[meteorite-list] Dawn Becomes First to Orbit a Dwarf Planet

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4503

NASA Spacecraft Becomes First to Orbit a Dwarf Planet
Jet Propulsion Laboratory
March 6, 2016

NASA's Dawn spacecraft has become the first mission to achieve orbit around 
a dwarf planet. The spacecraft was approximately 38,000 miles (61,000 
kilometers) from Ceres when it was captured by the dwarf planet's gravity 
at about 4:39 a.m. PST (7:39 a.m. EST) Friday.

Mission controllers at NASA's Jet Propulsion Laboratory in Pasadena, California 
received a signal from the spacecraft at 5:36 a.m. PST (8:36 a.m. EST) 
that Dawn was healthy and thrusting with its ion engine, the indicator 
Dawn had entered orbit as planned.

"Since its discovery in 1801, Ceres was known as a planet, then an asteroid 
and later a dwarf planet," said Marc Rayman, Dawn chief engineer and mission 
director at JPL. "Now, after a journey of 3.1 billion miles (4.9 billion 
kilometers) and 7.5 years, Dawn calls Ceres, home."

In addition to being the first spacecraft to visit a dwarf planet, Dawn 
also has the distinction of being the first mission to orbit two extraterrestrial 
targets. From 2011 to 2012, the space-craft explored the giant asteroid 
Vesta, delivering new insights and thousands of images from that distant 
world. Ceres and Vesta are the two most massive residents of our solar 
system's main asteroid belt between Mars and Jupiter.

The most recent images received from the spacecraft, taken on March 1, 
show Ceres as a crescent, mostly in shadow because the spacecraft's trajectory 
put it on a side of Ceres that faces away from the sun until mid-April. 
When Dawn emerges from Ceres' dark side, it will deliver ever-sharper 
images as it spirals to lower orbits around the planet.

"We feel exhilarated," said Chris Russell, principal investigator of the 
Dawn mission at the University of California, Los Angeles (UCLA). "We 
have much to do over the next year and a half, but we are now on station 
with ample reserves, and a robust plan to obtain our science objectives."

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 mission participants, visit:

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

For more information about Dawn, visit:

http://www.nasa.gov/dawn

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

Dwayne Brown
NASA Headquarters, Washington
202-358-1726
dwayne.c.brown at nasa.gov

2015-080