So a temp lock option might actually work. However, we do have to remember that this is probably happening due to the climate model in US2. Fire/lave, ice, water, even organics and mineral compositions are affected by how far or close a planet is to a star. Too close, it strips it all away. Too far, and it freezes over.
What you're saying is that a temp lock wouldn't be scientifically accurate, right? Well, I don't think that matters. The player will be aware that the temperature is constant because he manually chose to. It is also not scientifically accurate to instantly triple a planet's mass by simply changing the value in a field, for example. Anyway, I'm glad you agree with my idea
No, I wasn't implying it would make it inaccurate, I just said the climate model in US2 changes a saved planet's look, like water and ice, when placed in a new simulation. I was pointing out a possible reason for why your black earth was not the same, hence why I mentioned the climate. The climate dictates a planet's temperature, which is why it will be frozen, liquid water, or hot when placed in a new sim.
Climate in US2 overrides user input, that's why when you want to set a specific temperature for a planet, say, a hot Venus, but at the distance of our earth-to-sun, it eventually resets and levels out at the calculated temp at that distance.
Now this brings up a new idea. What if you wanted to have a certain planet trap most of its greenhouse gas and heat by making it a hot planet? For example, you terraform a planet, set a hot temperature, the atmosphere should trap that heat and NOT equalize just because the simulation wants to. An override, so to speak, instead of the climate itself being the main override. That would be cool. Then we could have planets further way from a star trap more heat, if we so desired.
Now, if you're wondering, this is where it would become inaccurate because then you could have a planet as far away as pluto, but have it be as hot as venus (or more). Its still a cool idea because I've been wanting to save planets with certain temps, hot or cold, and have them stay that way when I place them in a new simulation.
I think we'll get there eventually.