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Gravity Wells

Posted: Wed Oct 15, 2014 1:08 am
by Mark
Given that the Ship Yard appears to be on-planet, the primary energy cost for most forms of space travel should be takeoff and landing. It would be interesting if smaller worlds imposed a smaller deuterium cost on space ships traveling from there; this would balance the more limited space available for development.

Re: Gravity Wells

Posted: Wed Oct 15, 2014 1:33 am
by fusion
So you are saying the smaller planets should allow less deuterium usage in trade of having less building fields?

Re: Gravity Wells

Posted: Wed Oct 15, 2014 1:19 pm
by athight
That's an interesting concept, possibly only implementable in new universes since the existing ones have long established players...
But definitely worth considering for the future.

Re: Gravity Wells

Posted: Wed Oct 15, 2014 2:37 pm
by Ozymandias
Good idea, but is it too complicacted?

Re: Gravity Wells

Posted: Wed Oct 15, 2014 10:34 pm
by Mark
fusion wrote:So you are saying the smaller planets should allow less deuterium usage in trade of having less building fields?
Not necessarily, but to be realistic, they should. It wouldn't really be complicated, just another term in the deuterium calculation that looked at the number of fields in your planet. Offhand I don't know whether there should be a one-to-one ratio between number of fields and energy required, but I'll look into in when I have the chance.

Remember, interplanetary travel is like putting on your climbing gear, hauling yourself and your bike up out of a giant crevice in the ground, riding your bike through a few roundabouts and stop signs, and then pulling out your parachute and jumping off of a cliff. Climbing out of that first crevice is back-breaking labor; a person could get pretty fit doing that every few weeks.

Re: Gravity Wells

Posted: Wed Oct 15, 2014 11:12 pm
by Mark
Yes, the calculation is simple. Because potential energy U = -GmM/r, and assuming constant density (p) across planets allows M to be taken as pR^3, this gives:

U = -Gmpr^2, for U(r) proportional to r^2.

But the number of fields should be a function of planetary surface area, something like n_fields = k*A, where k is a value between 0 and 1 expressing the usable land area. Given that surface area A = 4*pi*r^2, if we restrict k to similar values across planets, we find

n_fields = k*pi*r^2, for n_fields(r) also proportional to r^2.

Thus, a very simple linear modifier could be added to all ship movement, once for leaving the home planet (and preferably a second time for leaving the target planet if landing took place), something as simple as

Deuterium for liftoff = (Ship Fuel Consumption)*(n_fields / 500).

This would need to be added on after calculating deuterium spent on the journey, as it couldn't be affected by travel speed. The original deuterium cost for journeys would of course need to be scaled back by something like 50% to keep ship travel averaging about the same, but that would realistically allow easier travel from smaller, gravitationally weaker worlds and more costly travel from larger worlds.

(Please note that I carried this analysis out for fun, not in an attempt to strongarm or guilt Zorg into making these changes.)

Re: Gravity Wells

Posted: Wed Oct 15, 2014 11:38 pm
by athight
Query: do you envisage the number of fields including fields from terraformers? I'd imagine it wouldn't but it's debatable..

Re: Gravity Wells

Posted: Thu Oct 16, 2014 5:26 am
by Mark
That's a good point; it shouldn't. If the original number of fields isn't a clearly defined number, you would then need

Deuterium for liftoff = (Ship Fuel Consumption)*(n_fields - terraformer level) / 500

or something similar.

Re: Gravity Wells

Posted: Thu Oct 16, 2014 8:39 pm
by ach
it might be unrealistic to add deut. usage for the terraformer, since the terraformers are apparently used to create landmasses, but from what? probably the rest of the planet

likewise, should there be an increased cost of launching from moons?

this might help balance out the bigger fleeters, but only some if at all

Re: Gravity Wells

Posted: Fri Oct 17, 2014 1:46 pm
by the_real_impachik
It's a nice idea to have some tradeoff to smaller world i.e. that it can have some benefit and not just the cost of fewer building fields,

However I think that following the logic of this, all moons should have a much lower deut cost than launching the same fleet from planets. As it is mainly noobs that launch from planets, I don't see much in-game benefit from this idea.