The spaceport is a Megastructure that has little to no combat values, but can help the planet it orbits and its constructor economically.
Spaceports decrease industry cost of all structures on a planet, as well as generate a small percentage of planetary sales as revenue for the owner. If multiple spaceports are in orbit then the profit is split between the owners of the spaceport. At level 1, a Spaceport reduces industry cost by 1% and generate .1% of all sales as revenue. This caps at 10% industry discount and 10% revenue.
Spaceports are excellent investments for growing planets, but the four-Megastructure maximum around a planet can make placing one problematic.
A Spaceport must be built as an ACP, costing $250,000,000 and taking 100 turns. At level 1, they cost 15,000/turn.