Mating Airlocks to Cargo Hatches

[Terry Mixon]

As a side thought to the Enhanced Docking Clamp discussion, I was looking at how I needed to make a cargo pod that attaches to a highport to unload.

My initial thought was that I needed cargo airlocks on the station and cargo pod that is now clamped to the hull, but I grumbled about the wasted space in the cargo pod.

Then it occurred to me, couldn’t the airlock on the station mate with a normal cargo hatch and maintain the seal? The pod is clamped to the station, so there is no movement. The station is protected from blowouts. Even the interior of the pod should be protected. Boarding tubes do that sort of thing, after all.

Does that sound reasonable or is the risk to blowing out the cargo pod too high?

Maybe a special kind of airlock that extends from the station like an airline boarding ramp and seals right against a pod? I kind of like that idea, actually.

 

[Condottiere]

Sure.

Though, there would be protocols for safety breaches, and likely some form of standardization.

 

[Terry Mixon]

How about this?

Extendable Airlock

Airlocks consume a minimum of two tons and cost KCr1 per ton. Larger airlocks can be used for cargo bays.

An extendable airlock is a sealed unit built into a structure that deploys to mold one end to a cargo hatch or airlock on a vessel attached by a docking clamp. It adds 25% to the tonnage of the desired airlock and costs an additional Cr500 per ton.

 

[Condottiere]

Depends on what the extension is made from.

If it's thin plastic, won't add much in volume, or cost.

 

[Terry Mixon]

Depends on what the extension is made from.

If it's thin plastic, won't add much in volume, or cost.

I would imagine it is material as tough as the airlock itself. I'm not thinking a flexible tube here. It needs to be able to stand up under use.

 

[rinku]

Yeah. If you have two hatches mated, they basically form a rudimentary airlock and you can depressurise the room on your ship to deal with the room on the other ship being in vacuum. Although if they're both pressurised you just have one combined vessel which has an interior door at that point.

Extendable tubes could be made to fit big cargo hatches.

 

[Terry Mixon]

Yeah. If you have two hatches mated, they basically form a rudimentary airlock and you can depressurise the room on your ship to deal with the room on the other ship being in vacuum. Although if they're both pressurised you just have one combined vessel which has an interior door at that point.

Extendable tubes could be made to fit big cargo hatches.

Looking at the most likely sizes, a 10-ton airlock would handle the standardized cargo.

 

[phavoc]

I'd expect that standard airlock extensions would not be compatible with standard cargo hatches (assuming you are talking a hatch big enough to take a standardized container (at least). The two things are just too different to easily size between them.

Sure, you could do some hand wavium and make 'universal' docking extensions, but that seems too easy. I'd expect cargo hatches to come in all kinds of sizes - from a standard container, to one that might take 4 at the same time (stacked 2x2), or even larger. A lot depends on the expected mission of it - is it expected to open in a vacuum, or just landed on the planetary surface? Interfaces are going to be standardized across space (or at least by race) as it makes too much sense for the interoptability. There MIGHT be some variations between Imp and Zho, but that's where I'd let the 'universal' idea work.

Assuming a station regularly saw cargo pods then it might make sense for it to have a receiving bay to allow them to be brought inside, the doors closed and it processed. A standard hangar bay for a starship or large shuttle could also double as a cargo pod receiving bay. Though without dedicated facilities it slows things down - which is quite normal if the cost of a dedicated space is not justified through volume.

As for 'docking' with a cargo pod.... maybe? But that would kind of mean the ability for the station side (wouldn't be economical to make it standard on all pods) to have the ability to kind of 'swallow' one end of the pod so that a good seal could be established and the doors opened. Think of it like a standard tractor trailer loading bay that lets doors swing out and the pads on the bottom/sides keep out the weather. Certainly doable, but again, without the volume it may not be something you'd see at smaller stations. Engineered right (on both station portion and the pod) it should be quite safe to do so. And certainly technically feasible. Depending on how safe you'd want things to be would kind of dictate just how much of the cargo pod is inside the docking extension. If you really wanted to make it safe, which is not a bad thing in space, have it so that the section extrudes from the station hull a meter or two and there is an internal door that can be closed if their is a problem, sealing off the pod and your extension. Easy-peasy!

 

[Terry Mixon]

The way I see it, a docking clamp would be needed to secure the cargo pod. For each range, the extendable cargo airlock would be set up at the standard location on that range of pod so they could mate. It's not universal, though it likely is standardized.

A recieving bay would work for smaller pods. 30, 300, even 2,000 tons. Maybe even 5,000 tons. The monstrous 50,000 ton pods carried by the biggest merchant tenders would almost certainly need to be external. Cost-wise, all of them could attack to the appropriate docking clamp and load/unload so long as the cargo hatch is where the extending airlock needs it to be.

I like your extension, though. Good one.

 

[Condottiere]

 

[Condottiere]

 

[Fluffy Bunny Feet]

Looking at the most likely sizes, a 10-ton airlock would handle the standardized cargo.

For small ships this would not even be wasted space as the first cargo to come off would be loaded last and left in the airlock.

 

[swordtart]

I just depressurise the cargo hold. The small craft cargo pods handle it in space, vehicles on the ground. The only time you need to pressurise the cargo hold is if you have live cargo (though that would likely be a stable and have its own bulkheads and pressure doors) or for transiting to engineering if your ship is configured that way. Often there is a discrete pressurised walkway but donning a Vacc-suit isn't unprecedented.

Some ships might run with their cargo hold pressurised most of the time (so it can be used as supplementary recreation or workspace), but even these will depressurise when taking on cargo in space.

 

[ottarrus]

Seems to me that cargo locks are standardized per tonnage scale... 200 - 1000 tons have a Small Cargo Lock, ships of 1100 - 5000 tons have a Medium Lock, and 10k + ships either have Large Locks or are loaded via work pods.
Pressurization is a time waster, the cycling of locks and all, but one that's accounted for in the load schedules. A 'slow load' allows the crew in the cargo bay of the receiving ship to work in shirt sleeves, which is more comfortable and somewhat more efficient, and a 'fast load' is done in vacuum with everyone in suits.
I don't see a whole lot of gearheading needed in all this. It's pretty much a handwave where the referee says 'It takes [x] hours to load and stow your cargo'.

 

[mb345345]

I just depressurise the cargo hold. The small craft cargo pods handle it in space, vehicles on the ground. The only time you need to pressurise the cargo hold is if you have live cargo (though that would likely be a stable and have its own bulkheads and pressure doors) or for transiting to engineering if your ship is configured that way. Often there is a discrete pressurised walkway but donning a Vacc-suit isn't unprecedented.

Some ships might run with their cargo hold pressurised most of the time (so it can be used as supplementary recreation or workspace), but even these will depressurise when taking on cargo in space.

Imtu most cargo loading is done by bots with grav propulsion. They've become so ubiquitous I had to stat them out

 

[Condottiere]

Air being a rather rare commodity, likely sucked back into the main air reservoir.

Small cargo holds can likely be isolated and depressurized, as a matter of course.

Volume, configuration, and cargo packing, could be standardized for that.

 

[Terry Mixon]

I just depressurise the cargo hold. The small craft cargo pods handle it in space, vehicles on the ground. The only time you need to pressurise the cargo hold is if you have live cargo (though that would likely be a stable and have its own bulkheads and pressure doors) or for transiting to engineering if your ship is configured that way. Often there is a discrete pressurised walkway but donning a Vacc-suit isn't unprecedented.

Some ships might run with their cargo hold pressurised most of the time (so it can be used as supplementary recreation or workspace), but even these will depressurise when taking on cargo in space.

According to the Starship Operator’s Manual, a standard cargo container isn’t necessarily pressurized. That means you don’t know what you’ll get and the default needs to be keeping the bays pressurized. That means airlocks for cargo transfer are a thing.

 

[Condottiere]

Pressurization doesn't cost life support, so the default would be to let them.

 

[swordtart]

According to the Starship Operator’s Manual, a standard cargo container isn’t necessarily pressurized. That means you don’t know what you’ll get and the default needs to be keeping the bays pressurized. That means airlocks for cargo transfer are a thing.

View attachment 5398

Just because a container isn't sealed. doesn't mean it needs to be pressurised. A container full of ore can sit in vacuum quite happily. If it important for a cargo to remain under pressure, it is the shippers responsibility to ensure the container is pressurised, not for the carrier to ensure it is kept in a pressurised environment.

If you send a glass vase unprotected in a burlap sack if it gets damaged in transit it is your problem.

Airlocks for cargo are only a thing if you want them to be.

 

[Terry Mixon]

Just because a container isn't sealed. doesn't mean it needs to be pressurised. A container full of ore can sit in vacuum quite happily. If it important for a cargo to remain under pressure, it is the shippers responsibility to ensure the container is pressurised, not for the carrier to ensure it is kept in a pressurised environment.

If you send a glass vase unprotected in a burlap sack if it gets damaged in transit it is your problem.

Airlocks for cargo are only a thing if you want them to be.

With all different kinds of cargo, being able to remove atmosphere would be hit or miss. You do your universe your way, but it sure seems that the default should be a pressurized cargo bay.