Space stocks, including Rocket Lab, are experiencing a decline ahead of the SpaceX IPO. The reason for the decline is not entirely clear, with some outlets citing various factors such as a milestone achieved by a China rocket and an oil spike, while others suggest investors may be taking profits. The impact on different space stocks is mixed, with some outlets reporting declines for multiple companies, including Rocket Lab and Virgin Galactic, while others see potential for SpaceX to perform well.