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Old 08-12-2017, 04:55 PM
 
25,023 posts, read 12,512,629 times
Reputation: 12299

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Quote:
Originally Posted by rbohm View Post
we still need water for the astronauts, for drinking and bathing, and we need water for fueling hydrogen cells, and as i noted earlier, water make a great radiation shield. so we will still need to carry water with us, probably just not as much.
If we don't recycle water with near 100% efficiency, we may as well stay at home. Unless we go Orion (1960s nuclear-bomb-pushed Orion, not the capsule), in which case we can carry all the mass we want.

So I take it back about essentially having most of the Mars tech. The stuff we still need is rather boring, though - it's how to maintain a viable biosphere in isolation. Which crosses into - gasp! - environmental science, and that's not going to cut much ice with those who think "Big rockets!" when the word NASA is mentioned.

OTOH, if we can make a self-sustained environment (energy will be needed, obviously), we can go to a lot of interesting places. I still want to hit up the asteroids first. There's stuff there we want, and it's available at a much lower cost in delta-v.
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Old 08-12-2017, 05:01 PM
 
8,119 posts, read 6,151,887 times
Reputation: 2778
Quote:
Originally Posted by Crashj007 View Post
I'll see your "Twelve Monkeys" and raise you a gamma ray burst.
That would take the whole planet out.
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Old 08-12-2017, 05:33 PM
 
Location: Kansas/China
3,462 posts, read 1,556,351 times
Reputation: 2285
Quote:
Originally Posted by Dane_in_LA View Post
If we don't recycle water with near 100% efficiency, we may as well stay at home. Unless we go Orion (1960s nuclear-bomb-pushed Orion, not the capsule), in which case we can carry all the mass we want.

So I take it back about essentially having most of the Mars tech. The stuff we still need is rather boring, though - it's how to maintain a viable biosphere in isolation. Which crosses into - gasp! - environmental science, and that's not going to cut much ice with those who think "Big rockets!" when the word NASA is mentioned.

OTOH, if we can make a self-sustained environment (energy will be needed, obviously), we can go to a lot of interesting places. I still want to hit up the asteroids first. There's stuff there we want, and it's available at a much lower cost in delta-v.
Most travel outside the Earth gravity well will be provided by gravity itself. It takes 9 months to get from Earth to Mars using no fuel after leaving Earths gravity. That, imo, isn't very long. The Orion propulsion system would be worthwhile on longer missions, but we have good enough technology now propulsion wise for Mars. That's why SLS is using existing propulsion technology.

NASA is working on radiation shields as we speak, it's one of the top priorities to making space travel possible.

NASAs plan is fine. Developing the SLS system here at Earth and around the moon. Robotic trips to Mars in the 2020's to search for a landing location and pre-supply missions for future human missions. NASA isn't planning a human on Mars until the late 2030's. The current plan is humans will orbit Mars in 2033, and then return home without landing.

If SpaceX can keep on track with their Mars mission plans, we may see NASA adjust their plans to work with SpaceX and other companies.
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Old 08-13-2017, 09:49 AM
 
5,125 posts, read 2,639,450 times
Reputation: 1960
Like the saying goes no bucks ... no Buck Rodgers!
A radition shield could be as easy as a Tesla Coil in space generating a electromagnetic flux ... like the sailors of old finding the trade winds we know there are solar winds beconing us to explore and learn after all we come from star matter made by God . .
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Old 08-13-2017, 01:15 PM
 
Location: CT
3,369 posts, read 1,317,693 times
Reputation: 4346
Quote:
Originally Posted by WaldoKitty View Post
Not nearly fast enough. The population is unsustainable now.

And throughout much of the world, most of the growth is coming from the poor part of the planet, so wealth has little to do with it.
You're misunderstanding Urbanadventurer, wealth has everything to do with it, poor and impoverished societies procreate for survival, as they become more prosperous, large families become more of a financial liability hence the neutral or negative growth curve in first world countries. Is our current population unsustainable? IDK- do you mean feeding them? A lot has to do with geopolitical issues than capacity, by and large, most advanced societies are actually having problems with over abundance. From what I've studied, reduced biodiversity and energy would be the limiting factors for world population.
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Old 08-13-2017, 01:25 PM
 
7,425 posts, read 4,752,729 times
Reputation: 6138
Quote:
Originally Posted by Itinerantlocal View Post
This is so stupid, from the time frame of travel to space radiation its just a waste of money. The gov. could not take care of NOLA when it flooded. Now it wants to put someone on a planet that has no air or may not even have water? This is dumb folly.
Can you be more specific? I've liked some of the proposed missions.
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Old 08-13-2017, 01:45 PM
 
26,877 posts, read 20,200,581 times
Reputation: 15161
Quote:
Originally Posted by southwest88 View Post
Yah, just transporting humans or animals means you're carrying a lot of water - (humans are 65% oxygen, 10% hydrogen, & a similar range for animals, I assume). Sure, we'll carry extra water - reaction mass, drinking reserve, to run hydroponics, as fuel & etc. I'm not sure about radiation shield - if we use materials from the moon or asteroids to build the Mars ship, we might just use regolith with a backer of denser material, or electronic fields, to block ionizing radiation. It likely depends on safety margins for exposure to radiation, & the tradeoffs involved between enhanced regolith & whatever other options there are.

It also depends on the ship's engines - if we get to cheap fusion, mass may not matter. Otherwise, we'll try to reduce weight as much as possible.
Quote:
Originally Posted by WaldoKitty View Post
In terms of cheap atomic propulsion, we can do it now. But there is no will to do so.

See Project Orion.
Quote:
Originally Posted by Dane_in_LA View Post
If we don't recycle water with near 100% efficiency, we may as well stay at home. Unless we go Orion (1960s nuclear-bomb-pushed Orion, not the capsule), in which case we can carry all the mass we want.

So I take it back about essentially having most of the Mars tech. The stuff we still need is rather boring, though - it's how to maintain a viable biosphere in isolation. Which crosses into - gasp! - environmental science, and that's not going to cut much ice with those who think "Big rockets!" when the word NASA is mentioned.

OTOH, if we can make a self-sustained environment (energy will be needed, obviously), we can go to a lot of interesting places. I still want to hit up the asteroids first. There's stuff there we want, and it's available at a much lower cost in delta-v.
even in space with a warp driven star ship, mass will ALWAYS matter. are there problems we have to solve? sure, but that is how the technology is expanded. someone comes up with an idea on how to solve a problem.

also any settlement on mars will likely be underground, and let the mass of the planet block solar radiation. hydroponics and airponics will work nicely to grow the food we need to sustain a population on mars.

and much has been learned from biosphere ll, and much will be learned from the next such effort, that by the time we get to mars to colonize the planet, we should be ready for most anything that comes our way.

will this happen in our lifetimes? probably not. will we put a man on mars and bring him home safely in our lifetime? possibly, it depends on how much effort we are willing to put forth in the endeavor.
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Old 08-13-2017, 01:47 PM
 
Location: New Mexico
2,628 posts, read 931,604 times
Reputation: 2352
Default The stars my destination

Quote:
Originally Posted by Itinerantlocal View Post
This is so stupid, from the time frame of travel to space radiation its just a waste of money. The gov. could not take care of NOLA when it flooded. Now it wants to put someone on a planet that has no air or may not even have water? This is dumb folly.
Mars has an atmosphere, 95% of which is CO2 - & can be broken down into fuel or air - see https://en.wikipedia.org/wiki/Atmosp..._use_by_humans

"Potential for use by humans[edit]

"Main articles: In-situ resource utilization, Terraforming of Mars, and Colonization of Mars

"The atmosphere of Mars is a resource of known composition available at any landing site on Mars. It has been proposed that human exploration of Mars could use carbon dioxide (CO2) from the Martian atmosphere to make rocket fuel for the return mission. Mission studies that propose using the atmosphere in this way include the Mars Direct proposal of Robert Zubrin and the NASA Design reference mission study. Two major chemical pathways for use of the carbon dioxide are the Sabatier reaction, converting atmospheric carbon dioxide along with additional hydrogen (H2), to produce methane (CH4) and oxygen (O2), and electrolysis, using a zirconia solid oxide electrolyte to split the carbon dioxide into oxygen (O2) and carbon monoxide (CO).

(My emphasis - more @ the URL)

The air pressure is low, to be sure. Which probably means habitats, probably buried to avoid radiation & provide thermal barrier, & some protection against micrometeorites & etc. With a good energy source - or even concentrating solar - it should be possible to @ least provision initial exploratory/survey efforts.
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Old 08-13-2017, 01:56 PM
 
2,452 posts, read 982,968 times
Reputation: 2302
Going to Mars is not a stupid idea. Spending billions trying to kill one another is.

We have 6 billion + people on this planet. There are no new frontiers for us to expand to on this little ball of rock. The next frontier is OUT THERE, where we need to be. We can do it if we want to. Apparently no one gives a chit though.
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Old 08-13-2017, 03:03 PM
 
8,119 posts, read 6,151,887 times
Reputation: 2778
Quote:
Originally Posted by Scrat335 View Post
Going to Mars is not a stupid idea. Spending billions trying to kill one another is.

We have 6 billion + people on this planet. There are no new frontiers for us to expand to on this little ball of rock. The next frontier is OUT THERE, where we need to be. We can do it if we want to. Apparently no one gives a chit though.
When you can give us the speed needed then i am all for it pat.
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