Dawn has sent its first close-up image of Vesta, located approximately 190 million km away. The image, reveals the rugged surface of Vesta. This is the first good view of this small world, since its discovery, in 1807. Previous images, taken while Dawn was approaching Vesta, were of much less detail.
Asteroids are small rocky objects, mainly orbiting the Sun between the orbits of Mars and Jupiter. They are believed to be primitive objects, leftovers from the birth of the Solar System, which remained presumably unchanged. Their close study would yield new insights into the origin and evolution of the Solar System.
Vesta (530 km across) is the second largest object in the asteroid belt, after the dwarf planet Ceres (approximately 930 km across). Therefore, Dawn is the first artificial satellite of an object of the asteroid belt. Interestingly, Vesta is thought to be the source of a large number of meteorites that fall to Earth. Vest orbits the Sun every 3.6 years, at an average distance of approximately 353 million km.
"We are beginning the study of arguably the oldest extant primordial surface in the Solar System," said Christopher Russell, Dawn principal investigator. "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."
"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). "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."
Dawn’s main science mission will begin in August. The mission’s unprecedented observations would provide a new understanding of the formation of our Solar System. They will also help pave the way for future manned space missions.
Dawn has voyaged in interplanetary space for nearly four years and 2.8 billion km, deploying ion engines. These engines expel ions to generate thrust, and provide higher spacecraft speeds than any other technology currently available.
Following orbit insertion, Dawn will be approaching Vesta further, searching for possible moons around the asteroid. It will also obtain more images for navigation; observe Vesta's physical properties; and obtain other interesting data. In addition, Dawn’s team will measure the gravitational pull of Vesta on the spacecraft, to compute the asteroid's mass with much greater accuracy than has been previously available. Dawn will study Vesta for a year, then cruise to a new destination, Ceres, arriving in February 2015.
References
NASA
www.nasa.gov/
Official Dawn Mission Website
http://www.nasa.gov/dawn
http://dawn.jpl.nasa.gov