A solitary spacecraft 750 miles away orbits Saturn, gathering
information about the giant planet’s moons, rings, atmosphere
and magnetic field that may help scientists recreate the formation
of the solar system and the origins of life on Earth.
Launched in 1997, the internationally produced Cassini-Huygens
spacecraft reached its large, gaseous destination in July 2004,
with contributions from UCLA scientists and alumni. Onboard, a
suite of 12 instruments that includes a radio antenna, magnetic
field detector, dust collector and cameras photographing the planet
and its moons in various light wavelengths send data back to
Earth.
“A major goal of studying planets is to discover how the
solar system came into being, and Cassini is no exception,”
said Krishan Khurana, a professor of space physics at UCLA who was
consulted by the team of UCLA scientists working on Cassini’s
magnetic field detector. The team was headed by Christopher
Russell, a professor of geophysics and planetary physics at
UCLA.
“(Studying magnetic fields) tells us about the internal
space, the core material, of the planet,” Khurana said.
Magnetic fields are created by many planets in our solar system,
including Earth, Khurana said.
He explained that they help stabilize the surface of a planet by
protecting it from solar wind ““ particles (electrons) that
the sun sends out into the solar system ““ which would
otherwise strip away the atmosphere.
“Now for the first time, Cassini will map this (magnetic)
field from various latitudes,” Khurana said.
In addition, an in-depth study of Saturn’s ring system may
illuminate the origins of the solar system, said Linda Spilker,
deputy project scientist for Cassini and UCLA alumna.
Spilker added that Saturn’s rings, composed of chunks of
ice and dirt, orbit the planet like grooves on a phonograph record
and are a good analogy for the larger solar system: The rings may
have been created similar to the way the planets gathered around
the Sun.
“It may be that by studying Saturn’s rings, we will
learn how planets formed,” Spilker said.
The second part of the Cassini mission involves a trip to the
surface of Saturn’s biggest moon, Titan, which is larger than
the planet Mercury.
“If it had formed elsewhere in the solar system, it would
have been a planet,” Spilker said of Titan.
The Huygens probe will be launched from the Cassini spacecraft
on Dec. 24 and will enter Titan’s atmosphere in January 2005,
with hopes of discovering how life might have evolved on Earth.
Previous observations have shown scientists that smog-forming
materials, such as methane and ethane, compose Titan’s thick
atmosphere, comparable to what scientists believe existed on early
Earth over 4 billion years ago.
By studying Titan further, scientists hope to better understand
how early our planet’s atmosphere evolved, Khurana said.
“The atmosphere is very close to Earth’s atmosphere
““ enough that we’d like to understand it,”
Khurana said.
During its parachute-assisted dive to the surface, the Huygens
probe will measure temperature, wind velocity and pressure changes
in Titan’s atmosphere.
The probe’s fins will cause it to spin while falling, so
that its three cameras create a giant panorama view of the foreign
moon.
There is even a microphone to record Titan’s sounds, and a
light will ignite just before the Huygens probe reaches the
surface, like the “flash” of a camera, allowing the
device to send back detailed pictures of the surface.
Scientists hope the probe will finally determine whether
Titan’s surface contains liquid and whether that liquid holds
the oxygen that is necessary for life.
“The biggest mystery about Titan is, we still don’t
know what its surface is composed of,” Khurana said.
“We would love to know if there is ice on the surface, and
the quantity of the ice.”
Spilker said Cassini will study Saturn for at least four years,
providing scientists with a more detailed picture of the planet and
its surrounding moons than any of the three previous Saturn-viewing
missions.