The High School Aerospace Scholars (HAS) program is an out-of-school-time (OST) science, technology, engineering, and mathematics (STEM) program that aims to encourage and inspire Texas high school students to pursue STEM degrees and careers. The program gives Texas high school juniors the opportunity to participate in an interactive online learning experience highlighted by a weeklong summer program at the Johnson Space Center. This mixed research study investigated the influence and success NASA's High School Aerospace Scholars (HAS) program has had on student attitudes towards STEM and 21st century skills. This study also determined the effectiveness of the HAS program from the perspective of the parents of students participating in the HAS program, and the HAS program facilitators. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]