去太阳系的小行星定居是否可行
The science-fiction series The Expanse is set 200 years in the future: humans have established colonies on the Moon and Mars, and have begun colonising the asteroid belt.
科幻小说《苍穹浩瀚》系列设想在200年后:人类已经在月球和火星上建立了殖民地,并且开始在小行星带定居。
There are compelling reasons why we might wish to colonise the asteroid belt, but the predominant one is mining. Unlike the Earth, where precious metals tend to be buried underground, there is an abundance of metals like gold and palladium on the surface of asteroids. But they could also be used as a scientific research outpost.
人类想要殖民小行星带有很多令人信服的理由,但最主要的原因还是采矿。地球上的贵金属大都埋藏于地下,但小行星的表面即存在大量贵金属,比如金和钯。而且小行星也可以用作人类研究太空的科学前哨站。
在小行星上建定居店比在火星上定居要困难得多。
小行星带在火星和木星之间围绕太阳运转,有科学家认为它们是某颗行星的残骸。小行星分布在整个太阳系,其中大部分位于小行星带,共分为石质、碳质和金属这三种基本类型。它们有的大到直径数百米而有的却小到只有一间小房子那么大。
Companies like Planetary Resources and Deep Space Industries are already investing in asteroid mining and they could begin extraction by 2025. However, creating a settlement on an asteroid is far more complicated than simply mining one.
行星资源和深空工业等公司已经开始在小行星矿业上投资,预计2025年能够开始采矿作业。然而,在小行星上建立人类定居点要比在小行星上采矿来得复杂多了。
One of the main challenges will be the amount of radiation hitting the colonies. There will be solar radiation, Jupiter’s radiation belt and more from cosmic rays. “Cosmic rays are high energy particles, mostly just protons or high-energy nuclei. They zip straight through you and do bad things to you,” explains Martin Elvis of the Harvard-Smithsonian Centre for Astrophysics. On Earth, our atmosphere absorbs the most dangerous rays, and a space colony would need a similar shield. “A thick layer of water or ice could be used [for protection], but it would have to be several metres thick.”
其中一个主要风险是小行星殖民地将受到的高辐射量,诸如太阳辐射、木星的辐射带以及其他宇宙射线。哈佛——史密森尼天体物理中心的埃尔维斯(Martin Elvis)解释道,"宇宙射线是高能粒子,大部分是质子或高能原子核。这些高能粒子能直接穿透物体,非常危险"。在地球上,我们的大气层吸收了最危险的射线,而太空殖民地也需要类似的保护盾。 "可以利用厚重的水层或冰层(作为保护),但厚度最好能有几米。"
As well as radiation, long-term exposure to zero or micro-gravity is detrimental to the human body. “Astronauts on the ISS have to exercise for two hours every day with resistance machines and still end up with health problems from living in zero gravity for such a long time,” says astrophysicist Katie Mack, an assistant professor at North Carolina State University. Any long-term asteroid settlement would need some form of artificial gravity to mitigate this effect – possibly by spinning the entire structure.
除了辐射,长期处于失重或微重力下对人体也是有害的。北卡罗莱纳州立大学助理教授天体物理学家麦克(Katie Mack)说:"国际空间站上的宇航员必须每天用阻力机器锻炼两小时,但最终还是会因为长期处于失重状态而出现健康问题。"任何长期的小行星定居都需要某种形式的人造重力来缓解这种影响——有可能的话最好是能旋转整个定居结构。
It would also need some form of power generation. Most probes and satellites rely on solar arrays for power, but this may not be as effective for an asteroid colony. “As you move further from the Sun, you have the ‘Inverse Square Law’ coming into effect. If you are twice as far from the Sun, then you have a quarter of the energy coming in from a given area of solar collecting panels,” says science-fiction author and former astronomer Alastair Reynolds. By the time you get beyond the orbit of Mars and into Jupiter and Saturn territory then you have to build very large collecting areas to utilise solar power, but I do not see that as being a major problem.”
还需要想办法发电。大多数探测器和卫星依靠太阳能电池阵列来获得能量,但这对小行星来说可能不太管用。科幻小说作者和前天文学家雷诺兹说:"距离太阳越来越远,光的'平方反比定律'作用开始生效。如果你离太阳两倍远,那么你只能通过太阳能集热板一块区域收集到四分之一的能量,当越过火星轨道进入木星和土星的领域时,你必须有非常大面积的太阳能集热板,但我并不认为这是一个主要问题。"
The ideal type of asteroid to settle would be carbonaceous, as these are often 10% water. “Water is pretty common in space, as it is [made] of the most common elements in the universe,” says Elvis. “Water can also be broken down into oxygen and hydrogen, allowing you to breathe the oxygen.” The asteroid would also need to be at least 100 metres in thickness, to provide sufficient protection from radiation.
适宜定居的小行星的理想类型是碳质的,因为碳通常含有10%的水。埃尔维斯说,"水在宇宙中很常见,因为水是由宇宙中最常见的元素组成的,水也可以被分解成氧气和氢气,因此可提供呼吸的氧气。"小行星还需要至少100米厚的防护盾用来屏蔽辐射。
Settlements could be buried under the surface of an asteroid, which would provide radiation shielding. However, mining and excavating an asteroid is harder than it seems. “A lot of what we think of as asteroids are very loosely organised rubble piles that do not have any intrinsic structural integrity – they are not giant boulders,” explains Reynolds. “They are more just huge blobs or gravel held together by their own gravity.”
定居点可以隐藏在小行星表面以下,以屏蔽辐射。然而,开采和挖掘小行星比想象中要难得多。雷诺兹解释道,"我们看到的很多小行星都是非常松散的碎石堆,它们没有任何内在的完整结构——它们不是巨大的砾石,而更像是由自身重力结合在一起的一大团碎石堆。"
This lack of material coherence will also mean that any attempts to spin the asteroid – to artificially generate gravity within the asteroid – would subject it to additional forces and risk it disintegrating. Therefore, some mechanism to improve the asteroid’s durability will be required. “You would have to empty it out without messing the structural integrity and then spin it up whilst making sure that spin does not put too much stress on the remaining structure,” says Mack.
缺乏物质的凝结也意味着让小行星旋转的任何尝试——如在小行星内部形成人造重力,都会因额外的作用力导致小行星有有分解的风险。因此,我们需要引入一些增强小行星耐久性的机制。麦克说:"首先必须在不弄乱小行星本身结构完整性的前提下将核心部分挖空,然后在确保不会对剩余部分施加过大压力的前提下再去旋转这枚小行星。"
One suggestion is to create a metal mesh or cage surrounding the asteroid to prevent it disintegrating. This is not as prohibitive as it may first seem, as the asteroid belt has an abundance of metallic asteroids with the necessary materials which could be used.
为了防止小行星解体,建议搭建一个金属网或笼子将小行星包裹起来。这种做法并没有想象中那么遥不可及,因为小行星带上就有大量的金属小行星可提供需要的材料。
Many of the challenges facing asteroid settlements are similar to those of the proposed lunar base. Apart from gravity, the only other major difference is distance. The Moon and the ISS are comparatively nearby. The Moon is only a mere 225,623 miles (361,000km) away at its closest point, and the ISS is just inside the Earth’s atmosphere. On the other hand, the asteroid belt is approximately 160 million miles (256 million km) away.
小行星定居点面临的许多挑战与拟议中的月球基地类似。除了重力不同之外,唯一的主要区别是距离。月球和国际空间站距离相对较近。月球距离国际空间站最近的点只有225,623英里(约361,000公里),而且国际空间站就在地球大气层内;但是小行星带距离国际空间站大约1.6亿英里(约2.56亿公里)。
Any asteroid settlement would need to be a closed eco-system, and self-sustaining, as support from Earth will be extremely limited. “It could take months to get there and back, so if you have an emergency, you will have to deal with it on the asteroid. You will need an awful lot of people, you do not just go out there and have a [Star Trek] replicator,” says Elvis. Even sending a message to Earth could take an hour.
任何小行星定居点都必须是一个封闭的生态系统,并且能够自给自足,因为能得到来自地球的支持将非常有限。埃尔维斯说:"到达小行星再返回地球可能需要几个月的时间,如果遇到紧急情况,我们将不得不在小行星上解决。我们需要巨大的人力支持,因为这不是走出去拿一个(星际迷航)复制器那么简单。即使是向地球发送一个消息也可能需要一个小时。"
Building a settlement on an asteroid appears to be technically feasible but carries with it significant engineering challenges. Instead, it is far more likely that asteroids could be mined remotely by automated systems and drones. An option to support this could be to build a base on Mars, which could be used for coordinating the asteroid mining systems.
在小行星上定居在技术上似乎是可行的,但却面临重大的工程挑战。但通过自动化系统和无人机进行远程开采小行星可行性则比较大,其中一个选择可以在火星上建立一个基地用来协调小行星采矿系统。
“Both Mars and the Moon are more hospitable in terms of the gravity, as well as radiation shielding by using existing underground tunnels,” says Mack. There are already half a dozen satellites you can use for communications and the environment has been carefully studied.
麦克说:"火星和月球在重力方面人类都比较适宜一些,而且可使用这两个星体现有的地下隧道,因此辐射屏蔽效果也更好。"现在已经有六颗卫星可以用于通信,并且我们对火星和月球的环境也已经进行了仔细的研究。
There are some asteroids that travel in elliptical orbits around the Sun, with their path coming close to Earth and Mars. These could be hollowed out and used as a form of transport, while protecting astronauts from radiation and reducing the need for fuel. “We already know of a dozen or more asteroids that already would be easy to nudge into these orbits with anticipated technologies a few years from now,” says Elvis.
有一些小行星在太阳附近的椭圆轨道上运行,它们运行的轨道靠近地球和火星。这些小行星可以挖空作为运输渠道,同时也保护宇航员免受辐射危害并减少对燃料的需求。埃尔维斯说:"我们现在已经知道,几年后的技术可以轻松地把十几个或更多的小行星推进入这些轨道。"
There is also a proposal to build a spaceport on Phobos, which is a moon of Mars, and is considered by some to have once been an asteroid. This spaceport could be used a stepping-off point for later settling on Mars.
还有人建议在火卫一(又称为"福波斯")上建造一个太空港。火卫一是火星的月亮,有人认为它曾经是一颗小行星。这个太空港可以作为将来在火星上定居的一个中转点。
Whilst planets are the preferred location for manned bases, due to their gravity and atmospheric protection, we could very well colonise an asteroid. However, they would not be particularly comfortable places to live. The benefits will have to far outweigh the daunting challenges.
虽然行星有重力和大气层的保护,是人类在太空建殖民基地的的首选,但我们也可以在小行星上很好地定居下来,虽然住起来不是很舒服,但给我们带来的好处是远远大于令人怯步的挑战。