Citizen science engages the general public in scientific research, providing opportunities to enhance scientific literacy and inquiry skills. This study aims to explore how participation in the ‘Mission Galaxy’ citizen science project affects high school students' attitudes toward astronomy and science, the development of their scientific inquiry skills, and strategies to sustain their interest and engagement in citizen science activities. From a methodological perspective, a one-group pretest-posttest design was applied to investigate changes in students’ attitudes and skills. A total of 115 high school students participated in the study. Before and after participation, students completed a survey measuring their attitudes toward astronomy and science. Additionally, qualitative data were collected through semi-open questionnaire and interviews to analyze students’ experiences and perceptions. After participating in the citizen science project, students showed significant improvement in their confidence in learning astronomy (p=0.003) and their overall perception of science (p=0.018). Among scientific inquiry skills, observation (31%) and classification (25.4%) showed the most significant improvement, followed by inference (14.1%). In order to ensure students’ continued participation, it was confirmed that interface design and feedback system construction that stimulate participants’ interest and motivation are necessary. The results of this study provide important implications for exploring the meaning of educational use of citizen science projects and ways to induce continuous participation.