NASA spacecraft, New Horizon is getting close to dwarf planets
- January 26, 2015
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NASA's Dawn spacecraft is closing in on the dwarf planet Ceres, agency scientists say-the first time a spacecraft is expected to visit a dwarf planet.
A second such event is planned in July when another NASA craft, New Horizons, reaches Pluto, which was reclassified from planet to dwarf planet in 2006.
Ceres, about big enough to snugly fit Bolivia or Ethiopia on its surface, is much closer than Pluto. It orbits the Sun as part of the “main asteroid belt” between the planets Mars and Jupiter.
New pictures show Ceres at 27 pixels across. These aren't its best-ever images, according to NASA-the Hubble Space Telescope snapped those about a decade ago-but closer-ups later this month are expected to surpass the Hubble photos in quality.
Plans call for Dawn to then start circling Ceres March 6, for a 16-month study and more pictures.
“We know so much about the solar system and yet so little about dwarf planet Ceres. Now, Dawn is ready to change that,” said Marc Rayman, Dawn's chief engineer and mission director, based at NASA's Jet Propulsion Laboratory in Pasadena, California.
The latest images hint at “surface structures such as craters,” said Andreas Nathues, lead investigator for the framing camera team at the Max Planck Institute for Solar System Research, Gottingen, Germany.
“We look forward to the surprises this mysterious world may bring,” added Chris Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles.
A dwarf planet is defined as a planet-like body that is too small to clear most other bodies out of its path by means of its gravity as it orbits a star.
Ceres is measured to be the main asteroid's belt largest body. It has an average width of 590 miles (950 km), and is thought to contain lots of ice, with possibly even an ocean underneath. The newest images are from Jan. 13.
Dawn has already delivered more than 30,000 images and many insights about Vesta, the main asteroid belt's second heaviest body, NASA said. Dawn orbited Vesta, which has an average width of 326 miles (525 kilometers), from 2011 to 2012. Thanks to a new propulsion system called ion propulsion, Dawn is the first spacecraft ever targeted to orbit two deep-space destinations.
Source : www.world-science.net