올해 왕립 연구소의 크리스마스 강의 이 탐사의 항해에 마지막 국경에 인간을 던지는 데 걸리는 인간의 우주 비행과 무엇의 도전을보고.
의사로서 나는 NASA의 앞뒤로 영국과 사이의 여행 10 년 이상을 보냈다 존슨 우주 센터 휴스턴, 공간 환경의 영향을 연구에서 인공 중력 시스템에 생리 노화에 이르기까지 프로젝트에 객원 연구원으로 근무. 동시에 나는 마취 및 집중 치료 내 중학교 의료 교육을 완료했다. 그것은 함께 두 삶을 스플 라이스하려고 이상했다. 밤새 중환자 실에서 작업, 시프트 끝에 공항 향하고, 비행기에서 잠을 잡아, 다음 휴스턴 회의실에서 다음날 도착, 사람들이 주위에 앉아 어디 화성에 안전하게 사람을 보내는 방법에 대해 얘기.
그러나 두 연결된 것은 극단에서 인생의 도전이었다. 질병과 부상에 의해 도전 때 병원에서 나는 삶의 극단보고 있었다. 나사에서 나는 위협이보고되었다 물리적 세계와 우주의 극단에 의해 인간의 생리에 제기.
우리는 극한 환경에 대해 말할 때 우리는 그들이 인간의 생명 보호와 지원되지 않는를 지원하는 시간을 판단하여 자신의 긴축의 거친 아이디어를 얻을 수 있습니다. 그 측정 공간으로 궁극적 인 극단적이다: 인간의 생리에 유일하게 적대, 그것은 무엇이든지 인간의 삶에 대한 지원을 제공하지 않습니다. 보호되지 않은 공간 여행자는 단지 몇 초 동안 그 환경에서 살아남을 것.
당신은 의사가 할 수 있도록 충분히있을 것이라고 상상 - 그것이 인간의 우주 탐사에 관해서, 이해하고 인간의 생리를 조작 할 수있는 사람은 그 노력의 최전선에있을 것입니다. 그러나 의사는 압도적 공학의 문화 것과 가난한 두 번째 바이올린을 연주 - 좋은 이유.
우주 비행은 물리적 원리에 놀라 간단합니다. 뉴턴은 거의 그것을 뒷받침 역학을 이해하기 시작했다는 사실 너무 간단 400 년 전. 지구를 떠나 주위 궤도를 입력하려면, 그것은 결코 다시 땅을 발견하는 방식에 빠지게 열심히이 이루어질 수 있음을 - 먼저 열심히 그 궤도가 지구의 수평선 넘어 확장하는 전 세계의 객체를 던질 필요.
그리고 당신이 에너지의 엄청난 양의를 제공 할 필요가 지구 주위 궤도에 물체를 넣어. 넓은 의미에서 빨리 당신은 당신이 달성 궤도의 넓은 반경을 이동; 그것은 지구와 대기의 상위 계층 모두를 그리워 얻기 위해 충분히 넓은 궤도를 달성하기 위해 차량을 얻을 수, 와 같은 고도에서 당신을 배치합니다 국제 우주 정거장 약간 250 우리 위에 떨어져, 당신은 1만7천5백mph 주위에 여행 할 필요가.
즉, 작은 핵무기의 폭발 용량 엔진과 연료 탱크에 의해 추진 차량을 필요로. 이 여행, 낮은 지구 궤도로 지구 표면에서 - 소유즈 우주선에 탑승 - 팔분 조금 넘는 소요. 그래서 이유 나사의 문화가, 전 세계 우주 기관, 그래서 단단히 오히려 인간 생물학보다 엔지니어링의 요구에 뿌리를두고하면 해당 짧지 만 격렬한 기간에 거의 아무것도 없기 때문에 현대 의학 보호의 방법으로 제공 할 수있다. 실행 중, 하나 엔지니어링 작품 모두가 살고있다, 또는 그렇지 않습니다 모두가 죽어야.
실행을 통해 인간의 삶의 보존되지 의료 절차에 있지만 엔지니어의 설계 및 구축에 우주 비행사 요원을 싸고 엔지니어링 보호, 동심 층에 따라 달라집니다.
로켓 엔진은 완벽하게 발사합니다, delivering just the right thrust at just the right time, directed in precisely the right way. The tremendous force of that propulsion mustn’t be allowed to shake the vehicle, its systems or its fragile cargo of passengers apart. It is the job of engineering teams to make sure that the launcher and the vehicle are designed to perform in the face of forces that are trying to destroy them.
And perched atop that tower of kerosene and oxygen is a tiny capsule, with the volume of a handful of telephone boxes, and a couple of tonnes of supplies and three passengers crammed in among them. That capsule is a tiny bubble of life support, pinched off from the Earth and maintained artificially. 내부, still more machines provide a breathable atmosphere with enough pressure and warmth to support life in the void of space. If you survive the launch, your problems are really only just beginning.
국제 우주 정거장
It’s tempting to think of the International Space Station as a hi‑tech Big Brother house, floating high above the Earth. In some senses that is true: living conditions are harsh by any normal standard. There are few creature comforts and precious little privacy. It is a living arrangement bristling with the potential for huge social conflict. But remarkably that is largely avoided and in 15 years of operation there have been no evictions.
But the ISS is much more than an accommodation block. When crews go to live there they are taking up residence inside a machine upon which their lives depend every second of the day. They electrolyse water to produce oxygen, employ molecular sieves to scrub waste gases out of the air that they breathe, run heating systems from vast solar arrays that can pump out 80kW of power. That solar energy also drives four huge gyroscopes, which steady and steer the station, preventing it from tumbling out of control.
The International Space Station is far from tranquil: it hums and whines perpetually; fans are running all the time. Without gravity hot air doesn’t rise and cold air doesn’t sink. 이, as a consequence, no convection and without that it’s hard to get air to move or mix. That in turn causes problems, leaving astronauts prone to headaches in poorly ventilated areas, where exhaled carbon dioxide can build up. Hence the constant drum of motors churning air. The draughts on the ISS, like almost everything else that the crews depend upon for healthy living, are artificial. All of this effort just to maintain that bubble of life support in an outpost just 250 miles above our heads. The challenges involved are legion and we haven’t even started to talk about leaving low Earth orbit yet.
Back to the moon
There is unfinished business on the moon. It is nearly half a century since the Apollo programme landed a dozen men on its surface. And while it represents a treasure trove of scientific discovery, nobody has been back since. Low Earth orbit is 250 miles away and can be reached in minutes. The moon is about 250,000 마일 떨어진, takes days to get to and, in addition to isolation and the added complexity of the rocket science required, leaves crews extremely vulnerable to radiation. On Earth we’re protected from some types of radiation by the thick blanket of atmosphere above, which absorbs gamma rays, x-rays and ultraviolet radiation that would otherwise be harmful. But there’s another layer of protection that also keeps us safe: Earth’s magnetic field.
The magnetosphere filters out a particularly harmful species of radiation, which comes in the form of charged, high-energy particles – atomic nuclei spat out as a by-product of thermonuclear reactions in stars including our own. This type of radiation is particularly harmful and, during solar flares, can increase in intensity by many thousands of times. Presently we have little in the way of effective protection from the radiation that comes with the worst solar flares.
Mars and beyond
In recent years the idea of putting human crews on the surface of something other than the moon or Mars has found its way into the strategy documents of the international space agencies. This mission is less science fiction than you might think. The European Space Agenecy’s Rosetta mission, which so spectacularly landed the Philae lander on the surface of a comet last year, showed us that we could find and intercept a tiny target hurtling through space hundreds of billions of miles away. This has given agencies confidence that their idea of landing a human crew on an asteroid might be realisable.
But for now it is Mars that lies at the edge of possibility, and surviving that journey presents a challenge on a different scale. With Mars, the problem is distance and time. To get to the red planet you have to traverse hundreds of millions of interplanetary miles; 이상 1,000 times the distance Apollo crews travelled to the moon. With existing technology it would take between six and nine months to travel from Earth to Mars and the same again on the return leg.
That’s a lot of time spent without any gravitational load on your body. Weightlessness may look like fun, but like everything else, too much of it can be a bad thing. When physiologists first considered what effect the space environment might have on the human body, before anybody had even been into space, they correctly predicted that muscle and bone would waste. Those systems are sculpted by gravity and as anyone who has ever so much as looked at a gym knows, if you don’t use it you lose it. Because of this, crews aboard the International Space Station must subject themselves to a daily programme of resistive exercise to try and prevent some of that bone and muscle loss.
Weightlessness wreaks havoc with other systems. It upsets your senses of balance and co-ordination, making it more difficult for crew members to track moving targets, creating illusions of motion and, for the first few days of flight, generally making them feel pretty queasy. With the exception of the nausea, all of these problems tend to get worse the longer you spend weightless.
더 많은 최근, new – and potentially more worrying – problems have cropped up. For reasons that are not yet entirely clear the pressure in some astronauts’ brains appears to rise as a consequence of space flight, and this has been linked to alterations in their eyesight that sometimes persist for many years after their return to Earth. This phenomenon has only been noticed after long duration missions, which highlights the message: spending a lot of time in space isn’t great for your health.
But time also creates problems for life support systems. If you imagine the amount of food, 물, oxygen and power a single person might consume in a mission set to last up to three years (if you include the surface stay), that demands quite a sizable larder. Now multiply that by a crew of four or six and it looks like you need an impossibly huge spacecraft just to keep you fed and watered.
And that does become impossible unless you are able to recycle and reuse everything you can. Already aboard the space station astronauts recycle most of their waste water, including their urine. They scrub carbon dioxide out of their exhaled air and rebreathe the remaining oxygen. You might be able to go further still, by growing crops hydroponically, as a source of food and a mechanism of removing carbon dioxide and renewing the oxygen supply. If you choose the right plants you might even recycle the nitrogen in human solid waste. Which of course is a scientific way of saying that maybe you could use your own poo to fertilise your life-supporting crops.
A system as sophisticated as that is extremely difficult to assemble, manage and maintain, and it’s likely to be a while before we see greenhouses flying through deep space. For now life support engineers will content themselves with finding ways to recycle more and more of the resources they can, and in so doing reducing the amount of payload that crews have to set aside for the things that keep them alive.
There is a simple lesson from all of this: space is hard. All frontier endeavours are. But there is plenty to celebrate here. Since the start of the 21st century there has been a permanent human presence in space. What started as a surrogate battlefield for nuclear war has become a multinational programme of science, exploration and collaboration. This is not the place to get into a discussion of why we should explore space at all. There are many benefits that derive from human space exploration but one is more important than all the rest. Human space exploration inspires children to study and pursue careers in science, technology and engineering. It does so by showing them that within the limits of human imagination anything might be possible. I know this because it inspired me and throughout the whole of my life has continued to hold my fascination.
It is an enormous honour to give the Royal Institution’s Christmas Lectures. And yes, the take-home message is that space is hard. But the real lesson for this year’s audience is that this has been my adventure and it can be yours too.
How to Survive in Space will be shown on BBC4 in three parts on 28, 29 과 30 December at 8pm. Find out more on the Royal Institution’s website and join the conversation on Twitter and Instagram by following @ri_science or searching for #xmaslectures
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