來源：英語日語筆記
美國航空航天局將為月球創建新時區月球協調時
隨著數十個月球任務即將展開，一個標準的時間計量系統將給精確導航、對接和登陸帶來幫助
本星期（2024年4月2日），在一份總統辦公室備忘錄上，白宮正式責成美國航空航天局為月球創建一個時間標準，稱為協調月球時（LTC），這個時間標準可以讓各類國際機構用來協調它們在月球表面的活動。
白宮的這一舉動是在對一年前歐洲空間局提議創建一個月球共同時間參考系統的回應。預計在未來幾年，各種國家機構和私人公司的月球任務會更熱烈起來，因為已經有數十個月球任務在安排計劃里了。如果沒有共同的參考框架，混亂會接連而來，小到帶來不便，大到帶來嚴重問題，比如制圖不一致，導航錯誤。
一位不愿透露姓名的白宮科技政策辦公室官員對路透社記者喬伊-洛雷特（Joey Roulette）和威爾-鄧納姆（Will Dunham）說：“想象一下，如果全世界的時鐘都不同步，那將會是怎樣的一種破壞，日常事務又會變得多么具有挑戰性。”
2023年1月，法國國際計量局時間部門負責人帕特里齊亞-塔維拉告訴《自然-新聞》的伊麗莎白-吉布尼：“這就是為什么我們現在要發出警報，讓我們共同努力，做出共同的決定?！?/span>
白宮要求美國國家航空航天局在2026年年底之前實施最終的標準化時間系統，并表示該系統必須具備四個方面的品質：與協調世界時（UTC）的邏輯可追溯性，后者是管理所有地球時區的全球系統；足夠的具體性和準確性，可以為非常短的瞬間計時，這對于精確的科學研究和航天器著陸非常重要；在與地球失去聯系的情況下自給自足；以及可擴展性，以便其他天體或太空環境也能參照這一時間標準。
備忘錄指出，建立月球時區將更好地實現航天器之間的通信、數據傳輸、著陸、對接和導航?！岸x一個合適的標準——一個能夠達到在充滿挑戰的月球環境中運行所需的準確性和彈性的標準——將使所有航天國家受益。”
與地球不同，月球只有一個時區，沒有夏令時。但這并沒有讓美國國家航空航天局（NASA）的官員們在這個項目上感到輕松。質量和重力等因素會影響時間的流逝——在地球上，即使是海冰融化導致的質量逐漸重新分布，也迫使科學家們重新考慮我們的計時方法。
月球是一個較小的天體，引力要弱得多，因此時間走得更快、更不均勻：與地球時間相比，月球時間每天增加約 58.7 微秒，即便如此，月球時間還可能會因月球時鐘所在的海拔高度和經度而有所不同。
目前，美國國家航空航天局（NASA）的阿特米斯計劃打算在 2026 年 9 月之前將宇航員送回月球，這比實施協調月球時（ LTC ）的最后期限還早幾個月。在以后的任務中，該計劃將涉及建立月球基地，這將有助于未來飛往火星。其他國家也在為登月做準備，中國宣布了宇航員于2030年抵達月球表面的目標，印度計劃于2040年抵達月球表面。
同時，中國和俄羅斯都沒有簽署《阿耳忒彌斯協議》，該協議概述了和平與負責任地探索月球的框架。這兩個國家未簽署該協議是否會影響它們參與協調月球時（LTC）的工作，我們需要拭目以待。
美國國家航空航天局太空通信與導航項目經理凱文-科金斯（Kevin Coggins）告訴《衛報》記者戴安娜·拉米雷斯·西蒙（Diana Ramirez-Simon）："月球上的原子鐘和地球上的鐘表跳動的頻率是不同的。當你前往另一個天體，比如月球或火星時，每個天體都會有自己的心跳，這是有道理的"。
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.”
原文鏈接：https://mp.weixin.qq.com/s/_ry_rXKLi0XMGWurSPxYzA