Last month, my Physics First students entered the Cassini Scientist-for-a-Day essay contest, in which they had to argue why the Cassini team at the Jet Propulsion Lab should pick one of four possible targets for the NASA probe to study. Nationally, about 400 students participated, submitting 188 essays for judging.
Five of our 13 submissions made it to the semifinals, and one proceeded to the final round of judging. On that basis, we were invited to join an hour-long video conference with the Cassini scientists on Dec. 5. In the end, none of our submissions were winners, that honor going to two high school students in Palo Alto, California, and Wilmington, Delaware, but the success we did have is a measure of the hard work and talent of the students involved.
The Cassini-Huygens probe has been exploring Saturn and its moons since 2004. Huygens successfully landed on the moon Titan, while Cassini careens through the Saturnian system. The Cassini team has to decide which targets to image well in advance of the probe’s arrival, since there is a limited window of opportunity to take the pictures. There is no turning around to take a second look!
For the contest, the Cassini scientists narrowed the possible targets to four. Students had to pick one and write an essay of no more than 500 words explaining why the team should use the 91 minutes of available imaging time to obtain the most useful scientific results.
Target 1 included the moon Mimas emerging from the limb of Saturn and a section of the rings.
Target 2 was a wide-angle view of half of the planet, its ring system and an assortment of its 60 moons.
Target 3 showed the moon Prometheus near the edge of the planet and a section of the rings.
Target 4 focused exclusively on the moon Tethys.
The “winning” target was number 2, although Cassini was also able to image Mimas and Tethys during the imaging run.
This essay was one of the national finalists. It was written by a team of four ninth graders, whose names I have removed for their pirvacy.
The Cassini spacecraft will be flying past Saturn on Nov. 30, 2007, approximately 1,468,000 kilometers away from Saturn’s cloud tops. We have chosen one of four targets that the space camera can aim its lens at to examine and analyze. We decided target one would be the most valuable and informative for several reasons.
Target one is an image of Mimas, coming out from behind Saturn. Because Mimas is shown next to Saturn and its rings, we can estimate how Mimas may interact with its rings while it is orbiting. When we saw the crater, Herschel, we figured that if Mimas had collided with a rock in one of Saturn’s rings during its orbit, it may have created the large crater. On the probe, there are radar imagers that could examine the terrain of Mimas. The infrared, ultraviolet, and visual cameras could help determine the composition of Mimas and Saturn’s ring particles. By looking at the terrain on Mimas, we may be able to discover how the rock that caused the crater may have hit Mimas. We could determine what kind of ice Mimas is made of and what features its terrain may have that may have made Mimas more vulnerable to having large craters. Because Mimas is mostly made of ice, when it comes in contact with objects with great impact such as rocks, the impact energy may make Mimas heat up and melt the ice creating a crater. From this target, we may also be able to determine why the South Pole region has fewer craters greater than 20 km, but other areas have craters greater than 40 km, even though Mimas does not rotate while it is orbiting. We calculated that Mimas would be roughly 5,000 km in ring E, which means at some point, Mimas will collide with the rocks in ring E. Target one also shows a portion of Saturn’s rings, Mimas, and a portion of Saturn, which allows us to get a close look at three different objects all at once, so there is more to see and analyze in the photograph. The picture is also more visually appealing. The objects in the picture are well balanced out and vary in many shapes. This target would be a successful picture in items such as calendars and books, to grab the onlooker’s eye, and draw their attention to the beauty of Saturn, Saturn’s rings, and Mimas, and perhaps interest them into researching more on the subject.
We figured that from this photograph you can learn a lot more about Mimas’s interaction with Saturn and Saturn’s rings. While there was another image that had many moons, we did not choose it as our target because we figured that the information we could acquire in this target would not be as detailed as the information in target one. This photo will help determine the many things we talked about in this essay and much more about Mimas and how it interacts with Saturn and the rings around it.