来源：英语日语笔记
美国航空航天局将为月球创建新时区月球协调时
随着数十个月球任务即将展开，一个标准的时间计量系统将给精确导航、对接和登陆带来帮助
本星期（2024年4月2日），在一份总统办公室备忘录上，白宫正式责成美国航空航天局为月球创建一个时间标准，称为协调月球时（LTC），这个时间标准可以让各类国际机构用来协调它们在月球表面的活动。
白宫的这一举动是在对一年前欧洲空间局提议创建一个月球共同时间参考系统的回应。预计在未来几年，各种国家机构和私人公司的月球任务会更热烈起来，因为已经有数十个月球任务在安排计划里了。如果没有共同的参考框架，混乱会接连而来，小到带来不便，大到带来严重问题，比如制图不一致，导航错误。
一位不愿透露姓名的白宫科技政策办公室官员对路透社记者乔伊-洛雷特（Joey Roulette）和威尔-邓纳姆（Will Dunham）说：“想象一下，如果全世界的时钟都不同步，那将会是怎样的一种破坏，日常事务又会变得多么具有挑战性。”
2023年1月，法国国际计量局时间部门负责人帕特里齐亚-塔维拉告诉《自然-新闻》的伊丽莎白-吉布尼：“这就是为什么我们现在要发出警报，让我们共同努力，做出共同的决定。”
白宫要求美国国家航空航天局在2026年年底之前实施最终的标准化时间系统，并表示该系统必须具备四个方面的品质：与协调世界时（UTC）的逻辑可追溯性，后者是管理所有地球时区的全球系统；足够的具体性和准确性，可以为非常短的瞬间计时，这对于精确的科学研究和航天器着陆非常重要；在与地球失去联系的情况下自给自足；以及可扩展性，以便其他天体或太空环境也能参照这一时间标准。
备忘录指出，建立月球时区将更好地实现航天器之间的通信、数据传输、着陆、对接和导航。“定义一个合适的标准——一个能够达到在充满挑战的月球环境中运行所需的准确性和弹性的标准——将使所有航天国家受益。”
与地球不同，月球只有一个时区，没有夏令时。但这并没有让美国国家航空航天局（NASA）的官员们在这个项目上感到轻松。质量和重力等因素会影响时间的流逝——在地球上，即使是海冰融化导致的质量逐渐重新分布，也迫使科学家们重新考虑我们的计时方法。
月球是一个较小的天体，引力要弱得多，因此时间走得更快、更不均匀：与地球时间相比，月球时间每天增加约 58.7 微秒，即便如此，月球时间还可能会因月球时钟所在的海拔高度和经度而有所不同。
目前，美国国家航空航天局（NASA）的阿特米斯计划打算在 2026 年 9 月之前将宇航员送回月球，这比实施协调月球时（ LTC ）的最后期限还早几个月。在以后的任务中，该计划将涉及建立月球基地，这将有助于未来飞往火星。其他国家也在为登月做准备，中国宣布了宇航员于2030年抵达月球表面的目标，印度计划于2040年抵达月球表面。
同时，中国和俄罗斯都没有签署《阿耳忒弥斯协议》，该协议概述了和平与负责任地探索月球的框架。这两个国家未签署该协议是否会影响它们参与协调月球时（LTC）的工作，我们需要拭目以待。
美国国家航空航天局太空通信与导航项目经理凯文-科金斯（Kevin Coggins）告诉《卫报》记者戴安娜·拉米雷斯·西蒙（Diana Ramirez-Simon）："月球上的原子钟和地球上的钟表跳动的频率是不同的。当你前往另一个天体，比如月球或火星时，每个天体都会有自己的心跳，这是有道理的"。
NASA Will Create a New Time Zone for the Moon, Called Coordinated Lunar Time
With dozens of lunar missions on the horizon, a standard time-keeping system for the moon will assist with precise navigation, docking and landingThis week, the White House officially tasked NASA with establishing a time standard for the moon, called Coordinated Lunar Time (LTC) in the Office of the President’s memorandum, which international bodies can use to coordinate their activities on the lunar surface.The move comes about a year after the European Space Agency (ESA) proposed the creationof a common time reference on the moon. Lunar missions from national agencies and private companies are expected to heavily ramp up in the coming years, with dozens already scheduled. Without a common reference frame, confusion can ensue—from small inconveniences to graver problems, such as mapping inconsistencies and navigation errors.“Imagine if the world wasn’t syncing their clocks to the same time—how disruptive that might be and how challenging everyday things become,” an unnamed White House Office of Science and Technology Policy official tells Reuters’ Joey Roulette and Will Dunham.“This is why we want to raise an alert now, saying let’s work together to take a common decision,”Patrizia Tavella, who leads the time department at the International Bureau of Weights and Measures in France, toldNature News’ Elizabeth Gibney in January 2023.The White House is giving NASA until the end of 2026 to implement the final standardized time system, which it says must have four qualities: a logical traceability to Coordinated Universal Time (UTC), the global system that regulates all Earthly time zones; enough specificity and accuracy to time very short instants, which is important for precise scientific study and spacecraft landings; self-sufficiency in the event that connection with Earth is lost; and a scalability, so that other celestial objects or space environments could also reference this time standard.Establishing a lunar time zone will better enable communications between spacecraft, data transfers, landing, docking and navigation.“Defining a suitable standard—one that achieves the accuracy and resilience required for operating in the challenging lunar environment—will benefit all spacefaring nations,” according to the memorandum.Unlike on Earth, the moon will have just one time zone and no daylight saving time. But that doesn’t make the project any easier for NASA officials. Factors like mass and gravity can affect how time passes—here on Earth, even the gradual redistribution of mass due to sea ice melt isforcing scientists to reconsider our timekeeping.On the moon, a smaller body where the gravitational pull is much weaker, time moves more quickly and unevenly: Lunar time gains about 58.7 microseconds per day compared to Earth’s time, though even this can vary, depending on the altitude and longitude where lunar clocks may be located.NASA’s Artemis program is currently scheduled to send astronauts back to the moonno earlier than September 2026, a few months before the deadline to implement LTC. On later missions, the program will involve theestablishment of a lunar base, which will help enable future flights to Mars. Other countries are also preparing to populate the moon, with China announcing a 2030 target for astronauts to arrive on the lunar surface and India’s arrival intended by 2040.Meanwhile,neither China nor Russia have signedthe Artemis Accords, which outline a framework for peace and responsible exploration of the moon. It remains to be seen if the countries’ non-participation in this agreement may affect their involvement in LTC.Still, other officials see this step toward international lunar cooperation as necessary progress“An atomic clock on the moon will tick at a different rate thana clock on Earth,”Kevin Coggins, manager of NASA’s Space Communications and Navigation Program, tells the Guardian’s Diana Ramirez-Simon. “It makes sense that when you go to another body, like the moon or Mars, that each one gets its own heartbeat.”
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