The second paragraph states "each previous mission was unmanned, and for good reason, since no spacecraft survived the landing for more than a few hours." The vary next paragraph then states "a thick atmosphere of almost 97 percent carbon dioxide blankets Venus." This very same paragraph also says that the temperature on the planet is over 800 degrees Fahrenheit, and the atmospheric pressure is 90 times greater than what we experience onour own planet." The only thing that backs the author up is the three ideas they said could work in paragraphs 5, 7, and 8.