By Xinhua
Los Angeles : The Cassini spacecraft on Wednesday will skirt the edges of Yellowstone-like geysers erupting at the south pole of Enceladus during a flyby that will bring the craft to within 30 miles (about 48 km) of the Saturnian moon, Jet Propulsion Laboratory (JPL) said Tuesday.
During the close encounter, Cassini will sample water-ice, dust and gas in the plumes, aiding scientists trying to determine if liquid water, perhaps even an ocean, exists on the tiny moon, according to Los Angeles-based JPL, which manages the 3.3-billion-dollar Cassini-Huygens mission for NASA as well as the European and Italian space agencies.
The flyby comes as the plutonium-powered Cassini nears the end of its primary mission — a four-year tour of the solar system’s second-largest planet and many of its satellites. The craft first went into orbit around Saturn in June 2004.
Launched on Oct. 15, 1997, Cassini is the most highly instrumented and scientifically capable interplanetary spacecraft ever deployed, according to JPL.
In January, the Huygens probe that the spacecraft was ferrying landed on Titan — Saturn’s largest moon, and sent back stunning images from the surface until it was overcome by the frigid cold two and a half hours later.
Enceladus, a snow-white moon only 310 miles in diameter — is considered the brightest object in the solar system, according to JPL.
In 2005, Cassini’s instruments detected that the moon was spewing water vapor geysers to a height three times its radius.
The icy water particles — about as large as the width of a human hair — are shooting from the moon at about 800 mph.
“The eruptions appear to be continuous, refreshing the surface and generating an enormous halo of fine ice dust around Enceladus, which supplies material to one of Saturn’s rings …,” said JPL in a statement.
Scientists say that the gaseous envelope of the plumes contain water vapor, carbon dioxide, methane, perhaps ammonia and either carbon monoxide or nitrogen.
Closer analysis of the plumes may help determine how they were formed.
The flyby is the first of four planned for Enceladus this year. The Cassini spacecraft remains healthy and JPL plans to extend the spacecraft’s mission by at least two years.
Although Cassini is the first spacecraft to orbit Saturn, three other NASA craft have flown by the planet: Pioneer 11 in 1979, Voyager 1 in 1980 and Voyager 2 in 1981.