Author Topic: Standardized container cargo system for Cargo MCT  (Read 21933 times)

Offline oldAtlas_Eguy

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Since it is the intent of the cargo MCT for it to be reused by sending it back to Earth, the cargo must be offloaded at Mars. If it is in a standard container pressurized or unpressurized then to handle all cargo only requires a single simple system to perform the offload.

Further since half of all cargo at first will be pressurized it will need a container complete with thermal control, power (batteries) and hookups as well as airlock like hatch entry to maintain internal pressure. This container can also be a habitat module just that it is shipped on a cargo flight full of supplies. If the cargo to crew flight ratio is 10 to 1 and half containing habitat modules full of crew supplies then the Mars base will be quite roomy 5X the size per person of the crew MCT. If the MCT has a capability of transporting a container of 1000m^3 volume then the initial base could have several 1000m^3 of habitat volume for the first crews. Growing by 10s of 1000m^3 of volume each synod.  It is possible that by the 5th synod the base could have as much as 50,000m^3 of habitat volume. Enough space for 500 persons to have a person to volume ratio of 1 person to 100m^3.

If the pressurized containers utilize CBM like hatchways and a hexagonal shape as new cargo arrives it is delivered to the base and mated to an external CBM growing the complete size of the base covering more and more area. Also by concentrating radiation shielding only in the top and much less in the sides to almost none, a lot of weight and more efficient use of volume can be saved. Also the containers could then be unpacked by the base personnel just by opening the hatch once connected to the base. This does bring up the question on what to do with the trash?

But it would also be advantageous to also use a container for the unpressurized cargo as well. Some of it may be specialized factories that would become a part of the base but is best not pressurized. It could still have the CBM connections and possibly even airlocks for easy crew access to its internals. These would be unique singe item designs but of a standard external shape and size. Other containers would have outside equipment that would require probably human teams to unpack either in space suits or through teleoperated robots. But still the biggest problem is offload and transport from landing/takeoff field to the base. If all use a single set of handling equipment design then operations at Mars become significantly easier.

Offline The Amazing Catstronaut

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Re: Standardized container cargo system for Cargo MCT
« Reply #1 on: 06/06/2016 04:03 AM »
I like this suggestion - it provides an easy road to expansion by vastly simplifying the volume requirements laid upon the the different colonial elements. In addition, the habitats could be widely reconfigurable. Recreational/residential equipment could fold sideways into the floor and walls, maximising volume for cargo stowage during flight, and providing the option for the area to be repurposed later on. Hell, most of the equipment within the base could have common attachment nodes to the floors of the habitats, permitting a habitat to become a gym, an aquaculture, a warehouse, a family residence, a hospital, a lab, a factory, depending on the requirements of the colonists. They can reconfigure the colony according to their needs.
Resident feline spaceflight expert. Knows nothing of value about human spaceflight.

Offline oldAtlas_Eguy

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Re: Standardized container cargo system for Cargo MCT
« Reply #2 on: 06/06/2016 05:10 AM »
Too often the logistics considerations take a back seat, but for Mars they should be front and center. Cargo MCTs should be loaded and unloaded like container ships at a port.

The only problem I see is that first Cargo MCT being unloaded to get the unloading equipment out to unload the other cargo MCTs.

Offline GWH

Re: Standardized container cargo system for Cargo MCT
« Reply #3 on: 06/06/2016 05:30 AM »
Yes. I posted very similar ideas in other threads. Personally I've worked on a few projects designing sawmill equipment to be containerized or built in a manner where the structure does double duty for loading with shipping containers. Different environment but same principle of building for cost effectiveness within shipping constraints.
It is a very efficient method of construction in remote areas and modularity like that will be key to build a colony IMO.

Offline biosehnsucht

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Re: Standardized container cargo system for Cargo MCT
« Reply #4 on: 06/06/2016 06:11 AM »
TL;DR: Interplanetary Intermodal containers

I think there's an argument to be made for habs-as-containers (instant hab, pressurized cargo, etc), but there may also be uses for cargo containers that aren't pressurized.

For example, if you wanted to move some large construction equipment, you could either just tie it down to the cargo floor as-is or containerize it (making loading and unloading easier, as well as using the negative spare around it since you could pack the space around it and have it attached to the walls of the container).

Once you get said container down, you could in theory pop the walls off (so it's just edges and some cross braces), easily detaching the wall-attached items from the frame, drive the equipment out, etc, and now you have a reasonably sturdy frame... you could then put a few of these next to each other, with all but the 'interior' walls attached, slap an airlock or two on some ends instead of the regular ends, bury it in martian soil and go in and seal up the walls to make a larger hab space.

Granted, expandable habs may be a better bet ...

Another possible use is you could also not seal it, but use it as a garage (so still martian pressure, but more or less out of the way of dust etc, opening it only when needed to move equipment in and out).

In either case, I think it's almost guaranteed there will be some kind of standardized shape/size of cargo for handling (so that there's one side fit all crane to get it out, if the cargo hold is above the propellant tanks rather than below it, or PODS-style container movers can be used to move them into position away from the MCT). There would most likely be more than one kind of container, but they would all be interchangeable in exterior dimensions.

Offline Hotblack Desiato

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Re: Standardized container cargo system for Cargo MCT
« Reply #5 on: 06/06/2016 08:12 AM »
From what I have gathered (there is a thesis presentation somewhere on the forum, regarding retropropulsion during atmospheric reentry, and someone asked Musk on Twitter, he confirmed that it will work somehow like this), the MCT has a cylindrical container below the actual MCT (the part that will go back into space). The craft lands, gets refuelled, detaches from the container and lits its engines, leaving the container back on the surface.

This means, that the container must have its own heatshield, and that the MCT just uses its own heatshield for earth atmosphere reentry. But this also means, that the MCT-container dimensions are tied to the diameter of MCT, much like the standard TEU containers are tied to the dimensions for road transportability.

For cargo, the system should be quite simple, just have either a pressurized or unpressurized compartment, both with basic power supplies (even unpressurized goods may require heat or electricty).

The pressurized cargo container could have some sort of expandable outer hull (bigelow-style), so it can increase its storage volume. Obviously, the system can only expand its hull after MCT departed (otherwise the engines would burn a few big fat holes into that skin). This could be useful for fuel storage by installing flexible bladder tanks inside. Since fuel just requires a gas-tight structure, and some thermal insulation, it doesn't need to be very thick (5cm would be enough).
With a thicker expandable hull, it could be even suitable as extra internal space for living quartiers. It needs obviously some sort of floor installed.

Those containers are challenging from an engineering point of view, because they might even require some sort of air lock (or multiple air locks) as part of that expandable hull. And they may remove sharp rocks around it prior to expanding.

Offline oldAtlas_Eguy

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Re: Standardized container cargo system for Cargo MCT
« Reply #6 on: 06/06/2016 03:15 PM »
This is something like what you described. It was posted on the MCT thread.
http://forum.nasaspaceflight.com/index.php?topic=37808.msg1545272#msg1545272

Go back to that Max Fagin (former SpaceX intern) retropropulsion thesis defense video.

Whole vehicle lands, but only an upper portion returns to Earth. If the propulsion is in the upper portion (Dragon 2 heritage) the left behind cargo section can be used for most anything; habitation, cargo, or perhaps a dual  purpose.

How about some stripped down cargo sections hauling expandable & repurposeable tanks full of distilled water (thinking Thin Red Line's expandable tank tech.) AKA, 'how to ship hydrogen and oxygen without cryocollers', and the cargo bay volume could be repurposed for colony use later.



Offline the_other_Doug

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Re: Standardized container cargo system for Cargo MCT
« Reply #7 on: 06/06/2016 04:58 PM »
Too often the logistics considerations take a back seat, but for Mars they should be front and center. Cargo MCTs should be loaded and unloaded like container ships at a port.

The only problem I see is that first Cargo MCT being unloaded to get the unloading equipment out to unload the other cargo MCTs.

Um, yeah.  It's the old conundrum -- the first factory you build has to be a factory for building other factories.  Only after your first factory builds other factories do you actually start producing the materials you need.

It's almost a chicken-and-egg situation.  In this case, though, you can design a one-time unloading system that lets you deliver and set up your big, efficient unloading system for the second cargo ship.  The only question is, can all of these operations be not only automatic but fully autonomous?

We'll have to wait and see how SpaceX wants to handle it.  Which, of course, means waiting until at least this coming September... sigh...
-Doug  (With my shield, not yet upon it)

Offline Kansan52

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Re: Standardized container cargo system for Cargo MCT
« Reply #8 on: 06/06/2016 05:15 PM »
The CBM like (lite?) hatches are a good idea. A pressurized vehicle come up to the CBM, latches, you open from the pressurized vehicle. This vehicle could be stored in and unpressurized container, have an expandable body, and away you go.

The containers could be attached to nodes. One node could have an airlock so all the containers in the group can share that airlock.

Of course, you now have a trailer park in an area with lots of swirling winds!  ;)

Offline oldAtlas_Eguy

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Re: Standardized container cargo system for Cargo MCT
« Reply #9 on: 06/06/2016 05:35 PM »
There is another aspect to the container system that is overlooked by the traditional space launch and that is simplified LV/payload processing.

The down side for the Cargo MCT is that the container could be very big (up to 15m diameter and up to or more than 15m tall) and not be able to be transported easily. This then would suggest another co-located factory with the one that makes BFR's and BFS's to assemble the container and to then fill them with the cargo prior to the short trip to the launch site for loading on the next launch. Initially I see the rate of container manufacture to be ~1/month. At Musks 10:1 cargo to crew mission ratio this would be only enough to support 2 maybe 3 crew missions per synod. The whole thing here is to get the costs down from end to end of the cargo costs delivery to Mars:
- Purchasing (or building) the cargo in mass quantity in nearly OTS (off the shelf industrial quality)[if it breaks replace it so send replacement parts or even replacement complete systems]{NOTE: for use inside the pressure habitat industrial quality as long as it meets safety requirements makes OTS hardware even though it may weigh more than specifically designed lightweight systems in the long run be cheaper},
- Assembly of container near launch site,
- Container cargo launch to be contents agnostic [same shape, connections (power, thermal, comm), weight, moments and CG],
- Handling can be more automated because of the external sameness of all containers, and
- No LV integration required on most containers (there will always be a few exceptions)

The whole intent is to accomplish the task of building a colony for the lowest costs, not trying to minimize weight or to pack more stuff per trip or anything else. What results in lowest costs overall.

Offline oldAtlas_Eguy

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Re: Standardized container cargo system for Cargo MCT
« Reply #10 on: 06/06/2016 05:48 PM »
The CBM like (lite?) hatches are a good idea. A pressurized vehicle come up to the CBM, latches, you open from the pressurized vehicle. This vehicle could be stored in and unpressurized container, have an expandable body, and away you go.

The containers could be attached to nodes. One node could have an airlock so all the containers in the group can share that airlock.

Of course, you now have a trailer park in an area with lots of swirling winds!  ;)
The containers used as habitats would need some sort of leveling system to level the add on container to the others already there and also there will need to be some sort of anchoring method to attach to the feet to the ground similar to the systems used to anchor pre-manufactured homes. They are certified to Hurricane CAT 2-3 level winds (120mph). There is some safety in this in that each container/habitat can be made to be briefly (several days) of stand alone life support. The CBM like connections between container/habitats is the same double hatch system as used on the ISS that alow atmosphere isolation from either side. Basically if the pressure starts to drop more in one side vs the other the doors close using the pressure differential to secure the door. There will need to be a few airlocks also included in the design to handle going outside or for when a container has depressurized and a crew needs to enter and fix the leak or to escape the depressurized container.

Offline Lar

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Re: Standardized container cargo system for Cargo MCT
« Reply #11 on: 06/06/2016 05:51 PM »
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.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline the_other_Doug

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Re: Standardized container cargo system for Cargo MCT
« Reply #12 on: 06/06/2016 06:00 PM »
- Container cargo launch to be contents agnostic [same shape, connections (power, thermal, comm), weight, moments and CG]

The one thing you note that will likely be impossible is a common CG in each container.  With the vast variety of things that will be packed into these containers, the best you'll be able to hope for is an accurate assessment of the CG of each container, so each one can be loaded appropriately to try and trim up the CG of the BFR/BFS as a whole.

Also, these containers will have much more stringent tie-down requirements than any shipboard or even airborne containers out there today.  It needs to sustain, what, at least 5G acceleration and an instantaneous change from 5G to zero-G and back to something like 1G or 2G when the second stage kicks in, and then from the stage 2 max acceleration back to instantaneous transition to zero-G.  Your tie-downs have to be designed to handle that kind of stress.  Not to mention the deceleration stresses upon EDL at Mars.

But as for the CG issue, I think SpaceX will need to stretch the current state of the art a bit to get the accuracy they will need for the CG and mass distribution of each container, along with a proper analysis of maximum stress points within each container (and thus, where to check for strong-enough tie-downs in each container).  It may be a challenge initially -- I hope we don't lose an entire BFR upon launch because either the containers' CGs weren't figured correctly, or because a tie-down broke and mass shifted...
-Doug  (With my shield, not yet upon it)

Offline the_other_Doug

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Re: Standardized container cargo system for Cargo MCT
« Reply #13 on: 06/06/2016 06:08 PM »
Also, I think that these "CBM-like hatches" that are being discussed for the containers should be modified in our thinking to something more like "submarine-type hatches".  They will be supporting people walking between chambers, not floating.  They will likely have shin-breaking 50cm tall bottom sills, but should be more like two to two and a half meters tall, to allow even your tallest crewperson to walk through them without also risking head trauma... ;)

I like the idea of the containers being inflatable and, once emptied of surface equipment (and unstowed of in-hab equipment) become your hab spaces.  Economies of all kinds inherent in that concept... :)
-Doug  (With my shield, not yet upon it)

Offline oldAtlas_Eguy

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Re: Standardized container cargo system for Cargo MCT
« Reply #14 on: 06/06/2016 06:27 PM »
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.
The envisioned is a slightly flexible CBM like connection between containers at 60 degree intervals around the circumference to account for temperature effects of shrinkage and expansion. This could simply be a flat plate area that can flex in and out like a drum head. Normally the pressure would exert a significant force pushing the CBM connections together. Use of an accordion would not really be necessary if the modules are place correctly and pushed together and anchored. Additionally a centrally located CBM top and bottom could also be done with sufficient structural elements around the sides to be able to stack the containers. Instant condo ;D

The sides are not expected to be removed. A ~1500m^3 container of ~14m diameter would be 10m tall. That is a very large empty space compared to the ISS experience. Three stories of 153m^2(1660 sqft) of floor space each level. Each level is equivalent of a 3 bedroom house. These things are not small.

Offline oldAtlas_Eguy

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Re: Standardized container cargo system for Cargo MCT
« Reply #15 on: 06/06/2016 06:33 PM »
Also, I think that these "CBM-like hatches" that are being discussed for the containers should be modified in our thinking to something more like "submarine-type hatches".  They will be supporting people walking between chambers, not floating.  They will likely have shin-breaking 50cm tall bottom sills, but should be more like two to two and a half meters tall, to allow even your tallest crewperson to walk through them without also risking head trauma... ;)

I like the idea of the containers being inflatable and, once emptied of surface equipment (and unstowed of in-hab equipment) become your hab spaces.  Economies of all kinds inherent in that concept... :)
Yes, envisioned would be exactly like you described vs the ISS round CBM except for top and bottom CBM ports if they are added to the container design.

There would also be the possibility of a slight ramp that retracts down when the door closes to eliminate the trip factor and sill damage for airtight seal. This allows use of wheeled carts for movement of items between habitat/containers.

Offline Lar

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Re: Standardized container cargo system for Cargo MCT
« Reply #16 on: 06/06/2016 07:38 PM »
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.
The envisioned is a slightly flexible CBM like connection between containers at 60 degree intervals around the circumference to account for temperature effects of shrinkage and expansion. This could simply be a flat plate area that can flex in and out like a drum head. Normally the pressure would exert a significant force pushing the CBM connections together. Use of an accordion would not really be necessary if the modules are place correctly and pushed together and anchored. Additionally a centrally located CBM top and bottom could also be done with sufficient structural elements around the sides to be able to stack the containers. Instant condo ;D

The sides are not expected to be removed. A ~1500m^3 container of ~14m diameter would be 10m tall. That is a very large empty space compared to the ISS experience. Three stories of 153m^2(1660 sqft) of floor space each level. Each level is equivalent of a 3 bedroom house. These things are not small.

Someone in this thread said something about taking entire walls off from adjacent containers to make larger work spaces. So that's what I was referring to there.

I would dispute that you can get away without accordions, unless you are sure that there will never be any quakes, any settling, any shifts, etc.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline oldAtlas_Eguy

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Re: Standardized container cargo system for Cargo MCT
« Reply #17 on: 06/06/2016 08:04 PM »
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.
The envisioned is a slightly flexible CBM like connection between containers at 60 degree intervals around the circumference to account for temperature effects of shrinkage and expansion. This could simply be a flat plate area that can flex in and out like a drum head. Normally the pressure would exert a significant force pushing the CBM connections together. Use of an accordion would not really be necessary if the modules are place correctly and pushed together and anchored. Additionally a centrally located CBM top and bottom could also be done with sufficient structural elements around the sides to be able to stack the containers. Instant condo ;D

The sides are not expected to be removed. A ~1500m^3 container of ~14m diameter would be 10m tall. That is a very large empty space compared to the ISS experience. Three stories of 153m^2(1660 sqft) of floor space each level. Each level is equivalent of a 3 bedroom house. These things are not small.

Someone in this thread said something about taking entire walls off from adjacent containers to make larger work spaces. So that's what I was referring to there.

I would dispute that you can get away without accordions, unless you are sure that there will never be any quakes, any settling, any shifts, etc.
I think he was referring to using the unpressurized containers to build a larger open space by using the structural elements of the container without the sides if they had any to begin with. By stacking several and by logically orienting them, a large open space could then be created by welding plates on the sides top and bottom. An area of some multiple of the container volume could be created (it would still have the structural supports in the inside to hold up the the sides and roof) so that say a park could be created that is like 50,000-100,000m^3 of open space. An open space of say 30m high by 75m in diameter. Would involve ~57 container frames.

Offline Lar

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Re: Standardized container cargo system for Cargo MCT
« Reply #18 on: 06/06/2016 08:10 PM »
ok.

I would still dispute that for regular container to container joints that you would just use a press-fit or even bolts, because as you got bigger and bigger, the end containers will be under increasing strain if things shift.

Even here on earth, large buildings get expansion joints or earthquake fault line joints.
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"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline oldAtlas_Eguy

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Re: Standardized container cargo system for Cargo MCT
« Reply #19 on: 06/06/2016 08:21 PM »
ok.

I would still dispute that for regular container to container joints that you would just use a press-fit or even bolts, because as you got bigger and bigger, the end containers will be under increasing strain if things shift.

Even here on earth, large buildings get expansion joints or earthquake fault line joints.
Yes a definite problem such that there may be a max number of clustering of containers with a significant expansion joint connection between clusters. But once the base has gotten big enough for that to be a problem (number of containers >7 there will be over a hundred inhabitants possibly several hundred. Each cluster being a community almost with clusters customizing for a particular activity.

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