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...was for nothing unless we go to the stars.
- Thread starter KoshN
- Start date
puzzle
Regular
Well, if they want the Moon as a venue, I have nothing against, but color me skeptical.
If technologies for habitation of space are being tested, it seems to make more sense to send robots to the Moon (possibly build a system for robots to hurl resources up from the Moon, like an electromagnetic gun capable of overcoming 16% of Earth gravity) and leave people to mostly inhabit movable ships/stations.
Why? Because landing in (and leaving from) the gravity well of the Moon at human-tolerable accelerations requires costly chemical rocket fuels. Human civilization has a terrible track record at producing those economically. All rockets currently capable of lift-off are essentially really fireworks, turning nearly all their energy to heat, and very little to directed movement.
Raw material however, can be hurled up from the Moon, perhaps not cheaply but efficiently and in quantity (and could be mined from asteroids even better). People will need a smooth ride, and those are terribly wasteful unless you travel with ion engines (and those are useless for liftoff). Besides, the damn Moon thing doesn't even appreciably spin so I think you can't build a "short" space elevator on it either.
Living on high Earth orbit or a Lagrange point of the Earth-Moon system, and learning to fetch resources from the Moon and build from them, sounds *much* more appealing in many senses, than squatting on the Moon.
They can't be thinking that we'll be able to inhabit a fraction of space if we stay depending on chemical rockets to land on high-gravity bodies, and chemical rockets to lift off. Those cost like hell. We'll never have widespread space travel if we keep depending on those.
But if they do want it, I guess they've thought about it. So I'm not opposed to trying, and while I'll watch their experiments with interest, I will watch developments in scramjets, beam-powered launch methods and space elevator tech with even more interest. Because those promise to get an appreciable mass out of Earth's gravity well economically, even if you have to transport it in small handfuls of a couple of tons.
If technologies for habitation of space are being tested, it seems to make more sense to send robots to the Moon (possibly build a system for robots to hurl resources up from the Moon, like an electromagnetic gun capable of overcoming 16% of Earth gravity) and leave people to mostly inhabit movable ships/stations.
Why? Because landing in (and leaving from) the gravity well of the Moon at human-tolerable accelerations requires costly chemical rocket fuels. Human civilization has a terrible track record at producing those economically. All rockets currently capable of lift-off are essentially really fireworks, turning nearly all their energy to heat, and very little to directed movement.
Raw material however, can be hurled up from the Moon, perhaps not cheaply but efficiently and in quantity (and could be mined from asteroids even better). People will need a smooth ride, and those are terribly wasteful unless you travel with ion engines (and those are useless for liftoff). Besides, the damn Moon thing doesn't even appreciably spin so I think you can't build a "short" space elevator on it either.
Living on high Earth orbit or a Lagrange point of the Earth-Moon system, and learning to fetch resources from the Moon and build from them, sounds *much* more appealing in many senses, than squatting on the Moon.
They can't be thinking that we'll be able to inhabit a fraction of space if we stay depending on chemical rockets to land on high-gravity bodies, and chemical rockets to lift off. Those cost like hell. We'll never have widespread space travel if we keep depending on those.
But if they do want it, I guess they've thought about it. So I'm not opposed to trying, and while I'll watch their experiments with interest, I will watch developments in scramjets, beam-powered launch methods and space elevator tech with even more interest. Because those promise to get an appreciable mass out of Earth's gravity well economically, even if you have to transport it in small handfuls of a couple of tons.
A_M_Swallow
Regular
vacantlook
Super Moderator
Aside from the quotation from a scene of B5, what does this topic have to do with Babylon 5?
puzzle
Regular
I see... it seems the L1 point is closer to the Moon than I had imagined (58'000 km isn't very much higher than geosynchronous orbit from Earth) and the stress on the cable *is* very much lower than with Earth.
If an elevator can be built, that would mean convenient travel of both people and materials both ways, and provide a shortcut across several difficult choices.
With a lunar elevator, one could have the cake and eat it too, in many senses.
If an elevator can be built, that would mean convenient travel of both people and materials both ways, and provide a shortcut across several difficult choices.
With a lunar elevator, one could have the cake and eat it too, in many senses.
puzzle
Regular
You can only lift off with ion engines from very light objects (with current technology, asteroids perhaps). A whole G is unimaginable for current ion engines. Think more like 0.01 G. It's their fuel efficiency which makes them appealing in open space, nothing else.
They can work for years instead of seconds, but really are totally pitiful at providing appreciable force.
Switching them on has a point only after you've reached stable orbit where your energy output doesn't need to occur in a short time anymore. Below stable orbit, you either output enough energy in a given time to reach orbital velocity, or gravity will helpfully take you back down.
They can work for years instead of seconds, but really are totally pitiful at providing appreciable force.
Switching them on has a point only after you've reached stable orbit where your energy output doesn't need to occur in a short time anymore. Below stable orbit, you either output enough energy in a given time to reach orbital velocity, or gravity will helpfully take you back down.
darth_librarian
Regular
Eulogising about the need to go into space is all very well, but there are more practical reasons why the US, China and Russia all have their eyes on the moon.
Helium-3 is seen as a key potential fuel for fusion reactors, the kind that the States envisage having running in around 50+ years.
( http://news.bbc.co.uk/1/hi/sci/tech/226053.stm )
The moon is belived to be a plentiful source of the gas, which is rare on Earth. You do the maths there.
As with Iraq, Afghanistan and Chechnya, if the is a need for a super-power to go there and take ownership to ensure energy production, then they will do so, no matter the cost in cash or blood. Same with the moon, and the asteroids. Nothing glamerous there i'm afraid...
Helium-3 is seen as a key potential fuel for fusion reactors, the kind that the States envisage having running in around 50+ years.
( http://news.bbc.co.uk/1/hi/sci/tech/226053.stm )
The moon is belived to be a plentiful source of the gas, which is rare on Earth. You do the maths there.
As with Iraq, Afghanistan and Chechnya, if the is a need for a super-power to go there and take ownership to ensure energy production, then they will do so, no matter the cost in cash or blood. Same with the moon, and the asteroids. Nothing glamerous there i'm afraid...
puzzle
Regular
I certainly hope that fusion can be made feasible without rare elements. Seems to work fine with hydrogen in stars. Might be less efficient, but ought work fine with hydrogen in reactors too.
But if some cost does end up being measured in blood, and the cost happens to be high, sadly the same asteroids may indeed take a sudden turn for Earth some day in future - for they also make useful weapons.
So nothing stands for certain, but there is always benefit from capability to live in a wider habitat. Because a narrower habitat can often disappear (or can be made to disappear) too easy.
People don't have the tools to take on the Sun yet, so we can take its existence and stability for granted. For a long while anyway.
But tools for taking on Earth will be viable in foreseeable future, I'd predict sooner than in 50 years. The only feasible countermeasure may prove to be reducing dependence on Earth.
But if some cost does end up being measured in blood, and the cost happens to be high, sadly the same asteroids may indeed take a sudden turn for Earth some day in future - for they also make useful weapons.
So nothing stands for certain, but there is always benefit from capability to live in a wider habitat. Because a narrower habitat can often disappear (or can be made to disappear) too easy.
People don't have the tools to take on the Sun yet, so we can take its existence and stability for granted. For a long while anyway.
But tools for taking on Earth will be viable in foreseeable future, I'd predict sooner than in 50 years. The only feasible countermeasure may prove to be reducing dependence on Earth.
vacantlook
Super Moderator
But this a discussion of real life science, and not the story and characters of Babylon 5, so wouldn't this belong in another forum?
vacantlook
Super Moderator
I guess my organizational side is rearing its ugly head. It's just that aside from the prelude of a quote from B5, this thread hasn't exactly talked about B5.
crazyhorse
Anarchist
In B5 we see a good example of why man should reach for the stars,the possibility of Earth being destroyed.
Just for VL
Seriously though it is an issue.Disaster movies aside there is a real possibilty that an asteroid hits Earth,climate change makes the planet virtually uninhabitable ect.The only way for humanity to survive is to expand outwards.
As for a moon base I would say that the benifit of even a low gravity would outweigh the costs of any Lunar launches.The ability to function longer outside of Earth would have to be a consideration in any plan.Plus it would be cool to go there on holiday,something I hope is possible before I die.
Just for VL
Seriously though it is an issue.Disaster movies aside there is a real possibilty that an asteroid hits Earth,climate change makes the planet virtually uninhabitable ect.The only way for humanity to survive is to expand outwards.
As for a moon base I would say that the benifit of even a low gravity would outweigh the costs of any Lunar launches.The ability to function longer outside of Earth would have to be a consideration in any plan.Plus it would be cool to go there on holiday,something I hope is possible before I die.
Recoil
Regular
For what its worth...
I agree with Vacant Look.
I think this should be in the off-topic forum. Not saying it should be moved (because who really cares I guess). But lets face it. The quote is B5 related, but the actual topic is non-B5 related, and has to deal with real-life events.
I agree with Vacant Look.
I think this should be in the off-topic forum. Not saying it should be moved (because who really cares I guess). But lets face it. The quote is B5 related, but the actual topic is non-B5 related, and has to deal with real-life events.
