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January 20, 2015

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Spacecraft closes in on dwarf planet, takes pictures

Jan. 20, 2015
Courtesy of JPL
and World Science staff

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.

The Dawn spacecraft watched Ceres for an hour on Jan. 13, from 238,000 miles (383,000 km) away.


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.


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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 reach a dwarf planet. A second visit to a dwarf planet is expected 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 start circling Ceres March 6, for a 16-month study. “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. Ceres is measured to be the main asteroid’s belt largest body. It has an average width of 590 miles (950 kilometers), 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. 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.