system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Where do the rockets that a spacecraft leaves behind go?

If they fall down to earth does that mean they come crashing down on land or sea? And isn't that dangerous threat to people who may be on ground or maybe a ship like a Cruise ship?
gpt
>If they fall down to earth does that mean they come crashing down on land or sea? 

Yes

>And isn't that dangerous threat to people who may be on ground or maybe a ship like a Cruise ship?

Not really, no. We can predict the crash zone, and plan the mission to make that zone an empty patch of ocean. The location of launchpads all over the world are influenced by having good options for crash zones.