衛星有助馬航客機搜索 但能力有限
An international charter of 15 space agencies was activated last week to search for the missing Malaysia Airlines jet, and by Thursday it provided what appeared to be the best lead yet to the airliner's disappearance.
自上週啓動國際憲章向15個空間局調用衛星尋找馬來西亞航空(Malaysia Airlines)失聯飛機以來，週四衛星數據似乎提供了迄今爲止關於這架飛機的最佳線索。However, experts warned that satellite technology is limited in its capability when it comes to searching huge swaths of territory.
不過專家警告說，當涉及搜索大面積領域時，衛星技術能力有限。Satellite data has been critically important to the search, from narrowing down the aircraft's likely destination to spotting possible debris in a vast area of ocean. Flight 370 disappeared from radar early on March 8 en route to Beijing from Kuala Lumpur. It was carrying 239 passengers and crew.
衛星數據對搜索行動至關重要，從縮小飛機可能目的地的範圍，到在遼闊海洋上發現點滴的可能碎片，無不要依賴衛星。370航班3月8日由吉隆坡飛往北京途中從雷達上消失。機上有乘客和機組人員共239人。
'This is a very difficult case. Normally we know what the area of interest is. This is essentially a camera in space, and if you don't know where to point it then it's a big challenge,' said Adina Gillespie, product development manager at DMC International Imaging, a UK-based commercial satellite imaging provider.
總部位於英國的商業衛星影像提供商DMC International Imaging產品開發經理艾迪娜•吉萊斯皮(Adina Gillespie)稱，這次的情況非常棘手，通常情況下需要知道關注的區域在哪裏。她表示，從本質上講衛星就是太空中的照相機，如果不知道要對準哪裏，那麼將面臨非常大的挑戰。Ms. Gillespie is also a secretariat member of the International Disasters Charter, an alliance of 15 space agencies including NASA and the China National Space Administration, which pools satellite assets during times of crisis. China invoked the charter on March 11, three days after Flight 370 disappeared.
吉萊斯皮還是《空間和重大災害國際憲章》(International Disasters Charter)祕書處成員。該憲章是由美國航空航天局(NASA)、中國國家航天局(China National Space Administration)等15個空間機構組成的合作機制，在發生危機時可集中調用衛星資源。在370航班失聯三天後，中國於3月11日要求啓動該憲章。The charter is usually invoked for natural disasters, such as the February eruption of Mount Kelud in Indonesia, which forced tens of thousands of people in East Java to flee their homes.
自然災害通常可啓動這一憲章，比如2月份印尼克盧德火山(Mount Kelud)噴發，導致東爪哇數萬居民撤離。'For events like this we will task a satellite [to cover the area of interest] once a day, or more,' Ms. Gillespie said. 'We can automate some aspects of it. For example we can run a program to identify bright things [in the images].' She said such programs had been run in the search for Flight 370, but cloud cover in the target areas had limited their usefulness.
吉萊斯皮說，在這類事件中我們會安排一顆衛星每天搜索目標區域一次或多次。她說，某些任務可以自動完成，比如可以利用程序來確認圖像中的明亮物體。她說，尋找370航班的過程中就利用了這類程序，不過目標區域上方的雲層限制了這些程序的有效性。In the case of missing Flight 370, satellite images from commercial operator DigitalGlobe were used to locate two objects that authorities believe may be from the aircraft. DigitalGlobe is a Colorado-based provider of high-resolution satellite imagery used by both public and private clients.
在搜尋馬航失聯航班的過程中，DigitalGlobe提供的衛星圖像定位了兩個據信可能是客機殘骸的物體。DigitalGlobe是一家位於科羅拉多州的高分辨率商業衛星圖像供應商，它的客戶既有官方機構也有私人公司。According to Australian authorities, who are leading the search efforts where the objects have been sighted in the southern Indian Ocean, the images were captured on March 16 but took four days to be analyzed and passed to the appropriate authority. 'The biggest delay in the process is in the analysis part of it,' Ms. Gillespie said.
據澳大利亞政府稱，上述衛星圖像攝於3月16日，但光分析就花了四天時間，之後才傳給相關部門。由於疑似殘骸出現在南印度洋，澳大利亞是這片區域的搜尋主力。吉萊斯皮說，整個搜尋過程中最耗時間的就是分析。Australia's maritime agency has been careful to emphasize that the images are not conclusive evidence that Flight 370 crashed. 'The images have been assessed as being credible but it is possible they do not relate to the search,' it said in a statement.
澳大利亞海事部門謹慎地強調，從衛星圖片這一證據並不能就得出結論認爲MH370已經墜毀。該部門在一份聲明中表示，圖片經評估後被認爲可靠，但也有可能與失聯客機的搜索行動無關。DigitalGlobe declined to comment in detail on their images. 'We do not have any additional information at this time as relevant search parties follow up on this important lead,' the company said Thursday.
DigitalGlobe拒絕就其圖片詳細置評。該公司週四表示，眼下該公司沒有更多的信息，相關搜索方正在跟進這一重要線索。Commercial imaging satellites typically have a range of capabilities, according to the German Aerospace Center, which says satellites typically scan areas 15 square kilometers (nearly 6 square miles) but can zoom out to 60 square kilometers or 2,300 square kilometers.
據德國航空航天中心(German Aerospace Center)表示，商業影像衛星的能力通常有一定的範圍。該中心表示，衛星通常能夠掃描15平方公里（近6平方英里）的區域，但可以擴大到60平方公里乃至2,300平方公里。'Satellites could definitely be helpful to detect a crashed airplane on land, which has been most probably burnt or exploded,' said Hendrik Zwenzner, deputy head of the Center for Satellite-Based Crisis Information at the German Aerospace Center. 'As for the ocean the main problem is to narrow down the area where the plane possibly crashed.' He said most satellites would need the search area to be limited to just a few hundred square kilometers, which would take a 'couple' of days to scan.
德國航空航天中心星基危機信息中心(Center for Satellite-Based Crisis Information)副主任茨文茨納(Hendrik Zwenzner)稱，毫無疑問，衛星有助於探測在陸地上墜毀的飛機，在陸地上墜毀的飛機很有可能燒燬或發生了爆炸。他還說，至於對海上進行探測，主要問題是要縮小飛機可能墜毀區域的範圍。他說，大部分衛星需要搜索區域限制在只有幾百平方公里，掃描需要花幾天時間。In answer to a question about the usefulness of satellites to track the movements of Flight 370, Mr. Zwenzner's colleague and the head of the Center, Tobias Schneiderhan, added that only low resolution satellites acquire data continuously. 'But those are not useful for the search. Even those pass each point on earth only once or twice a day,' he said.
在回答一個有關衛星追蹤MH370航班活動情況的有效性的問題時，茨文茨納的同事、星基危機信息中心主任施奈德漢(Tobias Schneiderhan)說，只有低分辨率衛星才能連續獲取數據。他說，但這類衛星對搜索沒有用處，即便是這類衛星每天也只經過地面各點一兩次。
