Training Camp: Students can attend the Training Camp as many times as they would like, as long as they meet eligibility requirements and are selected from the National Open Exam the year of camp. IESO: Those that travel to IESO, which includes main and guest competitors, may only attend once to both camp and IESO.  Exception: Due to cancellation or a virtual format, the members of the 2020 and 2021 U.S. Earth Science Teams have the choice of returning to camp if eligible.