Answer:
The rhetorical device that Kennedy uses to support his argument is:
O Rhetorical question: he issues a statement about fire in the form of a question
Kennedy is using a rhetorical question to support his argument. He is asking whether space can be explored and mastered without feeding the fires of war, which is a way of emphasizing the importance of peaceful exploration and the potential benefits of space travel. By asking this question, Kennedy is encouraging his audience to consider the benefits of space travel and the importance of peaceful exploration.