忘了可重复使用火箭吧，这个更牛！

Reaction Engines公司设想的“云霄塔”（The Skylon）概念太空飞机，有望采用该公司的SABRE发动机技术。图片由BAE Systems提供

忘了可重复使用火箭吧。英国军工巨头BAE系统公司刚刚向一种有望颠覆航天经济学的新型飞机引擎投入了3200万美元资金。

如果说眼下对于商业航天领域有什么普遍看法的话，那就是SpaceX和Blue Origin这样的精益型行业新星正在借助新的技术和商业模式超越这个领域中的传统企业，比如波音、洛克希德-马丁和Aerojet Rocketdyne。

不过，作为欧洲最大国防承包商和彻头彻尾的老牌航天企业，BAE系统公司投入了3000万美元的技术可能把这些“搅局者”搅个底朝天。

BAE收购了英国小型技术公司Reaction Engines两成股份。两公司高层表示，Reaction Engines的协同吸气式火箭发动机（SABRE）概念可能在航天动力领域再次引发革命。如果研制成功，这种喷气/火箭混合发动机就可以让飞机从普通跑道上起飞，然后以20马赫以上的速度进入空间轨道，也能让它像普通飞机一样在跑道上着陆，而且自始至终都只使用自身的动力。

有了这种可重复使用的太空飞机，发射卫星以及向太空输送其他货物的成本估计有望下降90%；同时，以它为基础，人们还能开发出可在四小时内飞抵世界上任何角落的客运飞机。BAE高层相信，该公司管理复杂空天研发项目的能力可以在2025年之前把Reaction Engines的技术从概念变成飞上天空的原型机。

Reaction Engines董事总经理马克•托马斯说：“看看其他可重复使用太空飞机的概念就会发现，他们依靠的动力不一而足，有火箭，有喷气发动机，也有冲压式喷气发动机。我们拿出来的方案则把所有最好的元素都纳入了一个动力系统。所以，我觉得目前我们遥遥领先。我还没有看到任何能直接跟我们竞争的东西。”

按照设计，SABRE引擎可以像常规喷气发动机那样吸入空气来工作。在这个阶段，它可以让飞机加速到5马赫，也就是音速的5倍（时速超过3800英里，或6120公里）。然后，这种引擎可以“变身”为火箭发动机，把飞机送入太空。返还地面时，这种引擎还能“变回来”，用传统的喷气动力让飞机在普通跑道上降落。同一台发动机可以反复使用，因而不需要为安装垂直火箭发射塔投入资金，就连SpaceX设想的可重复利用火箭发射塔的翻新费用都省了。

催生SABRE引擎的点子最早出现在30多年前。但基础领域的一些技术障碍让这个概念一直停留在纸上谈兵阶段，比如说，其中的一大问题是怎样让发动机充分散热，以免自燃。Reaction Engines的工程师取得的关键性技术突破之一就是热交换器，它可以在不到1秒钟时间里让发动机的进气温度从1800华氏度（约982摄氏度）降至零度以下。这样，SABRE发动机的飞行速度就能超过常规喷气发动机。

BAE航天业务工程主管克里斯•奥勒姆指出：“这可能从根本上改变人们航天的方式。”他认为，如果能达到设计目标，这项技术就有望带来一种新的飞机发动机，而且在飞行速度和性能上都要强得多。

同时，对BAE来说，这项技术能让该公司在不断增长的航天市场谋得关键的立足之地。虽然BAE北美公司确有相当数量的航天业务，比如卫星零部件制造之类，但它的商业航天发射业务尚未形成规模。奥勒姆说：“我们对这个市场很感兴趣，而且正打算用另外一种方式开展业务。我们没有随波逐流，而是在寻求突破，或者说寻找一种新的东西。”

如果BAE能帮Reaction Engines的工程师把SABRE引擎送上天，它就有可能成为BAE正在动力领域寻找的革命性突破。关键在于，借助BAE提供的3200万美元资金，Reaction Engines还可以从英国政府那里获得9000万美元的研发拨款。作为协议的一部分，BAE将向Reaction Engines派遣一名董事，并成为后者的首选供应商。作为非上市公司，Reaction Engines在对SABRE引擎进行大规模测试和开发时还要依靠BAE的支持。

两家公司计划先建造用于地面试验的原型机，并在2020年之前点火测试，随后在2025年以前完成原型机试飞。如果一切顺利，配备SABRE引擎的太空飞机就有望在2030年之前飞上太空，然后返回地面。

那么，超高速点对点客运，或者说在四小时内飞抵地球上任何角落的前景如何呢？Reaction Engines董事总经理托马斯说，有了这样的技术，人们当然有可能做到这一点。但考虑到安全以及技术方面的多个因素，短期内更为实际的目标是让太空飞机以25马赫的速度定期往返于空间轨道和地面之间。

托马斯表示：“目前许多人都热衷于点对点客运，在四小时内到达世界上任何地方的想法总会让人兴奋不已。但这是个巨大的挑战，而且和航天相比，这样做的难度绝对要高好几个数量级。最近我还对一位澳大利亚人说，可惜的是，飞往澳大利亚比飞向太空还难。”（财富中文网）

译者：Charlie

校对：詹妮

The Skylon, a conceptual spaceplane envisioned by Reaction Engines, could one day be powered by the company's SABRE engine technology. Courtesy BAE Systems

Forget reusable rockets. BAE Systems just invested $32 million in a new type of aircraft engine that could upend the economics of spaceflight.

If there’s a popular narrative in the commercial spaceflight industry right now, it’s one of lean upstarts like SpaceX and Blue Origin tapping new technologies and business models to outmaneuver their legacy aerospace counterparts like Boeing BA -0.02% , Lockheed Martin LMT -0.90% , and Aerojet Rocketdyne AJRD 0.47% .

But BAE Systems BAESY 0.63% , Europe’s largest defense contractor and a legacy aerospace company through and through, is betting $30 million on technology that could disrupt those disruptors.

BAE has taken a 20% stake in Reaction Engines, a small British technology company whose conceptual SABRE engine technology could drive the next revolution in aerial propulsion, company executives say. If it works, the hybrid jet/rocket engine could launch an aircraft from a traditional runway, power it all the way to orbit at more than 20 times the speed of sound, and bring it back for a conventional runway landing—all under its own power.

Such a reusable spaceplane could trim the cost of launching satellites and other cargo to space by an estimated 90% and lay the groundwork for passenger aircraft that could reach any point on the planet within four hours. BAE executives are confident that the company’s acumen for managing complex aerospace R&D programs can take Reaction’s technology from concept to prototype to the sky by the middle of the next decade.

“When you look around at other concepts for reusable spaceplanes they rely on multiple kinds of propulsion—rockets, jet engines, ramjets,” Mark Thomas, managing director of Reaction Engines, says. “What we’ve achieved here is a combination of all of those best elements in a single propulsion system. So I think we’re well ahead of the game here—I’ve not seen anything that’s a direct competitor.”

As designed, the SABRE engine would power an aircraft up to Mach 5—that’s five times the speed of sound, or more than 3,800 miles per hour—like a conventional air-breathing jet engine. The engine would then transition to rocket power to propel the aircraft to space. On its return journey the aircraft could then transition back to jet power and land like a traditional jetliner on a conventional runway. The same engine could then be used again and again, dispensing with the waste of expendable rocket stages—even the expense of refurbishing reusable rocket stages like those envisioned by SpaceX.

The ideas underpinning Reaction’s Synergetic Air-Breathing Rocket Engine, or SABRE, were first developed more than three decades ago. But some fundamental technology hurdles—chief among them how to move enough heat out of the engine so that it won’t burn itself up—have kept the concept on paper up to this point. Among the critical technology breakthroughs Reaction engineers claim is a heat exchanger that can cool incoming air as hot as 1,800 degrees Fahrenheit to subzero temperatures in a fraction of a second, allowing the engine to function at higher speeds than traditional air-breathing jet engines.

“This could fundamentally change the way aerospace works,” says Chris Allam, engineering director for BAE’s aerospace business. If the technology works as designed, he says, it could spawn a new breed of aircraft engines capable of much higher speeds and performance.

And for BAE, it offers a critical toehold in the growing space access market. While BAE’s North American arm does a fair amount of business in satellite components and the like, the company has no significant presence in the commercial space launch industry. “It’s a market we’re interested in but we were looking for a different way of doing it,” Allam says. “We were looking for a breakthrough or something new as opposed to just joining everybody else.”

If BAE can help Reaction’s engineers make SABRE fly, it may prove to be the revolutionary propulsion breakthrough the company is looking for. Critically, the $32 million raised from BAE will also unlock an additional $90 million in grants from the UK government for research and development. As part of the deal, BAE will get a seat on Reaction’s board and become a preferred supplier to Reaction. The privately-held Reaction will also lean on BAE for support in mounting a large-scale aerospace testing and development program for the SABRE engine.

The companies plan to have a ground-based demonstrator engine prototyped and firing by 2020 and a further prototype flying on a test aircraft by 2025. If there are no show-stoppers along the way, a SABRE-powered spacecraft could propel itself to space and back by the end of the next decade.

And what about that super-high-speed point-to-point passenger travel—four hours from anywhere to anywhere on the globe? It’s certainly possible with this kind of technology, Reaction’s Thomas says. But given various safety and technical considerations, a spaceplane making regular trips to orbit at 25 times the speed of sound is the more realistic near-term proposition.

“A lot of people are excited about point-to-point travel at the moment, the thought of going anywhere in the world in four hours just excites people,” he says. “But that is hugely challenging, it’s just orders of magnitude more difficult. I was telling someone from Australia recently that, unfortunately, it’s more difficult to get to Australia than it is to get into space.”