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Warfare in space


America seeks faster ways to launch military satellites


If one gets destroyed, a replacement needs to be on its way soon


By shooting a missile into one of its own satellites in March, India upped the ante. The immediate intention, suggests Jeffrey Caton, a retired American air-force colonel who teaches at the Army War College, was to fire “a shot across the bow” of India’s rival China. The Chinese had, after all, blown up one of their own satellites in 2007, in a similar demonstration of their ability to do such things. India’s test, along with the wider profusion of anti-satellite weapons, has lent credence to the worries of defence chiefs around the world who believe that future conflicts between great powers will stretch into space.


Satellites are too militarily useful to pretend that adversaries will consider them off-limits, says William Roper, the air force’s assistant secretary for technology and acquisitions. America must therefore ready itself for warfare in space. America is, indeed, especially vulnerable. It has more space assets than any other country and relies on them more for its war-fighting capability. Moreover, as John Hyten, the vice-chairman of America’s Joint Chiefs of Staff, eloquently puts it, America’s kit in space consists mainly of large, “exquisite” satellites that make for “big, fat, juicy targets”.

卫星的军事用途太大,不能想当然地认为敌人将它们视作禁区,美国空军技术与收购助理部长威廉·罗珀说道。因此,美国必须为太空战争做好准备。其实美国特别脆弱,拥有的太空资产最多,太空战力对它们的依赖度最高。正如美国参谋长联席会议副 主席约翰·汉顿雄辩地指出,美国的太空设备主要由巨大“精致”的卫星组成,它们会成为“肥美多汁的大目标”。

First responders
One approach to reducing the risk this poses is to make those targets less fat and juicy. That is happening, as both civil and military satellite users shrink their hardware and scatter its functions over multiple pieces of equipment. In particular, people are deploying more of the modular designs known as cubesats. Among other things, that means individual satellites are smaller and cheaper, and therefore easier to stockpile in advance. But for this approach to be really useful, it must also be possible to launch them quickly if, for whatever reason (whether enemy action or otherwise), an orbiting asset stops working and needs replacing.



Relativity Space, another American firm, also plans to print its rocket, the Terran 1. This will carry a payload of 900kg. Its first orbital launch is scheduled for next year. Relativity Space’s biggest printers produce five-metre sections of propellant tank. Its most precise ones create engine parts with an accuracy of 40 millionths of a metre. A conventionally manufactured rocket of similar size would contain, the firm says, nearly 100,000 parts. Terran 1 has less than 1,000. That simplifies the supply chain and accelerates the testing of parts.

另一家名为Relativity Space的美国公司也打算利用3D打印机生产Terran 1号火箭,有效载荷900公斤,计划于明年进行首次轨道发射。公司最大的打印机
辽宁体彩网_[官网首页]为推进剂贮箱生产5米长的部件,最精确的打印机生产发动机零部件,精确度达四千万分之一米。辽宁体彩网_[官网首页]据公司透露,利用传统技术生产类似尺寸的火箭包含将近10万个零部件,Terran 1号火箭包含的零部件不到1000个。辽宁体彩网_[官网首页]这可以精简供应链,加快检测零部件的速度。

Bright ideas
Speeding up launcher production in this way helps. But it will not be enough if America is to fulfil its goal of launching replacement satellites with a day’s notice. That is one reason, says Mr Roper, why the air force is now buying, at a series of pitching events that started in March, ideas for ways of prevailing in “high end” orbital combat. Encouragingly for proposers of such ideas, little bureaucracy is involved. Settlement for those accepted is immediate—the air force sidesteps its lumbering payments system by using official credit cards to transfer money instantly to people’s PayPal accounts. Those who present clever proposals can thus pocket awards exceeding $100,000 within minutes. The latest of these pitching meetings, on November 5th and 6th, resulted in on-the-spot contracts worth $22.5m.



Such launches, Virgin Orbit says, can take place above nasty weather. They also make it easier to reach east-to-west “retrograde” orbits, because the launching plane can fly in the opposite direction to Earth’s spin, reducing the launch velocity required for such an orbit. Though Virgin Orbit’s system has yet to put a satellite into orbit, Britain’s Royal Air Force seems interested. In July it announced a deal to launch small satellites on notices possibly as short as a week. By today’s standards, that is, indeed, pretty responsive.

据Virgin Orbit公司透露,这种发射方式不受恶劣天气的影响,而且更易于将火箭送达自东向西的“逆行”轨道,因为发射平台的飞行方向可与地球自转方向相反,从而降低“逆行”轨道所需要的发射速度。尽管Virgin Orbit公司尚未向轨道发射卫星,但似乎引起了英国皇家空军的兴趣。6月份,皇家空军公布一项协议,可能在收到通知后的短短一周内发射小型卫星。以当今的标准来看,这响应速度确实够快的。