Orbital Dawn - Manual

Planetary
Exploration
Mission Description
Dawn is a planetary space science mission funded by NASA’s Discovery Program for which Orbital is
partnered with Principal Investigator Chris Russell of UCLA and the Jet Propulsion Laboratory (JPL).
Dawn’s primary scientific objective is to advance our understanding of the origin and evolution of
the solar system by studying two of the largest asteroids, Vesta and Ceres, which appear to have
remained intact since their formation 4.6 billion years ago. Earth-based studies indicate that these two
protoplanets have very different and complementary compositions which may provide clues to the
conditions and processes of planetary formation.
Powered by solar electric ion propulsion, the Dawn spacecraft has traveled to the main asteroid
belt between Mars and Jupiter. In July 2011 Dawn arrived at Vesta and spent a year orbiting the
asteroid conducting remote sensing observations using a suite of science instruments. The spacecraft
departed Vesta in August 2012 and is currently en-route to Ceres where it will perform the same set of
measurements.
About Dawn's Ion Propulsion
The Dawn spacecraft is NASA's first purely scientific mission powered by solar electric ion propulsion,
the world’s most advanced and efficient space propulsion technology. Ion propulsion is providing
the velocity needed for its journey to Vesta. Ion propulsion will also be used during asteroid proximity
operations to raise and lower the orbit altitude. Dawn’s ion propulsion system is based on the
technology successfully demonstrated by Deep Space 1.
Vesta, the brightest asteroid, is named
for the ancient Roman goddess of the
hearth and is the only asteroid visible
with the naked eye.
Ceres, the largest asteroid and the first
to be discovered, revolves around the
Sun once every 4.6 terrestrial years and
has a diameter estimated at about 960
km (575 miles).
The ion propulsion system employed
by Dawn and pioneered on NASA's
Deep Space 1 mission represents
the culmination of over 50 years of
development of electric engine systems
in space begun by Dr. Wernher von
Braun.
Mission:
NASA Discovery program
Customer:
UCLA, Jet Propulsion Laboratory
FACTS AT A GLANCE
Dawn prior to launch
Dawn
Investigating the "Dawn" of Our Solar System
LEO