DailyTech - Cassini's Last Day, New Mission Awaits

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Science Cassini's Last Day, New Mission Awaits
Levi Beckerson (Blog) - June 30, 2008 7:55 AM

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2 comment(s) - last by grath.. on Jul 2 at 8:53 PM

Looking like an artist's rendition, an enhanced color mosaic taken by Cassini as it drifted through Saturn's shadow clearly shows all of the giant planet's rings. (Source: NASA, Jet Propulsion Laboratory)

A trusty space probe ends its primary mission, begins secondary.

NASA's Cassini space probe is just one of the fantastically durable craft roaming our solar system at the moment. At present, all eyes are fixed on Mars and deservingly so. The Phoenix Mars Lander has turned up some incredible finds on the small red planet. But currently the amount of data returned by the lander pales in comparison to what the Cassini probe has sent back about Saturn, its rings and its moons.

Cassini launched from Cape Canaveral, Florida, on 15 October, 1997. It took nearly seven years to reach Saturn, but did so flawlessly on 30 June, 2004. Since that day, it has been ceaselessly taking measurements, images and other data and sending them back to Earth for scientists to analyze.

The probe not only answered many questions for planetary and astronomical scientists, but spurred them to ask even more. After Cassini's flawless performance over the last four years of its primary mission, NASA decided to extend its livelihood for at least an additional two years.

The new mission will further study two of Saturn's moons, Titan and Enceladus, as well as gather more data on the planet's climate cycle and magnetosphere. It will also have to the chance to see something from a unique perspective that Earth-based telescopes cannot – the planet's equinox in August of 2009 will allow sunlight to pass directly through the plane of the intricate ring structures.

Cassini's secondary mission, dubbed Cassini Equinox Mission, will last until September of 2010. Another two years of outstanding service could even see a third mission, dedicated to Titan and Enceladus.

Today marks the four year anniversary of Cassini's arrival to Saturn and is the last day of its primary mission in the system. Tomorrow it embarks on a new mission which will no doubt return a wealth of valuable data, intriguing images and undiscovered secrets.

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Good article, but...

By marsbound2024 on 6/30/2008 1:12:17 PM , Rating: 4

I sorta wish you outlined some of the more intriguing discoveries in this article instead of merely linking to some. It is the last day of the nominal mission, but you could have also mentioned a bit about the importance of the extended mission. The extended mission--which I guess is called the "Saturn Equinox Mission"--seeks to study the rings more in depth with lighting conditions provided by Saturn's equinox in August 2009.

Also, I like numbers: at least sixty more orbits of Saturn, twenty-three more Titan flybys, seven flybys of Enceladus, and one for Dione, Helene and Rhea.

I can't wait to see what more Cassini brings back. I only hope that if not in this extended mission, in the next, that mission controllers take far more risks with the probe. Fly exceedingly close to the rings and/or to the moons. Perhaps gradually spiral Cassini into a tighter and tighter orbit around Saturn (death-spiral, not a death plunge like Galileo) until the gravity cannot be overcome and the orbit cannot be changed. But hey, at least Cassini may return some extraordinary data and images from such risks.

RE: Good article, but...

By grath on 7/2/2008 8:53:35 PM , Rating: 2

Perhaps more relevant to the purpose of the article would have been some information on the factors that determine the health and longevity of the spacecraft. How long do they expect the supply of propellant to last assuming the extended missions stay on profile, what is the status of the science and telemetry packages and are they showing signs of age, is the radioisotope thermal generator still performing to spec and how long until its power output drops below the point where they have to reduce the science capacity, etc.

As for taking risks with the spacecraft, they wont do that until they know its on its last legs typically when they run out of propellant, at which point I expect they will use the last of the propellant to put Cassini into an equatorial orbit not for a death spiral as you describe, but rather to study the ring system up close for an extended period until it eventually gets smashed or sand blasted to death, after which it will just be another constituent of the ring system. As opposed to Galileo which they didnt want to leave in orbit because it might eventually impact Europa and contaminate the potential biosphere there. Leaving Cassini in the ring system would effectively eliminate the risk of contaminating Saturian moons such as Titan which is also theorized to have a potential to support life.

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