Serpens Solidus Posted October 25, 2016 Share Posted October 25, 2016 About the gravity issues: Problem solved. Link to comment Share on other sites More sharing options...
tater Posted October 25, 2016 Share Posted October 25, 2016 You (the general "you") don't want to start looking like a Mars One loon. The reality is that as long as some society or societies might seem on the hook to rescue people, or otherwise feel sorry for them, survivability absolutely matters. We send people and resources to the other side of the world all the time and spend treasure to save even people who hate us (us being the West) who are victims of disasters. At some point, with hundreds of people, and even children on another world, what happens when the cost of rescue is just writing a check for ITS flights to go get them? Back in the day (the Age of Exploration), such failed colonies could just pound sand. There is much less of a sink or swim mentality, now, sadly. Link to comment Share on other sites More sharing options...
Northstar1989 Posted October 25, 2016 Share Posted October 25, 2016 10 hours ago, kerbiloid said: That doen't matter very much from the colony pov. Much more important is what will happen with baby growth. Presumably, nothing good. And of course, nobody will try this neither on LEO, nor on the Moon. (Unless cyberpunk takes over.) I believe that, as a biologist with a strong background in developmental biology (my main areas are Stem Cell Biology and Virology- but Stem Cell Bio is a subset of Developmental Biology, andcrequires a very strong background in embryonic development to understand) I am far more qualified to assess this possibility than you. It is unlikely 0.38 g's would interfere with embryonic development. Most of embryonic development has nothing to do with gravity anyways, and is patterned by chemical messengers (it's not gravity that tells an embryo which end is the head and which is the anys, it's determined early on in development by a completely arbitrary division of chemicals. One end gets more of a certain chemical than the other, and from this point onwards that end develops as the head and the other as the tail of the embryo.) The only parts of embryonic development affected by gravity merely require enough for liquids to settle and density-gradients to form. There is absolutely no reason 0.38 g's should be any worse for a developing fetus than 1 g. Link to comment Share on other sites More sharing options...
tater Posted October 25, 2016 Share Posted October 25, 2016 Space medicine people I have heard talks from are concerned enough about lunar gravity, that some have suggested that lunar habitats might require centrifuges for crew in long term habitation. They also have effectually no data, however (Apollo crews were not there long enough to matter). We know that 0g (really microgravity) has issues that exercise regimes cannot entirely counter, and we know 1g is just fine. Everything in between is nothing more than educated guesses until we actually have some data. I tend to think 0.38 is probably fine---but I don't know for sure, nor can anyone else without data. Link to comment Share on other sites More sharing options...
Northstar1989 Posted October 25, 2016 Share Posted October 25, 2016 (edited) 10 hours ago, Nibb31 said: What you have is a hypothesis. Without experimentation, it has no more value than an opinion. With all due respect sir, it is YOU who are making unscientific claims. The base from which you start in science is NOT to assume strange things will occur under a certain set of conditions (such as embryonic development in refuced gravity) unless proven otherwise. The basic assumption from which you must ALWAYS start, if you make ANY assumptions at all, is that nothing unusual will happen under a given set of conditions unless given reason to believe orherwise. We have no reason to believe anything unusual will occur under 38% gravity, so that MUST be our assumption unless proven otherwise. Anything else is unscientific. While we have plenty of sata on unusual behaviors of materialschemicals/cells in microgravity ("zero" gravity), 38% gravity is *NOT* microgravity. While a glance at how far 0.38 g's falls arithmatically from 0 g's might lead one to stupidly believe we would expect behavior closer to microgravity than Earth gravity, that's a completely misleading assumption based on nothing but an arbiteary number. What matters for things like biological systems are numbers like settle-rate, and factors influencing the development of bubbles in liquids. And all of these are MUCH more similar in behavior to Earth gravity under Mars gravity than they are to microgravity. Think of it this way- if you divided a given period of time by settle-rate to determine how long it took for settling to occur, you'd get discreet numbers for Earth and Mars gravity. But if you did the same for microgravity you'd be dividing by zero, or an obscenely small number- which is an entirely different behavior altogether. Lacking any evidence that reduced (but non-trivial) gravity affects human health or development, we must proceed from the baseline assumption that it doesn't- because any other baseline assumption would require us to invent new physical processes and principles, without data or evidence for their very existence- and would thus be highly unscientific. Regards, Northstar Edited October 25, 2016 by Northstar1989 Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted October 25, 2016 Share Posted October 25, 2016 Sigh. This thread is doing it again. For all we know, Musk is already planning to send a bunch of mice, etc, on one of those Red Dragon pathfinders he's mentioned. Link to comment Share on other sites More sharing options...
Northstar1989 Posted October 25, 2016 Share Posted October 25, 2016 (edited) 12 minutes ago, CatastrophicFailure said: Sigh. This thread is doing it again. For all we know, Musk is already planning to send a bunch of mice, etc, on one of those Red Dragon pathfinders he's mentioned. Most likely. And if he is, I eagerly await published data on mouse embryonic development on Mars. I will of course keep a keen eye on the data (I am sufficiently knowledgeable about the subject that I could analyze the raw data for myself- and will be able to determine for myself if the papers on the subject are drawing conclusions reasonably supported by the data one way or another... You'd be surprised how often in biology papers make conclusions the data does not support...) for any evidence that embryonic development is proceeding abnormally beyond what can merely be explained by the high-radiation environment. But if it is not, that's an *excellent* indication it won't in humans either- as mice and humans are sufficiently closely evolutionarily related that mice are the usually preferred model system for studying processes that occur in humans... (the shared evolutionary ancestry leads to extreme similarities in the biochemistry on a molecular level, and high agreement for results in mouse studies and results in humans for most subjects except nutrition and toxicology, due to significant differences in liver function between mice and men) Regards, Northstar Edited October 25, 2016 by Northstar1989 Link to comment Share on other sites More sharing options...
Darnok Posted October 25, 2016 Share Posted October 25, 2016 31 minutes ago, Northstar1989 said: We have no reason to believe anything unusual will occur under 38% gravity, so that MUST be our assumption unless proven otherwise. Anything else is unscientific. It is very scientific to think that same living organism is going to have different behaviour in two different environments. What needs to be proven is how much different behaviour will that be. If you are making assumption that same organism is going to act in same way in two very different environments, then you are the one that should deliver proof, since this claim makes all hypothesis about evolution questionable. 42 minutes ago, Northstar1989 said: we must proceed from the baseline assumption that it doesn't- because any other baseline assumption would require us to invent new physical processes and principles, without data or evidence for their very existence- and would thus be highly unscientific. It would be scientific and cautious. Link to comment Share on other sites More sharing options...
kerbiloid Posted October 25, 2016 Share Posted October 25, 2016 1 hour ago, Northstar1989 said: t is unlikely 0.38 g's would interfere with embryonic development. Not embryonic. Early childhood, when the body grows. Link to comment Share on other sites More sharing options...
DerekL1963 Posted October 25, 2016 Share Posted October 25, 2016 45 minutes ago, Northstar1989 said: We have no reason to believe anything unusual will occur under 38% gravity, so that MUST be our assumption unless proven otherwise. Anything else is unscientific. On the contrary - given that we evolved at 1g and the demonstrated fact that there are medical consequences of long term living at 0g, there's every reason to presume that there will long term medical consequences at .38g. The unscientific one here is the one pronouncing as a fact that there will be no consequences despite a complete absence of data. Link to comment Share on other sites More sharing options...
Green Baron Posted October 25, 2016 Share Posted October 25, 2016 (edited) Of course there are consequences to the body under 0 or low g. There are short- and long term effects. People returning from 0g after months are in a bad shape and must be carried. The bones lost calcium, the muscles have atrophied and the cardiovascular system has lost a lot of it's capacity, and these people were well trained when they left. This can partly be countered by 0g-training, but only partly. On earth we move under 1g the whole day (those of us who do), bone strength, muscles, levers and mechanics in the body, the whole metabolism and chemistry is laid-out to maintain the body-functions under the conditions here and the body functions must be stipulated or they decay. So, yes there will be modifications to the body under 0.4g and these will have an impact on health, to "normal mortals" more than to astronauts who usually are well trained and in good health, like there are modifications to the body of a couch potato and a decathlete. And still the couch potato has to breathe, sleep and eat under 1g. People who stay in 0 or low g for a long period will certainly run into trouble sooner than the ones on earth. Edited October 25, 2016 by Green Baron Link to comment Share on other sites More sharing options...
Eklykti Posted October 26, 2016 Share Posted October 26, 2016 21 hours ago, kunok said: Colonization without doing any biological research is absurd, if only for the huge cost of making the first settlement in mars, to then discover that (for example) humans body develops illness at an exponential rate in low or no gravity There will be no biological research if we don't have the transport ability. And if no one develops the transport just because of lack of scientific data, there will be no scientific data because no one needs it anyway. So if the transport ships come first, and a small scientific expedition arrives and then decides that conditions are unacceptable, they can just come back (so we need a craft that can come back, and SpaceX it creating exactly what's needed) and send another, more prepared expedition after medical data is processed from the first one and some possible solutions are proposed for the problems they encountered there. Space is dangerous, but life on Earth isn't perfectly safe too. But it can be made safer even here by developing new technologies for space, because some of them will eventually be useful in our everyday life, and not just for astronauts. Link to comment Share on other sites More sharing options...
Tullius Posted October 26, 2016 Share Posted October 26, 2016 (edited) 3 hours ago, Eklykti said: There will be no biological research if we don't have the transport ability. And if no one develops the transport just because of lack of scientific data, there will be no scientific data because no one needs it anyway. So if the transport ships come first, and a small scientific expedition arrives and then decides that conditions are unacceptable, they can just come back (so we need a craft that can come back, and SpaceX it creating exactly what's needed) and send another, more prepared expedition after medical data is processed from the first one and some possible solutions are proposed for the problems they encountered there. Space is dangerous, but life on Earth isn't perfectly safe too. But it can be made safer even here by developing new technologies for space, because some of them will eventually be useful in our everyday life, and not just for astronauts. I think the gravity is not much of an issue, since we already know that humans can survive in 0g for over a year without too much problems. So an expedition to Mars should not be problematic in terms of gravity, no matter how the reaction of the human body to 0.38g is. For longer stays, it would certainly be interesting, if 0.38g doesn't cause the same negative impact as 0g, but for a short stay, it is a non-issue. The real problem is the radiation: Only 27 humans have ever left Earths magnetic field that protects us from the radiation in interplanetary space, and those only left it for a couple of days. And that is what SpaceX needs to prove, besides that their ship technically works. They need to prove that humans can survive this radiation with acceptable negative impact, even if there is a giant solar storm. And so we need to test the spacecrafts radiation shielding and the resilience of the human body to the remaining radiation levels, without exposing people to unacceptable risks. We know that SpaceX plans an unmanned test flight before sending the first humans, i.e. a test of the technical part of the mission. But there is no statement about how they want to make sure that the crew is safe. Maybe they will add an additional crewed flight in high Earth or lunar orbit to check if the crew survives the radiation levels, or maybe they just add such a ridiculous amount of shielding that the radiation inside the crew compartment is no more than the radiation on ISS, removing the need for a separate test. Edited October 26, 2016 by Tullius Link to comment Share on other sites More sharing options...
kunok Posted October 26, 2016 Share Posted October 26, 2016 3 hours ago, Eklykti said: There will be no biological research if we don't have the transport ability. And if no one develops the transport just because of lack of scientific data, there will be no scientific data because no one needs it anyway. If only there were mammals littler than us, and comparable enough. Send laboratory mice, they weigh like 40 grams, you can even make a return mission, when they die from old (in a optimist scenario) or see how they reproduce in mars low gee, and return the mars born ones. Change it to some other mammal if mice ain't good enough. SpaceX could use that red dragon, it would be something that can be done inside a capsule, unlike terrain experiments. Why send humans when there isn't data? Is not like there wasn't animals before humans in the space exploration 3 hours ago, Eklykti said: Space is dangerous, but life on Earth isn't perfectly safe too. But it can be made safer even here by developing new technologies for space, because some of them will eventually be useful in our everyday life, and not just for astronauts. The problems is the huge amount of everyone dies scenarios here. We can't have people in the ISS the duration of a mars mission without supplies currently, and that's a fact. Life support is the biggest problem, not the rocket, and I don't see spaceX working on that at all, I would like to be wrong Link to comment Share on other sites More sharing options...
tater Posted October 26, 2016 Share Posted October 26, 2016 5 hours ago, Tullius said: I think the gravity is not much of an issue, since we already know that humans can survive in 0g for over a year without too much problems. This is untrue. There are likely permanent issues associated with a year in microgravity according to all current information I have seen. We simply do not know what the really long term effects of reduced gravity will have on people. What, for example is the threshold for completely ceasing bone loss? 0.1g? 0.3g? First manned missions would be round trip, anyway, and assuming they stay till the return launch window, that would actually provide some data. Of course if they have some insurmountable issues, then ITS exists without a place to go... Link to comment Share on other sites More sharing options...
Tullius Posted October 26, 2016 Share Posted October 26, 2016 4 minutes ago, tater said: This is untrue. There are likely permanent issues associated with a year in microgravity according to all current information I have seen. We simply do not know what the really long term effects of reduced gravity will have on people. What, for example is the threshold for completely ceasing bone loss? 0.1g? 0.3g? First manned missions would be round trip, anyway, and assuming they stay till the return launch window, that would actually provide some data. Of course if they have some insurmountable issues, then ITS exists without a place to go... I probably didn't explain my thoughts right. I tried to say exactly the same: For the first round trips, gravity is not a problem (less than 2 years in space, current record 437 days in space for single mission, 879 days for total time in space), since the effects will be sufficiently small (and we know them rather well). Afterwards, it may be a problem, but that is not the problem of a manned ITS flight, that is the question if we can create a permanent settlement on Mars. Link to comment Share on other sites More sharing options...
tater Posted October 26, 2016 Share Posted October 26, 2016 Yeah, "mission" flights are fine, the issue is the "colonization" glop. The problem (on topic to SpaceX) is that flag planting missions are NASA territory, and are substantially less ambitious than ITS, unless somehow space agencies buy ITS flights for "mission" based use (round trips). This would be ideal, as it could mitigate some expense, and provide useful data. The trouble of course is that NASA is a very involved customer for contractors, and would not buy seats, they'd demand all sorts of redundancies that would not be ideal for ITS. Look at Mars Direct, and how it was altered into the Mars Reference Mission/Architecture. It was made substantially more complex... because NASA (they are necessarily risk averse for human missions). Link to comment Share on other sites More sharing options...
Darnok Posted October 26, 2016 Share Posted October 26, 2016 1 minute ago, tater said: Yeah, "mission" flights are fine, the issue is the "colonization" glop. The problem (on topic to SpaceX) is that flag planting missions are NASA territory, and are substantially less ambitious than ITS, unless somehow space agencies buy ITS flights for "mission" based use (round trips). This would be ideal, as it could mitigate some expense, and provide useful data. The trouble of course is that NASA is a very involved customer for contractors, and would not buy seats, they'd demand all sorts of redundancies that would not be ideal for ITS. Look at Mars Direct, and how it was altered into the Mars Reference Mission/Architecture. It was made substantially more complex... because NASA (they are necessarily risk averse for human missions). And that is why they send astronauts without radiation shield on Moon and disable Space shuttle abort mechanism As for ITS it could replace entire planned lunar space station? Not to mention it could make Earth space station/space hotel in one go. Even used by governments or super rich bankers as additional security something like "space air force one", since on orbit should be a lot safer during nuclear conflict? Link to comment Share on other sites More sharing options...
DerekL1963 Posted October 26, 2016 Share Posted October 26, 2016 9 hours ago, Eklykti said: There will be no biological research if we don't have the transport ability. If only we had some way of performing the research without going to Mars - oh, wait, we do. A centrifuge in LEO will do just fine for basic research into the effects of Mars gravity on small mammals. Link to comment Share on other sites More sharing options...
tater Posted October 26, 2016 Share Posted October 26, 2016 31 minutes ago, Darnok said: And that is why they send astronauts without radiation shield on Moon and disable Space shuttle abort mechanism The Space Race was a PR battle over geopolitics. Utterly different risk thresholds applied. Ejection seats were never meant to always be in Shuttle, it was solely for man-rating the craft. 31 minutes ago, Darnok said: As for ITS it could replace entire planned lunar space station? Not to mention it could make Earth space station/space hotel in one go. Even used by governments or super rich bankers as additional security something like "space air force one", since on orbit should be a lot safer during nuclear conflict? ITS will not replace anything. This thread is about SpaceX, and it needs to stay on topic, but that's not the way NASA buys stuff now, or ever in the past. Maybe that will change someday, but it's not even on the horizon right now. Major projects will involve multiple contractors, as they have since Washington ordered the first large Frigates for the USN. Link to comment Share on other sites More sharing options...
Darnok Posted October 26, 2016 Share Posted October 26, 2016 28 minutes ago, tater said: The Space Race was a PR battle over geopolitics. Utterly different risk thresholds applied. Ejection seats were never meant to always be in Shuttle, it was solely for man-rating the craft. Which means live doesn't matter when order comes 28 minutes ago, tater said: ITS will not replace anything. This thread is about SpaceX, and it needs to stay on topic, but that's not the way NASA buys stuff now, or ever in the past. Maybe that will change someday, but it's not even on the horizon right now. Major projects will involve multiple contractors, as they have since Washington ordered the first large Frigates for the USN. This thread is also about "future plans" and new markets for SpaceX products, to me, looks like plans for future. SpaceX is private company and I can't see anything wrong with idea that would allow using ITS by foreign governments or by rich private people. Lockheed and Martin are selling military tech to other countries, so why SpaceX wouldn't sell space tech to new markets? Link to comment Share on other sites More sharing options...
TheEpicSquared Posted October 26, 2016 Share Posted October 26, 2016 This is completely off topic from Mars plans, but I wonder what a falcon 9 with SRBs would look like, and if it would even be feasible. I know it isn't meant for boosters, but then again, neither was the atlas v . I know reusability would be a problem (there would be no place for landing legs). Link to comment Share on other sites More sharing options...
Nibb31 Posted October 26, 2016 Share Posted October 26, 2016 7 minutes ago, TheEpicSquared said: This is completely off topic from Mars plans, but I wonder what a falcon 9 with SRBs would look like, and if it would even be feasible. I know it isn't meant for boosters, but then again, neither was the atlas v . I know reusability would be a problem (there would be no place for landing legs). Why would you want to use SRBs when you have the Falcon Heavy ? Link to comment Share on other sites More sharing options...
TheEpicSquared Posted October 26, 2016 Share Posted October 26, 2016 (edited) Just now, Nibb31 said: Why would you want to use SRBs when you have the Falcon Heavy ? True, I just was wondering. Falcon heavy is the obvious choice. Edited October 26, 2016 by TheEpicSquared Link to comment Share on other sites More sharing options...
tater Posted October 26, 2016 Share Posted October 26, 2016 19 minutes ago, Darnok said: SpaceX is private company and I can't see anything wrong with idea that would allow using ITS by foreign governments or by rich private people. Lockheed and Martin are selling military tech to other countries, so why SpaceX wouldn't sell space tech to new markets? Sure. Private entities have no reason to go to Mars, there is no possible return on investment. Foreign governments with the money to invest in Mars have their own space programs, and will not be buying ITS, as it doesn't provide jobs back home, so I don't see that happening, either. First things first---there has to be a reason to go to Mars for anyone to pay money. NASA could potentially pay some money to SpaceX, because SpaceX is a US company (as Musk said to a question, they don't hire non-Americans for most stuff because they want to work for customers like the USAF). I'm fine with speculation on plans, but they should be rooted in realistic expectations. Link to comment Share on other sites More sharing options...
Recommended Posts