Space

April 25, 2012

NASA Dawn spacecraft reveals secrets of giant asteroid Vesta

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 and 130 miles 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 Munster 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 minus10 degrees Fahrenheit (minus 23 degrees Celsius) in the sunniest spots to as cold as minus 150 degrees Fahrenheit (minus 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 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-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.

 




All of this week's top headlines to your email every Friday.


 
 

 

Headlines August 31, 2015

News: Pilot killed in crash was helping wounded veterans – A pilot who died in a small plane crash in the desert northeast of Los Angeles was giving free glider rides to wounded military veterans. Turkey carries out first air strikes as part of anti-Isis U.S. coalition – Turkish fighter jets have carried out their first air...
 
 

News Briefs August 31, 2015

Pakistan officials: U.S. envoy discusses Afghan peace efforts Pakistani officials say visiting U.S. National Security Adviser Susan Rice has discussed efforts to revive Afghan peace talks. Rice met with Prime Minister Nawaz Sharif and army chief Gen. Raheel Sharif Aug. 30. Two Pakistani officials say they discussed efforts to revive talks between the Afghan government...
 
 
Courtesy photograph

F-22 inaugural deployment to Europe

Courtesy photograph A pair of F-22 Raptors fly near the coastline of Panama City Beach, Fla. Four F-22 Raptors, one C-17 Globemaster III, and approximately 60 airmen arrived at Spangdahlem Air Base, Germany, to train with allie...
 

 
ILS photograph

Boeing-built satellite will create first global high-speed broadband network

ILS photograph The Inmarsat-5 F3 satellite launched Aug. 28 aboard a International Launch Services Proton Breeze M rocket from Baikonur, Kazakhstan. EL SEGUNDO, Calif.–When the third Boeing-built [NYSE: BA] Inmarsat-5 sat...
 
 

Civil Air Patrol joins total force ‘Airmen’

When conducting missions for the Air Force as the official Air Force auxiliary, the Civil Air Patrol is now included in the Air Force’s definition of the total force. CAP has provided 74 years of support to emergency services, aerospace education and cadet programs. In August 2015, the Air Force updated Doctrine Volume 2, “Leadership,”...
 
 
DOD photograph by Air Force MSgt. Adrian Cadiz

Carter announces manufacturing initiative to aid war fighters

DOD photograph by Air Force MSgt. Adrian Cadiz Defense Secretary Ash Carter announces the creation of a National Manufacturing Innovation Institute to produce hybrid electronics during a speech at the National Full Scale Aerody...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>