NASA is making a rule that some people from China can't help with its cool space projects anymore.
They want to keep their space secrets safe and sound, so only certain people can work on the rockets and robots.
The United States and China are both trying hard to explore space, which is like a big race to see who gets to the moon first.
It's a very exciting time for space travel, with many discoveries yet to be made by scientists and astronauts.
