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Post by porphyry on Feb 18, 2010 14:56:21 GMT -4
Hi everyone, Aside from the Apollo flights, I'm curious about what we really know about the survivability of humans and other biological organisms in deep space environments. From what I've read about "space colonization" (O'Neill, Savage, Prado, NASA materials, etc.) there seems to be a consensus that beyond a certain amount of time, humans need some sort of shielding from the effects of high-energy cosmic rays to live and work in or beyond the Van Allen belts. Shielding proposals include massive amounts of water or lead, or electromagnetic devices. I assume that unmanned outer-space probes provided some information about the flux levels of the various radiation components in deep space. To what extent was it possible in the 1960's, to simulate the effects of outer space radiation on animals or humans in terrestrial labs? And to what extent is it possible now? (I'm naively guessing that some of the high-energy particles could only be modeled in particle accelerators which would produce thin pencils of rays.) Gillianren wrote: the Soviets sent animals around the Moon which came back alive.I believe this is a reference to this mission discussed in Wikipedia: en.wikipedia.org/wiki/Animals_in_spaceThe first tortoise in space was launched September 14, 1968 by the Soviet Union. The Horsfield's tortoise was sent on a circumlunar voyage along with wine flies, meal worms and other biological specimens. These were the first animals in deep space. The capsule was recovered at sea on September 21.The article does not mention any American experiments along these lines, either before the Apollo missions or at any time since. Nor any Russian experiments after this first one. Did the Wikipedia article miss anything? Have their been any deep space biological experiments since 1968? Does anyone know exactly what information the Russians released about the deep-space tortoise, flies and meal worms? A skeptic might also wonder why the US should believe any information the Soviets disclosed. When deep-space missions to the moon, Mars or the Asteroids are discussed, whether the purpose is scientific exploration, colonization / exploitation of extraterrestrial resources, or simply national prestige, everyone agrees that long-term human presence is essential. And everyone agrees that it can't happen without radiation shielding. So I would imagine that there would be significant engineering / scientific curiosity about the biological effects of deep space radiation, and that there would be programs designed to get experimental validation of theoretical models & designs. Of course a key aspect of McGowan's skepticism is the most peculiar lack of any evidence of such projects, programs or experiments. Most likely McGowan and I are missing something here? Your comments are invited. Thanks. |
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Post by PhantomWolf on Feb 18, 2010 15:45:51 GMT -4
Hi. A lot of this information is already avaliable here if you do a search on Van Allen belts. A quick summary. The Soviet scientists who studied the animals sent on Zond 5 published a paper in a western journal about their results. When it came to scientific experimentation there was no reason to believe the USSR was fudging results. The paper is availible online and someone linked to it in one of the rescent VA Belt discussions. It appears that the Soviets also carried detectors on eariler Zond and Luna missions, publishing those results prior to 1967. Recent and large discussion thread on space radiationThe US had Radiation detectors onboard the Suyevor craft so knew the levels of Radiation on the Lunar surface. By 1968 the VA belts had been well mapped by various unmanned craft, both Soviet and US. What was missed: The so called "Killer Electrons." These are very high energy electrons in the VA Belts. They tend to be rare and unlike their name suggests, one of them won't kill you. The third VA Belt. So weak that it's presence never registered on the detectors of the time. Gamma Radiation on the moon. Again very, very weak, caused by the interaction of the lunar regolith with cosmic radiation. Detectors of the time just couldn't pick it up because it wasn't strong enough. The KREEP Area of the moon. No one had done a geological/Radiological survey of the moon so it wasn't known about, the radiation it produced was assumed to be solar or cosmic in origin. Is this significant? Short answer. No. What about all the writers saying we need radiation shielding for long term space exploration? They are right, but the important bit is "long term". An astronaut can survive between one and two months on the lunar surface without adverse effects (barring a solar event that is aimed at the moon while they are on the sunny side.) Trips to Mars and beyond are likely to take up to a year or two. Apollo was all done and dusted in 10 days, only a max of three on the Lunar surface. We're talking the difference between taking a day trip to the beach and building a home there. The first you simply check the weather and go, perhaps apply a little sunscreen to stop from burning. The second you have to take into account how high any storm surge could get, whether the shore is eroding, and a lot more before committing to the project. That's why there is a difference in space travel too. |
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Post by gillianren on Feb 18, 2010 16:08:25 GMT -4
Fudged results would be discovered soon enough; neither side was the only one putting in the study and sending out probes.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Feb 18, 2010 16:30:01 GMT -4
There is no need to send live biological specimens into deep space. You can send instruments into space to measure and categorize the radiation environment. How biology reacts to radiation can be studied through laboratory experiments on Earth. You then just have to put two and two together.
It is well documented that the United States extensively studied the biological effects of radiation and invested greatly into measuring the space radiation environment. This was enough to deduce what they needed to know.
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Post by porphyry on Feb 18, 2010 16:48:18 GMT -4
Phantomwolf,
ZOMG, that thread you linked is 23 pages long! The title gave no clue about what the thread is covering. I guess I've got some reading to do, but from your summary, it sounds like no conclusive data was ever located. I don't see any reason to presume either that the Soviet lunar scientists told the truth in their paper, or that they didn't.
Gillianren,
How could fudged results have been discovered? Aside from Apollo, that is. According to all the data anyone is presenting, there haven't been any experiments by either side, other than that one 1968 probe. Since the Apollo missions were only 10 days long, they aren't helpful either in establishing what might happen over periods of months or years.
Bob,
I can imagine that you could attempt to replicate deep space conditions in the laboratory on earth, but how could you ever be confident that your model was completely accurate? Wouldn't scientists want to verify these models at some point through actual experimentation in deep space conditions?
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Post by gillianren on Feb 18, 2010 17:22:01 GMT -4
You seem under the perverse impression that Apollo is our only source of information about space, radiation, and so forth. That isn't remotely true. When the Soviets sent probes with instruments to test what space was like, if their data didn't match ours, that would have been a huge thing. The Van Allen Belts were known long before Apollo--from unmanned probes. Pretty much from the moment we sent things into space, we were testing what was out there. Just because we've only given you one specific, it doesn't mean that's all there was. Might you consider doing some of your own research for once?
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Post by cos on Feb 18, 2010 17:32:04 GMT -4
Of course a key aspect of McGowan's skepticism is the most peculiar lack of any evidence of such projects, programs or experiments. Most likely McGowan and I are missing something here? Your comments are invited. Thanks. I think Mr McGovan has fallen down the 'I haven't looked so it can't exist' hole (again). A snippet from that 23 page link you were referred to (page 5 - thanks to Count Zero). ......peculiar lack of any evidence of such projects, programs or experiments.? He hasn't looked. |
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Post by chew on Feb 18, 2010 17:49:50 GMT -4
Phantomwolf, ZOMG, that thread you linked is 23 pages long! ;D That was my first thought, "Oh man, he sent him to that horrendously long thread." To pull out some of the crunchy bits of that thread, one of our esteemed members, drewid, made videos that plotted the trajectory of one of the Apollo missions. This doesn't directly address radiation in space but it does show how the missions were designed to avoid the inner zones of the Van Allen Belts. It's on page 21 of that thread: apollohoax.proboards.com/index.cgi?action=gotopost&board=theories&thread=2614&post=75933 |
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Feb 18, 2010 17:52:35 GMT -4
Bob, I can imagine that you could attempt to replicate deep space conditions in the laboratory on earth, but how could you ever be confident that your model was completely accurate? Wouldn't scientists want to verify these models at some point through actual experimentation in deep space conditions? What you are ulitmately trying to find out is how space radiation will effect a human being. If your claim is that the only way to know for sure is to send a living specimen into space, then shouldn't that living specimen have to be a human? Why is sending turtles and fruit flies into space any more valuable to understanding the space environment effect on humans than what can learn through instrumented space probes, well constructed lab experiments, and well studied exposure cases? |
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Post by chew on Feb 18, 2010 18:02:42 GMT -4
Oh, oh, don't forget the tired, unfounded, unreferenceable, old gem that it will take 6 feet of lead shielding to survive a trip to the Moon!
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Post by PhantomWolf on Feb 18, 2010 18:02:54 GMT -4
Phantomwolf, ZOMG, that thread you linked is 23 pages long! The title gave no clue about what the thread is covering. I guess I've got some reading to do, but from your summary, it sounds like no conclusive data was ever located. I don't see any reason to presume either that the Soviet lunar scientists told the truth in their paper, or that they didn't. Unfortunately a lot of its length is due to people repeating themselves in different manners to try and get one rather stubborn poster to understand what was being said. Your summary of my summary is also wrong. There was a lot of knowledge before Apollo, at least for the information that was needed. Not every bit of radiation is important in long term space travel, only that which will have an effect. Take for example Alpha Particle Radiation. This can be blocked by nothing more then a sheet of paper or a few inches of air, so I can happily walk about in a room flooded with a high flux of Alpha Radiation and never be harmed. It wouldn't even get through my first layer of skin. Alpha emitters are only dangerous if ingested. The radiation we have learned about post Apollo is so weak it would not have had any effect on the crews above the background radiation we already knew about. Its like building a house near a fault line. You use seismographs to record the tremors that occur and then build to withstand the biggest ones. If you then get a better detector and find out that there are many far smaller tremors occuring, you don't start panicing, because you are already protected from them. In the same way, the designers of the Apollo equipment (CSM, LM, and Spacesuit) considered whether the equipment was able to handle the situation they knew about, and anything they didn't because it was weaker, would have been blocked anyway. In the case of the Apollo equipment, the layers that were created for insulation and mirco-meteor protection, were also effective against the particle radiation that the Astronauts would be facing. Finally, the USSR had no reason to lie about its science and every reason not too. They didn't know that the US would not repeat their experiment exactly and had they come up with different figures, the US then could have used that against the USSR, just as the USSR could have used it against the US had they been fudging their results. Scientists love nothing more than to shoot down other scientists data when it is vulnerable, and had the US probes been returning higher levels of radiation than the USSR had reported, the US scientists would have been all over it like a big wooly dog. |
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Post by porphyry on Feb 18, 2010 18:33:25 GMT -4
Everone, I agree that there were abundant unmanned missions by both the US and the Russians, and I don't question that accurate measurements were made and reported regarding the flux levels of various types of radiation. Phantomwolf, by summarizing that other thread by "no conclusive data" I mean no hard, experimental data from deep space biology experiments.
My question was about deep-space experiments with biological specimens of any kind, and there seems to be a consensus that aside from the Russian 1968 Zond probe, and the Apollo manned flights, there have been no other missions.
Of course now that we've established that fact, what we do with it is entirely another question.
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Post by Jason Thompson on Feb 18, 2010 19:01:02 GMT -4
What we do with that fact is ponder whether or not you actually have to go into deep space to test the effects of radiation. Is the absence of deep space space shots with biological payloads in any way significant from the standpoint of getting useful data?
The particle radiation environment in quiescent deep space is lower than in the van Allen belts, by quite a considerable margin. To assess particle radiaiton effects then sending something into the van Allen belts would be sufficient.
Electromagnetic radiation is not stopped by the van Allen belt, so in many ways the exposure to x-rays and gamma rays and the like is fully experienced in low Earth orbit.
So, do we need to go into deep space with biological payloads to assess the effects of radiation on a spacefaring person? No, because we can expose test subjects to radiation on Earth and in Earth orbit. Have there been high altitude and LEO test flights with biological payloads in which radiation effects were studied? Probably. In fact the Zond 5 mission is something of an anomaly, and was most likely more showboating by the Soviets to keep the US believing that a manned lunar flight was closer than it was (the Zond spacecraft could carry a human crew, which is why many in America believed Zond 5 would be followed by a manned Soviet circumlunar flight, and why they changed Apollo 8 to a circumlunar flight so quickly).
The suspicion over the lack of deep space radiation studies with biological payloads comes from a layperson's expectation of how these things need to be tested. Real science often doesn't live up to the layperson's expectation, because scientists know how to isolate variables and design experiments accordingly. Getting into deep space is not that easy, so if you can get your data by other means then that is the most desirable option. For a not-quite-perfect analogy, consider a boat designer wanting to test the suitability of a new metal alloy he has designed for use in ocean liner hulls. If he wants to know if his alloy is resistant to corrosion by salt water, does he need to go to all the trouble of building a boat and send it across the ocean, or can he use a sample of the alloy in a lab and immerse it in a bath of seawater?
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Post by captain swoop on Feb 18, 2010 19:42:23 GMT -4
Everone, I agree that there were abundant unmanned missions by both the US and the Russians, and I don't question that accurate measurements were made and reported regarding the flux levels of various types of radiation. Phantomwolf, by summarizing that other thread by "no conclusive data" I mean no hard, experimental data from deep space biology experiments. My question was about deep-space experiments with biological specimens of any kind, and there seems to be a consensus that aside from the Russian 1968 Zond probe, and the Apollo manned flights, there have been no other missions. Of course now that we've established that fact, what we do with it is entirely another question. What do you think is different about 'deep space' radiation? It's the same electromagnetic and partical radiation we have on Earth. We can send detetors to measure it. |
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Post by porphyry on Feb 18, 2010 20:10:56 GMT -4
Captain Swoop, I'm thinking specifically about the cosmic rays. Wikipedia says: en.wikipedia.org/wiki/Cosmic_rayCosmic rays are energetic particles originating from outer space that impinge on Earth's atmosphere. Almost 90% of all the incoming cosmic ray particles are simple protons, with nearly 10% being helium nuclei (alpha particles), and slightly under 1% are heavier elements, electrons (beta particles), or gamma ray photons.[1] The term ray is a misnomer, as cosmic particles arrive individually, not in the form of a ray or beam of particles. However, when they were first discovered, cosmic rays were thought to be rays. When their particle nature needs to be emphasized, "cosmic ray particle" is written.
The variety of particle energies reflects the wide variety of sources. The origins of these particles range from energetic processes on the Sun all the way to as yet unknown events in the farthest reaches of the visible universe. Cosmic rays can have energies of over 10^20 eV, far higher than the 10^12 to 10^13 eV that man-made particle accelerators can produce. (See Ultra-high-energy cosmic rays for a description of the detection of a single particle with an energy of about 50 J, the same as a well-hit tennis ball at 42 m/s [about 94 mph].) There has been interest in investigating cosmic rays of even greater energies.[2]
There's another optimistic little article in Wikipedia about the health effects of these rays. They say that the more energetic rays are less damaging than the lower energy ones, but that wouldn't make me feel confident about standing in the path of a single particle with 50J energy. That article also notes that shielding is difficult because of a cascading effect, high energy cosmic rays striking the shielding and throwing off more radiation. |
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