China launched an ambitious mission on Tuesday to bring back rocks and debris from the moon’s surface for the first time in more than 40 years — an undertaking that could boost human understanding of the moon and of the solar system more generally. Chang’e 5 — named for the Chinese moon goddess — is the country’s boldest lunar mission yet. If successful, it would be a major advance for China’s space program, and some experts say it could pave the way for bringing samples back from Mars or even a crewed lunar mission.