The competition is open to U.S. citizens and national and permanent residents who are enrolled or intend to be enrolled in full-time research-based graduate programs in an eligible STEM field. Undergraduates seniors and bachelor degree holders may apply before enrolling in a degree granting graduate program, however once enrolled in a graduate program graduate students are limited to only one application submitted their first or beginning of their second year. Generally applicants cannot have a masters or professional degree when applying, unless returning after two or more years and not enrolled in a graduate program.