How Solid Waste Management Works on the International Space Station國際空間站如何處理固體廢棄物

Launched in the year 1998 by a consortium of space agencies from the United States， Europe， and Japan， the International Space Station （ISS） was largely assembled in space， a remarkable feat in and of itself. Even more impressive is the fact that the station has been continuously upgraded over the decades since， allowing it to outlive every other space station program in history. The ISS is used for many kinds of experiments， which have in turn transformed our knowledge of astronomy and technology. It’s a testament to the incredible potential of human ingenuity， but that doesn’t mean it’s perfect.

國際空間站于1998年由美國、歐洲和日本的航天機構聯合發射。它大部分是在太空裝配的，這本身就是一項非凡的成就。更讓人贊嘆的是，國際空間站幾十年來一直在不斷升級，這讓它成為有史以來運行時間最長的空間站項目。國際空間站用于開展各種各樣的實驗，這些實驗反過來又刷新了我們對天文學和科技的認知。它證明了人類智慧擁有巨大的潛力，但這并不意味著它是完美無缺的。

Everything astronauts eat， and many of the items they use on a daily basis， are destined to become waste. With no landfills or recycling centers to handle all the mess， astronauts on the space station are left with essentially one option： ejecting their garbage into space. Yes， that’s really how they do it， at least for now， but NASA and the other agencies involved with the ISS are searching for new and better solutions.

宇航員的所有食物和許多日常用品都必然成為廢棄物。由于沒有垃圾填埋場或回收中心來處理所有的垃圾，空間站的宇航員基本上只有一種選擇：把他們的垃圾扔進太空。是的，他們確實是這樣做的，至少目前是這樣。但美國國家航空航天局和國際空間站其他相關機構正在尋找新的優化方案。

A brief history of space trash

太空垃圾簡史

During early NASA missions， such as Project Mercury， which put the first American astronaut in space in 1961， waste wasn’t really an issue because the flights were so short. Of the six Mercury missions， only one lasted longer than a day. During these flights， astronauts used bags to collect their waste， including urine and feces， which they could then dispose of upon their return to Earth.

在美國國家航空航天局早期的任務中——比如1961年將第一位美國宇航員送入太空的水星計劃——垃圾并不是問題，因為飛行時間非常短。在六個水星計劃任務中，只有一個任務持續時間超過一天。在這些飛行中，宇航員用袋子收集垃圾，包括尿液和排泄物，然后可以在返回地球時處理掉。

When Neil Armstrong became the first human to set foot on the Moon， he also dropped off a bag of trash， which included old food wrappers and containers of urine and feces. Subsequent Moon missions took the same approach， and there are now almost 100 bags of trash just sitting on the Moon. Meanwhile， the space agency’s shift in focus from the Moon to the International Space Station prompted an even bigger challenge. The ISS is built to sustain a crew of seven， with as much space as a large house， and there isn’t a convenient place to just ‘drop off’ your garbage.

當尼爾·阿姆斯特朗成為第一個踏上月球的人時，他也扔下了一袋垃圾，其中包括舊的食品包裝紙以及裝尿液和排泄物的容器。在隨后的月球任務中，宇航員們沿用了同樣的方法，現在月球上有近100袋垃圾。同時，美國國家航空航天局的工作重心從月球轉移到國際空間站，這帶來了更大的挑戰。國際空間站可以容納7名工作人員，它的空間相當于一所大房子，里面沒有一處方便隨手丟垃圾的地方。

How waste disposal currently works on the ISS

目前國際空間站如何進行垃圾處理

To remove waste， the ISS has its own version of garbage trucks. Every few months， small， unmanned craft are sent up to the ISS to deliver the supplies astronauts need to survive in space. After dropping off its shipment， the craft gets loaded up with garbage bags and sent back to Earth. However， you don’t need to worry about astronaut garbage falling out of the sky because the supply craft incinerate when they reenter Earth’s atmosphere. It might come as a shock to learn that the ISS crew disposes of trash by simply burning it up in the atmosphere， but sometimes they don’t even use special craft for it： They just toss it into space.

為了清除垃圾，國際空間站有特制的垃圾車。每隔幾個月，小型無人飛船就會被發射到國際空間站，運送宇航員在太空生存所需的物資。飛船卸貨后裝載垃圾袋返回地球。不過你不必擔心宇航員的垃圾會從天空掉下來，因為補給飛船在重返地球大氣層時會焚毀。國際空間站的工作人員處理垃圾的方式就是將其送入大氣層燒毀，這似乎聽起來讓人震驚。但有時他們甚至連特殊的飛船都不用：他們干脆把垃圾扔進太空。

Some trash is offloaded during space walks

在太空行走時丟棄垃圾

With the rarity of supply missions and the highly limited space aboard the International Space Station， astronauts don‘t always use unmanned craft for their trash disposal needs. There have been numerous instances in which astronauts have offloaded garbage while conducting spacewalks. A spacewalk is any instance in which an astronaut puts on their spacesuit and steps outside of the ISS. Spacewalks are often done to make repairs on the station， and to upgrade it with new equipment. Spacewalks also allow astronauts to conduct experiments in space， accomplishing things that could never be done in a terrestrial lab. Occasionally， they also serve as trash runs.

由于補給飛行任務非常少，國際空間站的空間又極為有限，宇航員們并不總是使用無人飛船來處理垃圾。在太空行走時丟棄垃圾的情況屢見不鮮。只要是宇航員穿上航天服走出國際空間站的活動都叫太空行走，通常是為了對空間站進行維修，以及更新設備升級換代。太空行走還可以讓宇航員在太空開展實驗，完成在地面實驗室永遠無法完成的任務，有時候還順便扔垃圾。

When astronauts throw trash out during spacewalks， it’s often pieces of old equipment that have exhausted their use or become outdated. For instance， in 2007， the ISS crew tossed out a 1，400-pound tank of ammonia coolant that they had been keeping as a backup for the station’s main cooling system. Once the need for the backup was eliminated， the size of the tank and the hazard presented by ammonia made disposing of the tank the logical choice. In other cases， trash ends up in space by accident， as occurred in 2017， when an ISS crew member lost hold of a debris shield from the station’s exterior.

宇航員在太空行走時丟棄的垃圾通常是耗盡使用壽命或過時的舊設備。例如，2007年，國際空間站的工作人員扔掉了一個1400磅（約635公斤）的氨冷卻劑罐，這是他們為空間站主冷卻系統儲存的備用液。一旦備用液不再需要，考慮到儲存罐的大小和氨潛在的危害，處理掉它就成了合理的選擇。還有一些情況，垃圾會偶然進入太空。比如2017年，國際空間站的一名乘員失手讓空間站外部的太空碎片防護罩飄走了。

The limitations of space waste disposal

太空垃圾處理的局限

Scientists have warned that space junk poses a threat to the climate， but the trash itself isn’t the biggest problem. The primary concern is with the supply craft that carry the offloaded garbage. These craft， along with numerous satellites that have been launched into orbit over the years， contain large amounts of aluminum， which can deplete the ozone layer. Even the rockets used to launch those spacecraft pollute the atmosphere with aluminum in their fuel. Furthermore， if enough aluminum builds up in the atmosphere， it could also affect the way the sun’s rays hit the planet， potentially altering global light and temperatures.

科學家曾經提醒太空碎片對氣候構成威脅，但是垃圾本身并不是最大的問題。首要隱患是裝載垃圾的補給飛船。這些飛船以及多年來發射進軌道的眾多衛星都含有大量的鋁，這些鋁會破壞臭氧層。就連用來發射那些宇宙飛船的火箭，由于燃料中含鋁，也會對大氣層造成污染。此外，如果大氣中積聚了足夠多的鋁，它還會影響太陽光照射地球的方式，可能會改變全球的光線和溫度。

Sometimes， the trash from the ISS fails to completely incinerate in the atmosphere， and that causes more problems. In 2021， astronauts used a robotic arm on the ISS to toss out a 5，800-pound pallet of dead batteries， the largest piece of trash ever discarded from the station. The junk orbited Earth for three years， but in March of 2024， it finally reentered the atmosphere. Part of it appeared to burn up， but a roughly 2-pound piece of equipment used to secure the batteries to the pallet ended up surviving reentry and subsequently crashed into a home in Florida. Although there were no injuries， it is an ominous look at the dangers of the ISS’s current waste disposal systems.

有時候，來自國際空間站的垃圾未能在大氣中完全燃燒，這會導致更多的問題。2021年，宇航員用國際空間站上的一個機械臂扔掉了5800磅（約2631公斤）的廢電池，這是國際空間站有史以來丟棄的最大一團垃圾。這塊垃圾繞地球運行了三年，而在2024年3月終于重新進入了大氣層。它的一部分似乎燃燒殆盡，但一塊大約2磅（約0.9公斤）的用于將電池固定在托盤上的設備在重返大氣層時得以保全，隨后墜入佛羅里達州的一戶民居。雖然沒有人受傷，但這預示著國際空間站目前的垃圾處理系統隱患重重。

Solutions for the future

未來的解決方案

NASA and the other space agencies involved with the International Space Station have been working to develop better waste disposal systems. In 2023， NASA contracted the Sierra Space company to build a new trash compaction system for the ISS that could greatly increase the amount of trash the station can store at a time. Furthermore， the system will be able to remove water from wet waste bags， making them less risky to deal with. The system is scheduled to be tested on the ISS in 2026.

美國國家航空航天局和其他與國際空間站有關的航天機構一直致力于研發更好的垃圾處理系統。2023年，美國國家航空航天局簽約請塞拉太空公司為國際空間站建造一套新的垃圾壓縮系統，它要能夠大大增加國際空間站一次可以儲存的垃圾量。此外，這套系統將能夠從濕垃圾袋中清除水分，從而降低處理它們時的風險。該系統計劃將于2026年在國際空間站進行測試。

Another exciting development in ISS trash disposal is the invention of a new trash ejection system. First used in 2022， the system allows astronauts to place their bags of trash directly into an airlock1 that will eject trash from the station back to Earth without the use of a supply vehicle. This would make it much easier to get rid of trash and free up space on the station.

國際空間站垃圾處理取得的另一項令人振奮的突破，是發明了新的垃圾彈射系統。該系統于2022年首次投入使用，宇航員可以將他們的垃圾袋直接放入壓差隔離室，在不使用補給飛船的情況下將垃圾從空間站彈射回地球。這樣，在空間站清理垃圾、釋放空間會容易很多。

（譯者為“《英語世界》杯”翻譯大賽獲獎者）