The US space agency, NASA, declared that the Dawn spacecraft, which was launched in 2007, has entered an approach phase in which it will continue to close in on Ceres, a Texas-sized dwarf planet never before visited by a spacecraft.
The Dawn spacecraft is scheduled to enter Ceres orbit on March 6, 2015. According to NASA statement, the spacecraft’s arrival at Ceres will mark the first time that a spacecraft has ever orbited two solar system targets.
Christopher Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles, said, “Ceres is almost a complete mystery to us.” The interplanetary explorer is currently 640,000 km from Ceres, approaching the asteroid at around 725 km per hour.
He added, “Ceres, unlike Vesta, has no meteorites linked to it to help reveal its secrets. All we can predict with confidence is that we will be surprised.” Dawn has previously explored the protoplanet Vesta for 14 months, from 2011 to 2012, capturing detailed images and data about that body.
Ceres, with an average diameter of 950 km, is the largest object in the main asteroid belt between Mars and Jupiter. When compared to Ceres, Vesta has an average diameter of 525 km, and is the second most massive body in the belt.
The two planetary bodies are thought to be different in a few important ways. Ceres have formed later than Vesta, with a cooler interior. Current evidence suggests that Vesta only retained a small amount of water because it formed earlier, when radioactive material was more abundant, which would have produced more heat. Also, in contrast, Ceres has a thick ice mantle and may even have an ocean beneath its icy crust.
The spacecraft uses ion propulsion to traverse space far more efficiently than if it used chemical propulsion. Thus, the spacecraft is closing in on Ceres using its advanced ion propulsion system to match solar orbits with the dwarf planet.
“Orbiting both Vesta and Ceres would be truly impossible with conventional propulsion. Thanks to ion propulsion, we’re about to make history as the first spaceship ever to orbit two unexplored alien worlds,” said Marc Rayman, Dawn’s chief engineer and mission director, said in a statement.
As per reports from IANS, Ceres is of great interest to astronomers and scientists, who believe that the small dwarf planet may also be a large water reservoir in the inner solar system aside from the Earth. However, scientists are unsure how much of that water is actually liquid.