How to schedule Outlook to export calendar entries as ics file?

While Outlook 2010 offers means to manually export the calendar as ics file, is there a way to have this done automatically on a regular basis?

You can run an add-in or run VBA code. Outlook doesn't have the typical event triggers, so either way you do it, triggering the event which may cause the biggest challenge.

Add-In

Here is an add-in, called Calendar ImportExport, which can Import/Export the calendar in many formats. It is also able to be run from a command line which can help you use Task Scheduler to meet your "automatically on a regular basis" requirement. This add-in might be the easiest way, but costs $19.95(USD).

VBA

Here is a VBA Code example CalendarSharing.SaveAsICal Method;

The following Visual Basic for Applications (VBA) example creates a CalendarSharing object for the Calendar folder, then exports the contents of the entire folder (including attachments and private items) to an iCalendar calendar (.ics) file.

This will require you to adjust your macro security. I still haven't figured out how to call this code from an event trigger. Might be able to call it from Task Scheduler, but not sure how yet. Will update this answer when I figure it out.