Students at Saddle Ridge Elementary and Middle School in Walker County had a space man in their midst today.  Ricky Arnold, a longtime NASA mission specialist talked to students about his education, his training, and his experiences in the world's only undersea laboratory and his two space walks, which totalled more than 12 hours.  The school had a space-themed day inside and out for its students in grades K-8. Arnold says other than walking in space, the best part of his job is fielding questions from students, and encouraging them to follow their dreams.