A Satellite contains the descriptive attributes of a Business Key. As such, a Satellite HASHDIFF should be constructed using the only the descriptive attributes of the Business Key. The Business Key, itself, should not be part of the Satellite HASHDIFF.
Note: While it is a common practice to include the Business Keys in the SAT to eliminate the need for JOINs to HUB to get the BKs, the SAT HASHDIFF should still not contain the Business Keys.