text: It is really worth spending years and millions of dollars to build a spacecraft that will tell NASA about Venus. We do not even know if the spacecraft will even make it there knowing that the atmosphere is almost 97 percent carbob dioxide. The auothor of this excerpt thinks it will happen. In the excerpt "The Challenge of Exploring Venus" the author states "each previous mission was unmanned, and for good reason, sice no spacecraft survived the landing for more than a few hours" (Challenge). Landing spacecrafts on the Venus is almost impossible. There is too many factors that NASA will not be able to figure out for the next fifty years. Also the author says "today, Venus still has some features that are analogous to those on Earth" (Challenge). One of the major reasons why people still want to explore Venus is because astronomers believe that it was once covered in oceans. The author calls Venus "our sister planet" because of how it was formed, like Earth.