2021年经济学人 一种用于飞机和导弹的新型燃料即将问世(1)（在线收听）

Hypersonic flight

高超声速飞行

The rockets' green glare

火箭的绿色光芒

A new fuel for jets and missiles is on the cards

一种用于飞机和导弹的新型燃料即将问世

The latest buzzword in the world's aerospace skunk works is "hypersonic". Speed and surprise have always been essential to warfare, and what better way to wrong-foot an enemy than by arriving unexpectedly on his doorstep in the form of an aircraft or missile travelling at Mach 5

世界航空臭鼬工厂的最新流行词是“高超音速”。速度和出其不意一直是战争的关键，还有什么比以5马赫的速度出人意料地以飞机或导弹的形式出现在敌人家门口更能让敌人措手不及的呢？

In that context, a notice posted at the beginning of the year by America's navy, soliciting proposals for a new research project, is intriguing. The project's objective is to "determine a form of boron or a boron-based chemical pathway that leads to implementation of boron in energetic compounds, especially fuels (solid and liquid)". The navy's engineers, it seems, are trying to revive an idea that might make hypersonic flight easier to achieve, but which was tested and then abandoned more than half a century ago. They hope to spice up aviation and rocket fuel with a long-neglected element.

在这样的背景下，今年年初美国海军发布的征求新研究项目建议的公告耐人寻味。该项目的目标是“确定一种硼的形式或一种基于硼的化学途径，使硼在高能化合物，特别是燃料(固体和液体)中得以实现”。看来，美国海军的工程师们正试图复兴一种可能让高超音速飞行更容易实现的想法，但这种想法在半个多世纪前经过了测试，然后被放弃了。他们希望在航空和火箭燃料中加入一个长期被忽视的元素。

Boron, atomic number five on the periodic table, is chemically a "metalloid"— meaning that it inhabits the debatable marcher lands between the empires of the metals proper, on the table's left-hand side, and the non-metals, on its right. Compounds of boron feature in washing powders and cleaning products ("borax"), antiseptics and water softeners, and also as additives in fibreglass, but such roles are humdrum. Boron does, though, burn like billy-o, generating a bright, green flame and releasing about 40% more energy per kilogram than conventional aviation fuel.

元素周期表上原子序数为5的硼，在化学上属于“类金属”——也就是说，它处在金属帝国(在元素周期表的左边)和非金属帝国(在元素周期表的右边)之间的争议地带。硼化合物用在洗衣粉和清洁产品(“硼砂”)、防腐剂和水软化剂中，也可作为添加剂的玻璃纤维，但这些作用是单调的。不过硼确实可以快速燃烧，产生明亮的绿色火焰，每千克要比传统航空燃料多释放约40%的能量。

In light of this, and of reports by spies of green flames emerging from the exhaust of an experimental Soviet rocket, America's air force experimented in the 1950s with stuff nicknamed zip fuel, which was laced with compounds of boron called boranes. The project was abandoned in 1959, for two good reasons. First, boranes proved extremely dangerous. They are toxic, meaning those working with them need special gas masks. They also ignite spontaneously in air, and may even explode. At least eight people involved in the zip-fuel project died in borane-related accidents.

鉴于此，还有间谍们的报告，他们发现苏联实验性火箭的排气口冒出了绿色的火焰，美国空军在20世纪50年代试验了一种叫做拉链燃料(高型能的飞机燃料)的东西，这种燃料含有硼烷的化合物。该项目于1959年被放弃，原因有二。首先，硼烷被证明是极其危险的，它们是有毒的，这意味着工作人员需要特殊的防毒面具。它们也会在空气中自燃，甚至会爆炸。至少有八名参与拉链燃料项目的人死于硼烷相关事故。