Automated download&installation of Errata Updates without RH Satellite.

Hello,

I have been browsing RedHat web reading and looking many information regarding the title of this discussion.Also I have read documentation about Spacewalk&Satellite.

Im going to explain what I have to do as I cannot use RH Satellite, so everything will make sense:

"I need to set up a machine which contanis up to date packages&updates&eratas (RHEL 5.9) so the rest of the platform will use it as a main repo(channel) server.I want to set up a local Yum repository, keeping it updated(reposync). "

Im new working with RedHat environments so I have some doubts I would like to clarify:

-Does an oficial Red Hat repo like "rhel-x86_64-server-5" contain errata&updates packages?
-Is it enough to make a "reposync" every night to have the repo updated?
-What is the difference between an oficial repo and the errata information?
-In case oficial repo doesnt contain errata&updates packages. How can I get this packages apart from manually download?
-I have read about spacewalk and the tool: spacewalk-clone-by-date. Is it what I need to download errata information?
-Can I use spacewalk-clone-by-date as a stand-alone tool without installing spacewalk?

I guess these are the questions I need to solve in order to achieve what I need, but It´s very luckily that Im missing something or what Im asking make no sense.

Thank you all for your time and help.