I know of no way to restore a deleted artifact but you can create a project baseline with a time stamp just before the artifact was deleted and open the artifact in the project history.

You can then create a new artifact in a separate browser tab/window and copy the contents from the project history view to the new artifact and set the attributes and links.

Now you do loose the comments and artifact history but least you can get the content back this way.

There is also the ability to change the permissions to remove the delete artifact from the author role, and create a new role so that only select people can delete. Some teams I know then create a trash bin folder where authors move artifacts to  that folder for separate deletion by those who have the delete role.