http://www.nytimes.com/2013/09/13/science/in-a-breathtaking-first-nasa-craft-exits-the-solar-system.html?pagewanted=all
This article published in the New York Times talks about a great achievement NASA just reached: having a spacecraft leave the solar system. In 1977, NASA launched the Voyager spacecraft to take pictures of Jupiter and Saturn, but stopped its picture taking to conserve energy in 1990. More recently, the Voyager team detected that it was getting close to the border between our galaxy and interstellar space. So, in order to gather more data they needed to write some more code. The problem being that the Voyager computer system is very old and most people today are not experience with that old of a system. So finally, they found the person for the job, Lawrence J. Zottarelli, a retired NASA engineer who came up with a solution. With his solution the team was able to estimate that the Voyager left the solar system approximately August 25, 2012. The purpose of this article is to inform the general public about a great achivement by NASA. The intended audience is readers of the New York Times, but also those who are interested in astronomy and space. Some rhetorical elements are flashback, and explanation. The organization of this article is somewhat chronological, but the author jumps around slightly.