around 10 miles across. Rocks crashing into the surface of Vesta seem to have exposed and spread this bright material. This impact process may have mixed the bright material with darker surface material.

While scientists had seen some brightness variations in previous images of Vesta from NASA's Hubble Space Telescope, Dawn scientists also did not expect such a wide variety of distinct dark deposits across its surface. The dark materials on Vesta can appear dark gray, brown and red. They sometimes appear as small, well-defined deposits around impact craters. They also can appear as larger regional deposits, like those surrounding the impact craters scientists have nicknamed the "snowman."

"One of the surprises was the dark material is not randomly distributed," said David Williams, a Dawn participating scientist at Arizona State University, Tempe. "This suggests underlying geology determines where it occurs."

The dark materials seem to be related to impacts and their aftermath. Scientists theorize carbon-rich asteroids could have hit Vesta at speeds low enough to produce some of the smaller deposits without blasting away the surface.

Higher-speed asteroids also could have hit the asteroid's surface and melted the volcanic basaltic crust, darkening existing surface material. That melted conglomeration appears in the walls and floors of impact craters, on hills and ridges, and underneath brighter, more recent material called ejecta, which is material thrown out from a space rock impact.

Vesta's dark materials suggest the giant asteroid may preserve ancient materials from the asteroid belt and beyond, possibly from the birth of the solar system.

"Some of these past collisions were so intense they melted the surface," said Brett Denevi, a Dawn participating scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "Dawn's ability to image the melt marks a unique find. Melting events like these were suspected, but never before seen on an asteroid."

Dawn launched in September 2007. It will reach its second destination, Ceres, in February 2015.

"Dawn's ambitious exploration of Vesta has been going beautifully," said Marc Rayman, Dawn chief engineer at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "As we continue to gather a bounty of data, it is thrilling to reveal fascinating alien landscapes."

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, Ala. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. in Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team.

To view the new images, visit http://www.nasa.gov/dawn.

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Fresh Impact Craters on Asteroid Vesta

This image, taken December 6, 2011, combines two separate views of the giant asteroid Vesta obtained by NASA's Dawn spacecraft. The images were taken by Dawn's framing camera. The far-left image uses near-infrared filters where red is used to represent 750 nanometers, green represents 920 nanometers and blue represents 980 nanometers. The image on the right is an image with colors assigned by scientists, representing different rock or mineral types on Vesta, revealing a world of many varied, well-separated layers and ingredients.

The fresh impact craters in this view are located in the south polar region, which has been partly covered by landslides from the adjacent crater. This would suggest that a layer of loose material covers the Vesta surface.

Image Credit: NASA, JPL-Caltech, UCLA, MPS, DLR, IDA

NASA'S Dawn Spacecraft Begins Science Orbits Of Vesta

Dwayne C. Brown

Headquarters, Washington

 

Priscilla Vega

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- NASA's Dawn spacecraft, the first ever to orbit an object in the main asteroid belt, is spiraling toward its first of four intensive science orbits. That initial orbit of the rocky world Vesta begins Aug. 11, at an altitude of nearly 1,700 miles (2,700 kilometers) and will provide in-depth analysis of the asteroid. Vesta is the brightest object in the asteroid belt as seen from Earth and is thought to be the source of a large number of meteorites that fall to Earth.

The Dawn team unveiled the first full-frame image of Vesta taken on July 24 http://go.nasa.gov/ohdkyh.

This image was taken at a distance of 3,200 miles (5,200 kilometers). Images from Dawn's framing camera, taken for navigation purposes and as preparation for scientific observations, are revealing the first surface details of the giant asteroid. These images go all the way around Vesta, since the giant asteroid turns on its axis once every five hours and 20 minutes.

"Now that we are in orbit around one of the last unexplored worlds in the inner solar system, we can see that it's a unique and fascinating place," said Marc Rayman, Dawn's chief engineer and mission manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

After traveling nearly four years and 1.7 billion miles (2.8 billion kilometers), Dawn has been captured by Vesta's gravity, and there currently are 1,800 miles (2,900 kilometers) between the asteroid and the spacecraft. The giant asteroid and its new neighbor are approximately 114 million miles (184 million kilometers) away from Earth.

"We have been calling Vesta the smallest terrestrial planet," said Chris Russell, Dawn's principal investigator at the UCLA. "The latest imagery provides much justification for our expectations. They show that a variety of processes were once at work on the surface of Vesta and provide extensive evidence for Vesta's planetary aspirations."

Engineers still are working to determine the exact time that Dawn entered Vesta's orbit, but the team has reported an approximate orbit insertion time of 9:47 p.m. PDT on July 15 (12:47 a.m. EDT on July 16).

In addition to the framing camera, Dawn's instruments include the gamma ray and neutron detector and the visible and infrared mapping spectrometer. The gamma ray and neutron detector uses 21 sensors with a very wide field of view to measure the energy of subatomic particles emitted by the elements in the upper yard (meter) of the asteroid's surface. The visible and infrared mapping spectrometer will measure the surface mineralogy of both Vesta and Dawn's next target, the dwarf planet Ceres. The spectrometer is a modification of a similar one flying on the European Space Agency's Rosetta and Venus Express missions.

Dawn also will make another set of scientific measurements at Vesta and Ceres using the spacecraft's radio transmitter in tandem with sensitive antennas on Earth. Scientists will monitor signals from Dawn and later Ceres to detect subtle variations in the objects' gravity fields. These variations will provide clues about the interior structure of these bodies by studying the mass distributed in each gravity field.

"The new observations of Vesta are an inspirational reminder of the wonders unveiled through ongoing exploration of our solar system," said Jim Green, planetary division director at NASA Headquarters in Washington.

Dawn launched in September 2007. Following a year at Vesta, the spacecraft will depart in July 2012 for Ceres, where it will arrive in 2015. Dawn's mission to Vesta and Ceres 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, Ala.

UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. in Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team.

For more information about Dawn, visit http://www.nasa.gov/dawn.

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Close-up View of 'Snowman' Craters

A set of three craters, nicknamed "Snowman," are seen in this image of the northern hemisphere of Vesta. This image was obtained by the framing camera on NASA's Dawn spacecraft on July 24, 2011 from a distance of about 3,200 miles (5,200 kilometers).

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

Update -- New Event Time NASA To Unveil Vesta Images At News Conference

Trent J. Perrotto

Headquarters, Washington                                        

 

Priscilla Vega                    

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- NASA will host a news conference on Monday, Aug. 1, at noon EDT, to discuss the Dawn spacecraft's successful orbit insertion around Vesta on July 15 and unveil the first full-frame images from Dawn's framing camera. The news conference will be held in the Von Karman auditorium at NASA's Jet Propulsion Laboratory (JPL), 4800 Oak Grove Dr., Pasadena, Calif. Journalists also may ask questions from participating NASA locations or join by phone.

To obtain dial-in information, journalists must contact JPL's Media Relations Office at 818-354-5011 by 8 a.m. PDT on Aug. 1.

NASA Television and the agency's website will broadcast the event. It also will be carried live on Ustream, with a live chat box available, at http://www.ustream.tv/nasajpl2.

The news conference panelists are:

-- Colleen Hartman, assistant associate administrator, Science Mission Directorate, NASA Headquarters, Washington

-- Charles Elachi, director, JPL

-- Marc Rayman, chief engineer and mission manager, JPL

-- Christopher Russell, Dawn principal investigator, University of California, Los Angeles

-- Holger Sierks, framing camera team member, Max Planck Society, Katlenburg-Lindau, Germany

-- Enrico Flamini, chief scientist, Italian Space Agency (ASI), Rome, Italy

Although Dawn is collecting some science data now, the mission's intensive collection of information will begin in early August. Observations of the giant asteroid Vesta will provide unprecedented data to help scientists understand the earliest chapter of our solar system. Dawn is the first spacecraft to orbit an asteroid in the main asteroid belt between Mars and Jupiter. After spending one year orbiting Vesta, Dawn will travel to a second destination, the dwarf planet Ceres, and arrive there in February 2015.

For more information about Dawn, visit http://www.nasa.gov/dawn.

For NASA TV streaming video, downlink and schedule information, visit http://www.nasa.gov/ntv.

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NASA Dawn Spacecraft Returns Close-Up Image Of Asteroid Vesta

Dwayne C. Brown

Headquarters, Washington                               

 

Priscilla Vega

Jet Propulsion Laboratory, Pasadena, Calif.

PASADENA, Calif. -- NASA's Dawn spacecraft has returned the first close-up image after beginning its orbit around the giant asteroid Vesta. On Friday, July 15, Dawn became the first probe to enter orbit around an object in the main asteroid belt between Mars and Jupiter.

The image taken for navigation purposes shows Vesta in greater detail than ever before. When Vesta captured Dawn into its orbit, there were approximately 9,900 miles (16,000 kilometers) between the spacecraft and asteroid. Engineers estimate the orbit capture took place at 10 p.m. PDT.

Vesta is 330 miles (530 kilometers) in diameter and the second most massive object in the asteroid belt. Ground- and space-based telescopes have obtained images of Vesta for about two centuries, but they have not been able to see much detail on its surface.

"We are beginning the study of arguably the oldest extant primordial surface in the solar system," said Dawn principal investigator Christopher Russell from the University of California, Los Angeles. "This region of space has been ignored for far too long. So far, the images received to date reveal a complex surface that seems to have preserved some of the earliest events in Vesta's history, as well as logging the onslaught that Vesta has suffered in the intervening eons."

Vesta is thought to be the source of a large number of meteorites that fall to Earth. Vesta and its new NASA neighbor are currently approximately 117 million miles (188 million kilometers) away from Earth. The Dawn team will begin gathering science data in August. Observations will provide unprecedented data to help scientists understand the earliest chapter of our solar system. The data also will help pave the way for future human space missions.

After traveling nearly four years and 1.7 billion miles (2.8 billion kilometers), Dawn also accomplished the largest propulsive acceleration of any spacecraft, with a change in velocity of more than 4.2 miles per second (6.7 kilometers per second), due to its ion engines. The engines expel ions to create thrust and provide higher spacecraft speeds than any other technology currently available.

"Dawn slipped gently into orbit with the same grace it has displayed during its years of ion thrusting through interplanetary space," said Marc Rayman, Dawn chief engineer and mission manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "It is fantastically exciting that we will begin providing humankind its first detailed views of one of the last unexplored worlds in the inner solar system."

Although orbit capture is complete, the approach phase will continue for about three weeks. During approach the Dawn team will continue a search for possible moons around the asteroid; obtain more images for navigation; observe Vesta's physical properties; and obtain calibration data.

In addition, navigators will measure the strength of Vesta's gravitational tug on the spacecraft to compute the asteroid's mass with much greater accuracy than has been previously available. That will allow them to refine the time of orbit insertion.

Dawn will spend one year orbiting Vesta, then travel to a second destination, the dwarf planet Ceres, arriving in February 2015. The mission to Vesta and Ceres is managed by JPL for the agency's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, which is managed by NASA's Marshall Space Flight Center in Huntsville, Ala.

UCLA is responsible for Dawn mission science. Orbital Sciences Corp. of Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are part of the mission's team.

To view the image and obtain more information about the Dawn mission, visit http://www.nasa.gov/dawn.

To follow the mission on Twitter, visit http://www.twitter.com/NASA_Dawn.

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