Although it is almost ten times smaller than the Earth’s Moon, Ceres is the largest object in the asteroid belt (the cluster of asteroids and minor planets between Mars and Jupiter). It is the only celestial body of this cluster which is unambiguously rounded by its own gravity. The only Dwarf planet in the Inner Solar System, Ceres has awoken scientists’ interest because its craters indicate the presence of ice or salts. Besides, in January 2014, emissions of vaporized water were noticed from several regions on the dwarf planet. Today, NASA’s spacecraft Dawn has begun orbiting Ceres to investigate it, after having been around the asteroid Vesta for a year.
Dawn was sent on its mission in 2007, aiming to explore the celestial objects in the asteroid belt, a zone of the Solar System filled with traces of the formation of the Sun and planets, which is estimated to have occurred 4.5 billion years ago. The cost of the whole mission rises up to $473 million. The spacecraft was programmed to slip into orbit around Ceres in order to take pictures of the dwarf planet. The process of entering the orbit went very smoothly, unlike most analogous situations, which generally require a slowing down of thruster firings. This time, the orbit capture happened gradually, without need for intervention.
The confirmation from the Dawn spacecraft will be received by flight managers some hours later, because the device is out of contact with Earth. Now that it has begun to circle Ceres, Dawn will remain in its orbit for 16 months, in order to take pictures of the icy surface of the dwarf planet and help us find out whether there is still any activity beyond it. “The real drama is exploring this alien, exotic world,” Marc Rayman, mission chief engineer at the NASA Jet Propulsion Laboratory, enthusiastically declared.
Ceres is the last stop for the NASA spacecraft. Dawn was able to travel that far because of its ion propulsion engines, which guarantee a constant acceleration and are thus better than other thrusters used before. The space vehicle is scheduled to spiral closer to the surface of the dwarf planet in order to study the reflective surfaces spotted inside a crater (possibly salt or ice) and to find out whether water vapour emission is still on-going.
image source: The Japan Times