Rockets and hope
Although the rocket launches are largely disappointing, Homer interprets failure as a chance for growth, which makes rocket launching a symbol for his home. Just like he wants the rocket to launch into the sky, he also wants to see his life propel upward somehow. His visual fascination with rocketing is a symbol for his urgent desire to be propelled into a different life than coal mining, which is painful, difficult, truly dangerous work.
Homer and his father
Homer's name is a symbol for the mythic quality of his life, but that's not why his father named him that. His father is also named Homer, so ironically, Homer Jr goes by Sonny the whole time. Yet, sharing a name with one's father is symbolic. It represents the father's desire to see his son take the mantel of his life and carry it further. Then, his son does exactly that, but it isn't until the end of the novel that they realize what has been accomplished.
Miss Reily
Teachers are literal reminders to students that although nothing can replace a parent's approval, there are other adults who see the world in various ways. That is critical, because Sonny needs to know whether he is entertaining a "pipe dream," so to speak. Miss Reily provides a tangible, concrete path for Sonny to do what he wants, which is to apply himself and succeed in life. She represents the way teachers instill hope in young students.
Football
Another way out of Coalwood is to mine through high school and to find a scholarship for college that way, by becoming incredibly strong so that colleges will recruit the student for football. Sonny is constantly being reminded that he is physically weak and will never go to college, so football is a symbol of frustration and despair, because Sonny has to wonder whether he is good enough to fulfill his dreams; his community doubts the path he has chosen.
The ultimate outcome
Sonny's path is well documented. After college, this memoirist literally did go on to work with NASA as an expert of rocket science. Ever heard the saying, "This is not rocket science?" Well this literally is rocket science. He becomes a strategist and scientist, showing the full value of this story. The non-fiction quality is a real, tangible reminder to the reader that fate rewards those who pursue their dreams with discipline, sacrifice, and excellence. Notice that of course, rocket science is very difficult.
