Ground Vehicle Reality check, and spaceships question

[YankeeGamer]

First of all, do any of the Spaceships supplements have rules for ground drives, such as massive tracks, allowing the construction of Jawa sandcrawlers, Ogres, and other supremely large vehicles?

Second of all, reality check, not game rules--would it even be possible to make a crawler in the quarter-million tone range that was armored and carried a useful payload. Full life support, fusion power...the works, and a crew of many hundreds, including labs, passengers, and more.

[Anthony]

You could make an almost arbitrarily large ground vehicle as long as it's flexible and doesn't have too much mass per unit area, but the result would be a train (if you stretch it in one dimension) or something like a crawling mat (if you stretch it in two), and it would basically have the stats of a swarm of smaller vehicles that happen to be linked together, rather than a single large vehicle.

[awesomenessofme1]

Originally Posted by YankeeGamer

First of all, do any of the Spaceships supplements have rules for ground drives, such as massive tracks, allowing the construction of Jawa sandcrawlers, Ogres, and other supremely large vehicles?

Not a Spaceships supplement, but Pyramid #3/34: Alternate GURPS has an article ("Alternate Spaceships") that includes rules for ground vehicles.

[YankeeGamer]

The terrain it will be driving over is Earth's frozen atmosphere, and in most places, it's relatively smooth, as it turned to liquid first. A train has a terrible visual appeal, but much longer and wider than it is tall would look cool. Speed--well, it doesn't get into races; 20-40 mph top speed on the flat is just fine. "I cannae give ye 40 miles per hour much longer, captain, we're gonna blow the tracks!"

Ground clerance should be pretty good generally.

How deep would a frozen atmosphere be? A lot of the planet will be sticking up above the smooth surface, and thus require smaller exploration craft.

I'm looking at a quarter million tons--well, call it 300,000 since that's a spaceships hull size. I'll definitely be making use of the smaller systems rules.

Meanwhile, I might just wing it, with the propulsion occupying 1 space in each hull section. Cost is unimportant, much as the cost of the Enterprise didn't matter to Captain Kirk

[Agemegos]

Originally Posted by YankeeGamer

How deep would a frozen atmosphere be?

Atmosphere pressure is about 101 400 N/m² and the force of gravity is about 9.8 N/kg, so the mass of the atmosphere is about 10 347 kg/m². The density of frozen nitrogen is hard to find out, but about 1 040 kg/m³, so your frozen atmosphere will be roughly 10 m deep.

Since the air liquefied first it will have run downhill and formed a layer about 14 metres deep over the frozen oceans and lakes. Everything more than 46 feet above sea level will be exposed.

[Agemegos]

Originally Posted by YankeeGamer

Second of all, reality check, not game rules--would it even be possible to make a crawler in the quarter-million tone range that was armored and carried a useful payload.

There are some 14,000-tonne coal loaders in Germany. If I recall correctly Bagger 293 is the largest of them. It does 0.65 km/hr.

[Celjabba]

I think the Nasa crawlers are still the biggest self-propelled land vehicles, at a bit under 3k ton.

B293 excavator is over 14k ton, but need to be plugged in a 16MW power source.

Heaviest train was just under 100k ton loaded, with 682 ore cars.

None of those come anywhere near the speed you want.

You could probably have a quarter-million tons train, as long as you keep the weight per axle low enough. It would be about 20 km long, however.

Keeping the ground frozen would be a challenge however.

[YankeeGamer]

NASA's crawler is designed to go a short distance with a huge object on its top deck, so speed was not an object. Likewise, the coal loaders are not intended to move quickly. I'm actually thinking of something that looks similar to the NASA crawler--wide and fairly flat, with massive tracks at each corner. As I think of the scale that its operating under, 5 to 10 MPH should suffice; at 5 mph, crossing the Atlantic would take about a month--a perfectly acceptable time frame.

With the planet in interstellar space, would there be danger of liquifying the atmosphere?

Here's a tentative design (and a bit of rule of cool if need be to allow it to function)

Enterprise class Megacrawler

This is a crawler designed for long range exploration on a “Pail of Air" scenario, long after the disaster. Utterly enormous, this SM +13 vehicle is expected to be away from known settlements for years. Tech level is overall 9, with weapons and communications being at TL 8. It’s rectangular in shape, perhaps 1000 feet long, 500 feet wide, and 200 feet thick. There is an enormous tower at the “front” of the Enterprise, bristling with sensors. “Front" is in quotes because it is fully bidirectional. It has a ground clearance of somewhere around 75 to 100 feet, but there will be places that it simply can not go. For that purpose, it carries 10,000 tons of smaller surface exploration vehicles in an underbody hangar. Cargo might include some disassembled replacements.

The whole system crunches across smooth terrain at a blistering 5 to 10 MPH cruising speed, and slower when it needs to pick its way through more challenging terrain. High ground clearance and the sheer mass and toughness of the vessel means that things like a small orchard or even abandoned homes can be treated as relatively smooth. (The limits of the machine will be discovered on its maiden voyage.)

Systems Table:

Front
(1) Metallic Laminate Armor dDR 70
(2) ?????
(3) Habitat 30 workspaces, 1000 spaces, total life support
(4) Possibly Open Space
(5) Enhanced Multipurpose Sensor Array TL 8
(6) Tracks
CORE: Control Room

Central Hull
(1) Metallic Laminate Armor dDR 70
(2) Cargo 15000 tons
(3) Habitat 30 workspaces, 1000 spaces, total life support
(4) (Probably a refinery and mining using the smaller subsystems rule from Spaceships 7)
(5) Fabricator
(6) Tracks
CORE: Fusion Plant 2 PP

Rear Hull
(1) Metallic Laminate Armor dDR 70
(2) ?????
(3) Habitat 30 workspaces, 1000 spaces, total life support
(4) Cargo 15000 tons
(5) Hangar 10000 ton capacity
(6) Tracks

I just assumed that tracks would be one system per hull section, and guestimated the speed. The fusion plant is to run whatever weapons I install, and to generate heat enough to deal with interstellar temperatures.

There is a top deck, and the craft has full life support. Cargo is filled with spare parts for the first 5 year mission. The crew is probably going to be around 2000, including scientists, troops, etc. There will be weapons fitted for self defense; there are believed to be other surviving settlements, but no one knows who or if they will be friendly. I haven’t decided what weapons yet.


The open space is likely to turn into, at least in part, cargo, but a certain amount of open space is needed for growing fresh vegetables, a small park, and the like. (Since the home society has developed efficient, cheap excavation, open space is not in short supply despite their underground life.)

[awesomenessofme1]

Did you see my previous comment? Tracks, wheels, and other systems for land vehicles is available in Pyramid #3/34.

[Varyon]

The tracked drivetrains in Pyramid #3/34 only allow for vehicles up to SM+10. However, that's probably assuming a spherical or cylindrical vehicle - a flat one can probably work out alright at a higher weight class. A vehicle can have up to 2 tracked drivetrain systems; having one lets it go up to Move 3/30 (top speed ~61 mph) for 3 Power Points, having two lets it go up to Move 6/55 (top speed 112.5 mph) for 6 Power Points (regardless of how many you have, it's Move 1/10 per Power Point, with the exception of the Move 6/55 at 6 PP). For your desired top speed of 5-10 mph, it needs ~0.08-0.17 systems worth of tracked drivetrains, powered by up to 0.25-0.5 PP. An SM+11 system on an SM+13 vehicle would be 0.1 systems - one will work for a top speed of 5 mph (it technically would let you go up to Move 0.33/3.33, just shy of 7 mph, for 0.33 PP), two will work for a top speed of 10 mph (technically, Move 0.67/6.67, just over 13.5 mph, for 0.67 PP). If being over the technical size limit is problematic for you, saying it's actually 6 SM+10 systems works, so long as the vehicle is no taller than an SM+10 one would be (so, an approximate height limit of 50 yards - roughly 10 storeys tall - or so). At only 0.2 systems (for the 10 mph version), this frees up 2.8 systems worth of space compared to your current design; if you don't have anything else pressing, I'd suggest more cargo capacity. The vehicle is probably fine leeching power from the core power plant (at 10 mph, it uses up 0.5 PP; the remaining 0.5 should be enough to run the fabricator, as well as the refinery or mining system; if you need to mine and refine while on the move, you'll need to dedicate half power to the fabricator, which should result in half fabrication speed).

Just in case you're not familiar with the Move n/m designation, it means you can accelerate up to n yards per second each second, to a maximum speed of m yards per second. So, with Move 0.5/5 (requiring 0.5 PP), from a dead stop you move 0.5 yards the first second, 1 yard (total distance moved = 1.5 yards) the next second, 1.5 yards (total 3 yards) the next, and so forth, until you reach the top speed of 5 yards per second (just over 10 mph) the 10th second; beyond this, you're at Move 5 until you opt to slow down.