NASA probe starts Vesta mission

NASA's Dawn robotic science probe has entered the orbit around the asteroid Vesta to study the second most massive of its kind in the solar system. The year-long exploration will be the first probe to enter the orbit of an object in the main asteroid belt between Mars and Jupiter, NASA said. "Dawn's study of the asteroid Vesta marks a major scientific accomplishment and also points the way to the future destinations where people will travel in coming years," NASA Administrator Charles Bolden said in a statement. Dawn, which slipped into the orbit of the potato-shaped Vesta on Saturday, will be the first spacecraft to orbit two solar system destinations beyond Earth, Reuters reported. Dawn was first sent to Vesta in 2007 as the first stage of a USD 466 million quest to learn more about how the solar system formed 4.5 billion years ago. The mission aims to provide clues about planetary formation and the early image of Earth by taking precise measurements and pictures of the asteroids. The probe is scheduled to leave for its second destination, a dwarf planet called Ceres, in July 2012. Vesta and Ceres are two of the largest surviving protoplanets -- rocky bodies that nearly had enough mass to become full-fledged planets -- in the solar system. "These are two of the last unexplored worlds in our inner solar system," said Dawn project manager Robert Mase. Scientists believe Vesta is more similar to Earth or the moon than most of its other asteroid neighbors due to its iron core and possible lava flows. Ceres, on the other hand, resembles the icy moons of Jupiter and Saturn with water-bearing minerals and possibly a weak atmosphere. The largest object in the asteroid belt is relatively close to Vesta but it formed under vastly different circumstances. Dawn's Ceres mission is expected to last six months.