Cassini might get 7-year extension in its mission around Saturn (thus to 2017)

Saturn's moon Enceladus, probably the second most interesting moon in the system after Titan. Enceladus has a very young surface, cryovolcanism, and maybe a subsurface ocean.

A 7-year extension of Cassini's mission? DO IT. Saturn's not the easiest target to send a probe to and there's no telling when there will be another mission there (although Titan and Enceladus make it a pretty high priority so another one would happen eventually). Just like the rover mission on Mars, once a mission has gone through the most expensive part (building the craft and launching it), the rest just requires maintenance and that's definitely a good return on investment considering the volume of science that comes out of a mission like this.

Funding for the Cassini program is scheduled to end Sept. 30, 2010. However, the spacecraft remains in good shape and could continue to return valuable data for years to come, scientists say, provided NASA approves the necessary funding to extend Cassini's tour. Mission officials are preparing to present their case for a seven-year extension to NASA headquarters next month.

"The things that is magic about seven more years is that Saturn will reach its northern hemisphere's summer solstice," said Robert Mitchell, Cassini program manager at the Jet Propulsion Laboratory in Pasadena, Calif. "When we arrived in June 2004, it was a little ways past the southern hemisphere's summer solstice. If we could go seven more years, we would see nearly half of Saturn's orbit."

By monitoring Saturn during half of its 29-year trip around the sun, scientists hope to study the effect of seasonal changes on Saturn, its rings, and its moons Titan and Enceladus. Saturn's orbit is tilted 27 degrees relative to its equator. Just as it does on Earth, that tilt creates distinct seasons for different areas of the planet.

If the Cassini mission continues beyond 2010, scientists want to observe seasonal changes around Titan's lakes of methane and Enceladus' south pole where vents spew ice crystals and water vapor, according to Carolyn Porco, Cassini imaging team leader for the Space Science Institute in Boulder, Colo.

The current mission costs only about $80 million a year, and the extended mission would even be somewhat less expensive than that:

Any Cassini mission that extends beyond 2010 would include fewer scientific investigations and operate at a much lower cost than the current program. Initially, program officials hoped to plan an extended mission that would cost $40 million per year, or half the current funding level. "We concluded that wasn't quite enough to operate the spacecraft, keep it on track and conduct worthwhile science," Mitchell said.

As one might expect, almost all the comments below the article on space.com are also in support of extending the mission.