Changing a Baseline Requirement needs to be treated as a formal request for a change to the DM Functional Requirements Specification (FRS). The FRS is the highest level DM requirements specification, and is baselined at the LSST project level.

The process is:

• The DM System Scientist will write-up the request with a short description of the science case and any specific data requirements, and review the change with the Science Steering Team;
• The DM System Architect will assess the impact of the change in consultation with the appropriate DM Working Groups and then update the request with the impact analysis.
  • For example, when considering tradeoffs between producing a product "on-the-fly" vs. storing it:
    • the Data Access WG would determine the extent of new vs. replacement of existing schema placeholders, along with the net storage delta;
    • the Infrastructure team would estimate the cost delta for the change.
• The DM TCT will review the request and impact assessment in order to make a recommendation to the DM System Manager.
• The DM System Manager will examine the recommendation and the cost delta to determine if the change is affordable and compatible with LSST project schedules.
• If the change is compatible, the DM System Scientist will submit the change to the LSST CCB as a formal change request.

Should the DM System Manager determine that DM is unable to fund the change or it is incompatible with the DM schedules, he will advise the TCT of that determination. Should the DM TCT or the Science Council decide that the potential science rewards warrant it, the DM System Manager and System Scientist will then present the request to the LSST CCB to request additional DM funding or seek approval for a DM schedule delay.