NASA has selected three proposals for implementation for
the Solar Dynamics Observatory (SDO) mission. The SDO is the
first in a series of missions in the Living With a Star (LWS)
Program. SDO flight instruments will be flown on a NASA-
supplied Sun-pointing spacecraft in geosynchronous orbit that
NASA intends to launch in August 2007 for a prime mission of
five years.

“The Solar Dynamics Observatory is the cornerstone of the new
Living with a Star program,” said Dick Fisher, director of
the Sun-Earth Connection Division in NASA’s Office of Space
Science in Washington. “The SDO mission is designed to
provide new data concerning the nature and consequences of
solar variability to humanity and will directly contribute to
NASA’s mission to understand and protect the home planet.”

The LWS initiative addresses aspects of the Sun-Earth system
that affect life and society. The primary goal of the SDO
mission is to understand and, ideally, predict the solar
variations that influence life on Earth and humanity’s
technological systems. SDO will do this by determining how
the Sun’s magnetic field is generated and structured and how
this stored magnetic energy is converted and released into
the heliosphere and geospace in the form of solar wind (a
magnetized plasma), energetic particles, and variations in
the solar brightness.

The three selected proposals were judged to have the best
science value among the eight proposals submitted to NASA in
January 2002 in response to the SDO Announcement of
Opportunity. Each selected investigation will work with the
SDO office at NASA’s Goddard Space Flight Center (GSFC),
Greenbelt, Md., to finalize the spacecraft’s accommodation of
the instrument sets. Total cost of the payload to NASA from
development through five years of operation is about $123
million. The SDO spacecraft is being provided by GSFC.

The investigations selected by NASA for SDO are:

* Helioseismic and Vector Magnetic Imager (HVMI), as the
prime SDO investigation will study the origin of solar
variability by characterizing and developing an understanding
of Sun’s interior and the various components of its magnetic
activity. Dr. Philip Scherrer of Stanford University, Palo
Alto, Calif., is the principal investigator. Instrumentation
will be developed with the assistance of a Lockheed Martin

* Solar Heliospheric Activity Research and Prediction
Program (SHARPP) uses two instruments: an Atmospheric Imaging
Assembly (AIA) and a white light coronagraph (WCI). SHARPP’s
instruments will study the dynamic solar atmosphere, linking
the HVMI interior and surface measurements to the overlying
corona to learn how and why the Sun’s atmosphere varies. With
unprecedented time and spatial resolution, SHARPP should
develop space weather predictions for the terrestrially
important phenomena. Dr. Russell Howard of the Naval Research
Laboratory, Washington, D.C. will lead a large international
team as the SHARPP principal investigator.

* Extreme Ultraviolet Variability Experiment (EVE) will
measure the solar extreme ultraviolet (EUV) irradiance with
great detail and precision and apply physics-based modeling
to advance understanding of the EUV irradiance variations
based on the Sun’s magnetic features. Solar EUV energy heats
the upper atmosphere of the Earth. The EVE investigation is
lead by Dr. Thomas Woods from the Laboratory for Atmospheric
and Space Physics of the University of Colorado, Boulder,

“Both government and civilian users of space weather data
have expressed keen interest in the new information
anticipated from the SDO mission,” Fisher said.

Living With a Star is part of the Sun-Earth Connection
Division within NASA’s Office of Space Science, Washington.
The SDO mission brings together teams from university,
industry, and NASA Center communities and is a multilateral
international collaboration involving participants from
Belgium, Denmark, France, Germany, Italy, Japan, England, and
the United States.

For more information on NASA’s Living With A Star program,