NASA is extending the international
Cassini-Huygens mission by two years. The historic spacecraft's
stunning discoveries and images have revolutionized our knowledge of
Saturn and its moons.
Cassini's mission originally had been scheduled to end in July 2008.
The newly-announced two-year extension will include 60 additional
orbits of Saturn and more flybys of its exotic moons. These will
include 26 flybys of Titan, seven of Enceladus, and one each of
Dione, Rhea and Helene. The extension also includes studies of
Saturn's rings, its complex magnetosphere, and the planet itself.
"This extension is not only exciting for the science community, but
for the world to continue to share in unlocking Saturn's secrets, "
said Jim Green, director, Planetary Science Division, NASA
Headquarters, Washington. "New discoveries are the hallmarks of its
success, along with the breathtaking images beamed back to Earth that
are simply mesmerizing."
"The spacecraft is performing exceptionally well and the team is
highly motivated, so we're excited at the prospect of another two
years, " said Bob Mitchell, Cassini program manager at NASA's Jet
Propulsion Laboratory in Pasadena, Calif.
Based on findings from Cassini, scientists think liquid water may be
just beneath the surface of Saturn's moon, Enceladus. That's why the
small moon, only one-tenth the size of Titan and one-seventh the size
of Earth's moon, is one of the highest-priority targets for the
extended mission.
Cassini discovered geysers of water-ice jetting from the Enceladus'
surface. The geysers, which shoot out at a distance three times the
diameter of Enceladus, feed particles into Saturn's most expansive
ring. In the extended mission, the spacecraft may come as close as 15
miles from the moon's surface.
Cassini's observations of Saturn's largest moon, Titan, have given
scientists a glimpse of what Earth might have been like before life
evolved. They now believe Titan possesses many parallels to Earth,
including lakes, rivers, channels, dunes, rain, snow, clouds,
mountains and possibly volcanoes.
"When we designed the original tour, we really did not know what we
would find, especially at Enceladus and Titan, " said Dennis Matson,
the JPL Cassini project scientist. "This extended tour is responding
to these new discoveries and giving us a chance to look for more."
Unlike Earth, Titan's lakes, rivers and rain are composed of methane
and ethane, and temperatures reach a chilly minus 290 degrees
Fahrenheit. Although Titan's dense atmosphere limits viewing the
surface, Cassini's high-resolution radar coverage and imaging by the
infrared spectrometer have given scientists a better look.
Other activities for Cassini scientists will include monitoring
seasons on Titan and Saturn, observing unique ring events, such as
the 2009 equinox when the sun will be in the plane of the rings, and
exploring new places within Saturn's magnetosphere.
Cassini has returned a daily stream of data from Saturn's system for
almost four years. Its travel scrapbook includes nearly 140, 000
images and information gathered during 62 revolutions around Saturn,
43 flybys of Titan and 12 close flybys of the icy moons.
More than 10 years after launch and almost four years after entering
into orbit around Saturn, Cassini is a healthy and robust spacecraft.
Three of its science instruments have minor ailments, but the impact
on science-gathering is minimal. The spacecraft will have enough
propellant left after the extended mission to potentially allow a
third phase of operations. Data from the extended mission could lay
the groundwork for possible new missions to Titan and Enceladus.
Cassini launched Oct. 15, 1997, from Cape Canaveral, Fla., on a
seven-year journey to Saturn, traversing 2.2 billion miles. It is one
of the most scientifically capable spacecraft ever launched, with a
record 12 instruments on the orbiter and six more instruments on the
European Space Agency's Huygens probe, which piggybacked a ride to
Titan on Cassini. Cassini receives electrical power from three
radioisotope thermoelectric generators, which generate electricity
from heat produced by the natural decay of plutonium. The spacecraft
was captured into Saturn orbit in June 2004 and immediately began
returning data to Earth.
The Cassini-Huygens mission is a cooperative project between NASA, the
European Space Agency and the Italian Space Agency.
For more information on the Cassini-Huygens mission, visit:
www.nasa.gov/cassini">http://www.nasa.gov/cassini
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