As noted in comments there are mirrors but if this is an operational concern for you or your business, the solution is simple; host your own repository.
There are at least two freely available tool for doing this. I prefer Artifactory and there is also Nexus.
You set up all internal maven clients to connect to it instead of repositories elsewhere. Your repository then goes out to Maven central et. al and caches those artifacts.
This way you'll always have access to all the artifacts that you've been using. If Maven central goes away, you won't be left with broken builds.