dependable submodules

I have a submodule from, example, github. I do not however want to be
reliant years from now, that this remote repository on github is in
existant. Yet, I want to be able to easily do a git pull in the
submodule as long as it's around.

Is there a way to achieve this?

IOW, I may have

    myrepo/somefile.txt
    myrepo/another_project/.git/...
    myrepo/another_project/another_project_file.txt

and I'd like to, when I clone repo, to be able to get all files from
repo independently of the remote repo's existence.

Currently, if I do `git clone --recursive myrepo new_repo` I can get
almost the behavior I want with the exception of the other project
being pulled remotely, which means I would *have* to have a network
connection to do so, but as mentioned, I don't want that dependency.

-d