The longest previous hypersonic scramjet flight test, performed by a NASA X-43 in 2004, was faster, but lasted only about 10 seconds and used less logistically supportable hydrogen fuel.

先前最长的冲压式喷气发动机下极超音速飞行测试，是在2004年由NASA的X-43进行的，速度更快，但只持续了10s。

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Both planes were going to take off on July 25th, but Latham failed to get up early enough, After making a short test flight at 4, 15 a.m., Bleriot set off half an hour later.

两天飞机都打算在7月25日起飞，但莱瑟姆那天起床晚了。布莱·里奥凌晨4点15分作了一次短距离试飞，半小时后便正式出发了。

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But ultimately, this mission is a test flight, so we'll know a lot more afterward than we'll know beforehand.

但最终，这是一个测试飞行任务，因此我们将知道更多以后会比我们事先知道。

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The B-52 took to the skies Tuesday, but no other information about the test flight was available, John Haire, a spokesman for Edwards Air Force Base in California, said in an email.

MSN: Hypersonic aircraft taken out for a trial run on B-52 bomber

But Mr Aldrin disagreed with the view that astronauts should test capabilities for a long-duration flight on the Moon before attempting a journey to Mars.

BBC: Moon astronauts urge Mars mission

Like Amazon, the company is secretive, but last September it revealed that it had lost an unmanned prototype vehicle during a short-hop test flight.

ECONOMIST: Brain scan