Ocean studies shoot for moons

SEATTLE -- The skills and technology used to explore the extreme depths of the Earth's oceans will soon find work in outer space. Scientists are making plans to probe the icy seas of Jupiter's moons and drop a lander to the bizarre gasoline-like lakes of Titan, a moon of Saturn.

"The possibilities of studying the extraterrestrial oceans in the solar system is now real," said Torrence Johnson, a scientist at the Jet Propulsion Laboratory.

Johnson, speaking Saturday at the national meeting of the American Association for the Advancement of Science, said researchers are drawing up plans to send orbiters to Ganymede and Europa. The two Jupiter moons may be covered with oceans under miles-thick layers of ice.

Oceanography, said Johnson, is no longer just an Earth science.

"The universe is awash with water," he said. "Europa probably contains twice as much water as all of the oceans of Earth."

Early plans call for orbiting the Jovian moons with craft that can measure tides and penetrate ice with special radar. These are techniques oceanographers have used to probe the Earth's waters.

Later plans would mean landing packages on the icy surfaces and perhaps drilling down, searching for liquid water, the most likely domain of life, Johnson said.

Some researchers believe radioactive and tidal heating may form deep reservoirs of liquid water beneath the ice and that life forms may exist there, enduring the extreme pressures and darkness. Oceanographers have found some bacteria living in such conditions in the Earth's black depths.

Studies for the exploration of the oceans of Jupiter's moons will be completed next year. Johnson said the National Aeronautics and Space Administration will draw up plans for the projects.

Exploration of the surface of Titan, a moon of Saturn, will start even sooner. The Cassini spacecraft, launched seven years ago, will reach Saturn in July and drop a probe to the moon's surface in January.

Titan, a frigid world about half the Earth's size, is the only moon in the solar system with a thick atmosphere. Smog generated by a thick nitrogen atmosphere four times denser than the Earth's obscures Titan's surface.

"Titan is the largest piece of unexplored real estate in the solar system, said Ralph Lorenz, a University of Arizona planetary scientist and a leader of the Cassini project.

Radar images from Earth telescopes and infrared photos from the Hubble Space Telescope have penetrated Titan's smog and detected bright and dark regions.

An analysis of the infrared data suggests the dark regions are seas of methane and ethane, hydrocarbons that could form compounds similar to gasoline.

"The simplest explanation may be that these smooth areas are lakes or seas," Lorenz said.

Deep below the surface of Titan, through miles of ice, scientists believe there may be oceans of liquid water, perhaps saturated with organic compounds that could support life.

"If you introduce microbes into that then they may survive," Lorenz said.

He said if internal heat from Titan caused water to geyser up into the atmosphere, the resulting chemistry would produce many organic molecules, perhaps forming amino acids necessary for life.

"It will be interesting to explore how far Titan has gone toward organizing life," he said, But, he added, "I don't expect to find any living Titans."