We present the results of the first series of successful two-way laser ranging experiments from a ground station, the Lunar Laser Ranging (LLR) station in Grasse, France, to a spacecraft at lunar distance, the Lunar Reconnaissance Orbiter (LRO). A 15 × 18 × 5 cm, 650-g array of twelve 32-mm diameter solid corner cubes is mounted on its anti-nadir deck. Ranging to this small retro-reflector array onboard a lunar orbiter from a ground station was a challenge compared to ranging to larger lunar surface retro-reflectors. Grasse measured 67 returns in two 6-min sessions on September 4, 2018. Clear returns were also recorded during two additional sessions on August 23–24, 2019 for which active slewing by LRO was performed to bring the array in view of the station. The measured echos yielded range residuals less than 3 cm (two-way time-of-flight RMS < 180 ps) relative to the reconstructed LRO trajectory. This experiment provides a new method of verifying theories of dust accumulation over decades on the lunar surface. It also showed that the use of similar arrays onboard future lunar landers and orbiters can support LLR lunar science goals, particularly with landing sites near the lunar limbs and poles, which would have better sensitivity to lunar orientation.

中文翻译：

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第一个双向激光测距月球轨道器：从格拉斯站到 LRO 后向反射器阵列的红外观测

我们展示了第一系列成功的双向激光测距实验的结果，从地面站，法国格拉斯的月球激光测距 (LLR) 站，到月球距离的航天器，月球勘测轨道器 (LRO)。一个 15 × 18 × 5 厘米、650 克的 12 个直径为 32 毫米的实心角锥阵列安装在其反天底甲板上。与测量更大的月球表面后向反射器相比，从地面站到月球轨道器上的这种小型后向反射器阵列是一个挑战。格拉斯在 2018 年 9 月 4 日的两个 6 分钟时段内测量了 67 次回波。在 2019 年 8 月 23 日至 24 日的另外两个时段中也记录了明确的回波，其中 LRO 进行了主动回转，将阵列带入台站。测得的回波产生小于 3 cm 的距离残差（双向飞行时间 RMS < 180 ps) 相对于重建的 LRO 轨迹。该实验为验证月球表面几十年来尘埃积累理论提供了一种新方法。它还表明，在未来的月球着陆器和轨道器上使用类似的阵列可以支持 LLR 月球科学目标，特别是在靠近月球四肢和极地的着陆点，这将对月球方向具有更好的敏感性。