How Astronauts vote from space? What does the law say?

US Presidential Elections is just around the corner, it will be against Democratic candidate Joe Biden and current Republican President Donald Trump. Both of them are involved in their campaigns. But during this election, some people are going to be in space. In such a situation can they vote? If they can, how will it be carried out? What does the law say for such special cases? Watch this video to know what American law says about this.