如图

单个文件不要超过4GB，请看官网上的手册说明。
spaceengine.org/manual/making-addons/planet-textures/
http://spaceengine.org/manual/making-addons/planet-textures/
第六部分，第三小节：
3) The pak file should be less than 4GB in size. If your addon is bigger than that, split it into several smaller pak files.
pak文件应该要小于4GB。如果你的插件大于这尺寸，分成数个小的pak文件。