If you aspire to be an astronaut, which of the following is a meaningful and reasonable goal?

Enrolling in extracurricular aerospace activities is a meaningful and reasonable goal for someone aspiring to be an astronaut because it allows for practical engagement with the field of aerospace. This choice involves active participation in programs that may provide hands-on experience, networking opportunities, and skill development relevant to space exploration. Such activities could include joining aerospace clubs, attending workshops, or participating in competitions, all of which can enhance one's understanding of the field and improve qualifications for becoming an astronaut.

In contrast, while reading every book on astronomy or watching documentaries about space can be informative, these activities are more passive forms of learning and may not translate directly into the skills or experiences necessary for an astronaut. Forming a study group with fellow aspiring astronauts could be beneficial for collaboration, yet it doesn't necessarily provide the practical experience that extracurricular activities can offer. Thus, actively participating in aerospace-related activities is the most direct and impactful route toward reaching the goal of becoming an astronaut.