雙語新聞：美國國家航空航天局NASA將使用特殊航天器離開空間站

The American space agency NASA has a new plan for deorbiting the International Space Station (ISS). The plan involves developing a new spacecraft to safely guide the ISS during its final reentry through Earth's atmosphere.
美國國家航空航天局制定了一項新的國際空間站脫軌計劃。該計劃包括開發一種新的航天器，在國際空間站最后一次重返地球大氣層時安全引導國際空間站。

NASA cooperates with four other space agencies on the station. These include the Canadian Space Agency, the European Space Agency, Japan's Aerospace Exploration Agency and Russia's Roscosmos.
美國國家航空航天局在空間站上與其他四個航天機構合作。其中包括加拿大航天局、歐洲航天局、日本宇宙航空研究開發機構和俄羅斯航天局。

The ISS began serving as a space research center more than 22 years ago. It has been widely praised as a scientific success. But, NASA and its international partners say the ISS has a limited technical lifetime. NASA has said it will keep operating and sending astronauts to the ISS until 2030.
國際空間站22年前就開始作為一個空間研究中心。它被廣泛贊譽為科學上的成功。但是，美國國家航空航天局及其國際合作伙伴表示，國際空間站的技術壽命有限。美國國家航空航天局表示，將繼續運營并將宇航員送往國際空間站，直到2030年。

After that, the U.S. space agency plans to use privately developed space laboratories for its space research needs. NASA says this will permit it to pay space station operators only for the goods and services it needs.
之后，美國航天局計劃使用私人開發的太空實驗室來滿足其太空研究需求。美國國家航空航天局表示，這將允許其僅為其所需的商品和服務向空間站運營商支付費用。

NASA has already chosen several American companies to develop future space stations. These privately-operated stations will aim to serve the science needs of NASA, as well as other nations' space agencies and other organizations.
美國國家航空航天局已經選擇了幾家美國公司來開發未來的空間站。這些私人運營的空間站將致力于滿足美國國家航空航天局、其他國家的航天機構和其他組織的科學需求。

In a report to the U.S. Congress last year, NASA established its plans for the ISS. The report said the agency aims to make the station's final years its most productive. Among the goals NASA declared: "To support deep space exploration and continue to return medical and environmental benefits to humanity."
在去年提交給美國國會的一份報告中，美國國家航空航天局制定了國際空間站的計劃。該報告稱，該機構的目標是使空間站的最后幾年成為最富有成效的幾年。美國國家航空航天局宣布的目標之一是：“支持深空探索，繼續為人類帶來醫療和環境效益。”

The agency recently announced its new deorbiting plan for the ISS after considering other options to retire it. A past plan, or option, involved the use of several Russian spacecraft. But NASA officials rejected that plan and decided a new, specially designed spacecraft would better serve the needs of the deorbiting operation.
在考慮了退役國際空間站的其他選擇后，該機構最近宣布了其新的國際空間站脫軌計劃。過去的一個計劃或選擇涉及使用幾艘俄羅斯航天器。但美國國家航空航天局官員拒絕了這一計劃，并決定一艘新的、專門設計的航天器將更好地滿足脫軌操作的需要。

Other options included a plan to take apart the space station in space and transport its pieces back to Earth. Another plan would have seen the ISS sent to a higher orbit, where it would remain out-of-service. A third option involved a non-controlled reentry operation. NASA said none of these met its requirements for safety and effectiveness.
其他選擇包括在太空中拆除空間站并將其碎片運回地球的計劃。另一個計劃是將國際空間站送往更高的軌道，在那里它將停止服務。第三種選擇涉及非受控再入操作。美國國家航空航天局表示，這些都不符合其安全性和有效性的要求。

The agency recently released a request for proposals to companies interested in building the new the spacecraft. NASA calls it the U.S. Deorbit Vehicle (USDV). It says it can be a completely new vehicle or an existing design that is changed to meet all needs of the deorbiting process. The agency said it is seeking proposals now because the effort "will take years to develop, test, and certify."
該機構最近向有興趣建造新航天器的公司發布了一份征求建議書的請求。美國國家航空航天局稱之為美國脫氧飛行器（USDV）。它說，它可以是一輛全新的車輛，也可以是一種現有的設計，可以進行更改以滿足脫軌過程的所有需求。該機構表示，目前正在尋求提案，因為這項工作“需要數年的時間來開發、測試和認證”。

NASA has said when it is time to retire the ISS, it will begin taking the first steps to slowly lower its operating altitude. This part of the process can likely be carried out by the ISS and its systems, without the need for additional spacecraft.
美國國家航空航天局表示，當國際空間站退役時，它將開始采取第一步，慢慢降低其運行高度。這部分過程可能由國際空間站及其系統進行，而不需要額外的航天器。

But the final part of the operation, reentry, will center on guiding the ISS though Earth's atmosphere to a pre-chosen target in an unpopulated area in the ocean. NASA says this final part "is expected to require a new or modified spacecraft using a large amount of propellant."
但行動的最后一部分，即重返大氣層，將集中引導國際空間站穿過地球大氣層，到達海洋中無人區的預先選擇的目標。美國國家航空航天局表示，這最后一部分“預計需要一個使用大量推進劑的新的或改進的航天器”。

The targeted landing spot has been identified as a place called Point Nemo in the South Pacific Ocean. This is a stretch of open water between New Zealand and the southernmost part of South America. The U.S. National Ocean Service identifies Point Nemo as the point in the ocean that is farthest from land.
目標著陸點已被確認為南太平洋的一個名為尼莫角的地方。這是新西蘭和南美洲最南端之間的一片開闊水域。美國國家海洋局將尼莫角確定為海洋中距離陸地最遠的點。

NASA predicts that most ISS equipment will burn up or vaporize during the intense heating that happens during atmospheric re-entry. But it says some denser or more heat-resistant elements are expected to survive and land in the targeted ocean area.
美國國家航空航天局預測，在重返大氣層期間發生的劇烈加熱過程中，大多數國際空間站設備將燃燒或蒸發。但它表示，一些密度更大或更耐熱的元素有望在目標海域生存并降落。