An image of asteroid Vesta, the most massive asteroid, acquired by NASA’s Dawn spacecraft, currently in orbit around Vesta. Vesta was about 180 million km away from Earth, at the time of taking the image. Dawn was at a distance of about 5,200 km from Vesta.
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
NASA's recently published wonderful images of asteroid Vesta, acquired by the Dawn spacecraft, currently in orbit around Vesta, for a year-long study of this small enigmatic world. (The name Vesta comes from Roman mythology.) The images reveal Vesta’s rugged terrain, including numerous impact craters and large grooves. Intriguingly, Vesta is characterized by a huge deep crater (460 km wide), located near its south pole.
The asteroids are small rocky objects, orbiting the Sun mainly between the orbits of Mars and Jupiter, in a zone termed the asteroid belt. They are believed to be primitive material, leftovers from the formation of the Solar System. By studying Vesta, scientists hope to gain a better understanding of the origin and evolution of the Solar System.
Vesta (about 530 km across) is the most massive asteroid, and the second most massive object in the asteroid belt, after the dwarf planet Ceres (about 930 km across). Vesta orbits the Sun every 3.63 years, at an average distance of approximately 350 million km. Vesta’s day is very short, since it takes five hours and 20 minutes, to rotate once about its axis.
Dawn is the first mission ever to orbit an object in the asteroid belt. It will image Vesta, and study its chemical composition, applying three instruments. Dawn arrived at Vesta, and successfully entered orbit around it, on 16 July 2011. On 11 August 2011, Dawn achieved the first science orbit, the first of four orbits, on which it will conduct its main study of Vesta.
Dawn was launched in September 2007, from Cape Canaveral Air Force Station in Florida, aboard the powerful Delta II rocket. It has voyaged through the interplanetary space, for nearly four years, and traversed 2.8 billion km, to reach Vesta.
When Dawn accomplishes its mission, it will leave Vesta orbit, and begin a new long journey to a new target, the dwarf planet Ceres. It is expected that Dawn will reach Ceres in 2015. One of Dawn’s primary goals is to contrast the formation and evolution of Ceres and Vesta, which are believed to have evolved differently.
References
NASA
www.nasa.gov/
Wikipedia
Further Reading
http://www.nasa.gov/dawn