來(lái)源：英語(yǔ)日語(yǔ)筆記
美國(guó)航空航天局將為月球創(chuàng)建新時(shí)區(qū)月球協(xié)調(diào)時(shí)
隨著數(shù)十個(gè)月球任務(wù)即將展開(kāi)，一個(gè)標(biāo)準(zhǔn)的時(shí)間計(jì)量系統(tǒng)將給精確導(dǎo)航、對(duì)接和登陸帶來(lái)幫助
本星期（2024年4月2日），在一份總統(tǒng)辦公室備忘錄上，白宮正式責(zé)成美國(guó)航空航天局為月球創(chuàng)建一個(gè)時(shí)間標(biāo)準(zhǔn)，稱為協(xié)調(diào)月球時(shí)（LTC），這個(gè)時(shí)間標(biāo)準(zhǔn)可以讓各類國(guó)際機(jī)構(gòu)用來(lái)協(xié)調(diào)它們?cè)谠虑虮砻娴幕顒?dòng)。
白宮的這一舉動(dòng)是在對(duì)一年前歐洲空間局提議創(chuàng)建一個(gè)月球共同時(shí)間參考系統(tǒng)的回應(yīng)。預(yù)計(jì)在未來(lái)幾年，各種國(guó)家機(jī)構(gòu)和私人公司的月球任務(wù)會(huì)更熱烈起來(lái)，因?yàn)橐呀?jīng)有數(shù)十個(gè)月球任務(wù)在安排計(jì)劃里了。如果沒(méi)有共同的參考框架，混亂會(huì)接連而來(lái)，小到帶來(lái)不便，大到帶來(lái)嚴(yán)重問(wèn)題，比如制圖不一致，導(dǎo)航錯(cuò)誤。
一位不愿透露姓名的白宮科技政策辦公室官員對(duì)路透社記者喬伊-洛雷特（Joey Roulette）和威爾-鄧納姆（Will Dunham）說(shuō)：“想象一下，如果全世界的時(shí)鐘都不同步，那將會(huì)是怎樣的一種破壞，日常事務(wù)又會(huì)變得多么具有挑戰(zhàn)性。”
2023年1月，法國(guó)國(guó)際計(jì)量局時(shí)間部門負(fù)責(zé)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(xiàn)在要發(fā)出警報(bào)，讓我們共同努力，做出共同的決定。”
白宮要求美國(guó)國(guó)家航空航天局在2026年年底之前實(shí)施最終的標(biāo)準(zhǔn)化時(shí)間系統(tǒng)，并表示該系統(tǒng)必須具備四個(gè)方面的品質(zhì)：與協(xié)調(diào)世界時(shí)（UTC）的邏輯可追溯性，后者是管理所有地球時(shí)區(qū)的全球系統(tǒng)；足夠的具體性和準(zhǔn)確性，可以為非常短的瞬間計(jì)時(shí)，這對(duì)于精確的科學(xué)研究和航天器著陸非常重要；在與地球失去聯(lián)系的情況下自給自足；以及可擴(kuò)展性，以便其他天體或太空環(huán)境也能參照這一時(shí)間標(biāo)準(zhǔn)。
備忘錄指出，建立月球時(shí)區(qū)將更好地實(shí)現(xiàn)航天器之間的通信、數(shù)據(jù)傳輸、著陸、對(duì)接和導(dǎo)航。“定義一個(gè)合適的標(biāo)準(zhǔn)——一個(gè)能夠達(dá)到在充滿挑戰(zhàn)的月球環(huán)境中運(yùn)行所需的準(zhǔn)確性和彈性的標(biāo)準(zhǔn)——將使所有航天國(guó)家受益。”
與地球不同，月球只有一個(gè)時(shí)區(qū)，沒(méi)有夏令時(shí)。但這并沒(méi)有讓美國(guó)國(guó)家航空航天局（NASA）的官員們?cè)谶@個(gè)項(xiàng)目上感到輕松。質(zhì)量和重力等因素會(huì)影響時(shí)間的流逝——在地球上，即使是海冰融化導(dǎo)致的質(zhì)量逐漸重新分布，也迫使科學(xué)家們重新考慮我們的計(jì)時(shí)方法。
月球是一個(gè)較小的天體，引力要弱得多，因此時(shí)間走得更快、更不均勻：與地球時(shí)間相比，月球時(shí)間每天增加約 58.7 微秒，即便如此，月球時(shí)間還可能會(huì)因月球時(shí)鐘所在的海拔高度和經(jīng)度而有所不同。
目前，美國(guó)國(guó)家航空航天局（NASA）的阿特米斯計(jì)劃打算在 2026 年 9 月之前將宇航員送回月球，這比實(shí)施協(xié)調(diào)月球時(shí)（ LTC ）的最后期限還早幾個(gè)月。在以后的任務(wù)中，該計(jì)劃將涉及建立月球基地，這將有助于未來(lái)飛往火星。其他國(guó)家也在為登月做準(zhǔn)備，中國(guó)宣布了宇航員于2030年抵達(dá)月球表面的目標(biāo)，印度計(jì)劃于2040年抵達(dá)月球表面。
同時(shí)，中國(guó)和俄羅斯都沒(méi)有簽署《阿耳忒彌斯協(xié)議》，該協(xié)議概述了和平與負(fù)責(zé)任地探索月球的框架。這兩個(gè)國(guó)家未簽署該協(xié)議是否會(huì)影響它們參與協(xié)調(diào)月球時(shí)（LTC）的工作，我們需要拭目以待。
美國(guó)國(guó)家航空航天局太空通信與導(dǎo)航項(xiàng)目經(jīng)理凱文-科金斯（Kevin Coggins）告訴《衛(wèi)報(bào)》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(dòng)的頻率是不同的。當(dāng)你前往另一個(gè)天體，比如月球或火星時(shí)，每個(gè)天體都會(huì)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