In your games what is the largest ship that can land on a planet.

[Grav_Moped]

Square-cube law. (Wikipedia).
Volume (and presumably mass) increases faster by tonnage than the ship's footprint.
Large enough ships will settle into solid ground unless the landing pad is literally, cleared bedrock all the way across (and maybe even then, if it's large enough). And settling unevenly might do not-nice things to the hull.

 

[Marcatlas]

Square-cube law. (Wikipedia).
Volume (and presumably mass) increases faster by tonnage than the ship's footprint.

A little flaw in your ointment. The square–cube law (or cube–square law) is a mathematical principle, applied in a variety of scientific fields, which describes the relationship between the volume and the surface area.

If the average weight off a ton of starship is 1000 kg then a 100 ton ship would weight 100,000 kg. and a 200 ton ship would weight 200,000 kg.

 

[Grav_Moped]

A little flaw in your ointment. The square–cube law (or cube–square law) is a mathematical principle, applied in a variety of scientific fields, which describes the relationship between the volume and the surface area.

If the average weight off a ton of starship is 1000 kg then a 100 ton ship would weight 100,000 kg. and a 200 ton ship would weight 200,000 kg.

... But the surface area of the bottom wouldn't scale linearly by volume.

 

[Marcatlas]

... But the surface area of the bottom wouldn't scale linearly by volume.

Doesn't need to scale by volume. Volume doesn't matter. You scale by WEIGHT. You picked the wrong paradigm. If the landing feet on the 100 ton ship have 8 square meters of surface area, the feet on the 200 ton ship just need to be 16 square meters to exert the same ground pressure per square meter

 

[Spinward Flow]

Starship plus booster is currently 5000 metric tons.
Elon has plans for bigger things to come

 

[Enoki]

I tend to assume that what really matters to see if a ship can 'land' planetside is the capability of the local infrastructure to handle it.

Big heavy starships will need pads or runways capable of handling their weight, both mobile and stationary. They're also going to need more specialised equipment for fueling, loading/unloading and passenger transfer. While a 1000dton ship might get away with packed earth landing pad and a top off into the purifiers from the local water supply a 10,000dton ship isn't going to have a good time at any port not capable of handling a ship of that size.

If the ship is stationary when it lands (no 'rolling' landing like a plane), all it needs is the ground pressure exerted by the landing surfaces in contact with the ground to be sufficiently low that the soil will support it. Landing on water, the ship needs to be designed such that it:

A. Has sufficient reserve buoyancy to float
B. That it is of such a shape that wave motion etc., won't capsize it.

If the ship has to move over ground while in contact with it then total weight becomes an issue as that coupled with the vibration of movement can destabilize the soil and cause the ship to sink in on soft or not fully compacted ground.

 

[bookwyrm]

Aramis mentioned long ago that in his Traveller, 5k dton is the biggest that can land on a planet. I went with that for my Traveller. Larger ships have to stop at a high port.

I consider these ships to be able to land at a star port or bedrock. Other surfaces can only handle lighter ships, while in a big enough water environment, they can float.

 

[Condottiere]

You could specify how much tonnage each landing pad can support.

Wilderness, might require keeping the lifters running.

 

[warwizard]

For the HePLAR adhearants landing with cargo is what we are talking about, it is not 1mt/DT the ship's average density depends on what % of the internal volume is fuel tanks which are 1mt/DT. a 100 DT ship at J-1 1g might have only 25% if the internal volume as 1mt/DT. the rest of the ship is 2 DT of jump drive at 2 to 3 mt per m3. Power plant at 6 to 2 mt/m3 depending on TL and so forth. The average J1 ship is a lot closer to 5mt/DT and armored warships come closer to 10mt/DT. Now this is all empty weights. Merchants will be landing with a cargo aboard which for the J1 ship is likley to have at least the density of water, and that is close to half of the ship's internal volume which pushes the average density up to 10mt/DT. so for a safe landing a unstreamlined ship needs to have at least 10,000 mt of thrust per planet's g local, and fuel reserves to feed the HePLAR for (planet size) hours.

 

[punkrabbitt]

OK, so I am going to say my campaign would cap at about 5,000 dT, because that is about as big a ship as I ever expect the characters to interact with.

 

[Krikkitone]

Doesn't need to scale by volume. Volume doesn't matter. You scale by WEIGHT. You picked the wrong paradigm. If the landing feet on the 100 ton ship have 8 square meters of surface area, the feet on the 200 ton ship just need to be 16 square meters to exert the same ground pressure per square meter

Which effectively means a limit on the average HEIGHT of the landed ship. The ship could be 100 million tons and landed just fine if it is a massive flat pancake never any higher than ~10 meters. (of course it might be hard to find a landing spot big enough…a flat area ~11 km on a side)

If a ship is going to land that means it needs to have the stability of a building…. so the largest ship that can land is the largest building that can be built at that TL (at TL 11 there a buildings that are so large/designed to use gravitics to keep themselves from collapsing… although that might not fully count as landed..ie can’t turn the power plant all the way off)

 

[Marcatlas]

If a ship is going to land that means it needs to have the stability of a building…. so the largest ship that can land is the largest building that can be built at that TL (at TL 11 there a buildings that are so large/designed to use gravitics to keep themselves from collapsing… although that might not fully count as landed..ie can’t turn the power plant all the way off)

The Pentagon is about 164,000 tons (as Trav measures ships) and was built at TL 5. So, no trouble landing Traveller's largest ships

 

[Krikkitone]

Which effectively means a limit on the average HEIGHT of the landed ship. The ship could be 100 million tons and landed just fine if it is a massive flat pancake never any higher than ~10 meters. (of course it might be hard to find a landing spot big enough…a flat area ~11 km on a side)

The Pentagon is about 164,000 tons (as Trav measures ships) and was built at TL 5. So, no trouble landing Traveller's largest ships

They would have to be built like the Pentagon though (flat…no more than ~20 meters tall). No 300,000 ton spheres or 1km tall tail sitters landing (if they are made of TL 5 materials)

 

[Marcatlas]

They would have to be built like the Pentagon though (flat…no more than ~20 meters tall). No 300,000 ton spheres or tall tail sitters landing.

Just land the sphere on a hard pan plain and let it crush the ground down. It won't go far as there is only so much comprehensibility. And a sphere with a Trav ultra strong hull won't be harmed at all

 

[Krikkitone]

Just land the sphere on a hard pan plain and let it crush the ground down. It won't go far as there is only so much comprehensibility. And a sphere with a Trav ultra strong hull won't be harmed at all

(that’s not TL 5 materials though)….. That said a sphere made of TL 12+ could be large and land…. but there would be a size where it would get crushed by its own weight if landing. (wheras a flat disc the same tonnage would not get crushed by its own weight)

 

[Marcatlas]

(that’s not TL 5 materials though)….. That said a sphere made of TL 12+ could be large and land…. but there would be a size where it would get crushed by its own weight if landing. (wheras a flat disc the same tonnage would not get crushed by its own weight)

And neither are Traveller space ships. Yes, at some size it wouldn't work. But with a sphere shape that. would be VERY large. I have no real idea how large. But we always can have them land at lower grav planets. Would be a sight for the natives to see

 

[mike wightman]

Empire State Building - 365,000 tons. At ten metric tons per displacement tons that means a 36,500t tail sitter could land.

The Burj Khalifa at 500,000 tons is a 50,000t ship tailsitting.

 

[chipla]

Empire State Building - 365,000 tons. At ten metric tons per displacement tons that means a 36,500t tail sitter could land.

The Burj Khalifa at 500,000 tons is a 50,000t ship tailsitting.

Neither of those is just built on some spare land. There’s a significant amount of infrastructure (foundations, pilings and the like) that stops them sinking. In the case of New York this is failing (turns out building a city in a swamp isn’t ideal).

 

[mike wightman]

So the landing pad is built to the same standards as the building foundations. If the building stays up so would an AHL.

 

[whartung]

The Pentagon is not designed to handle the stresses of flight. I imagine it doesn't take bending very well, for example.