IN A clean room at the Airbus Defence & Space (ADS) factory north of London, scientists are working on LISAPathfinder (pictured), a hexagon-shaped satellite due to be launched next year. The aim of the ambitious space mission is to try, for the first time, to find and measure gravitational waves—ripples in space-time predicted by Einstein’s general theory of relativity. If that’s possible, earthlings would have further evidence that the theory is true, and they should also, eventually, be able to locate black holes more accurately.

To do all that, however, LISA first has to get to a “Lagrange point”, a place where spacecraft can float stably while getting no farther from the earth. This is essential for detecting the gravitational waves. The only force that could then ruffle LISA would be solar wind, explains Justin Byrne, a deputy director of ADS. Solar wind is so light, however, that developing thrusters soft and accurate enough to counteract it has been “the trickiest bit of all”. It would take 1,000 of the thrusters developed for LISA to lift a single piece of paper; LISA has just four.

This is the kind of technological achievement that has made Britain a leader in satellite design and construction. This week ADS was celebrating the European Space Agency’s Rosetta mission to comet 67P/Churyumov-Gerasimenko. The probe, Philae, that landed on the comet, was assembled largely in Germany. But Rosetta itself was, for the most part, constructed in the same clean room where LISA is being built; Mr Byrne himself was one of the designers of Rosetta when the mission was first conceived about 20 years ago. Altogether ten British companies were involved in the Rosetta mission, making up 20% of the contractors used among 14 European countries. Some of the fancy kit on Philae was British, such as the miniature laboratory built at the Rutherford Appleton laboratory near Oxford to a design from the Open University.

This outsized contribution to the Rosetta mission is now typical of Britain’s place in the firmament of satellite construction. About one-quarter of the world’s commercial communication satellites are built in Britain and 40% of the world’s small satellites. Most of those are built by Airbus’s Surrey Satellite Technology Limited (SSTL), the world leader in the field. It has launched 43 satellites since it was started by an academic at Surrey University, Sir Martin Sweeting. The whole space sector directly employs 35,000 people, and the supply-chain accounts for thousands more jobs. London-based Inmarsat is one of the world’s largest satellite operators, specialising in mobile telephony. The space sector has a turnover of about ￡11 billion a year.(Economist)

翻译：

空中客车防务及航天公司(ADS)位于伦敦北部的工厂里，科学家们正在一尘不染的工作室中致力于丽萨探路者号的研发。丽萨探路者号是一枚预计明年发射的呈六边形状的人造卫星。该项雄心勃勃的航天使命的目标就是首次尝试寻找并测量引力波，也就是爱因斯坦的广义相对论中所预言的时空中存在的涟波。如果引力波真的存在，那么世人就能够进一步的证明其理论的真实性，并且最终他们也应该能够更加准确地定位黑洞的方位。

然而，要想完成所有的任务，丽萨首先就必须到达“拉格朗日点”，只有到达了拉格朗日点，宇宙飞船才可以在不远离地球的情况下平稳漂浮。这是探测引力波的必要条件。据ADS的副主任贾斯汀·伯恩(Justin Byrne)解释称，唯一会干扰丽萨的力量就是太阳风。不过太阳风的质量很轻因此只要将推进器设计得足够轻巧和精准就可以与太阳风的力量相抗衡，但这恰恰是“最棘手的问题”。丽萨需要配备1000台这样的推动器才能吹起一张纸;而现在丽萨仅有四台。

英国在丽萨探路者上取得的科技成果确立了其在人造卫星的设计及建造领域的领导地位。本周ADS就在庆祝欧洲太空总署的罗塞塔号探测器圆满完成追逐丘留莫夫-格拉西缅科彗星的任务。此外，虽然在彗星上着陆的“菲莱”号探测器大部分都是在德国完成组装的。但是罗塞塔号探测器本身大体都是在建造丽萨的同一间纤尘不染的工作室完成的;伯恩自己也是20年前罗塞塔号计划构想初期的设计人员之一。罗塞塔号计划中总共有10家英国公司参与，占据了欧洲14国所有承包商的20%。并且“菲莱”号上一些精细的工具就是英国制造，例如微型实验室就是由英国开放大学设计，并由牛津附近的卢瑟福·阿普尔顿实验室生产。

在罗塞塔任务中的突出贡献是英国如今已成为卫星建造领域领头羊的典型表现。世界上大约有四分之一的商用通讯卫星是英国制造，小型卫星的比重则为40%。并且大多数卫星都是由隶属于空客集团的萨里卫星技术有限公司(SSTL)负责生产。SSTL掌握了世界领先的卫星尖端技术，自从萨里大学的教授马丁·斯维廷爵士开启卫星发射活动以来，SSTL已经成功发射了43枚人造卫星。其下属的空间部直接领导的员工就有35000人，而且其相关的供应链产业也创造了几千个工作岗位。以伦敦为中心的国际海事卫星组织(Inmarsat)是世界上最大的卫星基地之一，专攻移动电话制造。空间部每年大约能创造110亿英镑的营业额。