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Voidships vs. the Mighty Force of Gravity


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#1 bogi_khaosa

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Posted 22 January 2014 - 11:48 AM

OK this is probably more an engineering question than a game one. :)

 

For a game I'm going to run --

 

If a largish Imperial ship were on a planet's surface (Earth gravity), would it support its own weight? Or would it collapse?



#2 Brother Orpheo

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Posted 22 January 2014 - 12:51 PM

Interesting question. it might depend on whether it was constructed within an artificial gravity (enclosed void dry dock) or in the open void. Astronomical phenomena such as gravity riptides put a lot of stresses on a vessel, and I'm sure they're built with the understanding that they may run afoul of them from time to time. I'd say anything larger than a cruiser would fold. I think BFG had rules for low-orbit planetary assaults, and there have been a few (fluff) instances of voidships entering and leaving atmosphere, with the only noteworthy occurrence being the havoc this causes on weather patterns.

 

What's the context of your query? 


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#3 DJSunhammer

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Posted 22 January 2014 - 12:54 PM

I can think of three examples of an Imperial ship on or near a planet's surface. In two of them, the ships crashed and later relaunched back into space. In the other, the ship floated near the surface of Mars. Granted, the ship in the last case was the Emperor's flagship during the Great Crusade, so you shouldn't assume current Imperial ships can do what that ship did. I would think that most of the major Imperial ships could be able to survive a crash landing though, including the ability to support it's own weight without collapsing.



#4 Lynata

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Posted 22 January 2014 - 12:55 PM

Battlefleet Gothic had transports and frigates capable of atmospheric entry - anything larger than that would crash / break apart.

 

However, that is just one source of fluff, and we have a lot of products with a different take on the subject (possibly even Rogue Trader? not sure) ... also, OP's query sounds more like something looking for real world physics rather than the various contradictory instances of 40k pseudoscience?


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previous characters: Comrade-Trooper Dasha Malenko (1207th Valhallan Ice Warriors), Sister Elana (Order of the Sacred Rose), Leftenant Darion Baylesworth (Rogue Trader frigate Artemisia)

#5 Adeptus-B

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Posted 22 January 2014 - 02:11 PM

If this came up in my campaign, I would probably rule that anything smaller than a cruiser can land/take off, and anything cruiser-sized or larger cannot.


Edited by Adeptus-B, 22 January 2014 - 02:11 PM.


#6 LordBlades

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Posted 22 January 2014 - 02:13 PM

Kroot Warpsheres from Rogue Trader Battlefleet Koronus are battleship-sized and stated to be capable of landing/taking off planets.


Edited by LordBlades, 22 January 2014 - 02:14 PM.


#7 bogi_khaosa

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Posted 22 January 2014 - 06:40 PM

Interesting question. it might depend on whether it was constructed within an artificial gravity (enclosed void dry dock) or in the open void. Astronomical phenomena such as gravity riptides put a lot of stresses on a vessel, and I'm sure they're built with the understanding that they may run afoul of them from time to time. I'd say anything larger than a cruiser would fold. I think BFG had rules for low-orbit planetary assaults, and there have been a few (fluff) instances of voidships entering and leaving atmosphere, with the only noteworthy occurrence being the havoc this causes on weather patterns.

 

What's the context of your query? 

 

The characters are in a ruined ship (Hey guys don't read this!!!!), which has to drop out of the warp somewhere, and to make things easier I'm thinking of just having it materialize on a planet's surface.

 

I realize this may not be possible though, hmmm.



#8 Lynata

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Posted 22 January 2014 - 07:35 PM

It's the Warp. If you want, just about anything is possible. ;)

 

Including retransference into a planet. What better opportunity than to insert a bit of Journey to the Center of the Earth into 40k? Or Pandorum, if you will. With just a sprinkle of a certain Star Trek episode, which would also allow for some subtle horror elements.


current 40k RPG character: Captain Elias, Celestial Lions Tactical Marine   
previous characters: Comrade-Trooper Dasha Malenko (1207th Valhallan Ice Warriors), Sister Elana (Order of the Sacred Rose), Leftenant Darion Baylesworth (Rogue Trader frigate Artemisia)

#9 WilliamAsher

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Posted 22 January 2014 - 08:11 PM

Ships can survive landing.  It is just less likely the larger they are.  It depends on the surface they are on more than anything.  If a large ship is supported only at the ends, it will probably break up.  If it lands on a (relatively) soft surface that distributes its weight better, then it should be ok. 



#10 Kshatriya

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Posted 25 January 2014 - 06:08 PM

Rogue Trader has a ship background package that is essentially "this is an old ship that once crash-landed on a planet and was eventually recovered." Probably not under its own power. There are a lot of factors regarding if it could support its weight, in part the nature of the landing, whether void shields were active at the time, etc.



#11 WilliamAsher

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Posted 25 January 2014 - 10:03 PM

Faith and Coin has a crashed ship that broke up upon landing, but the players are able to determine that the void shields were intact when it crashed by how intact the ship is (other than breaking up).  Planetbound of Millennia is probably my favorite ship background, and the players ship in my campaign actually started still on the planet.  Lifting it was part of their first Endeavor.


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#12 bogi_khaosa

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Posted 25 January 2014 - 11:33 PM

I kind of want the thing to start collapsing in on itself all around the players under its own weight, making them have to find some way off as quickly as possible.



#13 Marwynn

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Posted 25 January 2014 - 11:34 PM

I don't think that larger vessels recovered from planetary surfaces were actually brought up in one piece. Maybe one piece at a time, then re-assembled in orbit.

 

Voidships are usually not meant to land. Lighter voidships, and by lighter I mean 6 million tons and less than 2km long, should be able to land. But a Light Cruiser or a Cruiser's roughly 20 to 30 megatons and about 5km long. This is why they have space stations after all.


Edited by Marwynn, 25 January 2014 - 11:35 PM.

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#14 bogi_khaosa

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Posted 25 January 2014 - 11:46 PM

The thing has antigravity, which I suppose could help offset its titanic weight. Until it loses power.



#15 Kshatriya

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Posted 26 January 2014 - 02:12 PM

I don't think that ANY RT ship is designed to land, even the really small or light ones. They all send down shuttles and heavy lifters to move cargo.



#16 Adeptus-B

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Posted 26 January 2014 - 02:40 PM

I kind of want the thing to start collapsing in on itself all around the players under its own weight, making them have to find some way off as quickly as possible.

 

Ah- in that case I would have the ship emerge from the warp too close to a planet, and the gravity starts tearing the ship apart, forcing the PCs to find Salvation Pods before it is completely destroyed. When the Pod lands on the surface, you can have a lot of fun with a fertile Imperial world being decimated by the wreckage (some it highly radioactive) raining from the sky, destroying settlements, causing a 'nuclear winter', etc. Somebody's got some 'splainin' to do...


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#17 Kshatriya

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Posted 26 January 2014 - 03:50 PM

As usual, blame the mutant (Navigator). :P


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#18 Radwraith

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Posted 30 January 2014 - 05:23 PM

Lynata is correct. In BFG, Escorts and transports could land while larger ships could not. However, The Blood angels flagship (Which was ostensibly at least a battleship) crashed and relaunched after essentially performing minor repairs and damage control! Further, In the old 40k epic had cruisers descending into low orbit to deploy troops (Via grav cones). The basic rule that I've taken is that while most ships (gm's call) are capable of entering the atmosphere and remaining airborne landing requires specialized receiving facilities (Docks) unless the ship is specifically capable of a "dry landing". (Such as an assault transport)

 

Further: It is hardly a "Routine" operation to bring a full sized voidship down for a landing. I have a whole set of "Houserules" that deal with this subject. 

 

As to the engineering involved: I think most voidships, given their descriptions would survive being planetside and might even be able to be re-lifted if repaired. A planet's surface is a relatively stable field whereas gravity riptides and warp rifts are not!

A voidship's hull is designed to deal with almost inconceivable stresses (Many shipboard weapons hit as hard or harder than a nuke in RT!) so the stresses of atmospheric entry pale by comparison. Even crashing often does not compromise the hull unless the ship was heavily damaged before hand (Which of course, It usually is if it crashed in the first place!). 

 

Anyway; This article has my thoughts on this:  https://drive.google...dit?usp=sharing


Edited by Radwraith, 30 January 2014 - 05:32 PM.


#19 Alrik Vas

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Posted 02 February 2014 - 01:40 AM

As usual, blame the mutant (Navigator). :P

Indeed, always blame the mutant!



#20 Brother Anselm

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Posted 02 February 2014 - 04:45 AM

In the Salamander Tome of Fire story a Strike Cruiser crash lands and after repairs to its engines manages to lift off again. A Marine Malevolent Strike Cruiser also descends into the atmosphere, low enough to cast a shadow and provide close fire support.






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