You could adjust the population modifiers so that space yard rate is low until you hit 2 billion people.
But, really, why should a planet be unable to build a spaceyard before reaching 2 billion people?
We could set up a spaceyard on earth's moon, and run it perfectly fine with a few thousands of people. The small planet/low gravity just makes things easier to launch when they're done.
And its not as if the resources have to be produced locally.
PS:
As for multi-slot shipyards, you CAN do that!
All you need to do is:
- copy a normal spaceyard facility, and name it "SpaceYard expansion Project" or somesuch.
- make sure the expansion facility has the same family number as the other space yards, but HAS ZERO SPACE YARD ABILITIES
- give the expansion facility a roman numeral of zero.
- place the expansion facility BEFORE the other space yards in the facility.txt file.
In game, you build the Expansion facility, then upgrade it to a full-fledged shipyard.
Suddenly, you have a two-facility-slot sized spaceyard with double the production.
If you prefer, you can make the expansion upgradable only into a weaker copy of the shipyard, or a "resource X only" shipyard.
With that sort of thing, you can custom-build your spaceyards, say having a Core yard (2k/2k/2k) plus 3 mineral expansions (+3k/0k/0k) plus a rad expansion (0k/0k/+1k)
For a total of 5k minerals, 2k organics and 3k rads of build rate per turn, and taking up 5 facility slots.
[ July 31, 2002, 00:20: Message edited by: Suicide Junkie ]