A Comprehensive Probe of Gravity via Lunar Laser Ranging

阿波罗(阿帕奇点天文台月球激光测距行动)旨在通过测量1毫米精度的月球轨道形状来测试我们当前重力理论--爱因斯坦的广义相对论--的基础。这项技术涉及从阿波罗宇航员放置在月球上的反射器上反射激光脉冲。测量激光脉冲的往返飞行时间确定了到月球的距离，从而可以追踪月球轨道的形状。在阿波罗之前，这项技术将月球轨道的形状确定为2-3厘米的精度，并验证了广义相对论的正确性约为0.1%的精度。通过使用3.5米望远镜和现代仪器，阿波罗能够达到1毫米范围的精度，因此将允许对广义相对论进行0.01%的精度测试。阿波罗目前正在进行常规操作，收集其第一批数据。根据这一奖项，阿波罗将改进其技术，并产生其首个科学成果。月球测距技术的简单优雅，再加上它与我们历史上鼓舞人心的阿波罗登月计划的联系，使阿波罗成为向公众传达科学兴奋的合适工具。该奖项由物理司和数学和物理科学局多学科活动办公室共同出资。

APOLLO (the Apache Point Observatory Lunar Laser-ranging Operation) aims to test the foundations of our current theory of gravity--Einstein's General Relativity--by measuring the shape of the lunar orbit to one-millimeter precision. The technique involves bouncing laser pulses off reflectors placed on the moon by the Apollo astronauts. Measuring the round-trip time-of-flight of the laser pulses determines the distance to the moon, thus allowing the shape of the lunar orbit to be traced.Prior to APOLLO, this technique determined the lunar orbit shape to 2-3 cm precision, and verified the correctness of General Relativity to about the 0.1% level of precision. By using a 3.5 meter telescope and modern instrumentation, APOLLO is capable of one-millimeter range precision, and will thus allow 0.01% precision tests of General Relativity. APOLLO is now in routine operation collecting its first data. Under this award, APOLLO will refine its technique and produce its first scientific results. The simple elegance of the lunar ranging technique, coupled with its connection to our historically inspiring Apollo lunar program, make APOLLO an apt vehicle for communicating the excitement of science to the public. This award is co-funded by the Physics Division and by the Office of Multidisciplinary Activities in the Mathematical and Physical Sciences Directorate.