Extraplanetary Launchpad Integration

This release contains the last big piece of functionality that was defined at the start of the project - integration with Extraplanetary Launchpads. Now, building rocket parts is possible with the same tiered construction system that the rest of the mod uses. Building rocket-parts off-world is kerbal-intensive; you'll need bigger bases to be able to support it. To help with managing that, the dialog has been updated and reorganized to provide more information.