Northstar1989

Mars will never support plant life outside of pressurized and heated greenhouses at current pressures/temperatures. The atmosphere is too thin, and most plants would asphyxiate due to lack of Oxygen (plants photosynthize, but they also respirate and consume O2, like animals). The low pressure environment would also rapidly dehydrate plants (due to the low partial pressure of water vapir, any liquid water would instantly boil), and the rapid evaporation would also cause plants to simultaneously freeze due to evaporative cooling... If none of that did it, the incredibly low temperature of the soil (the atmosphere on Mars is too thin to significantly cool plants- or manned habitats for that matter) would quickly kill/freeze plants as well. Your only option for growing plants on Mars is in a pressurized, heated greenhouse. Preferably in growth-trays lifted off the ground- since the main source of heat loss on Mars is conduction with the ground, not convection with the incredibly thin atmosphere or radiation (which follows the 4th power of temperature- and so isn't a very substantial source of cooling at biological temperatures). What you *could* try to do is grow crops in processed/treated Martian soil in a pressurized/heated greenhouse. It's not really that useful to do so, however, as soil isn't really necessary for many plants- a large number of crops grow well in soilless conditions, via hydro- or aeroponics. Regards, Northstar

[snip] There HAVE been a series of articles by a certain cadre of economists lately, pushing for abolishing the Cirporate Income Tax. But that does NOT mean "Economists of all leanings" agree on this issue. That's just a bunch of pro-corporatw [snip]. The reasons for that push have to do with drawing corporations away from countries by offering lower corporate taxes (although US rates are already some of the lowest in the world after tax credits and loopholes- we have one of the highest statutory rates but lowest effective rates of any developed nation), encoraging wealthy individuals to invest money (Corporate Tax Rates don't affect prices, but DO affect rates of Return on Investment for private investors), and keeping companies considering leaving the contry here, not the basic economic logic corporate income taxes work along. Corporate Income Taxes, unlike Personal Income Taxes, do NOT affect the price of goods. That's because corporations still pay their workers the same, and for the most part (unless you are selling luxury goods targeted at the ultra-rich) consumers still have the same amount of money to spend. Thus the price that will net you the optimal balance between sales volume and per-unit profit is completely unaffected. Corporate Income Taxes hurt corporate after-tax profits, but they DON'T change the pricing that will maximize those profits. Corporations attempting to "internalize" the tax in such a case by raising their prices would only be self-defeating- because it would only serve to reduce their sales-volume and hurt their bottom line even further. Once again, you talk about a subject you know nothing about and don't understand. And economics are off-topic and dangerously close to forbidden content anyways, so drop it. We don't need moderators slapping us both on the wrist.

As usual, you have no sense of scale, Nibb. We *already* spend TENS OF BILLIONS of dollars on NASA each year (currently around $18 billion, but it's exceeded $20 billion in the very recent past). If Musk were able to offer early tickets (before a colony were established) at "only" $12 million a seat (48 times his long-term price estimate), there would be nothing to stop NASA from sending maybe 100 colonists a year. It would only require some reshuffling of NASA's existing budget priorities. Heck, at that pricetag Musk could easily fund the first 500 colonists out of his personal wealth! (Musk is valued at around $10 billion, and that wealth is only likely to increase as Tesla takes off! Plus, there's always some profit involved in the saleprice of an item- for instance SpaceX sells expendable Falcon9 launches fir around $60 million, but it only costs them around $40 million a launch according to the best guesses of industry experts). For reference, a Falcon 9 can carry 22.8 metric tons to LEO in expendable mode. So at that same price, Musk could already sell tickets to Mars for around $16 or $20 million with a craft with the same payload cost as Falcon 9. If reusability really does bring down costs 10-fold, Musk will have no problem selling early tickets to NASA for $12 million... 1000 or 2000 colonists (and many times more tonnage in equipment) is more than enough to get started on a sustainable Mars colony in earnest. We'll get there- just probably not quite as quickly or easily as Elon Musk thinks we will. Regards, Northstar

Clearly you have zero understanding of economics. Prices are set to maximize total profits along a curve between per-unit profit and total sales (the higher your price the lower your sales-volume). What happens to that profit after the units are sold is irrelevant to optimal pricing. Taking a percentage of profits in tax does not affect prices in the real world- only in theoretical, rarely-realized economic situations of total market saturation, where company owners are already making the minimum profit they consider acceptable for running a given type of company, and would rather go out of businesses than make less.

Also, the town of Nanisivik remained continuously-occupied until 2002, a year after the closure of the lead-zinc mine that supported it. Even so, residents initially petitioned the government to redevelop the town as a skills-training center for the region (OTHER towns in the province DO remain occupied), and only left when the petition was denied AND heavy lead contamination was found in the hones- caysing them to be demolished by zealous government health and safety beaureaucrats. Pressure from environmentalist groups (who wanted to see the town abanfobed and returned to nature) also apparently strongly played into the whole situation- with their being heavily responsible for delays in later redeveloping the tiny town (population of 77 when inhabited) into a naval refueling station, and possibly even being the cause of the government refusal to build a training center there... So, as usual for you cynics, you don't know the facts. People actually WANTED to stay- they only left when their livelihoods did. That's economics (a tiny town with no industrial base and along no trade routes can't survive for long) more than anything. You either don't know the facts, or choose to skew them. Either way, the facts contradict your assertions. Regards, Northstar My claims aren't backed by science? It's YOURS that aren't. If my claims were actually false, you would have disproved them instead of making pointless threats to ignore me. Ignore me. Please do. I'll be much happier not having to deal with your constants perversions of facts and then equally incredulous claims that my claims (often supported by facts pulled directly from real world research studies) are inaccurate and that you (an individual who has made no claims to a science or engineering backgroun) know better than enginerrs and scientists, including myself. My claims are based on facts, yours are not. My statement on the relative importance of convective vs. radiative cooling, for instance? Comes directly from my physics training as a scientist, as well as having actually spent a period of time grading state science exams as a job where we had several questions on the relative importance if convection vs. radiation. This exam was for middle schoolers- but you would have failed it, since you apparently don't know that convection is much more powerful than radiation in situations like the ones we were talking about...

How many times do I have to say this- Mars is not the Artic (or Antartic) Circle! Although sunstantially more dangerous than Earth's polar regions, due to the reliance on life support systems and pressurized habitats, Mars is actually EASIER to keep warm on than the poles, and doesn't have constant blizzards to bury your habitats and solar panels so that you can't grow fresh produce in greenhouses or with growth lamps... (the lack of fresh food is one of the MAJOR reasons life on Earth's poles is unappealing. The other main reason is how difficult it is to keep warm there...) Mars is much easier to keep warm at than the poles because the atmosphere is so much thinner. 99% of your thermal losses at Earth's poles come from conduction and convection, not radiative losses. On Mars, it's trivial to insulate habitats from the ground by raising them up an inch or two on tiny stilts. When you do this, you essentially create a layer of vacuum insulation (some of the best insulation physically possible) between your habitat and the ground, because the air us so thin that condyction/convection from it are negligible. Compensating for the remaining radiative losses is MUCH easuer than trying to keep a habirat warm at Earth's poles... Absolute temperature has almost zero meaning for thermal management of a human habitat. The rates of conduction and convection are far more important than those of radiation. Mars is much more thermally forgiving than Earth's poles for actively heated systems due to its incredibly thin atmosphere. Your and other Mars cynics' constant failure to recognize this and egregiously inaccurate comparison to the poles shows how much you really don't understand what you're talking about... Life on a Mars outpost would actually in many ways be more comfortable than life on the poles. Walks in spacesuits (which are designed to maintain a constant comfortable temperature) are much warmer and more pleasant than walks in parkas (which can't keep your face warm, or warm the air you breathe) The easier thermal management and lack of constant heavy/opaque snow deposits mean you can build glass/plastic dones for natural sunlight- and grow fresh food in greenhouses. The habitats would be high-tech and modern in design rather than crude metal boxes with no windows like people live in at polar outposts... All in all, life in a high-tech Mars colony would be much more dangerous, but a much more pleasant place to live than Earth's poles. AND, the early colonists would have an entire planet to explore, and the support and admiration of all mankind to encourage them, content in the knowledge they were carving out makind's future beyond Earth. Polar miners have no such comfort. Regards, Northstar

That's not true. Plenty of plans for Mars basecamps have been drawn up before (by organizations such as NASA) that SpaceX can draw on. Seriously, how do you get off saying these things? Your claims, like those of many of the other SpaceX cynics here, are pants-on-fire false, to use a term from fact-checking sites... The colonists were provided with tolerable climate conditions and food? Sure. That's why THOUSANDS of them starved to death or died of exposure early on. And the colonists would die the day the ITS left, despite being supplied with hundreds of tons of equipment sent to Mars in earlier launches? (since his presentation, Musk has been very clear on this point- the early launches will carry very few colonists and lots of cargo to set up an initial base) By the same logic the astronauts on the ISS would die the same day they arrived as well... You clearly know nothing about what you're talking about, and are talking from uninformed gut-feelings rather than facts. You're spreading nothing but falsehoods and misinformation, and haven't bothered to fact-check any of your claims before posting them (which I routinely do for my own claims). Your behavior is rude, detrimental to the conversation, and uninformative. I do not appreciate it and would like to respectfully like to express my profound distaste for your false statements and scare-tactics, and those of others like you in this discussion. No economy on Earth is self-sufficient anymore, regardless of the climactic conditions. It is extremely naive to say that just because these areas aren't self-sufficient, they couldn't be. People simply don't attempt to be self-sufficient in these areas (or ANYWHERE on the planet, for that matter) because it is difficult and would be extremely expensive... Nobody ever said it would be easy. Claiming anybody has is just a bogus straw-man argument you set up so you could beat it down... That doesn't mean it CAN'T be done. People can survive on the International Space Station with enough resupply and there are literally no resources there except solar power. On Mars, at least, you have a planet to shield you from radiation and provide gravity, and abundant mineral resources to work with... The Mars environment is UNQUESTIONABLY less hostile than the International Space Station. Don't quote resupply times at me- that's not a feature of the environment itself, and how hard an environment is to reach is an entirely seperate discussion from whether the environment is CAPABLE of supporting life. Nobody questions that early outposts on Mars would be heavily dependent on supplies from Earth many of which would be sent AHEAD of the majority of colonists). But, with time, a Mars colony would gain the ability to produce more and more goods and equipment of its own, and eventually become self-sufficient. This is NOT up for a debate- it's a FACT, a virtual guarantee if the colony survives long enough and receives enough support. The only question is not if, but when. Given outside support and new migrants, would it take a Mars outpost 50 years or 500 to become fully capable of supporting and growing itself? Regards, Northstar

Wrong, wrong, and wrong. Other people having jobs DOES directly benefit you. In a number if ways. First of all, people making more money means a larger government tax base. This means more programs that benefit you for the same tax burden on you, or that you end up with a refuced tax burden. Even when these jobs are crwated by government spending, the increased tax revenue alliws the government to recoup come of its costs in additional taxes, making the cost of a program a lot less than it looks like on paper... Second, more jobs mean a,tighter job market. Which means labor prices go up. Which means YOU make a higher salary or better wages at your job, whatever it is. The ONLY way this doesn't benefit you is if most of your incone cones from owning the means of productioninstead of selling your labor- that is, if you are filthy rich. Third, the concept of "net taxes" is stupid and misleading (there's,a reason it is rarely discussed even in sober economic circles, and certainly not on the news...) Many government expenses increase the incomes of people other than those receiving them. For instance, repaving a local main road drives up the incomes of asphalt manufacturers, road workers, AND the owners of long-haul trucking companies that depend on that road. It doesn't JUST benefit the citizens of the town where the road was repaved. Similarly, a Mars colonization program doesn't just increase the incomes of SpaceX employees. It also benefits aluminum and lithium miners, who dig up the metal for the rockets (or Carbon Fiber manufacturers if CF fuel tanks pan out), farmers and food processors who produce the food that goes on each ITS flight as part of the ticket price, Oil and Gas sector workers who help produce the Methane for the ITS launches here in Earth, and literally anyone who provides any of these individuals or their families with goods and services. In the end, MILLIONS of Americans (and even a few foreigners who produce some of these same raw materials and see increases in market prices for them) see increases in their incomes from something like ITS... It doesn't matter if a program increases the incomes of those who pay less than 12k in taxes a year to bring them closer to this point, or those who pay more than it to bring them further above it. A program like ITS generates tax revenue- and the standard of whether it helps increase the incomes of individuals who pay "net taxes" is a completely arbitrary and worthless distinction to bring up. Regards, Northstar

Why did the government pay for Apollo? Politicians will always find reasons to support their favorite programs, regardless of whether or not they make economic sense (and ITS *does* make sense). OK, now I *KNOW* you have no idea what you're talking about. Haven't you ever heard of the Corporation Tax? (also known as the "Corporate Income Tax" or "Corporate Taxes") Corporations *DO* pay taxes on their profits. DIRECTLY. And then theur employees in turn pay Income Taxes as well. So the government gets paid TWICE for any investment that generates economic activity.

SpaceX would never receive government money for doing nothing. They would receive subsidies for the external benefit of inspiring the rest if the country and world, which is a benefit worth paying for (and that we already DO pay for in other contexts- such as sports, mysuc, or inspirational speakers). Musk is investing and spending his personal fortune on this. He could have retired on his earnings from PayPal years ago. He's not doing this for himself. The government and taxpayer, meanwhile, receive a MASSIVE return on investment in the long run. In the form of technology developed for the Mars colonization program, which can help us here on Earth, and eventually patents produced on Mars itself by Martian inventors. Over a sufficiently long timeframe, that technology will DEFINITELY pay for the cost of whatever government subsidies are provided to the Mars colonization program. As Robert Zubrin once said "I think the greatest export from Mars will be patents".

You are intentionally taking a very narrow and obfusticated definition of Return on Investment for the basis of your argument. From the point of view if SpaceX, if tgey receive government subsidies to colonize Mars likely) and thus make back more money than thet spent, there is a positive Return on Investment. From the point of view of taxpayers and the US government, if a program like Apollo or IRA generates more economic value (in the firm of technology) than it costs, it ALSO has a Return on Investment. Your saying that "taxpayers" received no RoI on Apollo is a ridiculous assertation, based on an intentionally incorrect definition of "taxpayers". Taxpayers are not just middle-class Americans working in ordinary jobs- they are ANYONE who pays taxes. The term includes space industry engineers and scientists who were employed by NASA, the CEO's of the companies that came to own Velcro patents, and even the janitors at Kennedy Space Center. Thus ANYTHING that generates jobs or technology for the US economy as a whole benefits taxpayers. What I *think* you meant is that Apollo did not directly benefit SOME taxpayers- and that is a statement I will fully agree with. There were some winners and some losers with the Apollo program, like literally any other form of economic or government activity. A factory worker in Detroit who helped pay for Apollo through taxes probably was a net loser, whereas an executive at a furm manufacturing Velcro or a local restaurant oenee in Florida (where Apollo generated millions of dollars in local economic activity) was probably a net winner.

Oh, I never said the ither peoblems to do with actually surviving on the syrface are solved. They're most vertainly not- which is why I fully expect earlu colonists to die in huge numbers on Mars (but NOT en route to Mars) befire we get most of them worked out. But progress is sure to happen a lot faster when we've got inventor's boots on Martuan soil and lives on the line than when living on Mars is just some unlikely theoretical and an excuse to get grant money for unrelated research... The example of the colonization of America is, by definition, realustic because it ACTUALLY HAPPENED. And like I said, I'm LIVING PROOF as a direct descendent (on my mother's side) of Mayflower colonists that some early colonists actually did survive, despite the hardships. You can't get any more realistic than that. Nobody lives in Earth's deserts? The Israelis wouls beg to disagree. Through massive desalinization programs at the coast, diversion of river water, and pumping from aquifers they've managed to not only inhabot but farm some of their deserts with greenhouse agriculture. The reason most deserts are mostly unihabited is because the nearby populations are backwards and poor. Rich, technologically-advanced nations like Israel can and do inhabit deserts and farm them. Other desert-dwelling nations have existed in the past as well, but collapsed due to military pressure from wealthier neighbors inhabiting richer lands... Pointing to one desert and saying nobody lives there is proof that nobody lives in any desert on the planet is ridiculous. Regards, Northstar

You keep repeating that like some sort of religious mantra, despite having zero support for that assertation- and it's clear by this point you don't understand what "Return on Investment" means. RoI is literally anything where you soend money (Investment), and make money back later (Return), and specifically refers to the RATE that you get back your initial investment. ITS has RoI. It requires an *Investment* to build, and later brings in a *Return* in the form of ticket-sales. That is, *BY DEFINITION* a Return on Investment, just the same as building a soccer stadium or starting a bus-line. You don't have to make a physical product to have RoI, services such as transport and entertainment (ITS is a little of both) qualify as well. Further, ITS is a different product than LEO space tourism. With a different market. Many people would pay for a ticket to colonize Mars on ITS that wouldn't care for an orbital tourist-ride. And colonizing Mars is a lot more useful. Cheap LEO access has ZERO utility if you have nothing to do up there... (of course you can launch a few satellites, build a few stations - but this will never prove half as useful as colonizing Mars) I can't comment on the specific costs of Skylon- but that was never the point. The point was and is that once SpaceX establishes a route to Mars they will have opened up the market and demonstrated it can be done. They will also have created a future demand for interplanetary travel in the form of a Mars colony that corporations can reliably count on as a market when trying to raise capital for their plans for better systems to reach Mars. Optimized methods to reach LEO and Mars from other companies will undoubtedly follow a SpaceX-initiated colony. You need to STOP calling Musk's plans "lighting money on fire" and similar such. These comments are not only disrespectful of others' views on the plans and rude, they also reveal your complete and utter contempt for plans cone up with teams of highly-trained engineers and rocket scientists that are probably far smarter than you.. Deriding legitimate plans in harsh and contemptuous language doesn't make you sound smart, it makes you sound egotistical and conceited. Musk has a business model too. How is sellingbpeople tickets to Mars so fundamentally different from selling them tickets to Low Earth Orbit? The cost is higher, but so is the ticket price people are willing to pay for the service. People WILL buy tickets to a new frontier, no matter how dangerous. I am living proof of that- being descended from many of the first European settler families in North America, including THREE aboard the Mayflower. Most early settlers died, but more kept coming despite the risks (many early colonies died off entirely- take Roanoake Island for example). And they came for a ticket-price that was actually much steeper relative to people's assets than the $250-500k Musk will be asking for a ticket to Mars... Mars is dangerous, but there are no infections diseases, dangerous wildlife, or hostile natives to deal with. Some colonies will undoubtedly go the way of Roanoake Island's first colony, but more settlers will undoubtedly come nonetheless.

As Musk has stated many times, a Mars colony would act as a forcing function for cheaper space travel and access to LEO. Once humans are flying to Mars every year, things like the SKYLON program (the UK's plan for a fully reusable spaceplane, using cutting-edge hydrogen-oxygen hybrid jet/rocket technology), Mass Driver launch systems, Microwave Beamed Power (initially as a power-source for ultra high-ISP one-way Mars injections, like for cargo missions to supplement the ITS structure), Propulsive Fluid Accumulators (which could be powered by nuclear reactors,or Microwave Beamed Power), reusable nuclear space-tugs, asteroid-mining, and perhaps even fusion reactors for space propulsion or futuristic materials for a Space Elevator will all become much more worthwhile endeavors... And, all this economic activity is CERTAIN to have an impact on your life. The biggest problem with economies in developed nations right now is that they aren't really the subject of any substantial capital investments that grow their economies- most new factories are built in places like China. Space Exploration, on the other hand, requires a highly skilled workforce and is far, far less likely to be outsourced to China... Regards, Northstar

The ability to exchange top talent (engineers, scientists, etc.) between Mars and Earth would be useful in the long run, though it's certainly not necessary for a Mars colony to survive and grow. Ultimately thete are much bigger challenges/concerns to populating Mars than the gravity- like the fact everything has to be in an leakproof pressure vessel, and those tend to suffer fatigue and rupture over time... Regards, Northstar

Actually, we do know enough about lunar gravity to reasonably predict it would be disastrous for human health. People born and raised on Mars, by contrast (babies who left at an early age would have few problems) would probably have a very difficult, even impossible time, living a normal life on Earth unless they engaged in some *very* intensive weight-training from an extremely early age. Most simply wouldn't be able to return. The extreme bodybuilders of Mars might be ultra-lightweight boxers by Earth standards. But typical bone and muscle development for non-athletes would be enough to live a normal, healthy life on Mars, which is all that really matters... Also, I didn't say people with Earth bones would keep them. Over time bones and muscles would partially-atrophy and stabilize at a level that would be reasonable for Mars life, but very problematic for returning to Earth. The only way to avoid this would be frequent and intensive weight-training on Mars... Regards, Northstar

Lunar gravity isn't high enough for normal human health. Liquids settle too slowly on the Moon, we already know that. There's a BIG difference between lunar gravity (0.16 g), and Mars gravity (0.38 g). Mars gravity is more than 2x as strong! In fact Mars gravity is probably about the *bare minimum* necessary for (relatively) reasonable human health over a lifetime spent off-planet (i.e. I doubt lunar colonies will ever be a thing- the gravity is just too low). Don't get me wrong, Mars gravity is likely to cause some health problems. A higher risk of kidney stones and kidney failure, severe constipation, and osteoporosis mainly. But the increase in incidence of these diseases shouldn't be nearly bad enough to make colonization unfeasible, though they'll probably replace obesity, heart disease/stroke (the two are actually closely related, and bad cholesterol is a huge risk factor for both as it leads to clot-formation), and diabetes as the main public health menaces on Mars... (because food will be very limited on Mars- so people won't be able to literally eat themselves to death like on Earth). Early Mars colonists will probably be limited to a mostly-vegetarian, vegetable and cereal-rich diet. The main sources of animal protein will probably be silkworms and snails... (I know they don't sound appealing, but the Chinese/French eat them!) And when they eventually bring over the first mammals, they will be used entirely for milk production (as it's more calorie-efficient than meat-production). Regards, Northstar

Casting is not a usable method for producing modern rocket fuel tanks, actually. It's not precise enough. The *only* way we can currently produce fuel tanks to needed technical specifications is through reductive manufacturing (where you take a plate and machine it down). SpaceX managed to reduce the amount of machining a bit by adding reinforcing "ribs" to their tanks, but it's still the only way to make a rocket fuel tank. Certainly if 3D printing technology *vastly* improved in terms of speed, accuracy, and the strength of the manufactured products over the next 3 or 4 decades it might become an economical way to produce rockets, perhaps even expendable ones that could compete on a cost-basis with reusables. But that level of refinement of the technology is AT LEAST 40 years away, and like cost-effective fusion power, might *never* materialize. Musk is working within the realm of what's possible today and tomorrow, not what *might* be feasible in 40 years... Church bells are hardly high-precision components. Casting is, as an undisputable fact, NOT accurate enough for rocket parts- which need to be produced to insanely high precision due to the very narrow engineering margins on a modetn rocket... (Narrow engineerong margins are the main reason rockets are currently so expensive- in fact the whole principle behind Big Dumb Boosters was to produce a rocket with much more generous engineering margins, so that the rocket could be manufactured much more cheaply. BDB's would *NOT* be any less reliable than conventional rockets, but they would have *much* lower payload-fractions- which is why Musk thinks they're a bad idea. Smart rockets make better reusable rockets, as they amortize their much higher manufacturing costs over many launches, and they have a clear payload size advantage over comparably sized Big Dumb Boosters, making them cheaper in the long run...) Regards, Northstar P.S. If Musk and SpaceX fail to obtain promised low costs for re-using their Falcon rockets, I really do hope they'll switch to Big Dumb Boosters. Like it or not (Nibb, we all know your opinions on this subject, and you're wrong. But please don't derail this discussion by starting arguments about Big Dumb Boosters) BDB's are the next-best thing if you can't develop affordable reusables...

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

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

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.

Haha, you must think you're very clever. You're not. Everybody dies eventually, but there is zero reason to think that Mars gravity will have anything to do with it. Just because something is unknown or new doesn't make it dangerous, and the human body is incredibly resilient- capable of surviving a lot more than you think. Collecting data with a rotating habitat in LEO would be a pointless waste of money. Sure, we don't know for sure what will happen to the colonists' bodies in 0.38 g. But we have a pretty good idea, since we're quite sure it's enough for most physiological processes except maintaining Earth-like bone and muscle density (both will atrophy somewhat- but nothing like in microgravity). And there's nothing we can do to change the gravity on Mars anyways, so there's no point wasting millions of dollars on a short-term study that won't tell us anything informative, or the kind of long-term study that might- but would take hundreds of millions of dollars and 20 years of data-collection, and end up getting confounded by 100 variables you can't accurately match to Mars just by spinning a station in orbit anyways... We also don't know for sure what will happen if you stand on the moon alone and humm Kumbaya three times to yourself and hop around in a circle 3 times on one foot- but we have a pretty good idea, so I'm not going to waste a couple billion or even million dollars finding out. Mars will be an incredibly dangerous place to live- but not because of the gravity. The atmosphere (or rather, lack thereof) is by far the greatest danger. Habitats depressurizing, starvation, dehydration and freezing are what will kill colonists, not (likely minor) health complications from 0.38 g. It's a lot cheaper to find out what minor, probably treatable long-term health effects 0.38 g will lead to (I've told you emphatically already, basic, normal bodily functions will work just fine in 0.38 g) in the course of a mission that will *already* involve building a base with medical facilities and doctors, that you were going to carry out *anyways*, than to delay the ITS or carry out a study at current launch-prices... (thank you very much ULA for ripping us off for all these years on getting things to LEO) Regards, Northstar

We regularly send people to the ISS for 6-12 months, and that's longer than it will take to get to Mars. And, speaking as a biologist, it is *HIGHLY* unlikely 38% gravity would lead to any substantial ill health-effects. What do you think would happen, at 0.38 g that would be so bad, exactly? It's enough for fluids to settle and drain, and to load bones with several dozen pounds of weight (plus, it's not hard to enforce exercise regimens on Mars where people lift even heavier loads to offset some of the *moderate* expected decreases to bone and muscle density), which is really all that's necessary for human health... Regards, Northstar

Don't tell a biologist what we do and don't know about radiation exposure. Actually, we *DO* know the expected rad doses, and we *DO* have prior experience with the health effects of similar and even greater doses. We can expect an increased risk of cancer and some moderate percentage reduction of fertility, but nothing we can't deal with... We ALSO know the health effects of 4-6 months spent in 0 g. That's because we regularly send ISS astronauts up for 6 months to a year. Musk's plan only calls for a travel-time of 3-5 months, and Zubrin's revised plan calls for an average transit time of 6 months. NOBODY is suggesting people spending "more than a year" in microgravity (Mars *HAS GRAVITY* of its own- and speaking as a biologist I can make an educated guess it's probably enough for comparatively normal health- it's enough for fluids to settle and drain downwards, and that's basically the most important thing) so quit your irresponsible fear-mongering and start talking facts. Musk said that children won't be allowed initially. That doesn't mean some won't eventually be conceived on Mars by some of the younger parents in their 20's to 30's sent there. The most difficult problem will actually be convincing these colonists to have ENOUGH children when the time is right, since your typical 1.9 children per mother for developed nations (where life is much easier) won't lead to any population-growth... Regards, Northstar

Musk explicitly stated that children would be barred from flying on the ITS in the early years, becayse he feels they would be too much of a drain on the colony. So problem solved. In fact you never would have raised this as an issue if you actually did your homework before making wild statements. On that note, the risk of a cancer is much less than the risk from working in a mine, or even the risk from smoking cigarettes. This is just more scare-tactics, with absolutely no foundation in facts. Absolutely. It's actually kind of laughable, really. Some peopke are terrified of space radiation, but do far more to shorten their life-expectancy than cosmic radiation from a Mars joyrney ever could every time they light up a cigarrette, or eat their ninth double cheeseburger with extra cheese that week... Things like micrometeorites and structural failure of pressurized habitats ate much greater dangers for a Mars journey than backgroun cosmic radiation. The only *real* danger from radiation worth worrying about that much comes from solar storms, and it's easy enough to create a tiny, cramped, *heavily*-shielded (preferably, using plastics or water, due to their superior shielding mass-effectiveness) "storm bunker" for the ITS's 100-man crew to deal with that (in fact the larger your crew the relatively easier it is to create a sufficiently-shielded shelter with a given mass per-person, due to the Square-Cube Law...) Regards, Northstar Also worth noting- Solar Particle Events last hours to days (usually only a couple days at most). They are hardly instant-death, and what's more, can usually be predicted. So it's easy enough to put radiation sensors around the ITS habitat, and fire off warning klaxons telling the crew to head to the radiation shelter if the spacecraft is caught by an unexpected SPE scientists on Earth failed to forecast... You'd experience maybe one SPE on a Mars transfer most of the time, sometimes none if you were lucky- two if you weren't. So asking the crew to hang out in the radiation shelter for a day or two during a particularly long SPE would hardly be a frequent occurrence. You might even hold werkly solar-solar-storm drills on the spacecraft, much like you have fire drills on Earth, to test the warning systems and make sure people don't panic if there's an actual solar-storm emergency and know to calmly head to the rad shelter. It would give the crew something to do to keep them busy and stave off boredom during the long journey, while building crew discipline and organization, at the very least... Northstar