Dawn’s imagery of Ceres keeps getting better

These two views of Ceres were acquired by NASA’s Dawn spacecraft on Feb.

12, 2015, from a distance of about 52,000 miles (83,000 kilometers) as

the dwarf planet rotated. The images, which were taken about 10 hours

apart, have been magnified from their original size. Credit:

NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Excerpt from spaceflightnow.com


Images from NASA’s Dawn spacecraft on approach to the dwarf planet

Ceres show a world pockmarked by craters and mysterious bright spots,

and scientists are eager for a better look in the weeks ahead.

The latest images were taken Feb. 12 at a distance of 52,000 miles,

or 83,000 kilometers, from Ceres. NASA released the fresh views Tuesday.

Every picture taken of Ceres in the coming weeks will show greater

detail, as Dawn is set to be captured by the Texas-sized world’s gravity

March 6. The dwarf planet will pull Dawn into the first of a series of

survey orbits 8,400 miles from Ceres around April 23.

The imagery so far reveals Ceres as a cratered world, and Dawn will

make a global map of the dwarf planet during its time in orbit.

But several bright spots have captured the attention of scientists.

“As we slowly approach the stage, our eyes transfixed on Ceres and

her planetary dance, we find she has beguiled us but left us none the

wiser,” said Chris Russell, principal investigator of the Dawn mission,

based at UCLA. “We expected to be surprised; we did not expect to be

this puzzled.”

The suspense is compounded by Dawn’s slow rate of approach. The

probe’s ion propulsion system is gradually nudging Dawn on a trajectory

closer to Ceres, eventually moving the spacecraft close enough to be

grasped by the 590-mile diameter dwarf planet’s gravity.

“I want to know what is causing the bright spots,” Russell wrote in

an email to Spaceflight Now. “The increased resolution seems to have

moved us no closer to answering this mystery. I am frustrated by the

suspense. This is the one problem of ion propulsion: We are closing in

on Ceres very slowly.”

The latest photos have a resolution have 4.9 miles, or 7.8 kilometers, per pixel, according to a NASA press release.

Dawn’s framing camera will take its next set of images Feb. 20 at a

range of about 30,000 miles. After late February, the resolution of

Dawn’s imagery will be reduced as the spacecraft passes Ceres and flies

in front of it, before being pulled closer in early April for insertion

into orbit.

Soon after arriving in April, the spacecraft’s instruments will look

for the signature of water vapor plumes shooting into space from the

surface of Ceres, which may be blanketed in a crust of ice.

Dawn will orbit closest to Ceres in December at an altitude of 232 miles.

Dawn’s mission planners say the spacecraft could operate around Ceres until late 2016.

Ceres is the second destination for NASA’s Dawn mission, which

launched in September 2007 and visited asteroid Vesta in 2011 and 2012.

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Dawn’s imagery of Ceres keeps getting better