On RHN Satellite, alert-rhnsat.log has "ORA-1122 signalled during: ALTER DATABASE OPEN" during start of oracle service

Issue

• On RHN Satellite - oracle service cannot start or stop cleanly.
• Trying to login using sqlplus fails with error :

sqlplus $(spacewalk-cfg-get default_db)
SQL*Plus: Release 10.2.0.4.0 - Production on Sat Jul 13 13:39:26 2013
Copyright (c) 1982, 2007, Oracle.  All Rights Reserved.

ERROR:
ORA-01033: ORACLE initialization or shutdown in progress

Enter user-name: rhnsat
Enter password:
ERROR:
ORA-12162: TNS:net service name is incorrectly specified

SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus

• In alert_rhnsat.log we see :

ALTER DATABASE OPEN
ORA-1122 signalled during: ALTER DATABASE OPEN...
Sat Jul 13 07:42:47 2013
WARNING: inbound connection timed out (ORA-3136)
Shutting down instance: further logons disabled