NASA spacecraft nears dwarf planet Ceres

The NASA science spacecraft Dawn on Friday wrapped up a more than seven-year journey to Ceres, an unexplored dwarf planet in the main asteroid belt, between Mars and Jupiter.

Dawn shifted its path to allow itself to be captured by Ceres’ gravity at 7:39 a.m. Eastern time, becoming the first spacecraft to orbit a dwarf planet.

“We feel exhilarated,” said lead researcher Chris Russell of the University of California at Los Angeles in a statement after Dawn radioed back to Earth.

Dawn visited the asteroid Vesta before firing its electric ion engine to continue to Ceres, a round 600-mile-wide mini-planet that is the largest body in the asteroid belt. Earth’s moon, by comparison, is about 2,160 miles in diameter.

Scientists are eager for their first close-up look at a dwarf planet, believed to be a building block left over from the formation of the planets 4.6 billion years ago. “They’re literally fossils that we can investigate to understand the processes that were going on at that time,” said Dawn scientist Carol Raymond of the Jet Propulsion Laboratory.

Another NASA spacecraft, New Horizons, will fly by the distant dwarf planet Pluto in July. Pluto, once considered one of the planets of the solar system, has been downgraded to a dwarf planet.

Ceres, a namesake of the Roman goddess of agriculture, is already providing intrigue. Pictures relayed from Dawn last month show bright streaks on its surface, including two very bright spots inside a crater. “These spots were extremely surprising,” Raymond said. Scientists suspect Ceres may have had an underground ocean early in its history that later froze. Impacting asteroids or comets could then have exposed patches of highly reflective ice.

Europe’s Herschel space-based telescope previously detected water vapor on Ceres, a clue that impacting bodies may periodically send plumes of watery material shooting into space. “In the initial views of Ceres, we see many strange features —smooth areas, areas that chaotically fractured and craters of all shapes and sizes,” Raymond said. “Of particular interest are the bright spots ... which stand out against Ceres’ dark surface.”

It will take Dawn about a month to position itself for 14 months of observations of Ceres. In all, the mission is costing NASA $473 million.

Al Jazeera and Reuters