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Mars Space Science

Forget Space Travel, It's Just a Dream 542

Posted by CmdrTaco
from the oh-fine-then dept.
An anonymous reader writes "The clash of two titans — physics and chemistry — are major barriers to human space travel to Mars and beyond, and may well make it impossible ... at least with current technologies."
This discussion has been archived. No new comments can be posted.

Forget Space Travel, It's Just a Dream

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  • Math (Score:4, Funny)

    by Anonymous Coward on Monday April 11, 2011 @08:01AM (#35780274)

    If it is impossible in the real world, why not solve it with math?

    • Re:Math (Score:5, Funny)

      by Daimanta (1140543) on Monday April 11, 2011 @08:52AM (#35780856) Journal

      I looked into it (math undergrad) and I devised a way to shorten the lengthy spacetravel to Mars from 3 months to 1 + i months! Now, the only thing I have to do is to think of a way that lets people travel in complex time, but I think that it won't be too hard to solve.

      • by Z00L00K (682162)

        It always comes back to "it's impossible", "can't be done" and so on, then someone does it in an unexpected way and the rest of the world stands there looking stupid.

        Even if it looks mathematically impossible using regular math you may end up with a great solution using an unexpected approach on math - or you will need to develop the math after the fact has been proven.

      • Just rotate the ship 90 degrees.

    • Physics (Score:5, Insightful)

      by mangu (126918) on Monday April 11, 2011 @09:00AM (#35780956)

      We have known since the 1930s that the energy bounding atoms together is nothing compared to the energy bounding the atom nucleus together. In the 1940s we started learning how to use that energy.

      We have been stalling ever since. It's like we stopped developing automobiles because some people became afraid of them.

      • Re:Physics (Score:5, Informative)

        by Rei (128717) on Monday April 11, 2011 @10:47AM (#35782210) Homepage

        Even chemical fuels have hardly evolved as far as is physically possible. Metastable compounds offer a whole new class of propellants with performance as much as an order of magnitude greater than current propellants. Cryogenic solid and hybrid rockets have hardly even been studied yet (you can even use solid oxidizers). Etc. And then there's the whole other class of improvements: spacecraft mass. Anyone here want to argue that materials have advanced as far as they're ever going to? Anyone?

        Then, as you mentioned, nuclear energy is tremendous -- and need not be harnessed directly (you don't have to have a radioactive plume shooting out the back). There's also external energy delivery mechanisms, so your craft need not carry its energy onboard. And there are even some more radical concepts that I know some people who are working on. I can't discuss all of them, as not all of them have been published about yet, but I'll point out one that has: digital quantum batteries. This involves storing energy in arrays of nanocapacitors, whose small size enables quantum effects to require huge voltages for dielectric breakdown. When you take quantum effects into account for energy storage, the theoretical upper bounds on your energy density are similar to that of nuclear reactions (although the specific case I mentioned has tensile strength limits which are much lower -- but this does not apply to all systems).

        And finally, the whole premise of the article is totally wrong. The article acts as though energy costs are the primary -- or even a major -- cost of launching rockets. They're not. If you can make a rocket where your propellant cost is a significant fraction of your launch costs, you're doing something *right*. Rocket costs are overwhelmingly parts and labor. Anyone want to make an argument that parts and labor costs on a complex system can never be reduced? Anyone?

        Pretty much everything they wrote is wrong. For example, concerning the difficulty of mining water, etc off-world:

        Davies' hope is that the colonisers might be able to survive indefinitely by mining oxygen, water, hydrogen and other resources at the destination. While possible in principle, this would be very difficult in practice because of the low grade of the resources.

        *What*? We can't mine ice because it's "low grade"? What on Earth is he talking about? Many bodies in our solar system are covered in, or at least have regions of, nearly pure ice. Mars deposits 100% pure frost on surfaces near its poles. The frost will get contaminated by dust, of course, but it's freaking dust. If you can't filter dust out of water, something is wrong with you. "Other resources"? Like what, iron? Lunar regolith is 1-2% pure iron. Not iron oxide -- *metallic*. As in, "attract it with a magnet and then melt it". Iron miners on Earth would kill to be able to get iron that easily. Low grade resources my arse. The problem with off-planet mining is the cost and difficulty of engineering and transporting light-weight, highly autonomous mining/processing equipment and providing them with their needed consumables and maintenance. It has nothing to do with the quality of the resources.

        Who decided to give this person a platform?

        • This guy Alan Finkel is a self described "Neuroscientist and Entrepreneur". What concerns me is the latter. Generally, people that describe themselves as that have large egos and little to back it up with other than they got lucky with an idea and made some decent money. Since this guy's only other real credential is being a neuroscientist, I doubt he understands the finer details of space travel.
        • by Grishnakh (216268)

          Then, as you mentioned, nuclear energy is tremendous -- and need not be harnessed directly (you don't have to have a radioactive plume shooting out the back).

          Who cares if there's a radioactive plume shooting out the back? Obviously, you wouldn't want to use such a rocket for launches from Earth's surface, used within our atmosphere, but for a ship assembled in orbit to be launched to other planets, why not? This is definitely a case where anti-nuclear hysteria is holding us back.

          The article acts as though

    • Re: (Score:3, Insightful)

      by GooberToo (74388)

      and may well make it impossible ... at least with current technologies.

      When you make a prediction about the future and balance your entire argument based on current technology, you basically confirmed you're an idiot. The same absolute fucking idiots all said we can't fly, you'll suffocate in a car when it moves, reaching orbit is impossible, small electronic radio devices are nothing but scifi.

      The summary could have simply said, "today's technology has limits."

      So please, can we stop posting articles by fucktards, for fucktards?

      • OK, so explain to me how you will get past the laws of physics then? Your statement is equivalent to "All you assholes that say perpetual motion can't be achieved are just pessimistic fucktards." Yeah, right...

        Fundamentally the guy is correct. He may be incorrect in that we could build large nuclear powered VASIMIR / magnetohydrodynamic rockets, but those can't lift off from the Earth (insufficient specific impulse). Even if we built such a thing it only extends our range of action slightly. Someone might b

  • We've been able to do that since at least the early 80's.

    The question is can we make it worth the trip and comfortable?
    Probably not, but we need to make the trip, at least once, just so we can say we did and we can better prepare for the later real trip.

    Beyond that? We don't have the tech. Not yet.

    • by pecosdave (536896)

      Not tested and proven with human on-board anyways. Ion propulsion, solar sails and nuke ships are all possibilities of course.

      The big argument against the nuke ship is the radiation left behind when it launches. I'm more of a fan of building the thing in space with chemical rocket or projectile launch methods and then assembling it in orbit, escaping earth with chemicals rockets, THEN dropping nukes to go forward.

      • by camperdave (969942) on Monday April 11, 2011 @08:37AM (#35780638) Journal
        There are fully contained nuclear rockets [nuclearspace.com]. They are called gas core nuclear rockets, or nuclear light bulbs. The reaction uses uranium hexafluoride gas, spun into a vortex. This vortex is contained within a sealed, quartz walled chamber. The reaction produces a lot of UV radiation. Quartz is transparent to the UV radiation, so it escapes the container. Propellant is run past the quartz wall and absorbs the UV radiation, and heats up, expanding in the process. Voila, a nuclear rocket with no radioactive exhaust.
        • by radtea (464814) on Monday April 11, 2011 @09:52AM (#35781534)

          Voila, a nuclear rocket with no radioactive exhaust.

          False. Quartz is also transparent to neutrons, which will be copiuously produced by the fission reaction going on. I haven't looked at the link, and don't need to. If this thing is fission powered, there are neutrons. If there are neutrons the exhaust is going to be radioactive, unless the gas is pure helium-4, in which case the whole gas vortex UV thing is irrelevant. You can run 4He through a pebble bed reactor and have it come out non-radioactive (more or less.)

          • by mangu (126918) on Monday April 11, 2011 @12:02PM (#35783090)

            If there are neutrons the exhaust is going to be radioactive, unless the gas is pure helium-4, in which case the whole gas vortex UV thing is irrelevant

            If the gas is hydrogen it will not become radioactive. When a hydrogen nucleus captures a neutron it becomes non-radioactive deuterium.

            Hydrogen has the added benefit that it's the best gas for a propellant, so it would be used anyway.

      • We have the technology. It is just impossible to send humans and their living quarters and their supplies and a research station and a return vehicle and return trip supplies on a SINGLE chemical rocket. Once you start using more than one chemical rocket for this list, even at just two, it becomes possible. (Unless you can do the smart thing and use a single nuclear rocket instead.) We already have demonstrated that we can resupply a spacecraft in orbit, do docking and assembly in orbit, do precision landin

      • by koolfy (1213316) <koolfy@gma i l . c om> on Monday April 11, 2011 @09:41AM (#35781422) Homepage Journal

        building the thing in space with chemical rocket or projectile launch methods and then assembling it in orbit

        Do you have any idea of the time and complexity needed to do even minor operations in space ? (i.e. doing some structural work on a space station)

        This would take ages. Really, several generations. And cost trillions of dollars.
        it sound cool, but it just isn't realistic.

      • by Skarecrow77 (1714214) on Monday April 11, 2011 @10:08AM (#35781720)

        I thought the big problem with nuke ships was the momentum incurred, and shedding it in time to land without detonating on impact. Slowing down in space is a sonofabitch. On a trip to somewhere like Mars, you have to expend nearly as much energy slowing down as you did speeding up. You can't air brake into mars without one HELL of a big shield/parachute due to the relatively low atmospheric density (about 1% of earth). You basically gotta turn around and thrust directly 180' into your forward path until you're slow enough not to escape the gravitational pull of your destination.

    • by JasterBobaMereel (1102861) on Monday April 11, 2011 @08:48AM (#35780764)

      Got to space in Early 60's

      Got to the moon in the late 60's

      Both of these were single hop's, a trip to Mars is likely to be a staged journey, build the craft in orbit, or on the Moon, and use fuel from Space, the article assumes that the only possible way is a single hop from the earth to Mars (or further) taking everything, fuel, supplies with you.... This is impractical, but not impossible

      Making predictions about future technology is foolish at best .... go and speak to anyone in the 1950's about a compter with 6,000 logic gates, contained within 40 square mm they would say that was against the laws of physics and chemistry ... but the Intel 8800 had this in 1974

  • How about (Score:5, Interesting)

    by rossdee (243626) on Monday April 11, 2011 @08:01AM (#35780278)

    a space elevator aka beanstalk aka orbital tower.

    Once you get out of earths atmosphere and gravity well, you're halfway to anywhere (in the solar system)

    • Or even up to 90% of the way, depending on how big a detour you're willing to make to use the Interplanetary Superhighway, since it's all zero-energy trajectories.

    • Re:How about (Score:4, Informative)

      by ceeam (39911) on Monday April 11, 2011 @08:19AM (#35780448)

      The problem (for biological things, like human beings) is going out of Earth magnetic shield.

      • Re:How about (Score:4, Interesting)

        by CastrTroy (595695) on Monday April 11, 2011 @08:27AM (#35780532) Homepage
        Could you put a big magnet on the ship to channel the cosmic beams from the sun and use them to fuel the ship some how? I'm not joking. I'm not that knowledgeable in this area of expertise. But it seems like we have two problems, too much cosmic radiation, and a need for more fuel while in space. Could we harness the cosmic radiation and use it as fuel?
      • by gilleain (1310105)

        The problem (for biological things, like human beings) is going out of Earth magnetic shield.

        For example, from ion irons. Er, iron ions. el reg article [theregister.co.uk].

    • Re:How about (Score:4, Interesting)

      by michael_cain (66650) on Monday April 11, 2011 @09:10AM (#35781070) Journal
      You properly make the point that all the flashy things that people want to do in space (industry, manned missions to other planets, etc) fail over the same dull, dreary, problem: lifting significant mass to LEO remains prohibitively expensive. Make LEO cheap, and the other things are, if not simple, at least relatively straightforward.

      I always think it is worth pointing out that the US made an important decision between the time Apollo was announced and when it placed men on the moon: millions of poor and elderly would receive health care paid for by the government. TTBOMK, manned space programs have all started in countries that did not guarantee full-blown modern health care for their poor and elderly. Originally, the US and the Soviet Union. Today, China and India.
      • Re: (Score:3, Insightful)

        by mangu (126918)

        I always think it is worth pointing out that the US made an important decision between the time Apollo was announced and when it placed men on the moon: millions of poor and elderly would receive health care paid for by the government.

        Careful, comrade, you are not being politically correct. Everybody knows that the solution to end the $1.6 trillion deficit is to cut the $700 billion military spending, while leaving the $800 billion health care and $700 billion social security spending intact.

        If only the military spending didn't exist, I'm sure some hand waving could take care of the remaining $900 billion deficit. That is, if you forget that nearly half of those $700 billion military spending is manpower cost, which would become unemploy

        • by h4rr4r (612664)

          Social Security is self funding. That 700 billion comes out of the general budget. See the difference?

        • Re:How about (Score:5, Insightful)

          by Rei (128717) on Monday April 11, 2011 @11:43AM (#35782906) Homepage

          Everybody knows that the solution to end the $1.6 trillion deficit is to cut the $700 billion military spending, while leaving the $800 billion health care and $700 billion social security spending intact.

          The current extremes of our deficit are due to the fact that we're in the greatest recession since the Great Depression. In case you didn't notice. Our average deficits are a fraction as much. And our deficits are as much if not more a problem of continued tax cuts then they are of spending.

          That is, if you forget that nearly half of those $700 billion military spending is manpower cost, which would become unemployment benefits

          So military spending causes stimulus but other kinds of spending don't? Really? So old people don't buy stuff when they get their social security checks? Doctors and nurses live in caves and burn their cash for warmth?

        • Regardless of your priorities, your numbers are wrong. Unless you like to pretend nuclear weapon maintenance, Homeland Security, and veterans' affairs, among others, aren't a part of defense spending:

          895B Military/National Security Discretionary
          730B Social Security
          580B Income Security/Dept of labor
          520B Non-Military/Security Discretionary
          491B Medicare
          297B Medicaid

          Defense is the elephant in the room. Reforming all the other programs is noble, but Social Security had a surplus not so long ago and ma
        • by npsimons (32752) *

          I thought Medicare and Social Security were self-funding? How would it help to cut self-funding projects?

      • You properly make the point that all the flashy things that people want to do in space (industry, manned missions to other planets, etc) fail over the same dull, dreary, problem: lifting significant mass to LEO remains prohibitively expensive.

        But what he, you, and the author of the TFA all fail to realize is that expense is not a law of nature.

        There's nothing intrinsic about space travel that makes it expensive, fuel is cheap, aluminum is cheap, electronics are cheap... What's expensive is building

  • A sense of scale (Score:5, Informative)

    by elrous0 (869638) * on Monday April 11, 2011 @08:02AM (#35780286)

    Most people have no real appreciation of the scale involved in psace travel. As daunting as our own solar system is, even that pales in comparison to the scales involved in traveling to other solar systems. Currently it takes us about 9 years for a probe to reach Pluto. When I ask people to guess how long it would take that same probe to reach the nearest solar system (a mere 4.2 light years away), people's estimates are usually comically far off.

    120,000 years is the correct answer. Most people guess between 100-1000. That's why people think it is plausible for mankind to colonize space. They don't appreciate the scale we're talking about.

    • Re:A sense of scale (Score:5, Informative)

      by avgjoe62 (558860) on Monday April 11, 2011 @08:16AM (#35780420)

      TFA isn't talking about interstellar flight. It's talking about a human flight to Mars. And it ignores so much that I have to believe this was posted to /. just to generate page hits on the article.

      The article takes the idea that a human flight to Mars has to follow some model that hasn't seriously been considered for nearly a decade. The all-in-one, carry-our-own-fuel model that got us to the moon cannot be applied to Mars. The author is right in that. But nowhere does the article mention the possibility of sending unmanned flights out first [google.com] to land and prepare a site for later human exploration. If we can send our smart robots [marstoday.com] there to create a habitat and refine fuel on the surface of Mars, most of the problems mentioned in the article disappear.

      I find it ironic that the article mentions Moore's Law and the growth of human knowledge, then does not think to apply any creative thinking to the problem, just a tired old story about how difficult and expensive it would be to launch the all-in-one type of craft that got us to the Moon. Did the author not think we could use some of that processing power and knowledge to come up with new solutions using tried and tested technologies?

      • I'm pretty sure "carry our own fuel" is fine - but you plan for fuel boosts along the way like a giant video game. It's all about staging. The docking tech is a little weird but it has to be "relatively easy" to make the docking interface. Then you launch up a bunch of fuel cargo ships and park them all in orbit. Once you think you have enough, you string them all out in a row at intervals. Then you just 1-UP your way to Mars.

        Bonuses for multiplexing the types of energy - part solar, part stored fuel, debr

      • by hedwards (940851)

        TFA isn't talking about interstellar flight. It's talking about a human flight to Mars. And it ignores so much that I have to believe this was posted to /. just to generate page hits on the article.

        Well, the jokes on them because we don't RTFA around here.

    • by ShadyG (197269)
      What's the point of a scale, when there's no gravity?
    • Just a hint. "Star travel" and "space colonization" aren't synonymous. We could, with some determination, build a colony on the moon, with existing technology. Or, if not a real colony, then at least a research station. As time passed, our technology could grow to better support that colony, and at the same time, the colony could grow more self sufficient.

      Now, star travel is a whole different ballgame. Compare colonizing our solar system, to a baby learning how to crawl, then to walk. The baby is NOT

  • Um, ok... (Score:5, Insightful)

    by pushing-robot (1037830) on Monday April 11, 2011 @08:02AM (#35780290)

    ...But that's the thing about current technologies: They inevitably insist on becoming obsolete technologies.

  • by webrunner (108849) on Monday April 11, 2011 @08:02AM (#35780298) Homepage Journal

    So basically something we haven't invented the technology for is impossible until the technology is invented.

    I'm so shocked.

  • by js3 (319268) on Monday April 11, 2011 @08:03AM (#35780300)

    wow really? Even a monkey could have figured that out.

  • Forget air travel. (Score:5, Insightful)

    by Issarlk (1429361) on Monday April 11, 2011 @08:04AM (#35780314)
    There is only so much power you can get out of a locomotive, and it's never gonna make one fly in the sky due to the considerable weight of a steam engine.
  • by wjousts (1529427) on Monday April 11, 2011 @08:04AM (#35780318)
    Great summary. All of one sentence that tells us nothing, not even what the source is. I really don't understand what Slashdot wants for a submission so I've mostly stopped bothering.
  • Errr... Chemistry? (Score:5, Insightful)

    by Warwick Allison (209388) on Monday April 11, 2011 @08:05AM (#35780326) Homepage

    Plenty of interstellar ship concepts propose nuclear power and are therefore outside the "titanic" power of mere chemistry.

  • by Anonymous Coward on Monday April 11, 2011 @08:07AM (#35780332)

    An Orion engine could get you to the stars in 40 years, Mars in a few weeks. A solar sail can accelerate you almost up to the speed of light and travel to the ends of the universe. It's politics and economics that are major barriers to space travel, not physics and chemistry.

    • But you see project Orion dates back to the 1960s and was never implemented so it doesn't count as "current technology". Space travel is only practical with past technology. Why does this situation remind me of the decline of the empire in the Foundation series?
      • Quite a lot of what is happening at the moment reminds me of the Foundation series or the decline of the Roman Empire - slowing technological advances, loss of interest in science, weakening governance.....

        Roman civilisation never disappeared entirely. The Eastern Roman lasted until after the Renaissance started.

    • by Chrisq (894406)
      Wow, my next car will be a Mitsubishi [wikipedia.org].
  • by Scholasticus (567646) on Monday April 11, 2011 @08:07AM (#35780334) Journal
    Remember, any kind of space travel was thought impossible at one time ... until the multi-stage rocket was invented. We need more creative thinking and less of this overly pessimistic nay-saying.
    • by DarkOx (621550) on Monday April 11, 2011 @09:10AM (#35781068) Journal

      There are plenty of ideas out there that probably can work. Most of the technology exists, and just needs to be assembled into a single project. Its not even beyond the realm of economic possibility to implement some of these plans they question is why?

      What is there on the moon or Mars to make it worth going there. Why should anyone want to live there? Don't say over population even if the population on earth continues to grow at the current rate somehow it will be along time before conditions here would be more cramped then they would be on space/moon/Mars base. Don't say resources its pretty evident that supporting one person on a space/moon/Mars base would take more resources from Earth that keeping that same person right here on Earth. The only reason to do it is for practice colonizing and for the investment required it probably makes more since to try and simulate things here on Terra.

      There are for the most part know ways to build and power a multi-generational ship There is lots uninterrupted solar power and other radiation out there to scavenge for your day to day needs, and you could bring enough nuclear fuel from Earth to propel the craft. The trouble is where do want to go. Oh and your going to live the rest of your life in this box, you will never see the destination, nor will your children, their children, their children's children, and likely ten more generations after that. That is if you pick someplace nearby and NOTHING goes wrong. Who wants to take that risk and for what?

  • by kikito (971480) on Monday April 11, 2011 @08:11AM (#35780378) Homepage

    According to Physics and Chemistry self-propelled chariots are impossible STOP self-propelled flying vehicles are a fool's errand STOP Internet is that little net inside some pieces of underwear STOP.

  • Huh? (Score:2, Insightful)

    by Anonymous Coward

    Premise: You cannot go into deep space because chemical rockets have insufficient energy to get you there.

    Recommendation: Therefore you should only send people into space one way.

    Real purpose of article: For the Author to brag that he is wealthy enough to book a flight on Virgin Galactic.

  • Folks, save yourself some time and skip reading the article. It does not mention carbon freeze, or mini black hole based ionic propulsion, jumping into hyperspace, worm holes, tachyon particles, not even those ray blasting cannons that curiously recoil like a second world was naval gun, phasors that could be set to stun, or transporters.

    OK, OK I concede that stuff like flue powder, aparating and portals seem improbable, just to show that I am not unreasonable, and am considering only proven viable technologies.

  • That article is a joke. It doesn't even take into consideration very public recent development like http://www.fastcompany.com/1744745/russia-us-plan-a-nuclear-powered-space-rocket-should-we-worry [fastcompany.com]

    Plus Russia announced it created a nuclear reactor that was capable of being transported and used in a rocket some months ago. Plus the sun is an infinite source of energy when you are in space, which should make whatever fuel you are going to use last longer.

  • by Chrisq (894406) on Monday April 11, 2011 @08:13AM (#35780394)
    Its hard to tell because the article contains no facts or assumptions, but I think it is working on the assumption that the Mars space craft and all fuel will have to be lifted from the earth in one go. If we assemble the craft in earth orbit then fuel it in multiple trips the energy requirements to get it to Mars orbit will be much lower. At that point it can again use a "lander" vehicle to take the astronauts and equipment to the surface, a lot of which can be left behind for the return trip (as was done with the moonshots).
  • by bmo (77928) on Monday April 11, 2011 @08:16AM (#35780412)

    I mean, really, in 1969 we magically had all the tech to get to the Moon and back, it's not like we had to invent anything. /sarcasm

    People get paid to write this crap?

    --
    BMO

  • by tropgeek (1945298) on Monday April 11, 2011 @08:20AM (#35780466)
    NOM NOM, Nothing wakes you up in the morning, like crushing the hope of science dreamers everywhere.
    To quote Einstein: "Whoever undertakes to set himself up as judge in the field of truth and knowledge is shipwrecked by the laughter of the Gods."
  • by Epeeist (2682) on Monday April 11, 2011 @08:21AM (#35780478) Homepage

    Of all objects, the planets are those which appear to us under the least varied aspect. We see how we may determine their forms, their distances, their bulk, and their motions, but we can never known anything of their chemical or mineralogical structure; and, much less, that of organized beings living on their surface

    Said by Comte in 1842. There is a difference between unknown and unknowable.

  • by QuietLagoon (813062) on Monday April 11, 2011 @08:23AM (#35780498)
    Forget Space Travel, It's Just a Dream ... at least with current technologies

    .
    Isn't that what dreams are about? Inventing new technologies to do in the future what is not possible now?

  • by wisebabo (638845) on Monday April 11, 2011 @08:25AM (#35780518) Journal

    The quick answer (which I'm sure many posters have already said) is don't involve chemistry; use nuclear engines, or ion engines or solar sails or magnetic balloons. There is a lot more energy (million fold) in nuclear bonds that you can get from fission reactors or by using the fusion furnace at the center of our solar system.

    That said, I haven't really heard of good answers to long time LIVING (not just survival) outside of the earth's magnetic field/shield and without one-gee acceleration keeping our bodies reasonably fit. Want to COLONIZE Mars and not just go there for a flags and footprints mission? Well we have no idea if the 1/3 G gravity will keep the astronaut's bones from becoming brittle. Who knows if women can give birth to healthy infants in such an environment or even if we can grow crops there! (I really thought they shouldn't have cancelled the centrifuge that was to be a part of the ISS. Hopefully, if the Falcon 9 works out, it'll be cheap enough to add it later).

    I'm actually a little more optimistic about the long term ability of humanity to spread throughout the cosmos. In just a few decades, hopefully we'll know enough about our biology to really tinker with it. Getting rid of susceptibility to low gravity is a given of course but how about a little radiation hardening? (Some organisms can tolerate millions of times as much radiation as we can). Perhaps later we could learn to deal with decompression sicknesses (like marine mammals) so spacesuit design could become a lot simpler. Maybe we could learn the tricks of hibernation from bears and squirrels so long space flights wouldn't consume so many resources (and be so boring!).

    We might end up not quite the same as homo sapiens. Call it man plus. (For INTERSTELLAR travel, we'll need some pretty spectacular physics or some pretty radical reengineering of ourselves. How 'bout brains in boxes? Or better yet, just software running on commodity hardware?).

    But it might take awhile.

  • by John Hasler (414242) on Monday April 11, 2011 @08:43AM (#35780684) Homepage

    ...because chemistry is just applied physics.

  • by tekrat (242117) on Monday April 11, 2011 @08:44AM (#35780698) Homepage Journal

    I'd like to remind people that scientists as recently as the 1940's said that flight faster than the speed of sound was impossible. That flight beyond the atmosphere was impossible.

    Before that, they said that flight was impossible, and anyone travelling faster than 35mph would kill the occupant.

    Just ask any top-fuel dragster jockey about what's impossible. Engineers were swearing up and down that they had reached the limit of what internal combustion engines could do in the 60's, but the guys building the dragsters kept proving them wrong.

    I'm sure as far back as cavemen, there was a 'scientist' that was positive that man-made fire was impossible.

    The point is: Sooner or later, anyone that says that anything is impossible is proven wrong. Don't be a naysayer, be that someone that changes the world. Find the way to achieve the impossible.

  • by bradley13 (1118935) on Monday April 11, 2011 @08:48AM (#35780766) Homepage

    Reading Cosmos for science is like reading the National Enquirer for news. TFA presents a false dichotomy: it takes lots of energy to move stuff between space and the surface of the earth. Therefore space travel is impractical. Whats wrong with this?

    • First, one you establish a real, mostly self-sufficient presence in space, there is no moving stuff back-and-forth to earth. Raw materials are abundant, and getting in and out of weaker gravity wells (like the moon) is no problem.
    • Second, getting back into the earth's gravity well takes essentially no energy at all - only control.
    • Lastly, who says that "chemistry" is the only energy source. Nuclear power offers immensely higher energy densities. Like nuclear power for electricity, nuclear propulsion may well be safer than the chemical alternatives [nextbigfuture.com].

    Space travel takes a huge initial investment to establish a real infrastructure, including mining and manufacturing. After that, it's all gravy.

  • by scharkalvin (72228) on Monday April 11, 2011 @09:04AM (#35780996) Homepage

    It should be possible to get to Mars and back, however it won't be cheap. It would probably take the equivalent of as many Saturn V rockets as were ever launched to put enough material into Mars obit for ONE mission. This would include leaving in orbit the return rocket, and sending to the surface a return to obit craft (empty and landed by remote control or by computer). Then sending down the crew on a landing only craft and yet other landing craft with supplies. The crew wouldn't be able to take much back in samples, just dust perhaps. What would be sent back would be digitized data and photos.

    Mars is the only planet in our solar system that we COULD visit. There are also the asteroids and here at least the gravity well is shallow enough that a return trip is on par with the visit to the moon. The author of the article is correct in the degree of difficulty of a Mars trip compared to going to the moon. I can't imagine it being worth while to send astronauts to explore Mars because we have done very well using robots. But impossible? No, just very expensive, risky, and not worth the price considering what other exploration could be done with the money.

  • by memyselfandeye (1849868) on Monday April 11, 2011 @09:16AM (#35781146)

    This summary is such FUD, and the article is nearly so. The author is a Medical Doctor, and if Doctor's had their say humans would have never gone to low orbit in the first place! Physics tells us Moore's Law is not a Law, but rather an idiom that expresses human ingenuity in the field of electronics. Moore's Law does not say transistors can get indefinitely small, it says people can build cheaper and cheaper transistors on larger and larger circuits. I can double the payload capacity of LEO vehicles tomorrow. Give me a 747 at 40,000ft and a rocket, and I'll put up twice the cargo for half the cost of a conventional rocket launched from sea level. Physics says I can do that. I'm not sure what point the author is trying to make with Moore's law, but the comparison between human ingenuity in spaceflight and electronics, and the laws of nature, is mute. Just because it hasn't happened, doesn't mean it is impossible.

    Mistaking a large Keynesian space program that explicitly prohibits large leaps in engineering is a common mistake people make when it comes to the impossibilities of space travel. The space station was built, in part, because NASA and Congress didn't know what to do with the large 'space truck.' What do you do when you've got giant reusable vehicles with a HUGE cargo hold? Apparently, you build a space station with it!

    We have been living continuously in low orbit for decades without a single fatality. The only Americans who have ever died in space died coming and going, but once you’re up there it has been statistically much safer. One would think moving a group of humans 60-100M km over 9-15 months would be quite possible. We've been living in hostile environments here on Earth for almost a century now with submarines, where a person can't exactly go out for a walk 600ft under water. And in the last 40 years or so, the crews of big submarines have continuously lived underwater for months on end. We know how live in enclosed environments for long periods. If 200 men can go months on end without killing each other, I think a dozen over the hill astronauts might be able to do the same.

    The hard part of going to Mars is leaving Earth and then landing safely, landing being the most difficult but NOT impossible feat. Physics tells us that all the elements needed to create breathable air, fuel, water and return fuel for indefinite exploration of Mars can be found on Mars. Physics tells us the power needed to make these compounds can be made on Mars as well. All with ‘current’ technology despite the "low grade" resources, as claimed by the author!

    Physics tells us all the hazards of interplanetary travel can be reduced or mitigated. Physics tells us radiation can be reduced with shielding, as can micro meteorite impact dangers.

    If you want to really learn what Physics says we Can and Can't do, I'd suggest checking out on of the all time greatest book on the subject, "Spacetime Physics" [amazon.com] by Taylor and Wheeler from you public library.

    You think that's science fiction? How about this. Physics tells us it's possible to put all the DNA of earth on a tiny little probe the size of a dime, complete with tiny robots, that can be quickly accelerated to large fractions of c and travel between stars in decades. These probes can smash into planets and build life for us. Why send our descendants in large cumbersome bodies when you can send the information needed to create them. The technology to do this doesn't exist yet, but we are developing it Now. And physics doesn't say anything here is impossible.

  • by brainzach (2032950) on Monday April 11, 2011 @09:42AM (#35781430)

    This article is dead on. There hasn't been major progress in making rockets more efficient since the 1960's because the basics of chemistry and physics.

    If we spend hundreds of billions of dollars, we might be able to send a select few men to Mars, but it would be like the lunar landings in the past. It will be a one time event then people will realize that it is a waste of money and resources to do it again.

    The current technology won't work to make space travel apart of our daily lives. It won't support advances like suborbital commercial airplanes, space tourism, colonization, or mining the Moon and comets.

    There has to be major advances in technology to make space travel that are order of magnitudes more efficient before any of these dreams becomes a reality. These technologies are mostly theoretical and probably won't be available during our lifetimes. Until then, we will just continue to spend billions to send a select few into space like we have been doing since the 60's.

  • by rgbatduke (1231380) <rgb@@@phy...duke...edu> on Monday April 11, 2011 @10:50AM (#35782242) Homepage
    The article is IMO incorrect because it concentrates only on chemical reaction motors. There, of course, their answer is correct. But that isn't the only way to move around in the solar system. One question I ask my intro physics students is to contemplate the light sail as a means of propulsion. To do this, one simply works out the balance between solar gravity and radiation pressure to determine how thin a sail has to be in order to directly support its own weight (and the answer, of course, is "very, very thin":-).

    However, this isn't the end of the problem. I then ask them how much force is required to remain in orbit. The answer (neglecting the tiny amount of atmospheric drag in near earth orbits and e.g. tides) is "none" -- orbit is free fall where the centripetal force required to bend the trajectory into a circle is provided by gravity. A feasible light sail can be built that can exert enough force via reflected sunlight to provide an acceleration of (say) a millimeter per second squared for it and its payload in a scalable way, or even more (with sub-micron sail designs). Not much, but given 86400 seconds per day, that is as much as 86 m/sec (or nearly 200 mph) delta-vee per day, for free, every day. One can add a kilometer per second every two weeks, and that's enough to reach anywhere in the solar system in time, especially if you amplify it with a gravitational slingshot off of (say) the moon.

    Sure, it would take too long to move humans around, but that isn't the challenge -- we can move humans around now at large but not impossibly large expense, at least as far as Mars or Jupiter or Venus, even using chemical rockets although there are probably better solutions than chemistry in the long run. The only really hard part is getting things into low Earth orbit -- once there you are "halfway to anywhere" as Heinlein liked to put it (virial theorem) and light sails mean getting the rest of the way is scalably/reusably "free" if you don't care about taking order of years to get there. Light sails would let us move everything that isn't a human to e.g. the Moon or Mars to set up a more or less permanent base and maintain a long-term line of supply. Who cares if your food and water take years to get there, as long as they get there cheaply enough?

    A second thing that would change the economics (aside from either new physics or radically new ideas, e.g. a fusion-driven relativistic ion drive that again uses free or abundant energy to eke the maximum possible reaction thrust out of reaction mass by accelerating it to close to c where it has a lot of momentum per particle) would be to build light-sail driven robots to mine the asteroid belt for raw materials so that we wouldn't have to lift e.g. steel, nickel, and possibly even water up to Earth orbit. Those robots could equally well deliver mass back to Earth at e.g. the Earth-Moon Lagrange points and allow extended permanent habitats to be constructed there that are a light sail away from anywhere.

    The only thing preventing us from settling the solar system is time and the will to do it -- we could do it now for a tiny fraction of what our military forces cost us every year. Sure, it would be good to find solutions to the time problem -- it's easy and cheap if we don't mind transit times of decades, so perhaps working on various forms of suspended animation would permit humans to take the light sail route as well as their food, clothing, water, air, and construction materials. A Lagrange point colony with a decades-long, robot-filled pipeline of raw materials could create a steady flow of humans moving out to permanent colonies throughout the solar system on a timescale of centuries.

    Or, as some clever human posted yesterday, perhaps a flying saucer really did crash at Roswell. If so, then interstellar travel is indeed feasible somehow, which means that there is likely a solution waiting in new physics. If the federal government would just 'fess up
  • by plopez (54068) on Monday April 11, 2011 @11:57AM (#35783056) Journal

    Go to more of a "faith based" space travel, not encumbered by "Science".

  • In breaking news from 150 years ago: "The clash of two titans — physics and chemistry — are major barriers to human heavier than air flight, and may well make it impossible ... at least with current technologies."

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