Meet the people helping clear Santa's flight path for smooth sleighing - 是谁每年为圣诞老人的环球旅程默默护航？

The Peterson Space Force Base in the US city of Colorado Springs is normally busy tracking military targets. But this Christmas, it has another important mission: following the progress of Santa across the world on Christmas Eve. The North American Aerospace Defence Command - NORAD - has been doing this important work for the past 70 years. - 您知道吗？北美防空司令部（NORAD）已经连续70年，在平安夜追踪圣诞老人的环球旅程，默默为这抹红色身影保驾护航。点击 ▶ 收听完整报道。