短语词组短語micrometeorite penetration [航]微隕星穿透micrometeorite flux 微隕星流micrometeorite shielding 微流星防護micrometeorite crater 微月坑micrometeorite infall 微隕石降落micrometeorite activity 微隕星活動性micrometeorite detail 微隕星 返回 micrometeorite