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."
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
Plenty of interstellar ship concepts propose nuclear power and are therefore outside the "titanic" power of mere chemistry.
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.
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.
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
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:
*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?
..my sister, who got the Donnie Darko numbers tattooed on her arm so she looks like shes making fun of Holocaust victims
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.
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?
..my sister, who got the Donnie Darko numbers tattooed on her arm so she looks like shes making fun of Holocaust victims