Slashdot Mirror
Forget Space Travel, It's Just a Dream
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."
If it is impossible in the real world, why not solve it with math?
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)
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.
SJW: Someone who has run out of real oppression, and has to fake it.
...But that's the thing about current technologies: They inevitably insist on becoming obsolete technologies.
How can I believe you when you tell me what I don't want to hear?
So basically something we haven't invented the technology for is impossible until the technology is invented.
I'm so shocked.
ADVENTURERS! - ANTIHERO FOR HIRE - CARDMASTER CONFLICT
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.
Plenty of interstellar ship concepts propose nuclear power and are therefore outside the "titanic" power of mere chemistry.
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.
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.
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."
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.
TAANSTAFL
Robert A. Heinlein
Everything costs. Even if you do away with all of the world's currency, things will still cost. You will merely be stating the costs in another manner, ie, "manhours", or "credits", or - whatever.
"Windows is like the faint smell of piss in a subway: it's there, and there's nothing you can do about it." - Charlie Br
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
Puteulanus fenestra mortis
http://en.wikipedia.org/wiki/Mars_Direct
http://en.wikipedia.org/wiki/Mars_for_Less
Or try this, if you are more partial to video.
And then... there's the colonization option.
Best part is, no unobtainium needed. Everything is based on current, tried technologies already in use.
Mit der Dummheit kämpfen Götter selbst vergebens
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.
Yes, the GPP's numbers are definitely off. We had astronauts spend four days each way on the moon missions, so it isn't quite as bad as that. I do recall reading though that a trip to the outer planets of our solar system with our current technology would leave the astronaut quite damaged by radiation. This is pretty old news, BTW, and TFS reads like some sci-fi fan just got his bubble popped after learning a few facts. Kinda cute, but on the front page of slashdot it just gives all the "/. == digg" complainers more ammunition. As if they needed it...
Caveat Utilitor
Yes, of course you're entirely correct; whole body exposure to 10 Sv is lethal. Your parent is way, way off.
From your parent's post's own link - "Actual radiation dose measurements of Apollo crews measured by onboard dosimetry were, on average, 12 mSv." That's for the entire two way flight, not per hour.
He may have been talking about the calculated dose of 6 Sv in space at Earth's distance from the Sun if a major solar particle event occurred. That's 6 Sv TO THE SKIN PER EVENT, not per hour, or 0.9 Sv to the bone marrow. Or intersecting the path of a coronal mass ejection or solar flare, you could take 10's of Sv if floating naked in space, but fractions of 1 Sv inside a spacecraft. Cosmic ray exposure could be between 0.3 to 1 Sv per YEAR. While all these considerations are very serious, they are far from the cataclysmic levels portrayed by the poster.
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" 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.