直径四公里、厚三米的巨大的激光“薄饼”已送到月球上阿波罗11号着陆的地点,并从向后反射器上反射回来。这薄饼是一段持续时间为10~(-8)秒的高功率激光脉冲,发射装置是一台测距望远镜,装在美帝亚里桑那州的一座山的顶上。这台测距装置非常精确,能以1.5米或更高的精度测出地球和月球的相对距离。 The huge laser “pancake”, four kilometers in diameter and three meters in thickness, has been sent to the moon where the Apollo 11 landed and reflected from the retro-reflector. The pancake is a high-power laser pulse lasting 10 to 8 seconds. The launcher is a range-finding telescope mounted on top of a mountain in Midi-Arizona. This distance measuring device is very accurate, with a precision of 1.5 meters or more to measure the relative distance between the earth and the moon.