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#1 Re: Planetary transportation » Trains on Mars - Could a rail system provide martian need » 2012-06-27 22:56:35

Actually, I think rail gets built fairly early on Mars - at least just around the main base to start. Some other thoughts...

Railroads, I think, would mostly be a problem because of steel consumption. Construction of a railroad would actually be cheaper and faster per mile, in terms of work, than on Earth.

* You don't need traditional ballast, at least until you start warming Mars up. Just use water - the ice would be fantastically hard and strong under Mars conditions, and you could melt the top to a very fine level. Sink the concrete ties in it and attach the rails

* in the low gravity, bridging and viaducts would be simpler to build than on Earth, as well.

* Steel wheels are easier than rubber wheels on Mars.

An option which might be profitably discussed would be an ice plateway - a flattened ice road with two grooves for steel wheels, rather than two rails. While this would have severe issues in terms of maximum speed, we're not terribly concerned with maximum speed, are we? And such roads would be fairly inexpensive to build, and could be upgraded to rail as steel production allowed.

#2 Not So Free Chat » Kerbal Space Program » 2012-06-24 12:55:25

Trebuchet
Replies: 3

I suppose the first thing I should say is... I'm back.

The second thing is the topic of the post. Anyone else played this? It's a fun little space simulator, where you put together rockets and fly into space - orbiting, landing on moons, etc. It's still in development, but they plan to have a whole solar system set up eventually, rather than the one planet/one moon (two if you've pre-ordered the full version) they have right now.

I've managed landings on both moons as well as the grand tour (hitting both moons in one mission, then returning) and have been practicing orbital rendezvous maneuvers, which are more difficult, by far, than landing on the moons.

#3 Re: Interplanetary transportation » Liquid Aluminum Fueled Rocket » 2008-03-08 12:28:20

What's generating the thrust, anyways? As you pointed out, the outputs are solid. High temperature oxygen exhaust?

Edit: aluminum wire 'yarn balls', GCN, loosely wound enough to provide lots of surface area.

#4 Re: Interplanetary transportation » Liquid Aluminum Fueled Rocket » 2008-03-08 10:53:04

Why not build it hybrid? Make a strong pressure chamber, put a grate in the bottom to let hot gases out but not fuel, and fill the chamber with aluminum balls. Feed in LOX at a safe rate.

#5 Re: Not So Free Chat » Books You've Just Read? » 2007-01-07 21:55:55

Rxke: If you liked Stephenson's Snow Crash, then read his Cryptonomicon and be amazed.

#6 Re: Intelligent Alien Life » Why is the Universe silent? » 2007-01-07 21:40:48

I favor a different set ofexplanations: one is that the galaxy is empty because everyone else has already left. By the time anybody is capable of building giant interstellar spacecraft, they're capable of building O'Neill colonies at home. By the time their home star is crowded, they're probably capable of creating their own entire f'ckn universe. So there is a high possibility that intelligent species are 'just passing through'.

Another is that the galaxy is filled with two sorts of species: the silent and the dead.

#7 Re: Intelligent Alien Life » an inference that there are very few indeed e.t.'s out there » 2006-02-20 19:50:12

Perhaps a better way to demonstrate the silliness of using this line of argument to advance a few-ET's argument is the following analogy: would you fly overseas, just to talk to a cat?

If the aliens are so hellbent on talking to people, they probably acquired some DNA samples millenia ago and have been raising pet humans to be their inferior-intelligence sidekicks/companions. big_smile

#8 Re: Unmanned probes » Rat Flyby » 2006-02-19 02:50:12

Well, for a control, we could build a second rat carrier and just leave it in LEO, I suppose.

As for the flare shelter... rats are trainable. We could build a radiation shelter with a treat dispenser with doors that can be closed (to prevent rats from escaping). On earth, train the rats to run in the shelter when a buzzer sounds. In space, sound the buzzer every so often (and dispense treats) to reinforce the learning.

If you have a flare, sound the buzzer, then close the shelter doors once the last rat is in.

As for keeping a stable population: easy enough. Either choose all rats of one gender, or seperate the two genders of rat on the capsule. If breeding rats is on the agenda, you can put RFID tags on your first-generation rats and build a chamber which is connected to each chamber and selectively opens its doors for the RFID #'s mission control sends over. Or perhaps some other trick.

Just segregating male/female rats in different parts of the capsule seems easiest, though.

As for cleaning up after the rats... well, that's where some serious hard thought needs to be put in. I have no doubt it can be done; perhaps the floors for the rats are wire mesh and some sort of automated pooper-scooper runs underneath. The engineers can earn some money there.

#9 Re: Unmanned probes » Rat Flyby » 2006-02-17 22:06:12

Or to put it another way, people object to Mars missions on the basis of radiation en-route (I just saw a magazine article complaining about it), so why not try to quantify the effects of radiation on a Mars mission?

Basically, what I suggest is to build an automated rat habitat, stick it in a pod, and fire it on a Mars flyby. Any airtight can will do, so long as we outfit it with enough life support for a bunch of rats and guinea pigs. It zooms by Mars and returns to earth orbit, where the rats are either returned by some space vehicle, or are dragged to the ISS for an orbital checkup. We get a good biology experiment on the radiation exposure en route to Mars and back, and it probably would cost about as much as the 'cheaper-better-faster' probes we fired off a few years back, since it's not carrying anything other than rats, their associated life support, and essential spacecraft parts.

#10 Re: Interplanetary transportation » Thermal Protection » 2006-02-10 22:26:51

Kinda hard on the cork trees to use that for any sort of mass-use space travel.

Re-entry really is *the* problem for reuseable SSTO craft. The mass fraction is doable if you don't need to lug around all that cooling. Here's an idea: an aerogel heat shield protected on takeoffs by a disposable shroud. They have new carbon aerogels... trying to find the melting point, it should be lower than straight carbon, but not by much. Or perhaps... nevermind, this idea has already been looked at. NASA's Jet Propulsion Laboratory is looking at non-ablative aeroshells that is sort of a sandhich of carbon-carbon, silicon carbide, and carbon aerogels. No ablation, no problem - the materials have melting points from hell and the aerogel insulated very well to boot.

#11 Re: Interplanetary transportation » Warp Drive » 2006-02-10 20:44:01

It's probably just a cheap experiment that can be done without much overhead.

As for engines, though, "the best" depends on a whole host of factors. Our main problem isn't ISP - we got plenty of high-ISP engines - but sheer, raw thrust. Apart from the three listed up above (nuclear saltwater, gas-core nuclear, and VASIMIR) there is also the Longshot engine (inertial fusion powered by fission reactor, no good for anything other than cargo, but what range! Sucker can fly to nearby stars in a century or so) or Orion (paging Dr. Strangelove...)

Sometimes I think the best solution is simply to build the damn space elevator and build high-ISP, low-medium thrust craft in orbit, where you don't need to worry about fighting the earth's immense gravity. Build them big, like the size of a small space station, slowly boost them into a free-return orbit with ion engines or whatever, and then just shuttle people to and from those cycling craft with cheap expendable chemical stages. Forget high speed Buck Rogers stuff, because, unless you're in a tearing hurry, it's not how much thrust you can get out of the engine, it's how much thrust you can get out of a dollar.

#12 Re: Intelligent Alien Life » Dr Steven Greer & The Disclosure Project - The UFO Phenomenon » 2006-01-07 23:41:41

*kicking a dead thread, but...*

Somehow, Cobra's idea of independent alien nation-states (or equivalent) has always struck me as the most plausible scenario. To a unified, impossibly advanced alien species, a bunch of fanatic territorial intelligent primates has no redeeming use other than entertainment value, and thus would probaby be avoided like the plague except for the aliens' equivalent of National Geographic. ("Tonight, on Galactic Explorer, angry monkeys with nukes!")

On the other hand, independent alien nation states could always use some new members of the Coalition of the Willing, *especially* if they are fanatical-tending territorial killer apes.

Now, getting away from woo-woo UFO stuff... Personally, I wouldn't find it surprising if we were being monitored by aliens in a low-key means. Low-key, here, means a quiet, extremely long-lifetime interstellar probe which get sent to any star with a planet that 'looks right', has detectable signs of life via spectrum of its atmosphere, etc. Send them out, do a preliminary survey with a dropped probe or rover on the surface, then put them in some sort of semi-hibernating state unless they pick up radio signals or whatever. An alien rover dropped on Earth 12000 years ago, or whatever, is rather unlikely to be found. Heck, the aliens who sent it might have wiped themselves out in a war in the intervening time period. But I figure there's a reasonable probability of aliens having made at least an attempt at monitoring our planet.

#13 Re: Interplanetary transportation » Warp Drive » 2006-01-05 22:42:25

Same here, but as you point out - it's cheap. Go ahead and buy that lotto ticket with the spare change from your burger.

#14 Re: Intelligent Alien Life » The Extraterrestrial Pope - Religion and aliens, how will they mix? » 2006-01-05 21:58:09

Personally, I think that the advance of science leads to an increase in atheism and agnosticism. Therefore, advanced civilizations will probably be less dominated by big organized religions than ours is.

Actually, religious feeling comes and goes in intensity, without any seeming bearing on what science is doing at any given time. Emperor Julian II the Apostate preferred then-current philosophy and science to religion, there was an enthusiastic embrace of irreligiousness by the French Revolutionaries, etc. There's always a new Great Awakening that sweeps religion back in after a while. I think that Neal Stephenson's explanation for the intermittent popularity is probably right - an intelligent person will look at how people approach religion, conclude that 90% is crap, and erroneously forget that Sturgeon's Law applies to all human endeavors. That other 10% though, it's pretty damn important.

#15 Re: Interplanetary transportation » Warp Drive » 2006-01-05 21:01:51

http://news.scotsman.com/scitech.cfm?id=16902006

If it does work, I guess grandfather paradoxes will just have to be lived with. The sun doesn't revolve around the earth, after all, and life didn't come to a crashing halt when the apparently logical nature of things was shaken up in the Renaissance.

Of course, it's more likely that the experiment will fail. However, if it succeeded, it would mean that the Pluto Express's speed record is very short lived. Probes to the stars, anybody? Of course, if FTL is possible, this *really* raises big questions about the Fermi Paradox, and puts a new wrinkle on them. If FTL flight is possible, why aren't *we* already everywhere? ^_^

#16 Re: Not So Free Chat » Current Gasoline/Petrol Price$ » 2005-09-02 07:41:15

The just-finished survey on oil deposits in Colorado, Wyoming, and Utah revealed that the reserve there is *three times Saudi Arabia's original reserve*.

Wow. That's fricking huge.

I believe the 'oil economy' will be in good shape for some time to come, given that bit of news.

EDIT: The range quoted was 500 billion barrels to 1.1 trillion barrels. Saudi Arabia's reserve is something like 283 billion barrels. Still, that's a LOT of oil.

#17 Re: Not So Free Chat » Current Gasoline/Petrol Price$ » 2005-09-01 06:53:13

This would be where people start bothering their companies for the ability to telecommute, where it's feasible. I know I have.

#18 Re: Not So Free Chat » Katrina and New Orleans » 2005-08-31 22:58:51

Correct, and if you noticed, one of the other ideas I had was that the government pre-distribute evacuation plans in newsletters or fliers, telling people that if evacuation A is called people in this zip code should head up road X to locations Y and Z. Not everyone will follow this plan (because they have relatives somewhere that they plan to ride the storm out with, or whatever) but the percentage of people doing their own thing will probably cancel each other out, more or less.

#19 Re: Not So Free Chat » Katrina and New Orleans » 2005-08-31 22:33:31

Coca-Cola once had a trial run where they had floating soda prices on their machines determined by a thermometer. They called it off because of monumental negative goodwill their company racked up. That and vandalism of the machines. But your umbrella situation is comparatively tame.

As for calling my idea a glorified food stamp, I believe you're missing the point: I'm not arguing that it isn't government funds, I'm arguing the specific spirit and intent behind them that differentiate the two. The disaster card is essentially a debit card charged to FEMA and is a convenience for simplifying stuff that the government would end up doing anyways. The government could and IMHO should handle the problem of people unable to afford food in a different way... although this isn't the time or place to discuss that particular political tar baby.

The main point of that FEMA card, though, is to get people *out* of the disaster area. If they've gone X miles and the hotels are full, charge up another tank of gas and keep going. It allows them to *instantly* disburse aid at the press of a button the second a state of emergency is declared. If I were in charge of implementing it, I'd build it into state drivers' licenses somehow... something like that.

#20 Re: Not So Free Chat » Katrina and New Orleans » 2005-08-31 21:42:30

Yeah, and credit card food stamps is so conservative

Not food stamps. These cards would decentralize aid relief and disburse it to the hundreds of thousands of victims of a catastrophe who are the men and women on the spot making decisions to best save their lives and the lives of their families. It's spending less money smarter by bypassing the Big Monster Bureaucracy. What could be more conservative than that?

Anyways, do you have anything constructive to offer in terms of ideas, or are you content with being the self-appointed Conservative Thought Police today, just for a change of pace?

#21 Re: Not So Free Chat » Katrina and New Orleans » 2005-08-31 21:10:39

Actually, I was thinking more of having these cards pay for gasoline and hotel rooms for people fleeing the storms, but yeah, they'll work wonders for people on the fringy regions too.

The phone lines won't be a problem with WiMax and voice-over-IP. I imagine that in a couple years setting up temporary phone service will be much quicker.

Believe it or not, small hurricanes actually tend to help local economies. They create construction booms. My (foolish? brilliant? ruthless?) brother is already sneaking around north of Lake Pontchartrain to gauge the local business potential for his contracting business. Many more will follow.

This would be the broken window fallacy. The money required to rebuild is all lost opportunity costs.

#22 Re: Not So Free Chat » Katrina and New Orleans » 2005-08-31 17:48:26

IMHO valid evacuation plans should be made - realistic plans able to actually evacuate an urban area within a set time period, complete with neccessary improvements to infrastructure to effect such a plan. Perhaps portable train stops - most urban areas have track running through them, and such emergency evacuation centers could efficiently get people out of harm's way. FEMA needs to network cities together so that they can assign people to different cities, and municipalities should share evacuation plans with citizens. A pre-printed flyer mailed to neighborhoods which listed suggested evacuation plans - say, Plan A for a weak storm making a direct hit, Plan B for a sidewipe to the west, Plan C for a sideswipe to the east, and Plan D for a direct hit from a monster hurricane, which advises people to either sit tight or go a certain distance to suggested destinations, would be a great help.

Another interesting idea would be to somehow get Visa or Mastercard on board and come up with special 'emergency credit cards' which could only purchase certain goods and services up to a certain limit per card when the government declared an emergency in an area. This would limit the number of people who elect to stay behind for money reasons, although fraud would probably be a show-stopper, which is bad, because that would greatly simplify the accounting for disaster relief - aid could be directly distributed to victims without much in the way of middlemen.

#23 Re: Martian Politics and Economy » "Agreement" on Mars » 2005-08-31 07:42:09

The point could be made that getting away from jackasses IS for the betterment of their souls, Cobra. Or their sanity, at least.

As for home-grown Martian oppressors, the field's wide open - what would Earth be able to do about a tinpot dictator on Mars, invade?

#24 Re: Science, Technology, and Astronomy » Space Ring to Stop Global Warming? » 2005-08-31 01:33:23

What could be done is float giant white rafts - a foam ring with a shiny white reflective plastic sheet in the middle - in the ocean. Anchor them out in the middle of the ocean somewhere - most of the life is near the shore. Increasing the Earth's albedo by a percent or two is probably the cheapest way to cool off.

#25 Re: Not So Free Chat » Katrina and New Orleans » 2005-08-31 01:26:55

Actually, the strength and ferocity of hurricanes relies on long-term cycles in the Atlantic; it has nothing to do with global warming. There were lots of strong hurricanes in the 50's-60's and in the 30's too.

As for France, as far as I can tell the storms were 'just' storms, not hurricanes. While the winds and rain are nothing to make light of, actual tropical hurricanes are like no other storms on earth.

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