The veils of Saturn’s most mysterious moon have begun to lift in
Cassini’s eagerly awaited, first glimpse of the surface of Titan, a
world where scientists believe organic matter rains from hazy skies
and seas of liquid hydrocarbons dot a frigid surface.
Titan, a major target of interest for the Cassini orbiter, and the
destination of its piggybacked, European-built Huygens probe, may hold
clues to Earth’s hydrological cycle, its greenhouse effect, and even
the origins of life.
Images returned in mid-April by NASA’s Saturn-bound Cassini
spacecraft, showing features previously observed only in Earth-based
telescopes, have imaging scientists excited and optimistic about the
prospects for a successful upcoming exploration of the haze-enshrouded
moon that has intrigued planet-watchers for decades. Titan, nearly
the size of Mercury at 5,100 kilometers (3,200 miles) across, is the
largest single expanse of unexplored terrain remaining in the solar
system today.
The Titan-viewing geometry presently available to Cassini on its
approach to Saturn is not optimal. Nonetheless, surface features on
the moon several hundred kilometers (a couple of hundred miles) across
are apparent. Over the next two months, features as small as 44
kilometers (28 miles) should become visible.
“This is our first moment of reckoning,” said Dr. Carolyn Porco,
leader of the imaging team and director of the Cassini Imaging Central
Laboratory for Operations (CICLOPS) at the Space Science Institute in
Boulder, Colo. “The mere fact that we can see the surface at all with
just some rudimentary image processing, when the geometry for surface
viewing is not the most favorable, says that in a very short time, we
can rightfully expect to see sights on Titan that have never been seen
before by anyone.”
John Barbara, an imaging team associate and scientific analyst at
NASA’s Goddard Institute for Space Studies in New York, is interested
in detecting clouds in the lower Titan atmosphere and measuring their
motions. Seeing near-surface clouds through the hazy Titan atmosphere
carries the same challenges as seeing the surface. “At this stage in
the game, to discern large-scale surface features is really quite
exciting’, he said. ‘It’s a wonderful indication that, if there are
large cloud systems near the Titan surface, we will likely see them.”
The next test will come on July 2, when the spacecraft makes a 350,000
kilometer (217,500 mile) approach to Titan over its south pole,
offering the possibility, but not the certainty, of seeing features as
small as a few kilometers.
“Although we can see large-scale surface contrasts through even a
thick haze, the small-scale features can only be seen if the haze is
thin,” said Dr. Robert West, Cassini imaging team member and an
atmospheric scientist at JPL. “So we don’t yet know if or how well we
will be able to see fine details on the surface. But we will know for
sure on July 2, and if we are successful, a whole new world will be
opened to us.”
Titan may have familiar geological constructs like mountains, canyons,
craters, rivers, lakes, cataracts, wind-blown waves, shorelines, snow
fields and other terrestrial-like features. But because of the frozen
temperatures and the very un-Earthlike materials on its icy surface
and in its atmosphere, scientists are expecting the unexpected.
“The next few months will read like an episode from Star Trek,” said
Porco. “It will be exploration at its finest and is precisely why we
came.”
Cassini is scheduled to arrive in orbit around Saturn on June 30 PDT.
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The Jet Propulsion
Laboratory, a division of the California Institute of Technology in
Pasadena, manages the Cassini-Huygens mission for NASA’s Office of
Space Science, Washington. The imaging team is based at the Space
Science Institute, Boulder, Colo.
The Space Science Institute is a non-profit organization of scientists
and educators engaged in research in the areas of astrophysics,
planetary science and the earth sciences, and in integrating research
with education and public outreach.
The Titan images will be found at the Imaging Team’s website on
Thursday, May 6, 2004 at 7:00 a.m. MDT:
Additional information on the Cassini-Huygens mission can be found at:
http://saturn.jpl.nasa.gov
Heidi Finn
Cassini Imaging Central Laboratory for Operations, Boulder, Colo.
(CICLOPS)
Phone: 720.974.5859
media@ciclops.org
