How do ships dock with another ship?

[vutpakdi]

How do ships "dock" with another ship?

Do ships park near each other and people zip across in vac suits and maneuvering packs?

Or, is there some sort of docking collar/tube built into airlocks? My idea is that there is some sort of really short (less than 3 m), rather flimsy docking tube built into airlocks. When a ship "docks" with another, the tube extends and forms an airtight seal against the hull of the other ship (or meets the other ship's collar half way). The tube has a walkway (for magnetic boots) but no gravity.

What do you think?

Ron

 

[Morte]

Well, the T20 Kursis Charter mentions docking to a disabled ship airlock-to-airlock and stabilizing it through (not necessarily huge) buffeting via that coupling. So that implies a robust, rigid joint.

No, I can't get it to make sense either.

 

[far-trader]

It's my take that it will vary with the ships and circumstance.

There would seem to be two standard (yeah, you'd think standard would mean one ) airlock hatches, in two standard models (again

).

First you have your 1.5m x 3.0m (gross measure, actual opening somewhat less at about 1.0m x 2.0m) walk through model most common on ships with horizontal decks (parallel to thrust). It is usually a powered iris hatch, with auxiliary manual control. The other model is a swing or pivot manual only hatch. If the hatch is part of an airlock then it will include an accordion like extendable mating tube like you describe, capable of sealing against the hull of another ship or connecting to the other ships tube.

Second you have the same models but in a 1.5m x1.5m (gross measure, actually about 1.0m diameter opening) vertical hatches, more common on vertical decks (perpendicular to thrust). It has the same features as above.

The mating tube ends can be configured to match either type so connecting between the two is no problem, the only tricky bit is the zero-g tumble twist from one orientation to the other. As for the length there is a picture in a MT adventure (which one I'm not sure right now) showing a Type P and Type A 'parked' close to each other in space and a fairly long and rigid looking tube between the airlocks. From memory I'd say about 15m long and I think it goes from the Type A's horizontal to the Type P's vertical. Or was it the other way around? That picture is a big part of my choice of how it all works.

The only place I'd use a connection you can just walk through would be at a starport and it would have artificial gravity so normal non-spacers can get off and on the ship with ease. These would be made to mate with either the simple walk out horizontal type or the climb up vertical type.

 

[Granpafishy]

I don't know which version you're using, but with T4's FFS, it has a "Umbilical Docking Tube" That has a 50m reach, takes up 35m3 volume and 2.5m2 area.

 

[kaladorn]

I'd guess that you might have a docking system like in Event Horizon. The collapsible umbilical plus a number of retractable hydraulic arms with couplers of various natures on the end which 'hard dock' one ship to the other. In order to affix such a system, or even the 'soft dock' with just the umbilical tube, you need to match the spin, yaw, whatever of the other ship.

 

[Hecateus]

Somewhere around here there is a link to a NASA page on such things. edit: > TA-DA! <

Basically, I figure that docking mechanisms of each ship 'lash' together. A docking umbilical connects the special hatches placed for this pourpose (as needed, some ships can directly connect hatch2hatch), and an inflatable passageway is created along the umbilical. Bigger ships use a bigger umbilical to move bulk containers. Placement of the hatches vary, and can create some odd problems for gravity decks.

edit: from memory, the Shuttle docks with ISS from underneath the station for orbital rendevous reasons. It connects via it's hatch to a static umbilical/storage module underneath the station.

For most external hatches, docking or no, I imagine something simple and solid like those pressure doors found in commecial jetliners.

 

[savage]

It would also vary with the type of ship and or purpose. A vessel with a higher need to dock would have additional infrastructure (docking tubes) versus a hardened airlock, or open space docking tube.

MT Rebellion sourcebooks' adventure shows a patrol cruiser with an extended tube to a free trader. Patrol Cruisers have a higher need to dock safely in space. They'd also want a clear line of fire for weapons when wanting to board possible smugglers, move materials or personnel between their vessel and a boarded vessel.

So how would docking vary;
1. hardened air lock (probably all are hardened)
a. Possibly an extendable or shot line between the two vessels similar.
2. A no atmosphere, open, flexible docking tube.
3. A no atmosphere, enclosed flexible docking tube.
4. A atmoshere, enclosed, flexible docking tube.
5. A atmosphere, enclosed, hardened docking tube.

This doesn't include the high tech alternatives with gravitics, repulsors/tractors, and whatever.

There would also be variation by TL. Lower techs would prefer the first 2 alternatives...

Savage

 

[kaladorn]

You forgot 'boarding torpedos'.

There are reasons ships might not want to 'hard dock', even though it is safer. A corsair might want to not run the risk of getting stuck/tangled with a merchie when the PC shows up to investigate. Marines might be used to board while a Navy ship stands off a bit rather than coming directly into contact with a suspected 'Freedom Fighter' ship if the FF turn out to be a bit.... 'twitchy and martyrlike'.

There will be a variety of standard methods of docking. I say standard because this will let people buy and sell standard parts, things will mate up cleanly, etc. Think of how we do doors nowadays - there are a pile of standard sizes and types. You *can* get custom doors, but most people don't. Similarly, most locks/boarding solutions will fit some standardized formats.

 

[Jame]

What about a collapsible tube that's part of the airlock? It would take up a bit less space 'cause it's part of the lock's mechanism.

 

[kaladorn]

I assume that you may have several configurations of airlock:

Airlock, no boarding tube.
Airlock, flexible boarding tube
Airlock, collapsible rigid boarding tube

Also, airlocks are *unlikely* to be Iris hatches. For safety and integrity reasons, they are likely to be hinged hatches or roll-away. But they may be automatic or manual.

This is, of course, IMO.

And the airlocks we normally spec for ships probably don't have any differentiation particulars, so that's a matter of personal fluff until some gearhead puts this into the design system...

 

[Spinward Scout]

Yeah, I never understood why iris valves were used on outer entries. I would think the pressure would most likely suck the middle out towards vacuum (unless they used extremely hard and/or thick materials - at early Tech Levels this wouldn't happen), and as soon as the iris structure warped a few centimeters, you now have an opening to space. Think about it this way, unless you have the ship compartmentalized and the pressure doors closed all the time, the entire ship's air pressure is pushing on that one spot right in the middle of the iris valve where it's weakest - trying to escape to vacuum and equalize the pressure. I'm sure there's a good explanation of how this could be done right so what I described wouldn't happen... But I think about submarine hatches and how thick they have to be. And any submarine hatch is designed so the pressure pushes it closed. None of them open in - they all open out. Too much strain on the locking/closure mechanism if you don't. Too easy for the pressure to rip the door from it's frame. What does the Space Shuttle use? I think they were used because it looks neat on the outside of the hull..

just my .02Cr

Scout

 

[TheEngineer]

Hi Scout,

just remember that the highest pressure difference between in/out in space is normally just 100 kPa (~1 bar). Thats really not much and will not cause harm to even low TL structures.
If constructed in a correct way a valve could be as strong as any other open/close facility and so could resists pressure differnces in each direction.

Another important attribute of a valve might be, that it cannot easily be blocked in order to open it. But it might also be constructed to be able to CUT things getting between the valve elements when its closing.
For me, a major drawback of a valve would be, that its a nasty mechanical thing with a much higher tendency to malfunction compared to any normal hatch.

But to be honest, I like the valves mostly because they are much more "cinematic" than hatches

Besides:
The Spaceshuttle uses "normal" round hatches...

Regards,

Mert

 

[vutpakdi]

Originally posted by TheEngineer:

But to be honest, I like the valves mostly because they are much more "cinematic" than hatches

Maybe iris valves get used for outer hatches partly because of The Empire Strikes Back where someone (Lando?) goes through a dorsal iris valve to pick up Luke (who is hanging from the bottom of Cloud City).

Ron

 

[kaladorn]

The iris valve can probably be engineered to be good enough to hold in the air. But I think it is more mechanically complex than a normal hatch. Additionally, it would be probably harder to get open or closed if it stuck halfway (maybe not...). It just requires more things to function right, and when it comes to atmospheric integrity, KISS should be the rule.

 

[Hecateus]

These were used for hatches within the 'duck' network in the movie Alien. But not for outer hatches.