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When our basic colony will be in place it will have to be supplied and expanded in regular intervals.
The question is, how will that be done.
While cyclers seem to have an advantage for transporting people it seems to me that simple one way designs should be the preferred choice for cargo transport.
We could have capsules catapulted onto an Earth-Mars trajectory by a tether system. They would only be maneuverable on a very limited scale and use aerobraking to deorbit at Mars.
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Cyclers.
Perferably a 2 stage system. Heavy cargo is launched to low earth orbit, were it is met by the first cycler in a highly ellipical orbit, which then meets the second that just skips around earths gravity well.
If the interplanetary cycler is fast enough (Earth to Mars in less than 3 months) then it might be worth putting manned capsules on it. Otherwise there will be too many complexities in life support systems to use in a cycler, in will have to enter a stable orbit to prepare for its next trip.
"Yes, I was going to give this astronaut selection my best shot, I was determined when the NASA proctologist looked up my ass, he would see pipes so dazzling he would ask the nurse to get his sunglasses."
---Shuttle Astronaut Mike Mullane
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As far as supplying our colony or even building our 600 person colony and not to mention the expanding of our Mars colony to an even bigger size. I don't believe that we currently have the technology to do that. We may be able to get to Mars in small numbers and on a limited bases with present technologies. Because we would have to send every thing from the Earth into a 26 month launch window for almost six month. Even with a Cycler, you still pretty much have those same launch window constraints on you, beside the fact you have to build the Cycler too. As long as we are going to keep hitting those barriers, we are going to be severally limited as to what we can do on Mars and or whether or not we can develop Mars.
My suggestion is to use current technologies to get the space colonization going and then have a government sponsored program to develop new more advanced ship to overcome the current technological barriers that we are running into. Instead of trying to modify space ships that use the sling shot approach to moving around in the solar system, we deliberately go after developing a new powered rocket that runs 100% of the way and not just at the beginning and end of costing to and from Mars. It take a lot more energy to do that and you would only use it if you had a manned flight, but the cargo flight you would still use the sling shot approach for energy saving purposes. We would want to develop a rocket that excellerates have way to Mars and then decelerates the other half way to Mars so we could get to Mars in maybe one week or less. That means that we would have to build a small fleet of ship of say twenty or thirty space ships to have our colony on Mars and we would also have to develop a way to manufacture fuel supply to supply those ship that are going to be traveling between the Earth and Mars. So we would almost have to take our Mars Colony and our space ship building together or there would be no reason to try and build either one, because we can't get to Mars in sufficient number and we don't have a reason to build those ship if we don't have a base on Mars.
My policy is, when you run into technological barriers, then you have to develop higher levels of technologies to overcome those barriers that we ran into at a lower level of technology. My opinion is, if we aren’t trying to develop higher levels of technologies to colonize Mars, any attempt that we make to colonize Mars will ultimately fall apart because of both our technological & economical backwardness.
Larry,
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If the interplanetary cycler is fast enough (Earth to Mars in less than 3 months) then it might be worth putting manned capsules on it. Otherwise there will be too many complexities in life support systems to use in a cycler, in will have to enter a stable orbit to prepare for its next trip.
It seems to work for more than 3 months on the ISS with some progress docking on in between. I guess that much supplies could also be stored aboard initially.
Cyclers seem to be preferable to me because of better radiation protection and more living space on a long trip.
Neither argument is relevant for cargo transports, though.
You could also have more advanced propulsion for you don't have to throw it away each time.
we deliberately go after developing a new powered rocket that runs 100% of the way and not just at the beginning and end of costing to and from Mars. It take a lot more energy to do that and you would only use it if you had a manned flight
Indeed, especially if you go for high ISP, in which case energy efficiency will drop even more. For low ISP it is completely impractical because of all the excess fuel you need to take.
I wonder what the point is in shortening the flight times (aside from a longer launch window), since you can only send new craft every 2 years anyway.
As far as supplying our colony or even building our 600 person colony and not to mention the expanding of our Mars colony to an even bigger size. I don't believe that we currently have the technology to do that.
It might turn out to be closer than most think. I'm pretty much in love with the Rotovator concept at the moment. I wonder why it is not more popular, since it can be built with todays tech for not that much of initial investment.
It addresses Eart to LEO where most high ISP drives are useless because of the need for a high thrust/weight ratio (or fallout problems).
I agree with the concept of simultanously building the colony&tranport infrastructure and yes, researching new technologies is always a good idea, too.
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In a sense, there is no such thing as a fast cycler. Cyclers follow orbits that repeatedly take them between planets. If a cycler travels between the Earth and Mars in, say, three months, it's moving so fast that its orbit will naturally carry it out beyond Jupiter, and it won't come back to be used again for a decade or more. To reuse it sooner you have to put an engine on the cycler and fire the engine to change the cycler's orbit. That's not much more energy efficient than using the cycler between planets and storing it in orbit between flights (where it will have other uses).
As for the idea of a spacecraft that fires its engine all the time; I assume you don't mean an ion engine, but something more Buck Rogers-like; maybe a fusion engine. At the moment I doubt we'll ever master fusion; this is technology that has been trumpeted as twenty years away for the last fifty years. Even if we figure out how to build multi-billion dollar fusion reactors on Earth, making them into compact power sources for space is another matter. Maybe you're talking about 25th century technology. When was Star Trek set?
-- RobS
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There are 2 kinds of approaches to fusion power.
One is with a deuterium/trithium plasma confined in an electromagnetic field in the shape of a Möbius-Loop.
It is heated to many millions of Kelvin.
The construction of the first reactor has already begun, as far as I know.
It has several disadvantages though. The process creates large amounts of neutron radiation, which irradiates the walls. They have to be replaced regularly, causing more nuclear waste than a conventional fission reactor would.
It also has to be fairly large for a positive net energy output.
But it still has the advantage that no melltdown can occur.
The other way is called inertia fusion. It is done using powerful lasers that implode a pellet of deuterium. This works, too, the problem is the efficiency of current lasers of the required output is so small that you have negative net energy in the end.
The while it looks like more efficient lasers are getting more and more powerful, so maybe that can also be solved.
The old Star Trek was 23rd century, Next Generation and DS9 are 24th century and I've seen a new series on TV that seems to play in the 22nd.
We will have Warp travel by about 2060 according to Star Trek.
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I wish...
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There are 2 kinds of approaches to fusion power.
One is with a deuterium/trithium plasma confined in an electromagnetic field in the shape of a Möbius-Loop.
It is heated to many millions of Kelvin.
The construction of the first reactor has already begun, as far as I know.
It has several disadvantages though. The process creates large amounts of neutron radiation, which irradiates the walls. They have to be replaced regularly, causing more nuclear waste than a conventional fission reactor would.
It also has to be fairly large for a positive net energy output.
But it still has the advantage that no melltdown can occur.The other way is called inertia fusion. It is done using powerful lasers that implode a pellet of deuterium. This works, too, the problem is the efficiency of current lasers of the required output is so small that you have negative net energy in the end.
The while it looks like more efficient lasers are getting more and more powerful, so maybe that can also be solved.The old Star Trek was 23rd century, Next Generation and DS9 are 24th century and I've seen a new series on TV that seems to play in the 22nd.
We will have Warp travel by about 2060 according to Star Trek.
Do not forget the Deutrium/Helium 3 route a lot less radiation admittidely it needs more "heat" to work. But it also creates a lot of electrons which can simply be syphoned off to provide direct electricity. This advantage allows for much smaller structures to be built ie instead of the large power Nuclear sized plant that a deutrium/tritium plant needs to operate a two story structure would do. No need for heat exchangers etc
Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.
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the discusion of helium 3 for fuel has been touched on before in a few other threads not only by you Grypd but by others as well. these are great references as well for the topic of nuclear fuels.
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Thanks, I wanted to mention it myself but have forgotten. Another reason for going to the moon.
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Regarding resupply infrastructure, there are several issues to resolve to determine what system to use:
1. How much resupply you need to ship every twenty-six months. That will vary depending on the size of the base; the bigger the base, the less you have to ship per capita, because larger facilities will be more self-sufficient. Very small operations will need to import most of their food; larger operations will import luxury food items only (things hard to raise or make on Mars, like Godiva or Ghirardelli chocolate). My guess, for it's worth, is that resupply imports will start out running 2 to 4 tonnes per person per 26-month period, but a 600-person base might get it down to 1 tonne per person per 26 months.
2. How much new equipment you need to ship for the existing personnel. As people learn to work on Mars their productivity will increase. A 100-person base might not need some machinery and lab equipment that it will need a few years later, when the 100 people can do more. This might add another half tonne or tonne per person per 26 months.
3. How many new additional people are arriving every 26 months. They will represent expanded capacity and will need housing, wheeled vehicles, equipment, clothing, etc. Each additional person may require several tonnes of additional stuff. To give a simple example: a Mars base might need a wheeled vehicle with an average mass of 5 tonnes per every dozen personnel, so expanding the base from 60 to 72 people requires importing five tonnes of vehicle.
4. There will be big surges in cargo demand as the Mars facilities expand. When there are several hundred people there, the ability to make plastics for all sorts of items will be possible, but you might have to import 500 tonnes of stuff to set up the facility to make the plastic. Surges could also occur for expanding Mars surface spaceports, space vehicle repair capacities, metal working capacities, ore refining capacities, nuclear reactor manufacturing capacities, etc. Some of these might require populations on Mars of tens of thousands of people to justify them.
5. As the Mars facilities expand and interplanetary transportation gets cheaper, demand for consumer goods will change. A small base may have no children, and the first kids will have to depend on a few hand-me-down toys, but later on the girls will want the latest Barbie dolls, and if they aren't too expensive, they'll be imported! (I know, my 6 year old has about 12 of them!).
6. Most cargo will go absolutely el-cheapo; the cheapest way possible. At first that will mean Hohmann trajectories. Eventually it will probably mean solar sailing cargo craft that will take a year to traverse the distance to Mars. Reuseable shuttles will go up and dock with the cargo in orbit, then bring it down in their cargo bays. This will allow the interplanetary vehicle to be reusable. As capacity expands it will be possible to move thousands of tonnes between the planets at prices that should fall below $1000 per kilogram (note that at that price a Barbie doll will cost a few hundred bucks to import;a fine suit a few thousand). Ironically, as transportation prices fall, consumer imports per person could go up and "buy Martian" campaigns will occur.
7. Some items will always have to go fast, such as special medicines and emergency spare parts. These will be minimized in quantity. I doubt a cycler will ever be used for moving cargo; cargo needs a container, avionics, and big solar sails, and little else.
-- Robs
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I don't think it will be neccessary to send up a shuttle for most cargo, just add a simple heat shield and parachutes to the container and it can go down on its own. Rovers can collect them on the ground and I guess the high grade material the container is made of can be useful on Mars.
Solar sails will surely have a role to play both for interplanetary transportation and for altitude control of various orbiting craft.
Thanks for the insights on the development of the first settlement(s), they seem to be quite reasonable. I hope we will be at that point as soon as possible.
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I don't think the Martian atmosphere is thick enough for heat shield plus parachute landings; you'll need landing rockets and/or air bags. I am sure supply flights in the early days will be one way. But eventually there will be a role for a reusable Mars shuttle, especially if Mars is exporting PGMs, gold, deuterium, fossiliferous rocks (if they exist), etc. The shuttle would fly up to orbit with exports and return with the imports.
-- RobS
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Yes, a shuttle makes more sense if it is not going up empty. Haven't done any calculations about entering marsian atmosphere yet, but if you say some airbags added will be enough, that shouldn't be that much of a problem.
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I don't think anyone knows how to make airbags big and strong enough (and heavy enough!) to cushion a landing after use of just parachutes. I think at least solid rocket retro-rockets are also needed.
-- RobS
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Rob is right, a soft landing without rockets isn't practical even with parachutes. That thing with the Pathfinder and MER landers, where it hit the ground surrounded by air bags, that isn't a soft landing.
An early Martian base that maximizes ISRU abilities for almost all bulk items from Earth will mainly require prefabricated equipment from Earth...
-Nuclear reactors
-Fuel rods/pellets for same
-Brayton turbines
-Heat exchangers
-Water drilling equipment
-Heavy-Duty water cracking & Sabatier reactor
-Cryogenics condenser & tank liners
-Chemical plant, with polymer synthesis equipment
-Polymer and amorphous (BMGs/glass) processing equipment
-Microwave/Plasma or Carbonyl Complexation metal refinery
-Equipment to fasion and mill parts from metal/metal-carbonyl
-Heavy-duty waste water treatment
-Digging equipment
-Computers for base monitoring & operations
And so on and so forth... basically, lots of fairly heavy and big equipment that you can't let hit the ground and/or bounce, especially sensitive electronics. Alot of the bulk stuff, like:
-Water
-Oxygen
-Nitrogen
-Ammonia
-Methane
-Methanol
-Carbon Monoxide
-Glass
-Basic plumbing
-Bulk metals (limited)
-Plastics (simple chemistry only)
-Bulk foods
-Fish & small mammals
...Etc, the stuff you could drop out of the sky, you can make on Mars... Though I am not sure if the fluffy animals could handle the fall.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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In this case it is really a problem. You will need more complex machinery for landing with rockets. Still, getting up shuttles will be difficult at the beginning since they need a lot of fuel.
It would be quite a luxury to haul along large masses of bulk materials from Earth, that would make the colonization effort almost impossible.
Maybe we could make some kind of "soft ground" to let the capsules land on, it would have to be very large though. But I have no idea what this ground could be made of.
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I am in agreement with RobS. Most cargo transport will be driven to the absolute lowest prices possible, which I think will rule out a traditonal cycler. To many stages and far to much equipment to truly be cheap for cargo transport. RobS is right that for general cargo transport Solar Sails will likely become the cheapest option.
The solar sail has many advantages over other methods. If travel time is not of greatest importance you can launch the cargo whenever you wish. It may take a while to arrive, but allows you to continue launching cargo all the time instead of only every 26 months. Since a solar sail uses no propelent there is no payload penalty to launching even at conjuction, it just takes longer to get there. Also it is a method scalable to whatever launch vehicles are most efficent. Lastly there is no reason that a solar sail could not be reused. Once returned to earth orbit they could be met by another outbound cargo container and begin the journey again. Once mass produced the sails may be cheaper than the cost to put them in orbit in the first place, so it may make sense to simply dispose of them, but ever ounce that is not spent lifting the sail may be spent lifting something else instead.
He who refuses to do arithmetic is doomed to talk nonsense.
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I disagree:
Most cargo transport won't be bulk-anything to or from Mars for some time, because Martian reasources are sufficent to produce most bulk supplies... that is, after all, one of the main reasons for going there. All the CHONs, bulk metals, and other materials are already there in reasonable quantities, there just isn't going to be much "bulk" stuff to move where a solar sail would be preferred. Its going to be machinery and specialty materials, its going to be live foodstuffs, its going to be people. Getting these things to Mars in a timely and efficent manner isn't practical with a sail.
Nonliving things with microchips, organic componets, and other radiation-sensitive things too, especially if you want to depart during any time of the year, you will spend too long soaking up solar/cosmic rays with a sail. Plus, a multi-year trip one way ruins the responsiveness of the system. If you need something in months, not years (reactor parts, emergency medical evac, etc), its going to cost big time to rush a "fast" cycler. This isn't such a problem if all the cargo ships are fast. This may sound kind of silly, but I think we'll be seeing a signifigant need for fast(er) transit, in which case the cost of operating a growing Mars base will rise substantially.
The reason why cargo can't be sent by regular chemical or simple NTR rockets any time is a lack of specific impulse, that these engines would require an absurd amount of fuel to be able to leave whenever they wish. The solution, of course, is to not use these engines... Instead, employing a GCNR engine or a VASIMR powerd by an advanced reactor, and you would have a much wider practical window. And, frankly, by the time we could build large and durable solar sails, then one of these advanced engines should be practical too.
Plus, if you want to haul large masses every 26mo, one of these engines could haul much more payload per amount of rocket fuel. So, you launch and build up your fuel stockpile during the "off" year and launch your payloads to go during the "on" season.
With the advent of a high-Isp engine and RLVs on both ends, there really won't be that much of a reason to use solar sails. Once launch costs drop and these super-engines
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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I guess there will be a compromise between how much cargo you transport, how much radiation shielding is practical to send along and how fast you want it to arrive.
Agreed on the lack of need to transport bulk materials, but there might be machinery that has no fine electronics within where radiation protection is not an issue. Maybe it would even pay off to send such machinery on a slower transport and the electronics on a different faster and better shielded one.
With a martian orbital shuttle you would have the additional advantage of no big need for altitude optimization of the engine. But it might still be difficult to produce enough H2 or methane at the beginning even with that much less delta v needed.
The launch window will increase in lenght as better engines become aviable but there will be a "dark spot" for a long time when it is absolutely impractical to send anything (fast).
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Another advantage for cyclers with "fast" propulsion, you could perhaps make several trips in the time it takes for one solar sail transit.
As soon as you have access to polar ice or underground water, making bulk rocket fuel on Mars shouldn't be too hard. A real spaceplane or "Mega DC-X" on Earth would send up stuff on our end... barring a space elevator.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Early on, giant bags of MiracleGro would be useful. Those could bounce. :;):
Okay, in the longer run, harvesting CHONs is the only way to go however a few dozen tons of well formulated plant food gets your greenhouses off and running. Especially if ALL the CHONs are captured and fed back into the gardens, supplemented of course with easily obtain Marsian water and CO2.
Edited By BWhite on 1114960223
Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]
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If you are only talking about dozens of tonnes, then that is practical with one sortie of a heavy cargo delivery vehicle.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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While I agree that there will be little if any transport of raw materials. The amount of equipment necessary to build and expand a mars base is so large that this equipment will practicaly be bulk cargo transport for a long time to come. For the forseeable future there will definetly be cargo to fill all the Mars transport capacity we have and then some.
I disagree with the concept that all cargo is going to be time critical. In a sense none of it is, since at best it is going to take several months to get there untill some truely high technology options come online. So if there is some critical medicine or part that you need within a week-month, you are out of luck in anycase. So the stuff is going to take a while to get there no matter what.
And it's not like a solar sail takes THAT much longer to arrive at its destination. We are talking a year and a half to maybe 3 years. While it wouldn't make sense to keep people up there for so long, but I don't think any cargo is going to fail or any systems are any more likely to go bad due to radiation or whatever. And while there might be some cargo that might demand a more immediat travel time, for most of the infastructure enhancments, waiting a bit to get it isn't going to kill anyone.
And even with advanced options like VASMIR or GCNR or even fusion, you still pay an incredibly payload pentaly if you want to go faster or launch at any time. With a solar sail you pay no payload penatly at all, just a little time.
As for issues of cost, and acessability I think a solar sail comes out way ahead here of the alternatives GCNR talks about. A few preliminary orbital tests of Solar Sails have already been done (by the Japanese), which puts them way ahead of both VASMIR and GCNR which are little more than theoretical speculation. Furthermore the problems facing any sort of Gas Core Nuclear Reactor (which are necessary to both) are far more difficult than those facing a solar sail.
And finaly seperate transit systems for cargo (which can take a longer amount of time to arrive) and passangers will probably become necessary. Since I belive the amount of cargo will eventualy outnumber traditional cargo to such a degree that it make economic sence to invest in an alternative (and cheaper) deliver method if avaliable. In this sense solar sail has a minor advantage in that is in a sense independant of it's launch system. It does not have to be so massive as to assemply in orbit and could be scaled to meet whatever was avaliable. A GCNR or VASMIR virtualy requires either HLLV and/or on orbit assembly.
He who refuses to do arithmetic is doomed to talk nonsense.
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I believe that we should be looking at two different transport for deep space.
The faster more expensive transport for getting people to and from Mars to Earth or asteroids. This would be a GCNR engine or a VASIMR powered by an advanced reactor or possibly a fusion powered engine. For humans that the only way to go.
Then we should have a slower unmanned cargo version of possibly ion drive or something of that type of engine. They would take five or six months to get to and from Mars to Earth. I don't like either Solar Sail or Cyclers. I don't like Solar Sail, because they take one year to three years to get to Mars and they can only go out from the Earth to Mars, but can't come from Mars to the Earth, because it will be going contrary to the solar winds. I believe that we need to have something faster than that and that we need to set a time limit as to how slow our cargo ship going to get to Mars. Going to send your cargo to Mars and it going to take years to get it there is unacceptable for shipping something to Mars. I don't like Cyclers, because who going to build them and maintain them and then there the problem of catching them on either end of your trip to Mars or Earth. Building a fleet of unmanned cargo ship would be the best way to go and later on we could either upgrade new cargo ships or overhaul the old cargo ships as new technology comes on line. Both the Solar Sail Ships and Cyclers would tend to restrict development in space and commerce over choosing to setting up a system of private unmanned deep space ship freighters to carry those resources back and forth between Mars, Earth, Moon, Asteroid etc.
Larry,
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