"POTENTIALLY HAZARDOUS NEAR-EARTH OBJECT 1998 KN3"

FROM:  NASA 

This image shows the potentially hazardous near-Earth object 1998 KN3 as it zips past a cloud of dense gas and dust near the Orion nebula. NEOWISE, the asteroid-hunting portion of the Wide-field Infrared Survey Explorer, or WISE, mission, snapped infrared pictures of the asteroid, seen as the yellow-green dot at upper left. Because asteroids are warmed by the sun to roughly room temperature, they glow brightly at the infrared wavelengths used by WISE. Astronomers use infrared light from asteroids to measure their sizes, and when combined with visible-light observations, they can also measure the reflectivity of their surfaces. The WISE infrared data reveal that this asteroid is about .7 mile (1.1 kilometers) in diameter and reflects only about 7 percent of the visible light that falls on its surface, which means it is relatively dark. In this image, blue denotes shorter infrared wavelengths, and red, longer. Hotter objects emit shorter-wavelength light, so they appear blue. The blue stars, for example, have temperatures of thousands of degrees. The coolest gas and dust appears red. The asteroid appears yellow in the image because it is about room temperature: cooler than the distant stars, but warmer than the dust. JPL manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. Image Credit: NASA/JPL-Caltech

NASA DAWN SPACECRAFT REVEALS SECRETS OF GIANT ASTEROID VESTA FROM: NASA

FROM:  NASA
Photo:  Asteroid Vesta.  Credit:  NASA
 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.

NASA'S DAWN SPACECRAFT OBSERVES ASTEROID CALLED VESTA

The following excerpt is from the NASA website:
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.

NEEMO 15 AND WORK ON ASTEROID SURFACES

The following article excerpt is from the NASA website:

NEEMO 15 Commander Shannon Walker (NASA) and fellow aquanaut David Saint-Jacques (Canadian Space Agency) use a small telescoping boom as a means of translating across a simulated asteroid surface. Each end of the small boom can be anchored to the surface by either magnets or tethers and the astronauts can traverse the surface by alternating anchor points. Various translation techniques are being tested during this 13-day NEEMO mission.

NEEMO, which stands for NASA Extreme Environment Mission Operations, is one facet of NASA's Analog and Field Testing Missions. As NASA plans to expand human spaceflight and robotic exploration beyond low Earth orbit, astronauts are being trained to meet these challenges. Future destinations may include the moon, near Earth asteroids and Mars and its moons.

To prepare for the challenge of exploring these destinations in space, NASA conducts missions here on Earth, in remote locations that have physical similarities to extreme space environments.