Depending on the data you need to pull, you may be able to get the data from the API and bypass creating and running export jobs and parsing text files. The <Astra> tag in the spoke is equivalent to the Query API in terms of what you can request. If necessary, a spoke can make direct SQL queries against our DB Report Views and, though we don't recommend it, our tables. That is not possible via the API.
For example, this API call would get all SandboxSections for a Sandbox:
where "X" is the URL encoded expression "SandboxId==<guid>". More fields can be requested, of course.
And the following query would produce a sequence of Course SisKey by Student SisKey pairs for a given Sandbox. Obviously, you'll want more information from the Sandbox Section and/or Sandbox Student as well, but this is essentially the schedule stored in the Sandbox. Getting the ID of the Sandbox could be another query for a well-known named Sandbox.
Y = Url.encode("SandboxSection.SandboxId=="+guid);