So you want different container shapes for pressurised vs unpressurised? Because at some point you ARE going to need pressurised containers, and box shaped ones are not going to work (too heavy).I would be interesting to know how much cargo can be transported unpressurised.
My current WAG is 50% split initially. Without a great deal of self sufficient systems (farm, 3D printers, feedstock melters/formers, atmosphere recycle and production from Mars atmosphere) the base will need a lot of pressurized supplies. As the base matures more supplies/cargo will be un-pressurized (mining equipment, material processing, solar arrays, etc).Having these supplies used inside the base shipped as un-pressurized will mean it all has to transition through an airlock. This is extremely time consuming and waste a lot of base atmosphere in purge Mars atmosphere and pressure cycling. Also dust control will be very difficult to manage as well with so many cycles.If you design your pressurized container/habitat so that most of it can be manufactured from ISRU, this will also shift the % of type of cargo as well from bulk materials to complex machines/electronics. This would allow the base to increase its volume and provide even greater m^3 space per person than what was available initially.The containers need to be simple constructable on Mars even though they may weigh more. Its not weight but costs that is important in the $/effective task/utility:-cost of the equipment, -shipping costs [trip on MCT to Mars $/kg, NOTE: SpaceX goal is to get this below $500/kg, initially it will be ~$8,000/kg], -handling time loading and unloading [this is probably the most precious resource both on Mars and Earth], and -other considerations such as multi use so that there is little dead weight shipped everything has a use on Mars especially pressurized containers)
Quote from: JamesH65 on 06/08/2016 12:53 pmSo you want different container shapes for pressurised vs unpressurised? Because at some point you ARE going to need pressurised containers, and box shaped ones are not going to work (too heavy).I would be interesting to know how much cargo can be transported unpressurised.Quote from: oldAtlas_Eguy on 06/08/2016 04:28 pmMy current WAG is 50% split initially. Without a great deal of self sufficient systems (farm, 3D printers, feedstock melters/formers, atmosphere recycle and production from Mars atmosphere) the base will need a lot of pressurized supplies. As the base matures more supplies/cargo will be un-pressurized (mining equipment, material processing, solar arrays, etc).Having these supplies used inside the base shipped as un-pressurized will mean it all has to transition through an airlock. This is extremely time consuming and waste a lot of base atmosphere in purge Mars atmosphere and pressure cycling. Also dust control will be very difficult to manage as well with so many cycles.If you design your pressurized container/habitat so that most of it can be manufactured from ISRU, this will also shift the % of type of cargo as well from bulk materials to complex machines/electronics. This would allow the base to increase its volume and provide even greater m^3 space per person than what was available initially.The containers need to be simple constructable on Mars even though they may weigh more. Its not weight but costs that is important in the $/effective task/utility:-cost of the equipment, -shipping costs [trip on MCT to Mars $/kg, NOTE: SpaceX goal is to get this below $500/kg, initially it will be ~$8,000/kg], -handling time loading and unloading [this is probably the most precious resource both on Mars and Earth], and -other considerations such as multi use so that there is little dead weight shipped everything has a use on Mars especially pressurized containers)People are literally the only things that will travel pressurized, the pressurized containers will be different but they are not part of this topic because this is a topic about CARGO CONTAINERS.So far no one has articulated a single type of cargo that actually NEEDS pressure, just a nebulous 'need' unsupported by any reasoning, or at best reflexive copying of ISS methodology. The gap between the logistical paradigm need to do colonization and most commenters suggestions is huge. We are not talking about an initial landing here were talking about logistics to support hundreds of thousands of tons of cargo a year.Atlas Guy points to logistics of moving into and out of airlocks, but this ignores the fact that connecting a large pressurized container to a habitat is a very slow process, it takes hours in zero-g.The kind of air-lock I'm suggesting would naturally be the size of a shipping container (cause it probably is a specialty container similar to the tank posted earlier) and hold nearly it's entire contents. Dust is controlled by having a large tented garage like space covering the whole 'yard' where the containers being unloaded sit, containers enter the yard by truck through a dust trap, robots unload pallets and place them in the air-locks. Or if we can send a large enough airlock (perhaps inflatable) then the whole container can go into it directly off the transport truck.Empty containers are going to be accumulating on Mars clearly, but their are a million uses for them other then trying to LIVE in them, which is incredibly shortsighted because habitation on Mars is not just having a pressure vessel, it's having several tons of life-support equipment too. Uses for disassembled containers would include using them as foundation slabs, roofing to support regolith over real habitats, melting down the aluminum and making simple rods and spare parts for virtually every other piece of machinery. Their is literally no end of things you would do BEFORE trying to live inside a cargo container.Now naturally their WILL be pre-fabricated living units sent to Mars and these could be in the shape of a container, but it's more likely to be an expandable Bigelow type habitat folded up inside the container. Again that's a topic for another thread.
A lot of things can't handle zero pressure. embryos and live animals, for example. A lot of foodstuffs. A lot of materials that would outgas.... I think pressure is going to make things a lot simpler, actually.
in this scheme does the entire long side of a container need to be airtight when mated to an adjacent one and the interior walls removed? That's a fairly tall order I think. Requires some very stable foundations I would expect. Not undoable. But I could see them using something flexible and a several centimeter gap, so that the joins don't have to be perfectly aligned. Put bridge plates on the floor at the joint and put plates on the walls and ceiling to protect the flexible material.Think how an articulated tram/streetcar/bus has accordion pleating joints between sections.
Quote from: Lar on 06/06/2016 05:51 pmin this scheme does the entire long side of a container need to be airtight when mated to an adjacent one and the interior walls removed? That's a fairly tall order I think. Requires some very stable foundations I would expect. Not undoable. But I could see them using something flexible and a several centimeter gap, so that the joins don't have to be perfectly aligned. Put bridge plates on the floor at the joint and put plates on the walls and ceiling to protect the flexible material.Think how an articulated tram/streetcar/bus has accordion pleating joints between sections.Perhaps something like NASA envisioned some time ago. But it wouldn't need to land itself. Just have the wheels and legs that can be jacked up and leveled on feet. Multiple units connected together with semi-flexible connectors. Each unit could have up to four ports for connecting on 1, 2, 3, or 4 sides.
Once these modules are jacked up and connected together they will likely not be moved again so the wheels could be re-used on later arriving modules and/or vehicles such as trailers made on site to move people from the LZ to the base.
A few more stiffeners added
Quote from: lamontagne on 06/13/2016 10:28 amA few more stiffeners addedIf you make the spaceframe 6 sided, it wastes a bit more space around the cylinder than an 8 sided one, but the containers can be packed much more easily as a regular hexagon tiles a surface, but a regular octagon does not, it leaves square shaped hollows.I like rectangular containers better, and will again advocate for standard 20 foot sizes that are compatible with the current terran system. we want there to be so much freight that avoiding transship repack or difficulties interfacing with terran container handlers becomes important.