Simon Ross

In truth, I tend to agree with you, it's why I don't completely rule out the possibility of actual replicater type technology in the future. If all you are trying to replicate is a generic blueprint of a non living object be it a steak or a house brick then I think the level of complexity drops a LONG way ! What the steak tastes like however :-)

In truth, if I had a day spare to go into detail on how impressive Skylab was (and still is) I would. However I will simply refer you to probably the best book written on the subject http://www.amazon.com/house-space-Henry-S-F-Cooper/dp/0030166861 as it explains it much better then I ever possibly could

Please please, please check your facts ! Yes, ISS has 30,00+ cubic feet of pressurised volume, however, only 15,000 cubic feet is actually habitable ! http://www.nasa.gov/mission_pages/station/main/onthestation/facts_and_figures.html. Skylab had an actual 11,000+ cubic feet of HABITABLE living space http://www.space.com/21055-skylab-space-station-nasa-infographic.html How is mass a relevant metric ? To me it's quite a damning statistic, all that money, all those launches all that mass and we have barely got more living space in LEO then a single launch accomplished 40 years ago ! That's the downside of modular construction, a large part of your payload capability and space gets wasted due to the large number of interfaces you need to incorporate into the design. Engineers don't like interfaces !

And again, a one launch monobloc station would look nothing like the ISS, it would be designed in a completely different way, but please go do your research on the Skylab station to see what was possible with a SINGLE Saturn V launch nearly 40 years ago ! Even today, it's pretty damn impressive Interesting fact, after dozens of launches to build it, ISS has around 15,000 cubic feet of habitable volume, Skylab had 11,290 cubic feet of habitable volume from a single launch ! J

With ISS we didn't have any EHL capability, therefore the only way to get it into orbit was as modules.

Sorry guys, but for this to work on anything above the most simple objects you would pretty much have to re-write every known law of Quantum Mechanics ! Uncertainty Principle states that you can make an accurate observation of a particle's position and momentum... However you cannot do both at the same time ! This actually works very much the same with events in the universe we live in day to day.... Imagine a bullet in flight, you want to log it's exact position and velocity in a single instant of it's trajectory. Well, lets freeze frame it at that instant ! From here we can give an extremely accurate measurement of the bullet's position in 3D space, however we cannot gather any data on the velocity of the bullet, it's no longer moving. So lets set the bullet moving again. Now we can take an extremely accurate measurement of the bullet's velocity, however, the positional measurement we took of the bullet is no longer valid as the bullet has moved on from that position. Given this verified law, it is impossible to accurately scan and measure a single particle, let alone a complex object. For a very simple (non living object) there are ways around this in terms of multiple sampling and determing average positions and energy states. So say we scan a house brick for instance... After billions of individual scans we have collected enough data to enable us to replicate a house brick, however even an object as simple as a replicated house brick will still not be an EXACT copy of the house brick you originally scanned, there will always be accumulated errors in the data. Now go try this with something as complex as a human being ! Trust me, your going to end up with a puddle of organic mush !

In a word...No While it would be conceivably possible to replicate simple 'non living' items in the way described, you would still need the raw materials (chemicals, proteins etc..) that make up the original item to replicate it. As for a living organism, forget it. Basic uncertainty principle blocks that straight away

So I'm kinda interested What do you believe is the upper limit in terms of tonnage that can be raised to LEO ?

I'm sorry, but with respect, do you honestly believe Shuttle was an economic way of putting a 500 tone station into LEO piece by piece ? I'm pretty sure we could have used the $100 billion it cost to have developed a genuine super heavy lift booster and a non modular station and had an awful lot of spare change left over Using a man rated launch system to simply put hardware into LEO is economically crazy

Well aware of the square cube law, but doesn't invalidate the building of larger boosters ISS is a classic example, you can build a space station as a modular unit boosted to LEO on smaller spacecraft/shuttles or you can boost it into LEO as a complete unit using a 500 ton rated booster. Both approaches work, it all comes down to the economics and politics

I pretty much had the feeling of 'Here we go again' ! Was never a huge fan of the proposed Constellation hardware concept, but it did at least split out the manned and unmanned function of the two boosters And so we are back to Saturn V, oops sorry SLS Seems we really haven't learnt much in almost 50 years of space flight :-(

In reality, there are no practical engineering reasons why you cannot build a booster to launch 200, 500 or even a 1000 tons of payload to LEO The blocker is that there are no actual missions in the pipeline that require that level of lift capability, therefore, they don't get built

Simply us MJ for the stuff you have done manually so many times that there really isn't any challenge, ie... Get to orbit, Mun & Minmus encounters etc.. Just disable it for the stuff that still pushes you

Mesklin as described by Hal Clement in Mission of Gravity Gravity ranging from 700g at the poles to 3g at the equator Imagine trying to work out a landing there :-)

Because 45 years ago my friend I watched an incredible thing, two human beings landed on another planet with primitive technology and if you were not around at that time you simply will never understand what it meant or the passion it evoked. And these days, I'm 45 years older and I strongly suspect both you and I are never going to feel that sense of awe in our lifetimes again :-( For once as a species we put all the crap behind us and did something we can all be proud of. I don't ever see it happening again in my life time, but I hope it will in my children's

@Soda LOL, it's not a manned space programme my friend, heck it isn't even treading water

Wonderful to see the Luddites coming out on threads like this So, just a wake up call to those of you who think the 'N' word is a bad thing Without it, we don't have a manned space programme, not now, not in 20 years time, not ever ! Please feel free to sit back, protest and watch us all slowly fall back to a position where the world cannot afford to do the things this generation and maybe only this generation has the resources to do the things that we can possibly do to prevent another dark age. Feel proud of yourselves, pat yourselves on the back while the lights slowly dim, while billions starve and console yourselves that at least you saved the planet.

Errr smoke Kinda why most T72 tanks didn't last very long in the first gulf war

I'm sorry, but what is this bigger rocket ? The first couple of iterations of SLS don't even get the payload of Saturn V into LEO yet you think this is going to be the system to get us to Mars ? Sorry it isn't going to happen Please read up on your history, we had this payload capability 40 years ago, couldn't do it then with any reasonable chance of success In all that time, not a whole lot has changed other then NASA has changed from a civilian space programme with clear and funded goals to simply a means to keep a lot of aerospace engineers employed on make work

I go back to one of the OP criteria 'Technology:Must be viable today' Not proven, therefore not viable We cannot do it Sorry, I actually don't like that answer any more then you do :-(

Soda I'm actually an engineer, if you try to build 'proof of concept' models you do it where it is safe, you do it where humans can be kept from harm or in the worst possible case, they can effect an escape and rescue. The ISS should be the place we have flight tested these concepts Cold hard facts, we haven't No proof of concept for a 3 year unsupported life support system, no proof of concept for an artificial gravity system. Or do you think we should really be testing these things on an actual 3 year mission 35 million miles away with real life people ?

Kryten Your 100% correct. NASA is actually pretty closed mouthed about the number of in situ repairs and replacements that have had to be conducted to the ISS, we only hear about the major ones. So, seriously, does NASA have the experience to launch a 3 year unsupported mission to Mars ? Does it heck ! If we cannot build a closed system to support a structure 250 miles up we have no chance of doing it 35 million miles away

That would be very true if it was only a bulk supply issue. Unfortunately an awful lot of LS hardware has also had to be swapped out over the years. Again, you run into the issue of redundancy on any extended flight, something we really have not solved yet

Wish there had been an option for both sandbox & career. Actually play both, just depends on the mood I am in at the time

With respect Soda, but the whole point of the ISS was to test extended human habitation in space. Given that you would have at the very least expected the station to replicate an extended flight mission in terms of life support, generating an artificial gravity environment etc... None of that happened As I have already stated, if we cannot build a life support system capable of 3 years independent operation 250 miles above our heads, how in heck can we have any confidence that we can build one for a Mars mission ?