2008 Woodie Awards
Cassini Mission: Saturn ring study brings long-term comminment
Nichol Mathis, James Roe and Tiffany Silberger
Issue date: 9/29/05 Section: News
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Gurnett is a University of Iowa professor of physics and astronomy who worked on NASA space projects over several decades.
Cassini's purpose was to orbit Saturn while taking more accurate photographs and measurements than other previous spacecrafts. Gurnett referred to the Cassini mission as one of the most ambitious missions ever launched into space.
Launched on Oct. 15, 1997, the spacecraft weighed 1,200 pounds and took seven years to reach Saturn, arriving July 1, 2004.
As Gurnett spoke of Cassini's arrival to Saturn, he went into depth about the delicacy of placing a spacecraft in Saturn's orbit.
In order to slow the spacecraft down after arriving at Saturn's atmosphere, engineers fired the spaceship engine for 75 minutes. They did this without being able to see the spacecraft but had help from instrument readings. It took 80 minutes for the signal to reach Earth, informing scientists and engineers that the craft was in orbit.
Gurnett lectured on the Huygens probe that would be exploring Saturn's largest moon, Titan. One of the first pictures of Titan the Huygens probe sent back to scientists clearly pointed to evidence of erosion and drainage.
As Gurnett showed the picture to the audience, it was easy to see a system of canals leading from what looked to be, or once was, a large body of liquid.
Gurnett proposed that it could be liquid methane but could not be certain until more evidence was presented.
One audience member asked how a mission such as Cassini goes from a thought in a scientist's head to a spacecraft being launched.
Gurnett said it starts when NASA calls a meeting of scientists and basically asks, "What should we do next?"
NASA takes the ideas, looks them over and puts out what is called an announcement of opportunity. Any group can propose a study with hopes of NASA funding the project.
"The nature of the whole game is to find a balance between what is possible on the engineering side and what is financially possible," Gurnett said. "Scientists always want to do more than what's possible."