Results 121 to 150 of 251
Thread: Living on Mars?
-
2017-12-09, 06:25 AM (ISO 8601)
- Join Date
- Mar 2017
Re: Living on Mars?
Nevertheless, he is not an authority on subject. Not without presenting an actual research.
Limit is practical. 100 meter wide elevator tower would make sense only for an extremely advanced (mature) development of space elevators. The one we are not going to reach until we literally build hundreds - if not thousands - of space elevators all around globe, and the proceed to improve them again and again.
I.e. that is not something that is being discussed or suggested when we talk about actual space elevators.
I'm sorry, but having a hundred people on Mars is called "scientific expedition", not "colonization".
-
2017-12-09, 06:27 AM (ISO 8601)
- Join Date
- Mar 2017
-
2017-12-09, 06:35 AM (ISO 8601)
- Join Date
- Feb 2007
Re: Living on Mars?
I could see colonising The Moon as a better "stepping stone in the process of advancing space technology" than colonising Mars. Mars might be more of a digression.
Marut-2 Avatar by Serpentine
New Marut Avatar by Linkele
-
2017-12-09, 11:18 AM (ISO 8601)
- Join Date
- Jun 2011
Re: Living on Mars?
There's a pretty large gap between 100 person "scientific station" and a million per year "Evacuate the earth minimum shipping amount."
The SpaceX plan is to make it economically viable for 1 million pioneers to spend their own money to live on mars. They estimate that a million person colony has enough redundancy and population base to operate an industry that can make them ACTUALLY independant from earth.
They arnt going to make that viable with elevator cable "launches" every other week (because it takes half that time for the climber to go each way) and needing to repair LEO velocity paintchip damage. They need DAILY launches from hundreds of pads around the world to bring down the costs to airliner-like... so that's what they want to build.Last edited by Rakaydos; 2017-12-09 at 11:19 AM.
-
2017-12-09, 12:32 PM (ISO 8601)
- Join Date
- Jun 2013
- Location
- Bristol, UK
Re: Living on Mars?
I've said it before, living on Venus is a better idea than living on Mars (probably in another thread). Sure the temperature needs to come down, but a sunshade made out of thousands of autonomous solar sails around the https://en.wikipedia.org/wiki/Lagrangian_point Venus/Sol L1 point should do that fine, and keep the temperature down afterward if needed.
Space elevators on Earth are a great idea, hopefully we will build one and eventually more in the future, but for now we're stuck with rockets, because they work using the materials and techniques we have now.
On the whole, I agree that space not planets ought to be our species' future main home, but almost all of those now living on Earth will never leave it, most of the future non-Earth population will be born off the Earth, sure there are problems to be overcome, but I have no doubt that they can be overcome.The end of what Son? The story? There is no end. There's just the point where the storytellers stop talking.
-
2017-12-09, 12:35 PM (ISO 8601)
- Join Date
- Feb 2007
-
2017-12-09, 12:44 PM (ISO 8601)
- Join Date
- Jun 2013
- Location
- Bristol, UK
Re: Living on Mars?
The end of what Son? The story? There is no end. There's just the point where the storytellers stop talking.
-
2017-12-09, 12:53 PM (ISO 8601)
- Join Date
- Feb 2007
Re: Living on Mars?
It doesn't have to generate power for the residents of the proposed Venus colony - instead it can generate power for space stations under the "sunshade".
Marut-2 Avatar by Serpentine
New Marut Avatar by Linkele
-
2017-12-09, 01:43 PM (ISO 8601)
- Join Date
- Feb 2016
Re: Living on Mars?
A million people isn't a colony, it's a mass exodus
"If you want to understand biology don't think about vibrant throbbing gels and oozes, think about information technology" -Richard Dawkins
Omegaupdate Forum
WoTC Forums Archive + Indexing Projext
PostImage, a free and sensible alternative to Photobucket
Temple+ Modding Project for Atari's Temple of Elemental Evil
Morrus' RPG Forum (EN World v2)
-
2017-12-09, 04:49 PM (ISO 8601)
- Join Date
- Oct 2010
- Gender
-
2017-12-09, 05:14 PM (ISO 8601)
- Join Date
- Aug 2007
Re: Living on Mars?
That's not how a space elevator would be used. The design allows for multiple climbers on the tether at any given time. Yes, each one takes days to arrive, but once the first one arrives, the next one is just a couple of hours behind it. Also, the pods will be disposable: either flung into deep space, or put in a shell and dropped back to Earth. But they won't be taking up tether time to go back down.
GWLast edited by Grey_Wolf_c; 2017-12-09 at 05:17 PM.
Interested in MitD? Join us in MitD's thread.There is a world of imagination
Deep in the corners of your mind
Where reality is an intruder
And myth and legend thrive
Ceterum autem censeo Hilgya malefica est
-
2017-12-09, 05:31 PM (ISO 8601)
- Join Date
- Jun 2011
-
2017-12-09, 05:35 PM (ISO 8601)
- Join Date
- Jun 2011
-
2017-12-09, 07:39 PM (ISO 8601)
- Join Date
- Oct 2010
- Gender
Re: Living on Mars?
If they actually worked third world countries wouldn't be destroying their trade balance by purchasing grain shipments from the US, they would be building vertical farms.
You need a system that can actually work without massive and continuous external inputs from a wealthier place, otherwise Mars becomes forever dependent on material shipments from Earth. This is not a good situation to be in when you have no balancing exports.
-
2017-12-09, 08:06 PM (ISO 8601)
- Join Date
- Feb 2016
Re: Living on Mars?
"If you want to understand biology don't think about vibrant throbbing gels and oozes, think about information technology" -Richard Dawkins
Omegaupdate Forum
WoTC Forums Archive + Indexing Projext
PostImage, a free and sensible alternative to Photobucket
Temple+ Modding Project for Atari's Temple of Elemental Evil
Morrus' RPG Forum (EN World v2)
-
2017-12-09, 08:21 PM (ISO 8601)
- Join Date
- Oct 2010
- Gender
Re: Living on Mars?
They only work in specific regions. Civilization is an export, hence why those regions have seen mass migration to cities as food imports replace tiny self sustaining farms.
Comparing the two, if vertical farms work like third world farms no one in their right mind is going to go to Mars.
-
2017-12-09, 09:07 PM (ISO 8601)
- Join Date
- Aug 2007
Re: Living on Mars?
It does matter, especially when I hear nonsense like "it takes two weeks between launches" as a "problem" for space elevators. By all means tell me what numbers you have in mind, because I'm tired of having the burden of evidence dumped on me every time someone comes boldly announcing that space elevators are useless but can't be bothered to actually do even basic calculations themselves.
GWInterested in MitD? Join us in MitD's thread.There is a world of imagination
Deep in the corners of your mind
Where reality is an intruder
And myth and legend thrive
Ceterum autem censeo Hilgya malefica est
-
2017-12-10, 02:14 AM (ISO 8601)
- Join Date
- Nov 2006
- Location
- Watching the world go by
- Gender
Re: Living on Mars?
My understanding is that when people say things about how big of a climber a space elevator can support, they typically are talking about the case where they have the tether pretty much full and are just putting one on the bottom as fast as they take one off the top. If you have a bunch of climbers spaced evenly over the tether, they mostly add to the tension rather than to the orbital mechanics.
-
2017-12-10, 03:37 PM (ISO 8601)
- Join Date
- Nov 2008
Re: Living on Mars?
This seems wasteful. Mass in orbit is valuable. The pods should be recycled in place, either used in architecture, broken up for parts, scrapped for raw material or decomposed and used as extra reaction mass.
Near the top of the tether it might be worthwhile to use the previous batch of crawlers as counterweights to assist the climb of a new group of ascending crawlers.Last edited by Bucky; 2017-12-10 at 03:38 PM.
The gnomes once had many mines, but now they have gnome ore.
-
2017-12-10, 07:40 PM (ISO 8601)
- Join Date
- Jun 2011
Re: Living on Mars?
I'm not saying the elevator is somehow worse than "1 launch every other year" disposable SLS. I understand the elevator is scalable- if you need more capacity, you spend some capacity bringing up more filaments to make the tether stronger.
But there's no fundamental reason a rocket cannot me made with enough margin that it refuels and reflies after a single day. (Elon apparently wanted a 12 hour turnaround- the engineers convinced him that 24 hours was reasonably possible.) For the cost of creating a single edge-of-theoretically-possible elevator filament, how many reusable heavy lift rockets can you assemble and get a thousand flights out of, each?
Space elevators are popular because rocket technoligy has been stuck in the 70s for almost half a century. Looking at the lack of progress national spaceflight programs made, it's easy to believe that the saturn 5 was the best rocket that CAN exist.
But that's wrong. Microchips, CAD programs, new material technologies and new manufacturing techniques mean rockets can be... and with both Blue Origin and SpaceX, along with smaller companies like Electron and Reaction Engines Limited, are becoming... so much better options. The Space elevator isn't even possible yet, and it's already becoming obsolete.
-
2017-12-10, 08:30 PM (ISO 8601)
- Join Date
- Jun 2013
- Location
- Bristol, UK
Re: Living on Mars?
Including non-reusable fuel? Not many.
Space elevators are popular because rocket technoligy has been stuck in the 70s for almost half a century. Looking at the lack of progress national spaceflight programs made, it's easy to believe that the saturn 5 was the best rocket that CAN exist.
But that's wrong. Microchips, CAD programs, new material technologies and new manufacturing techniques mean rockets can be... and with both Blue Origin and SpaceX, along with smaller companies like Electron and Reaction Engines Limited, are becoming... so much better options. The Space elevator isn't even possible yet, and it's already becoming obsolete.The end of what Son? The story? There is no end. There's just the point where the storytellers stop talking.
-
2017-12-10, 08:57 PM (ISO 8601)
- Join Date
- Aug 2007
Re: Living on Mars?
The NASA design calls for using the first few thousands to build up the counterweight at the far end of the elevator.
Unless you can show me how that'd even be done, I don't think that is a thing that could happen with the tether-crawler design.
Again, stop shifting the burden of evidence onto me. This is your argument, YOU present the numbers that make your case. Figure out what ballpark numbers Elon is promising, and compare them to the numbers expected for a space elevator. Simply saying "I'm sure that X-Space will be cheaper" is not an actual argument.
GWInterested in MitD? Join us in MitD's thread.There is a world of imagination
Deep in the corners of your mind
Where reality is an intruder
And myth and legend thrive
Ceterum autem censeo Hilgya malefica est
-
2017-12-10, 09:36 PM (ISO 8601)
- Join Date
- Jun 2011
Re: Living on Mars?
"Propellant
Musk has famously stated at the National Press Club that the cost of propellant is only 0.3% the cost of the [falcon 9] rocket, which yields about $200,000 for a $60m launch."
https://space.stackexchange.com/ques...alcon-9-launch
The 2017 BFR is fueled with about 4000 tons of Natural Gas (Methane) and Medical grade oxygen. Best estimate put the fuel costs at $500,000 dollars for 150 tons to orbit. (Methane is cheaper per ton than the Falcon 9's Kerosene) The rocket itself is more expensive, but is intended to be flown 1000 times per airframe, amortising the costs significantly.
@greywolf: https://www.sciencedaily.com/release...0412105109.htm
Not up to space elevator standards, but I'm not including BFR refurbishment or amortization costs either, so I'll call it a wash.
At $15 per gram of carbon nanotubes, and a minimum strand mass of 750 tons (earlier in this thread) is 750 million grams, or over 11 billion dollars for a single strand.
With the same money, you could refuel the BFR over 20,000 times, presumably putting 150 tons into orbit each time.
-
2017-12-10, 11:32 PM (ISO 8601)
- Join Date
- Feb 2016
Re: Living on Mars?
It should be noted that the fuel is non-renewable as well
"If you want to understand biology don't think about vibrant throbbing gels and oozes, think about information technology" -Richard Dawkins
Omegaupdate Forum
WoTC Forums Archive + Indexing Projext
PostImage, a free and sensible alternative to Photobucket
Temple+ Modding Project for Atari's Temple of Elemental Evil
Morrus' RPG Forum (EN World v2)
-
2017-12-11, 12:02 AM (ISO 8601)
- Join Date
- Jun 2011
-
2017-12-11, 02:23 AM (ISO 8601)
- Join Date
- Aug 2008
Re: Living on Mars?
Fuel is also a pollutant when burned - and while that's pretty negligible at current rates (e.g. haloform production associated with the space shuttle which is at .25% of the world total) it can't be reasonably assumed that that stays true given a significant uptick in launches. Hydrogen-oxygen systems are generally better about this, but they aren't completely pure fuels as used and still cause problems.
Meanwhile if a space elevator is successfully produced the energy requirements drop precipitously.
-
2017-12-11, 02:38 AM (ISO 8601)
- Join Date
- Feb 2007
- Location
- Manchester, UK
- Gender
Re: Living on Mars?
And what do you do then? Just stop supplying your space colonies and space stations, which we're assuming you're going to have by this point (given the purpose of the thread)? Whereas if you built the space elevator, and hopefully did a decent job of it, you can keep using it to send stuff up.
-
2017-12-11, 08:43 AM (ISO 8601)
- Join Date
- Jun 2011
-
2017-12-11, 08:47 AM (ISO 8601)
- Join Date
- Jun 2011
Re: Living on Mars?
If that becomes a problem, they CAN reuse fuel, though not as cheaply. The Sabatier Reaction turns CO2 and H2O into CH4 and O2, and they are already building this tech for the mars end of the journy. Build it on the earth end as well, and counting the fuel lost in space forever, it's actually a net exporter of CO2.
-
2017-12-11, 01:04 PM (ISO 8601)
- Join Date
- Aug 2008