航天安全專家質疑維珍太空船系統

Safety procedures at Virgin Galactic, whose spacecraft crashed on a test flight last week, had too few safeguards to prevent a potential catastrophe, one of the world’s leading space safety experts has said.

維珍銀河(Virgin Galactic)太空飛船上週在飛行測試中墜毀後，一位世界一流的太空安全專家表示，該公司安全程序的保障措施太少，不足以防止潛在的災難。

Tommaso Sgobba, a former head of flight safety for the European Space Agency, said industry best practice calls for operators to build in “two-failure tolerance”, or sufficient safeguards to survive two separate, unrelated failures – two human errors, two mechanical errors or one of each. He believes that SpaceShipTwo’s systems fell short of that standard.

歐洲航天局(European Space Agency)前飛行安全負責人托馬索•斯戈巴(Tommaso Sgobba)表示，行業最佳實踐要求運營商內置“雙重容錯”，即建立足以抵禦兩個不相關故障的保障措施，這兩個故障可能都是人爲故障，也可能都是機械故障，亦或是人爲及機械故障各一個。他認爲“太空船2號”(SpaceShipTwo)達不到這個標準。

According to investigators, Virgin Galactic’s SpaceShipTwo disintegrated after a pilot wrongly unlocked the “feathering” mechanism – which slows the craft during its descent – too early. The mechanism then activated even though the separate lever to deploy it was not pulled. The craft’s co-pilot died in the subsequent crash.

據調查，維珍太空船2號是在一位飛行員太早解鎖“順槳”裝置（用於太空船降落時減速）後解體的。隨後這個裝置被啓動，即便用於展開順槳的另一個手柄並未被拉起。太空船隨後墜毀，副駕駛死於此次事故。

The feathering mechanism – which is vital to slow the aircraft but potentially deadly when it is accelerating – was typical of the safety systems that need to withstand human errors and mechanical failures, analysts said.

順槳裝置對飛船減速至關重要，但在飛船加速時啓動它可能是致命的。分析人士指出，順槳裝置需要承受人爲失誤和機械故障，形成一個典型的安全系統。

Mr Sgobba said SpaceShipTwo’s systems, which required two levers to be moved before the wings went in to a “feathered” configuration, appeared to be designed to be “one-failure tolerant” – to stay safe in the event of a single pilot error or mechanical failure. But the system had not worked that way. The design would not be acceptable in other safety critical-industries, such as aeroplane manufacture, he added.

斯戈巴表示，太空船2號要求在機翼進入順槳姿勢前拉動兩個手柄，但其系統貌似被設計成“單重容錯”，即只能在一次飛行員失誤或一次機械故障的情況下保持安全。但系統並未如此發揮作用。他補充說，這種設計是不會爲其他安全關鍵的行業（比如飛機製造）所接受的。

Loren Thompson, an adviser to US aerospace companies, said other safety-critical US businesses, including suppliers to Nasa, required at least the “two-fault tolerance” Mr Sgobba described. He said it was a “significant concern” that some private space operators applied less stringent standards.

美國航空航天企業的顧問勞倫•湯普森(Loren Thompson)表示，美國其他安全關鍵企業，包括美國國家航空航天局(Nasa)的供應商在內，至少都需要達到斯戈巴所講的“雙重容錯”。他說部分私人航天運營商採用較寬鬆標準是個“令人擔憂的重大問題”。

Virgin Galactic, which is part of Sir Richard Branson’s Virgin Group, said the locking mechanism for the feathers represented two separate safeguards. There was a “procedural” safeguard, as the lock was meant to stay in place until after the most dangerous, early part of the flight, and a “mechanical” safeguard, in the form of the lock itself.

維珍銀河公司隸屬於理查德•布蘭森爵士(Sir Richard Branson)的維珍集團(Virgin Group)，該公司表示順槳裝置的鎖定機構代表了兩個不同的保障措施。一個是“程序性”保障，鎖定機構應保持不動，直到飛船度過最危險的早期飛行階段之後，另一個是“機械式”保障，即該機構本身。

Mr Sgobba said procedural rules could be seen as a safeguard in some circumstances, but “they are considered the least desirable”.

斯戈巴表示，在某些情況下程序規則可以被看作保障措施，但“它們被認爲是最不可取的”。