Difference between revisions of "Talk:Unmanned setup of a whole settlement"
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why are caves the only option suggested for a settlement? Why not other ideas, like Transhab type modules buried in regolith? [[User:T.Neo|T.Neo]] 09:31, 23 July 2008 (UTC)
why are caves the only option suggested for a settlement? Why not other ideas, like Transhab type modules buried in regolith? [[User:T.Neo|T.Neo]] 09:31, 23 July 2008
==Landing on Mars==
==Landing on Mars==
Revision as of 18:35, 2 August 2010
"Since the Martian atmosphere is thin, the landing requires more than just wings. For previous missions additional boosters and parachutes were used. For a colonisation the preceding construction of a space elevator can potentially reduce the costs of landing large amounts of equipment on Mars."
"the landing requires more then just wings". You do not need wings to land. The only spacecraft to reenter and land with wings was the space shuttle (And its Russian counterpart, Buran). Landing could be achieved with a near-conventional aeroshell, parachutes and airbags that deflate on impact or a crushable section. Incorperating some sort of decent engine like that on the apollo lunar module would increase accuracy but also increase complexity. A space elevator would not reduce the costs of anything. A space elevator is a massive megastructure requiring untested construction methods and constant maintanance. The advantage of an aeroshell/parachute/airbag cargo lander is that the materials could be enriched with elements and compounds that are rare on Mars, so that they could be recycled at a later date. T.Neo 13:32, 21 July 2008 (UTC)
- Conventional lander technology is all we have at the moment. We have experience for small probes. We have no experience for landing heavy load on Mars. So, this is untested as well, and we have to develop new landers anyway. Probably, aeroshell/parachute/airbag is not feasible alone and requires additional support of rocketry. I find the idea of a space elevator interesting, because it seems to be possible due to the low gravity of Mars, even with known materials. But yes, it is untested hitherto. And no, it does not require constant maintenance if used just to land all the material for the settlement kick-off. The space elevator for landing is quite simple, and I suppose it might be cheaper than conventional landing technology for large amounts of equipment. However, I am not able to do the calculations. I wish, some experienced engineer from NASA or Roskosmos could help us with some calculations. -- Rfc 20:39, 21 July 2008 (UTC)
Other then the fact that the space elevator may actually be feasible on Mars, there is no real reason to use it. Constructing the space elevator and repairing micrometeoroid damage will cost huge amounts of money. What is needed is a very, very, very large rocket that is partially reusable, like the Sea dragon. By rocket assistance I am not sure if you mean a lunar lander type "hover" engine to steer to the landing zone, or solid rockets to decrease speed, similar to what the MER rovers used on decent. The upcoming Mars Science Laboratory will be a test at dropping large payloads on Mars, NASA seems convinced, so I am. And yes, someone from a space agency or with similar experiance would be very helpful to Marspedia. T.Neo 14:39, 22 July 2008 (UTC)
- Okay, if NASA has already plans then it ought to be feasible. For landing a single piece of payload this is probably the cheapest solution (or in other words the least expensive). A space elevator is definitely not cheap for a single piece of payload, but it might be the cheapest solution for a series of 50 pieces of payload to land on Mars. The lifetime of the space elevator would be limited to the settlement kick-off phase, may be a year. No repairing. To be honest, I have no idea, how much the construction cost. It's quite uncertain. -- Rfc 16:43, 22 July 2008 (UTC)
The cargo pallets would be MSL/sample return mission derived, with a service module for orientation and power during the cruse phase, and would be launched on something like an Ares V booster. The service module would seperate and possibly aerobrake into a stable orbit around Mars, to possibly become a communication or GPS satillite. The pallet would then reenter the atmosphere, protected by a CEV derived PICA heatshield. It would then deploy a supersonic parachute. On impact, a crushable zone or airbags would cushion the landing. A subsonic parachute could be included as well. There would be a margin of error, but the cargo would be collected and moved to the construction site. A space elevator would be something to be built by an established colony, not a developing or yet nonexistant one. Rendezvous with the elevator counterweight would be tricky, and require a large amount of fuel, meaning a payload penalty. Then the cargo, once landed, would have to be ferried to the base, which could be thousands of kilometers away from the equator where the cable is situated. Building the space elevator would also be a challenge, and require many launches, and some sort of landing like I suggest. Anyone you ask from NASA, ESA and Roskosmos would say the same, I bet.
P.S. why are caves the only option suggested for a settlement? Why not other ideas, like Transhab type modules buried in regolith? T.Neo 09:31, 23 July 2008 (UTC)
- In the article Landing on Mars there is discussion indicating a lack of faith in the parachute and airbags technique for large pieces of cargo. Wings as discussed in Supersonic in ground effect have not yet been demonstrated as a possible landing mechanism, but might work. It is possible to prove a concept with one instance of it working, but it is very difficult to prove a concept cannot work because there are so many different variations that might be tried. The question of whether a space elevator will be economic or not is affected by the amount of use it will get. If there is continuing trade for many years, the cost of establishing the elevator gets spread over many tons of cargo. If a space elevator for Mars is built out of lunar materials within a program of building a number of large space structures from lunar materials, then the cost of a space elevator is reduced. Micrometeoroid maintenance can be simplified for a space elevator by designing it with a micrometeoroid shield as described in Bringing up Phobos. The necessity of avoiding a collision between Phobos and a space elevator might mean that the space elevator concept would have to be delayed until the Mars colony has been long established.
- Very large rockets are very expensive to operate, and therefore should only be produced if there is a well defined plan for using on a regular basis the launching capacity that they are capable of. The infrastructure costs nearly as much to maintain if the rocket is launched once every two years or once a month. There are economies of scale to be had from more frequent launchings up to a rate of a launch every couple of weeks. The choice of large rockets has been affected by political pressure from space enthusiasts, but it is not economically justified. Some manufacturing capability in orbit will be necessary before colonies can be established on Mars and it might as well be established sooner than later. Since Human beings either in orbit or on Mars are a large liability, this manufacturing capability should be remote controlled, just as all economic activity in space so far has been without people laboring in outer space. The proper infrastructure can be developed so that people can do economic things in space, but putting people into orbit without this infrastructure is just a stunt.
- The Mars Science Laboratory will use a new landing technique, but still not one scaled to the large payloads people will want to establish a colony. The development work for landing on Mars must still be done before sending any people to Mars. --Farred 01:35, 3 August 2010 (UTC)
Landing on Mars
The color of Mars could be described as red or as rose. However putting on rose colored grasses when viewing the prospects of colonizing Mars does no good. If everything seems rosy because of illusion, that illusion will fail to provide the Martian colony that we want. For example, if the current parachute and air bag cannot just be scaled up for landing heavy equipment on Mars, simply insisting that it can only interferes with considering other options that might work, and delays their development. The seeming inadequacy of current methods is indicated in this web page: ("http://www.universetoday.com/2007/07/17/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/") If we need a four hundred foot diameter parachute manufactured in space out of aluminum oxide fiber and sent to Mars in stiff deployed condition instead of being packed, we will not learn about it unless we see a need to experiment. Such a parachute might merit investigation. It would avoid opening shock and might be sufficiently heat resistant to maintain structural integrity during the entire descent in Mars' low gravity well. The larger the diameter of the parachute, the less the max g loading. So let us be honest with ourselves about all necessary colonization technology. If we need space manufacturing for a healthy Mars colony, let us get on with it.--Farred 22:26, 5 March 2010 (UTC)
The expected max temperature for ballistic entry into Mars atmosphere is expected to be a thousand or more Kelvin degrees above the melting point of aluminum oxide so coating course aluminum oxide fibers with potassium oxide which decomposes at 490 Centigrade might protect the fibers through atmospheric entry by ablative cooling or it might not. A mixture of potassium and sodium oxides as a coating or Teflon as a coating are things that are conceivable. Engineers in this specialty would have a better idea.
One technology that I am fairly confident would work would be to have a delta winged entry vehicle or lifting body with insulation like that on the space shuttle. The insulation would be somewhat cheaper because Mars atmospheric entry is less demanding than Earth reentry. It would fly supersonic close to the ground then ignite its rockets for landing. Then it would perform a Pugachev's Cobra manuever loosing most of its horizontal velocity by drag and loosing the rest by rocket thrust. It would touch down on its tail. There is no question that this is possible. It is only a matter of money.--Farred 00:27, 10 March 2010 (UTC)