NASA's Asteroid Photographer Beams Back Science Data

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109
http://www.jpl.nasa.gov

Feature Aug. 11, 2011

NASA's Asteroid Photographer Beams Back Science Data

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-250&cid=release_2011-250

The Dawn spacecraft has completed a graceful spiral into the first of four planned science
orbits during the spacecraft's yearlong visit to Vesta. The spacecraft started taking
detailed observations on Aug. 11 at 9:13 a.m. PDT (12:13 a.m. EDT), which marks the
official start of the first science-collecting orbit phase at Vesta, also known as the survey
orbit.

Survey orbit is the initial and highest orbit, at roughly 1700 miles (2700 kilometers) above
the surface, which will provide an overview or "big picture" perspective of the giant
asteroid.

The primary objective of survey orbit is to image the surface with near-global coverage in
visible and infrared wavelengths with the mapping spectrometer, also known as VIR.
Dawn also will be using its framing camera to collect image mosaics that complement the
VIR spectral data to produce geologic and compositional maps of Vesta's surface.
Ultrasensitive measurements of the spacecraft's motion using radio signals will allow
improved understanding of the giant asteroid's gravity field. Dawn's gamma ray and
neutron detector will continue to collect background data.

The survey phase is planned to last 20 days. Each orbit takes almost three days, which
will provide the spacecraft seven trips around Vesta. After survey orbit, Dawn will
resume thrusting, taking about a month to spiral down gently to its next science orbit for
an even closer view. That orbit, known as High Altitude Mapping Orbit, or HAMO,
begins in late September. Dawn will spend about a month in HAMO, circling around
Vesta in half a day, rather than three. Dawn will orbit more than 60 times during HAMO,
allowing the camera to fully map the illuminated portion of Vesta at even higher
resolution, and enable the science team to generate stereo images.

For more information about Dawn, visit: http://www.nasa.gov/dawn and
http://dawn.jpl.nasa.gov .

Dawn launched in September 2007 and arrived at Vesta in July 2011. Following a year at
Vesta, the spacecraft will depart in July 2012 for Ceres, where it will arrive in 2015.
Dawn's mission to Vesta and Ceres is managed by the Jet Propulsion Laboratory,
Pasadena, Ca., for NASA's Science Mission Directorate in Washington. JPL is a division
of the California Institute of Technology in Pasadena. Dawn is a project of the
directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in
Huntsville, Ala.?? UCLA is responsible for overall Dawn mission science. Orbital
Sciences Corp. in Dulles, Va., designed and built the spacecraft. The German Aerospace
Center, the Max Planck Institute for Solar System Research, the Italian Space Agency
and the Italian National Astrophysical Institute are international partners on the mission
team.

-end-

Priscilla Vega
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-1357
Priscilla.r.vega@jpl.nasa.gov
2011-250

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