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Subject:
Space Travel
Category: Science > Physics Asked by: ssiva-ga List Price: $5.00 |
Posted:
13 Jun 2002 15:05 PDT
Expires: 13 Jun 2003 15:05 PDT Question ID: 25414 |
Given todays (6/13/2002) technology, what is the most cost effective system that could be built by 2010 to provide transportation to and back from the surface of the moon for millions of people? Please state the approximate cost and reason for your answer. |
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There is no answer at this time. |
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Subject:
Re: Space Travel
From: cerebro-ga on 13 Jun 2002 15:56 PDT |
Dear ssiva, The most cost effective way of traveling to space in the year 2010 might be a "scramjet" (an advanced space shuttle with reusable engines). Today Lockheed Martin and the NASA are currently working on a project called the X-33. Itīs main objective is to reduce the amount of space needed for the oxygen burnt in the combustion process therefore reducing the cost of previous tanks disengagements. Simple economics tell us that not being able to reuse "space aircraft" parts like a common airliner is one of the reasons why there is not a single cost effective method of transportation known yet. Although world wide more than $USD50 billion dollars are spent in space civilian operations. "To put a figure on these costs, it is noted that the cost of launching a payload into low Earth orbit is in the vicinity of $10,000 per kilogram, which is near the price of gold. It means that any object that we care to place in orbit becomes worth its weight in gold!" taken from Space travel why is it so expensive. the cost associated with moon travel might be very difficult to determine because you should also need to calculte the investment required to create a moon launching pad. I dont want to spend the 5 bucks listed here is an interesting site where you might gather the info http://www.atse.org.au/publications/focus/focus-stalker.htm |
Subject:
Re: Space Travel
From: mvguy-ga on 13 Jun 2002 16:46 PDT |
I don't know if it would be possible to start transport by 2010, but almost certainly any plan for placing millions of people on the moon would have to involve some sort of space elevator in order to be cost effective. One of the main problems with any plan is that it takes a massive amount of energy simply to place someone in orbit, as the first comment below indicates. The space elevator, which uses a long cable whose end is in geostationary orbit about 36,000 kilometers above the earth, reduces the cost of getting people in orbit to reasonable levels. Most of the talk about a space elevator has suggested that one could be built by the end of the 20th century. However, it may be possible to build one much sooner than that. In fact, Bradley Edwards, a physicist from Los Alamos National Laboratories, has developed a plan that could have an operational cable in place within 10 to 20 years. "The space elevator appears much closer to reality than has been suspected in terms of available technology, cost and schedule," Edwards said. "The major hurdle is the required carbon nanotubes, but that's getting closer each day." Information about Edwards is from an article in Space.com. http://www.space.com/businesstechnology/technology/space_elevator_001226.html According to a study presented at a 1999 workshop on the subject, the cost savings are incredible. David Smitherman, a NASA researcher who presented the paper, said costs could drop to a few dollars per kilogram to place someone in orbit. A passenger with baggage might add up to, for example, 150 kilograms and be lifted into orbit for only $222, he said, instead of the current $3.3 million. The information on this paper is from an article, "Audacious & Outrageous: Space Elevators" on the NASA site: http://science.nasa.gov/headlines/y2000/ast07sep_1.htm Here are some other sites of interest: Space Elevator Concept (Flight Projects Directorate) http://flightprojects.msfc.nasa.gov/fd02_elev.html How Stuff Works: Space Elevators http://www.howstuffworks.com/space-elevator.htm The Audacious Space Elevator FirstScience.com http://www.firstscience.com/site/articles/elevator.asp Space Elevator: Technology Development Needs http://std.msfc.nasa.gov/ast/presentations/6b_smith.pdf Space Elevator (Wikipedia) http://www.wikipedia.com/wiki/space+elevator Search Strategy "space elevator" ://www.google.com/search?q=%22space+elevator%22 I hope this helps. (I was researching this and had to leave suddenly, so I figured I should share what I have.) mvguy |
Subject:
Re: Space Travel
From: guymac-ga on 13 Jun 2002 16:57 PDT |
The X-33 program has been canceled. Furthermore, there was no evidence that it's technology (Single-Stage To Orbit) would dramatically reduce costs. Nor was it even a scramjet as you imply. It would be prohibitively expensive to provide resources to millions of people on the Moon. A much more suitable choice would be Mars, with its ample water ice reserves in the southern latitudes (recently detected by the Odyssey spacecraft). A promising concept to deliver humans to Mars is the "Mars Direct" scenario, championed by Robert Zubrin of the Mars Society. In this plan, the return craft is send ahead, it builds the propellants necessary for the return trip in situ--i.e. using the resources on the planet instead of sending them from Earth. This lessens the prohibitive costs of other plans. Now of course the bottleneck is first getting humans to orbit in large numbers. A number of promising concepts have been generated as a result of the X-Prize foundation which is offering a ten-million dollar prize to the first organization demonstrating viable space tourism by sending a two-person crew to orbit twice within two weeks. |
Subject:
Re: Space Travel
From: dannidin-ga on 14 Jun 2002 03:54 PDT |
You might want to take a look at the fascinating book "Islands in the Sky", edited by Robert Zubrin and Stanley Schmidt (see amazon.com reference below). It's a collection of papers about space travel, discussing the technical (and financial) aspects of the ideas discussed above (space elevator, Mars Direct plan, etc) and many more. Some of them, especially towards the end of the book, border on the ridiculous or at least very far off in the future (such as: how to direct our planet to a different star once the Sun is about to burn out...), but many are quite "down-to-earth" proposals about the very near future of space travel. I seem to remember the space elevator idea was dismissed there as impractical, because of the exponentially growing thickness the elevator cable would need to support its own weight 36,000 kilometers down, but maybe this problem can be resolved with the advent of new material science discoveries? http://www.amazon.com/exec/obidos/ASIN/0471135615/qid%3D1020348576/sr%3D12-7/104-9793268-8623922 Hope this helps, dannidin |
Subject:
Re: Space Travel
From: andrewxmp-ga on 14 Jun 2002 08:09 PDT |
Just a note- A scamjet engine will most certainly not work on a trip to the moon. It's design is based around compressing air and oxygen into a jet, as a gross simplification. Their is no oxygen, nor any form of atmosphere, in space. Perhaps a scramjet-based craft could gain momentum enough in the atmosphere to make it to the moon, but it could enver return. I believe that the X33 and related designs rely on more convential propulsion for reentry. |
Subject:
Re: Space Travel
From: cliffclavin-ga on 16 Jun 2002 14:00 PDT |
Following up on mvguy-ga's comment on "space elevators:" There is an excellent novel by Arthur C. Clarke (of "2001: A Space Odyssey" fame) titled "The Fountains of Paradise," which delves into the engineering considerations of building a space elevator or space tower in an entertaining and easy-to-understand manner. As mvguy pointed out, the major engineering hurdle -- a material with enough tensile strength that it wouldn't snap under its own weight -- is still just out of reach. It *could* be possible by 2010... Barring that, I doubt there is such a thing as a cost-efficient method for people to travel to the Moon, using current technology. Space vehicles are built pretty much on a "one-shot" basis; i.e., designed and constructed for one particular mission. There is a trend towards standardized, reusable spacecraft, beginning with the Space Shuttle; but even that is not a practical vehicle for passenger service to the Moon. Even if it were economically feasible to start such a service, it would be decades before the initial investment would be paid back. If someone was determined to do it, however, I would recommend a 3-vehicle system: one vehicle to take passengers up into orbit, another to make the trip to Moon orbit, then a third shuttle to make the surface landing and return. This would be much more efficient than trying to design one vehicle to do all three jobs, with two-thirds of the vehicle's systems acting as dead weight at any given stage. |
Subject:
Re: Space Travel
From: marduky-ga on 21 Jun 2002 23:20 PDT |
I don't know about the exact technologies and cost, but there is a competition to build a reuseable launch vehicle. I think the best bet would be to monitor the progress of the participants. Perhaps talking to some of them will help. They are trying to build their vehicles for maximum performance and minimal cost. www.xprize.com |
Subject:
Re: Space Travel
From: kjack-ga on 24 Jun 2002 12:54 PDT |
By 2010 the transportation of 'millions' of people to the moon will not be possible. If were asked today and just 'had' to do it my view would be we would transport sections of the space transport system to be used into space on the shuttle. We would then build the spacecraft in low earth orbit (say 200-300miles altitude). This would then run a mission profile very similar to the Apollo mission (free return loop with option to insert into moon orbit). The spacecraft would do an orbit insertion ( just slow itself down by burning the rockets in the direction of travel to allow Moon's gravity to hold it in an orbit around it). A part of the craft would go down to the Moon and part would wait in orbit around it. How big would the crew be? Well, 3-5 people maximum. The less the better. If the sun gives of a burst of solar radiation while they are in transit to or from the Moon it could prove fatal for the crew. As for millions, I don't think so yet. By the time we are thinking of transporting millions of people off of the Earth to another body it will be to a much further destination. The reason would be that either our Sun was at the end of its life or another large body was going to hit Earth.....at that point funding would not be an issue! |
Subject:
Re: Space Travel
From: chennes-ga on 25 Jun 2002 15:28 PDT |
Just a quick note about the X-33/VentureStar project: This project was cencelled last year due to massive cost overruns (as a previous reader mentioned). Further, its aim was to reduce the price of launching to orbit - it was certainly not capable of the velocity change required to get to the moon. Lastly, it was to be powered by a linear aerospike engine, not a scramjet (supersonic combustion ramjet). Again, as a previous reader mentioned, a scramjet is an airbreather, and isn't much good for anything but atmospheric flight. To get millions of people to the moon by 2010 is (for obvious reasons) never going to happen. But if the world pooled all of its resources, 2020 might be more reasonable. Now, branching into the realm of complete fantasy: If it were to happen in that kind of short-term, conventional or nuclear rockets are a must, and probably some combination of both. Zubrin's Mars Direct mission is expected to cost on the order of 50 billion US dollars (this is somewhere in the middle of several other people's cost estimates). This will land 6 people on Mars (actually, there are a lot more details than that - read the book if you want more). While not really comparable to a moon mission, an enormous amount of that money is spent just getting off the planet. So figure that 10 million people would require .1 million times this amount (a conservative estimate, I think). That puts you in the ballpark of about 5 quadrillion USD. This is not really taking into account any economies of scale, and is obviously just a blind napkin-calculation guess, but hey... Chris |
Subject:
Re: Space Travel
From: orbitalelement-ga on 27 Jun 2002 06:11 PDT |
Dear ssiva, It's interesting that no-one appears yet to have mentioned the Moon Society: http://www.moonsociety.org which is dedicated, inter alia, to: "the creation of a space-faring civilization which will establish communities on the Moon; promotion of large-scale industrialization and private enterprise on the Moon." The Moon Society's objectives are a little more modest than those posed in your question. Their "Project Leto" is a "full-scale simulation of an initial lunar lunar exploration base ... [it] will be marketed for outreach purposes, analog research, and as a tourist destination" (http://www.moonsociety.org/projects/leto/). The Moon Society is working with Artemis Society International on the "Artemis Project" which aims to go beyond the simulation stage and to establish a permanent base. See: http://www.asi.org/adb/01/basic-overview.html Again, this is more modest than your question implies (i.e. it *won't* be a colony for millions of people) although their timescale is, more-or-less, in line with your question, aiming to establish this base within 10 - 15 years or so (see http://www.lrcpubs.com/corporate/jul98pr.html). I am not personally familiar with the detail of these projects (I am a communications satellite engineer and not involved in manned or interplanetary projects) but it seems to me that, given the paucity of government funding (both in the US and outside) for returning to the Moon, it may well be that the good old commercial imperative is what finally gets the dream underway. Oh... and by the way... When your colonists do arrive on the Moon they'll find that a republic has already been declared, elections held, citizenship granted and real estate sold off! :-) See: http://www.lunarrepublic.com It's a funny old World, isn't it! |
Subject:
Re: Space Travel
From: ssiva-ga on 27 Jun 2002 11:24 PDT |
I just wanted to thank all the contributors so far. I have been doing some of the recommended reading, especially the web links and have been truly intrigued by the results. When I initially approached this question myself, I started doing the mathematics behind a giant linear magnetic accelerator for people pods that could get someone going fast enough on earth to leave the atmosphere without using rocket propulsion. If anyone has any comments on this, I would be very appreciative. Thanks again, ssiva |
Subject:
Re: Space Travel
From: remoran-ga on 01 Jul 2002 07:19 PDT |
The space elevator looks like the best bet at this point in time though I doubt if it will be built by 2010 due to the amount of nanaotubes (or equivalent) needed to be manufactured to build it. I think the persson who described this tech in great detail has the answer you are looking for. That was great reasearch. I learned a lot from that material. |
Subject:
Re: Space Travel
From: justinoogle-ga on 14 Sep 2002 12:51 PDT |
Orbit is easy. balloons... lots of them. The actual orbital travel cost to and from the moon could be cheap.. To and from the moon, hydrogen feul cells, solar power, lots of way to keep shuttles powered up for earth to moon orbital trips though re entering earths atmosphere would be tough. but it's simple (ok nothings simple) If you launch a rocket from sea level it will have to me many times larger and more powerfull than if you launch from say, 100,000 ft. A launch platform raised by balloons is already putting small satalites into space. Grapefruit sized satalites launched by rockets comparable to a hobbiests. What once cost millions now a mere 10,000 or less. Are we next? We have the technology, but there are too few casinos, rollercoasters and theme park attractions to get dad to shout; "pack up the suburban kids, we're going to disney moon!" |
Subject:
Re: Space Travel
From: prof_moriarty-ga on 28 Sep 2002 13:01 PDT |
The simple answer is: It can't be done. Not putting millions even into orbit by 2010, let alone to the moon. There are a number of launch technologies: 1) The successor to the space shuttle. Due to be finished by about 2015. Will probably still cost a fortune to launch things into space knowning NASA. 2) SuperGuns: Huge guns that can fire things into orbit the same way a normal gun fires projectiles. Many countries don't like the idea of this as it could potentially be used to launch projectiles to other countries. Note: There is no way this technology could be used to launch people. The g-forces would squish them. http://www.astronautix.com/lvfam/gunnched.htm 3) The space Elevator. My personal favourite. Arthur C Clarke famously said: "It will be built 50 years after people stop laughing at it". People stopped laughing a few years ago. The first conference was held this year (http://www.space.com/businesstechnology/technology/elevator_update_020819.html). This on has the most potential. It produces virtually not pollution (depends on the power plant used) and is always there. There is quite a lot of technology that would be required to allow this to be built, including: a strong enough material to hold the stuff: Carbon Nanotubes are the best idea, but they can't be produced in bulk just yet. The method of transport used to get up it would probably be magnetic levitation. Meaning superconducters and other related fields also need work. I believe this could be done by 2030 given the funds. This one also gives the cheapest method of getting into space. Lots of energy is required to get the goods to the top, but when the cars come down again, they get most of that energy back. The space elevator could also be used as a slingshot to throw things to the moon and other places along the ecliptic. 4) Electromagnetic launcher (ssivas intial idea). But this couldn't be used for humans because of the G's involved. People would get squished. Of course a very long runway thingy could be used which would lower the G's, but i think that that would result in huge amounts of wasted energy. In the first few hundred meters after leaving the launch rails the projectiles velocity would be halfed by the atomosphere and gravity. This would be best for places like the moon. http://www.cnn.com/2002/TECH/space/01/03/maglev.launches/ 5) A plane that has jets (stationary to mach 3), ramjets (mach 3 to mach 5), scramjets (mach 5 to mach 25), and rockets to get it from mach 25 to orbit (just a little push). This one is probably the closest and most cost effective. Moriarty |
Subject:
Re: Space Travel
From: theinvisibleman-ga on 16 Oct 2002 06:49 PDT |
Easy! well I guess if you take into count that you have to make an new source of propulsion or engine its not so easy. But that is the way to solve your problem: find a more efficient way of moving at high speeds and (something often overlooked but could help a lot) create a reusable cheap re-entry heat tile for spacecraft, or maybe just one that can do like 1000 re-entries or something. Both technologies could be discovered in a year and mass produced in five years but they have to be discovered first and that requires someone with the genius to this. Here are my crazy ideas on a new engine: I think we should figure out a way of easily creating positrons (Currently the only way is to collect radiation off certain elements, needless to say very in efficient). This is a tall order and might never get filled but if someone somewhere ever did this then the rest is feasible. You create a system of superconductor accelerators to create a beam of elections (not that difficult basically man made lightning - been done since the 1890's, of course this will be a little more controlled) then collide that beam with either another beam of positrons made in the same way (possible because superconductors repel all magnetic forces and positrons act the same way electrons do but with opposite charge) or have a cloud of positrons. Which ever way is more efficient. If this is done correctly with all the right angles and math then the result should be a beam of energy E=mc^2 style. This is because positrons are the electrons anti-matter and when they collide with electrons they both turn into pure energy, that is there mass (which is very small) X the speed of light squared (a really big number) = the amount of energy you get but here's the kicker: its in focused in a certain direction! So instead of the big boom of a nuke you get the power of say 20,000kt of TNT focused to push an object in the other direction. The resulting thrust could be regulated by how much electrons are used and the g-forces problem could be solved by only using enough energy to go orbital on earth and then hit full thrust in space. NOTE: the process could be more efficient with a 'heavier' particle like a neutron but the problem still lies with finding a good source of anti-neutrons or any antimatter. ALSO: If you think my numbers are off then correct me I just pulled them out of my head and didn't calculate anything so I am probably wrong. ONE MORE THING: Do not automatically say its impossible because its not, It could be done with radiation as the source of positrons but thats so inefficient the mass to energy ration wouldn't work. |
Subject:
Re: Space Travel
From: ldavinci-ga on 06 Nov 2002 15:45 PST |
I feel that the space travel has to be done in two stages. i) Some means of transport from earth's surface level to one that is already in the orbit. It could be done by various means but will be the one that does not involve fuel for accelaration due to safety issues. It could be multilevel magnetic acceleration, where the intermediate stages after provinding thrust float back to earth for reuse. ii) From the gravitationless orbiting platform, It could be again magnetic acceleration with electrical energy collected through high efficiency solar cells. There will not be any intermediate stage involved except at the collection point(ie. moon). iii) Conventional fuel based thrust will be used only for emergencies, micro manouvers and decelaration during re-entry. |
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