Intrepid solar spacecraft celebrates 10th anniversary

Nancy Neal-Jones/Cynthia O'Carroll
November 29, 2005
NASA Goddard Space Flight Center, Greenbelt, Md. 9 a.m.
EST
Phone: (301) 286-0039/4647

Release 05-50

INTREPID SOLAR SPACECRAFT CELEBRATES 10TH ANNIVERSARY

The Solar and Heliospheric Observatory (SOHO) spacecraft celebrates its 10th
anniversary Dec. 2. The SOHO mission, a collaboration between NASA and the
European Space Agency (ESA), has allowed scientists to make significant
advances in understanding the closest star, our sun. This includes
understanding the violent solar activity that causes stormy space weather,
which can disrupt satellites, radio communication and power systems on
Earth.

"It's impossible to overstate the importance of SOHO to the worldwide solar
science community," said Dr. Joe Gurman, U.S. project scientist for SOHO at
NASA's Goddard Space Flight Center, Greenbelt, Md. "In the last ten years,
SOHO has revolutionized our ideas about the solar interior and atmosphere
and the acceleration of the solar wind."

Some of SOHO's major scientific accomplishments include:

- Allowing space weather forecasters to play a lead role in the early
warning system for space weather and give up to three days notice of
Earth-directed disturbances.

- Supplying the most detailed and precise measurements beneath the surface
of the sun.

- Providing the first images of a star's turbulent outer shell (the
convection zone) and of the structure of sunspots beneath the solar surface.

- Making the sun transparent by creating images of the sun's far side,
including stormy regions there that will turn with the sun and threaten the
Earth.

- Discovering a mechanism that releases more than enough energy to heat the
sun's atmosphere (corona) to 100 times its surface temperature.



- Discovering that a series of eruptions of ionized gas (coronal mass
ejections) from the sun blasts a "highway" through space where solar
energetic particles flow. These particles disrupt satellites and are
hazardous to astronauts outside the protection of Earth's magnetic field.

- Monitoring the sun's energy output (the "total solar irradiance" or "solar
constant") as well as variations in the sun's extreme ultraviolet radiation,
both of which are important to understand the impact of solar variability on
Earth's climate.

- Identifying the source regions and acceleration mechanisms of the solar
wind, a thin stream of ionized gas that constantly flows from the sun and
buffets Earth's magnetosphere.

SOHO data are freely available over the Internet, and people all over the
world have used images from the observatory to discover more than 1,000
comets.

"I tip my hat to SOHO's engineering and operations teams, whose skills and
dedication have overcome multiple technical challenges over the last decade,
such as the loss of control of the spacecraft in 1998, the loss of the gyros
when we recovered the spacecraft a few months later, and a sticky high gain
antenna in 2003," said Dr. Bernhard Fleck, ESA Project Scientist for SOHO.

The observatory was originally designed for a two-year mission, but its
scientific insights have proven so valuable that NASA has consistently
granted it extensions, the latest of which allows the spacecraft to cover a
complete 11-year solar cycle.

For more information about SOHO on the Web, visit:


http://www.nasa.gov/vision/universe/.../soho2005.html


For information about NASA and agency programs on the Web, visit:


http://www.nasa.gov


Video in support of this release will be available on Dec. 2 and 5 on NASA
TV. NASA TV's Video-File news feed is broadcast on the agency's Media
Channel (Program 103) at 12 p.m. (Eastern), with replays at 3, 6, and 10
p.m. and 12, 6, and 10 a.m. The NASA TV Media Channel is available on an
MPEG-2 digital C-band signal accessed via satellite AMC-6, at 72 degrees
west longitude, transponder 17C, 4040 MHz, vertical polarization. In Alaska
and Hawaii, it's available on AMC-7 at 137 degrees west longitude,
transponder 18C, at 4060 MHz, horizontal polarization. A Digital Video
Broadcast compliant Integrated Receiver Decoder is required for reception.
For digital downlink information for NASA TV's Media Channel (Program 103)
on the Web, visit:


http://www.nasa.gov/ntv


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Jacques :-)

www.spacepatches.info