[meteorite-list] Movie Shows Ceres at Opposition from Sun

[Ron Baalke]

https://www.jpl.nasa.gov/news/news.php?feature=6845

Movie Shows Ceres at Opposition from Sun
Jet Propulsion Laboratory
May 16, 2017

NASA's Dawn spacecraft successfully observed Ceres at opposition on April 
29, taking images from a position exactly between the sun and Ceres' surface. 
Mission specialists had carefully maneuvered Dawn into a special orbit 
so that the spacecraft could view Occator Crater, which contains the brightest 
area of Ceres, from this new perspective.

A new movie shows these opposition images, with contrast enhanced to highlight 
brightness differences. The bright spots of Occator stand out particularly 
well on an otherwise relatively bland surface. Dawn took these images 
from an altitude of about 12,000 miles (20,000 kilometers).

Based on data from ground-based telescopes and spacecraft that previously 
viewed planetary bodies at opposition, scientists correctly predicted 
that Ceres would appear brighter from this opposition configuration. This 
increase in brightness, or "surge," relates the size of the grains of 
material on the surface, as well as the porosity of those materials. The 
science motivation for performing these observations is further explained 
in the March issue of the Dawn Journal blog.

Dawn's observations of Ceres during its more than two years there cover 
a broader range of illumination angles than almost any body in the solar 
system. This provides scientists with an opportunity to gain new insights 
into the surface properties. They are currently analyzing the new data.

The new observations and images were largely unaffected by the loss of 
function of Dawn's third reaction wheel. The spacecraft is healthy and 
orients itself using its hydrazine thrusters.

Dawn's mission is managed by JPL for NASA's Science Mission Directorate 
in Washington. Dawn is a project of the directorate's Discovery Program, 
managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. 
UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., 
in Dulles, Virginia, designed and built the spacecraft. The German Aerospace 
Center, Max Planck Institute for Solar System Research, Italian Space 
Agency and Italian National Astrophysical Institute are international 
partners on the mission team.

For a complete list of Dawn mission participants, visit:

https://dawn.jpl.nasa.gov/mission

News Media Contact
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau at jpl.nasa.gov

2017-140