1. Large Synoptic Survey Telescope (LSST)
  2. Change Control Process
  3. George Angeli and Robert McKercher
  4. LPM-19
  5. Latest Revision Date: December 10, 2015
    1. Change Record
    2. Table of Contents
  6. The LSST Change Control Process
    1. Summary
    2. Reference Documents
    3. Acronyms and Definitions of Terms
  7. The LSST Change Control Process
    1. 1 Introduction
    2. 2 Change Control Board (CCB)
    3. 3 The Process
      1. 3.1 Types of Change Request Submissions
      2. 3.2 Process Phases
    4. 4 Change Control Workflow
      1. 4.1 Voting Issue Workflow
      2. 4.2 Information Item Workflow
    5. 5 Voting
    6. 6 Change Control Board Meetings
    7. 7 Change-Controlled Document Archiving

LSST Change Control Process
LPM-19
Latest Revision Date 12/10/2013
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval of the LSST Change Control Board.
1
Large Synoptic Survey Telescope (LSST)

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Change Control Process

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George Angeli and Robert McKercher

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LPM-19

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Latest Revision Date: December 10, 2015
This LSST document has been approved as a Content-Controlled Document. Its contents are subject to
configuration control and may not be changed, altered, or their provisions waived without prior
approval. If this document is changed or superseded, the new document will retain the Handle
designation shown above. The control is on the most recent digital document with this Handle in the
LSST digital archive and not printed versions.

LSST Change Control Process
LPM-19
Latest Revision Date 12/10/2013
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval.
i
Change Record
Release
Date
Description
Owner name
1
5/4/2009
Initial Version superseding Document-478
Chuck Claver & Ruth
Kneale
2
6/19/2011
General Updates for NSF PDR
Victor Krabbendam
3
2/6/2013
Initial draft of a wholesale change to reflect
recently adopted changes to change control
processes and procedures. The changes simplify
and streamline the process and provide a
procedure document that is more clear and
concise.
George Angeli
3.1
2/10/2013
Incorporated comments from C. Claver and
Brian Selvy
G. Angeli
3.2
2/15/2013
Additional comments incorporated
G. Angeli
3.3
2/23/2013
Process clarified
G. Angeli
3.4
2/24/2013
Section 5 added and document formatted to
project standard
R. McKercher
3.5
5/17/2013
Added Section 4.1 describing the web-based
workflow.
R. McKercher
3.6
7/1/2013
General Editing
V. Krabbendam
3.7
9/2/2013
Editing
S. Kahn
3.8
9/3/2013
Implementation of LCR-135
R. McKercher
3.9
9/30/2013
Inter-document consistency fixes, formatting
and typo corrections. No content changed.
Changes approved via LCR-154
R. McKercher
10/4/2013
Implementation of LCR-157
R. McKercher
4
12/10/2015
Updated to include formal descriptions of
processes and procedures already being
followed. Improved grammar, syntax and
clarified descriptions throughout. Substantive
R. McKercher

LSST Change Control Process
LPM-19
Latest Revision Date 12/10/2013
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval.
ii
changes are: a) added subsystem chief
engineers to CCB membership; b) streamlined
workflow diagram and updated it to include
“PMCS-related”
and
“Approval
Pending NSF
branches;” c) added Section 3.1 Types of Change
Request Submissions to formally acknowledge
deviation requests and information items; d)
divided Section 4 into "Voting Issues Workflow"
and "Information Items Workflow" and added
descriptions of PMCS-related workflow for both
voting issues and information items; e) added
Section 5: Voting with explanation that voting
may be done at any time, defining three vote
options, and explaining that not voting at all will
be assumed to be "No Objection;" f) in Section 6
Change Control Board Meetings (was Section 5),
added third Wednesday of the month as
regularly scheduled meeting date and added
expectation that Chair will advertise items for
resolution at CCB meeting at least one week in
advance.
2/1/2016
Implementation of LCR-523
R. McKercher

LSST Change Control Process
LPM-19
Latest Revision Date 12/10/2013
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval.
iii
Table of Contents
Change
Record
...............................................................................................................................................
i
Summary
......................................................................................................................................................
iv
Reference
Documents
..................................................................................................................................
iv
Acronyms and Definitions of Terms ............................................................................................................. iv
1
Introduction
..........................................................................................................................................
1
2
Change Control Board (CCB) ................................................................................................................. 1
3
The Process ........................................................................................................................................... 2
3.1
Types of Change Request Submissions ......................................................................................... 4
3.2
Process Phases .............................................................................................................................. 4
3.2.1
Proposal Phase ...................................................................................................................... 4
3.2.2
Analysis Phase ....................................................................................................................... 4
3.2.3
CCB Review Phase ................................................................................................................. 4
3.2.4
Decision Phase ...................................................................................................................... 5
3.2.5
Implementation Phase .......................................................................................................... 5
4
Change Control Workflow ..................................................................................................................... 5
4.1
Voting Issue Workflow .................................................................................................................. 5
4.2
Information Item Workflow .......................................................................................................... 6
4.2.1
PMCS-Related Information Items Workflow ........................................................................ 7
5
Voting
....................................................................................................................................................
7
6
Change Control Board Meetings ........................................................................................................... 8
7
Change-Controlled Document Archiving .............................................................................................. 8

LSST Change Control Process
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Latest Revision Date 12/10/2013
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval.
iv

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The LSST Change Control Process
Summary
The LSST Change Control Process enumerates the rigorous methodology used by the project to establish
and maintain project baselines (technical, cost, and schedule) in a way that ensures transparency and
broad project representation in the consistent management of the system configuration. This policy
applies to Project Office and Project Systems Engineering configuration items. The process is also used
to review the activities of the subsystem’s
configuration control to ensure
project level concurrence
with low level changes and to promote transparency within the Project.
A key element of the LSST Change Control Process is the Change Control Board (CCB). The CCB has broad
project representation and has the responsibility to process all changes and recommend the appropriate
action. The recommendation is provided to the LSST Project Manager who is responsible for managing
the Project planning to accommodate the changes. Working within the delegated authorities, the
Project Manager is responsible to work with the subsystem managers, the appropriate Contracts
Departments and when DOE camera costs, schedule and scope are affected, with the SLAC Camera
Project Manager to develop plans. All actions are reported to, and approved by the LSST Director, and all
actions will follow the authorities defined within the LSST Project Execution Plan and the DOE LSST
Camera Project Execution Plan.
This document supersedes Document-478,
“Change Control and Configuration Management Process.”
Reference Documents
The following documents are applicable to the development or implementation of this CCP:
1) LPM-54,
“LSST Project Execution Plan”
2) LPM-51,
“LSST Document Management Plan”
3) LSE-90,
“LSST Technical Baseline Classified Index”
4) Document-9224,
“Change Controlled
Document Cover Page and
Style Guide”
5)
US DOE Office of Science “LSSTCam Preliminary Project Execution Plan”
Acronyms and Definitions of Terms
Glossary of Abbreviations
(
Document-11921
)
Glossary of Definitions
(
Document-14412
)

LSST Change Control Process
LPM-19
Latest Revision Date 12/10/2013
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval.
1

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The LSST Change Control Process
1 Introduction
The primary objective of the LSST Change Control Process is to establish and maintain project technical,
cost, and schedule baselines through a rigorous methodology that ensures transparency and broad
project representation in the consistent management of the system configuration. This policy applies to
Project Office and Project Systems Engineering configuration items. The process is also used to review
the activities of the subsystems’
configuration control to ensure
project level concurrence with low level
changes and to promote transparency within the Project.
The LSST technical configuration consists of system and subsystem requirements, interface control
documents, selected design documentation, drawings and design models and software. This
configuration information is archived in four electronic databases, depending on their nature: (i)
DocuShare, (ii) shop drawing and solid model database (PDMWorks), (iii) software version control, and
(iv) project management controls system (PMCS). The Project Manager and Systems Engineering
Manager specify the subset of configuration material to place under formal control. The project cost and
schedule baselines and project guidelines and procedures are also maintained centrally and subject to
the change control process.
The Subsystem Managers can make changes to their subsystems up to their delegated authority level,
unless a particular change affects system level controlled information, including subsystem
requirements and interfaces between subsystems. The Subsystem Managers may set up subsystem
change control boards to advise their decisions. Changes made by the Subsystem Managers are
regularly reported to the project Change Control Board.
Project controlled documents may not be changed without proper processing through the change
control workflow. Project controlled documents have specific handle designations for common and
immediate recognition. Software and model control status is managed within the specific management
tools but changes are still processed though this policy.
2 Change Control Board (CCB)
The Change Control Board (CCB) is an advisory body to the Project Director and the Project Manager.
The Project Manager is responsible for further disposition of (approve, reject, or promote) a change
request. The Project Manager will act within her/his decision authority level and promote to higher
levels any change outside her/his authority. Specifically, the Project Manager is responsible to work with
the subsystem managers, the appropriate contracts departments, and when DOE camera costs,
schedule, and scope are affected, with the SLAC Camera Project Manager to develop plans. All actions
are reported to, and approved by the LSST Director, and all actions will follow the authorities defined
within the LSST Project Execution Plan and the DOE LSST Camera Project Execution Plan.
Members of the Change Control Board are expected to offer comments and recommendations
regarding the change requests discussed. The comments and recommendations may be provided in

LSST Change Control Process
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Latest Revision Date 12/10/2013
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2
writing before or after the meeting in a well-defined time period, or verbally during the meeting.
The members of the Change Control Board are:
Systems Engineering Manager (Chair)
Project Scientist
Systems Scientist
Head of Safety
Subsystem Managers
Subsystem Scientists
Subsystem Systems Engineers
Subsystem Chief Engineers
The Director, Deputy Director, Chief Scientist, and Project Manager are included in all CCB
communication and invited to participate in any CCB meeting.
3 The Process
The change control process is uniform for technical, budget, and schedule changes, as well as for any
combination of these. Every change control action starts with the submission of an LSST Change Request
(LCR) form to the Chair of the Change Control Board, declaring the need for change, as well as the initial
expected consequences of the change. The LCR serves as the single ticket for this change; it documents
the process by capturing the notes, impact analysis and decisions associated with the change.
A change control request (LCR) needs to be initiated
To establish controlled documentation defining the baseline requirements, interfaces, design,
budget, and schedule of the project and the subsystems (Telescope and Site, Camera, Data
Management, as well as Education and Public Outreach), and
To change the established, controlled documentation.
The version/revision control processes for the drawing and solid model database and software version
control can initiate a formal change control request, if the new version violates formally controlled
information (“form, fit, or function” in system or subsystem requirements, interfaces between
subsystems, or controlled design). In these cases, the LCR can accompany the version submission, or can
be requested by Systems Engineering, based on its analysis during the version update process.
Each request is uploaded to the project archive, DocuShare, in a separate collection with all the
necessary supporting documents. As the request matures, its entire collection is moved through the
appropriate DocuShare collections: “Proposed,” “Studied,” “Pending,” “Approval Pending,”
and
“Approved” or “Rejected.”
The change control process workflow is shown in the following flowchart.

LSST Change Control Process
LPM-19
Latest Revision Date 12/10/2013
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
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3
Figure 1: Change Control Workflow Diagram

LSST Change Control Process
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Latest Revision Date 12/10/2013
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4
3.1 Types of Change Request Submissions
Voting Issue:
Proposals upon which CCB members are expected to vote. Examples of voting
issues might be (i) replacing ICD TBDs with real specifications or (ii) adding new requirements to
the Observatory System Specifications (LSE-30).
o
Deviation Request:
A subset of voting issues, these are requests for authorization to
depart from an established requirement or specification, rather than a request to
change said requirement or specification, prior to creation of a configuration item. An
example might be a request to depart from a specification in order to allow a vendor to
use an alternative technical solution with equivalent performance but increased
manufacturability.
Information Item:
Any proposal where the Project Manager has decided NOT to ask the CCB for
a recommendation. While the Project Manager has the authority to make cost, schedule, and
technical changes without requesting a CCB vote, information items follow the full change
control process for transparency and in order to maintain a record of the change and its
justification. Examples of information items might be (i) a change to the PMCS project plan
directed by the NSF or (ii) a project-level policy change that has no impact on cost, schedule, or
technical requirements.
3.2 Process Phases
3.2.1 Proposal Phase
If the proposed change is not valid
for example it proposes a change to a document not under formal
change control
the CCB Chair can reject the change request at submission. Also in this phase, the CCB
Chair can also request additional information and/or revisions from the Originator.
The objective is to prepare the LCR for project-wide distribution and analysis.
3.2.2 Analysis Phase
The Change Control Board is officially notified about the request. Project Systems Engineering, with the
active support of the subsystem teams led by their respective CCB members, initiates and manages
impact studies. Optionally, a draft of the affected document is prepared with the proposed changes
incorporated.
The objective is to adequately prepare the LCR for timely Change Control Board action.
3.2.3 CCB Review Phase
The request is considered by the CCB. Members of the board are expected to provide feedback
(“recommend,” “not recommend,” or “no objection” statements with as much comment as deemed
necessary). The comments and votes are open; they are available for the rest of the CCB during the
process and included in the public Minutes. The CCB can request further studies.
The objective is to advise project baseline decisions.

LSST Change Control Process
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The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
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5
3.2.4 Decision Phase
As described in Section 2, the Project Manager, in consultation with the Director, takes the necessary
steps to approve or reject the Change Request. Before disposing the request, the Project Manager can
also request further studies, clarification and/or revision.
The objective is to make project baseline decisions.
3.2.5 Implementation Phase
Project Systems Engineering implements approved changes to documents controlled at project level.
The flow down of these changes into subsystem controlled information is the responsibility of the
respective subsystems. The LCR is required to list all potentially affected documents, including those
under subsystem configuration control.
An approved change does not necessarily trigger a new release of the affected document(s), unless the
updated document was approved by the CCB. However, a clear and evident link must be established
between the original document
and the approved change request, representing a “red lined” section of
the document. Upon a new release, the Change Record of the document will explicitly reference the
LCRs authorizing the changes. New releases of controlled documents will be announced to the CCB.
The objective is to close the Change Control Action by fully implementing the approved changes or
reconciling the potential consequences of a rejection.
4 Change Control Workflow
Processing of Change Requests (LCRs) is managed through a workflow on the password-protected
Change Control Board website
(
https://www.lsstcorp.org/groups/ccb/
). The workflow tracks status,
records comments, and notifies users of required actions. The workflow also restricts the ability to
perform certain actions to only those parties with the authority to do so. The CCB Chair is responsible
for ensuring that the workflow progresses to the appropriate conclusion in a timely manner. Each
change in workflow status triggers email notifications that alert relevant parties to their required
actions.
At the workflow’s conclusion, the Document Specialist saves the LCR’s workflow history, which
includes the initial submission, comments, and CCB member’s
votes, and uploads
a PDF to the
appropriate LCR-specific collection in DocuShare.
Anyone with LSST Project credentials can submit a change request. The person who submitted the
request, the Chair, and the website administrator can edit the original submission. Once a request has
been submitted, the workflow status updates to “Proposed,” and the Chair receives an email
notification. The Chair may request additional information, reject the proposal without further
consideration, or assign an LCR number and advance the workflow for impact analysis.
4.1 Voting Issue Workflow
During the Analysis Phase, managers and scientific and technical staff should record statements of
support, objections, or concerns through the workflow comments. However, formal support documents
such as impact analyses or delta versions of documents affected by the proposed change shall be

LSST Change Control Process
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Latest Revision Date 12/10/2013
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval.
6
uploaded to the appropriate LCR-specific collection in DocuShare.
If the proposed change(s) would result in changes to the project plan in PMCS, the originator will answer
“Yes” to the “PMCS Related?” field
when submitting the request. In addition to those normally notified
by the system, the PMCS Specialist and the Project Manager receive email notifications when PMCS-
related LCRs are entered. The PMCS Specialist will record his or her impact analysis in the workflow
comments and provide links to any support files uploaded to DocuShare.
Following impact analysis and any adjustments to the LCR resulting from same, the Chair advances the
workflow to “Pending” status
and adds the LCR to an upcoming CCB meeting agenda. CCB members
receive email notifications that the LCR is ready for their consideration. CCB members shall record their
votes
using the workflow’s voting mechanism.
If the CCB recommends approval of the LCR, the Chair advances the workflow status to “Approval
Pending.” The Project Manager
receives an email notification that the LCR is ready for a decision. He or
she
may select “Approve” or “Denied.”
However, changes that would result in use of contingency funds or loss of schedule beyond certain
thresholds require an additional step
prior to the Project Manager’s decision. The Project Manager will
prepare an NSF approval form to be emailed to LSST’s NSF Program Officer
then advance the workflow
to
“Approval
Pending NSF.” When the Project Manager receives the agency’s
decision, he or she
will
upload the returned, completed approval form to the appropriate LCR-specific collection in DocuShare
and advance the workflow to
“Approve” or “Denied”
as appropriate.
The LCR’s lifecycle ends
either when the
LCR has been “Denied” or follow-up
action items have been
completed and the workflow administrator
advances the workflow status to “Fully
Implemented.”
4.2 Information Item Workflow
Proposals are designated as information
items at submission by selecting “No” in the “Voting
Allowed”
field.
The Chair advances the workflow to “Pending” status and adds the LCR to an upcoming CCB meeting
agenda. CCB members receive email notifications that the LCR will be presented at a future meeing.
Prior to the meeting at which the information item will be presented, CCB members and other scientific
and technical staff should record any statements of support, objections, or concerns through the
workflow comments.
Following the meeting at which the information item is presented, the Chair advances the workflow
status to “Approval Pending.”
The Project Manager receives an email notification that the LCR is ready
for a decision. He or she may select “Approve” or “Denied.”
However, changes that would result in use of contingency funds or loss of schedule beyond certain
thresholds require an additional step prior to the Project Manager’s decision. The Project Manager will
prepare an NSF approval form to be emailed to LSST’s NSF Program Officer
then advance the workflow
to “Approval Pending NSF.” When the Project Manager receives the agency’s decision, he or she will
upload the returned, completed approval form to the appropriate LCR-specific collection in DocuShare

LSST Change Control Process
LPM-19
Latest Revision Date 12/10/2013
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval.
7
and advance the workflow to “Approve” or “Denied” as appropriate.
The LCR’s lifecycle ends either when the LCR has been “Denied” or follow-up
action items have been
completed and the workflow administrator advances the workflow status to “Fully Implemented.”
4.2.1 PMCS-Related Information Items Workflow
If the information item would result in changes to the project plan in PMCS, the originator will answer
“Yes” to the “PMCS Related?” field when submitting the request.
In addition to those normally notified
by the system, the PMCS Specialist and the Project Manager receive email notifications when PMCS-
related LCRs are entered.
Following impact analysis by the PMCS Specialist (the results of which will be uploaded to the
appropriate LCR-specific collection in DocuShare), he or she will advance the workflow status to
“Approval Pending.”
The Project Manager receives an email notification that the LCR is ready for a
decision. He or she may select “Approve” or “Denied.”
However, changes that would result in use of contingency funds or loss of schedule beyond certain
thresholds require an additional step prior to the Project Manager’s decision. The Project Manager will
prepare an NSF approval form to be emailed to LSST’s NSF Program Officer then advance the workflow
to “Approval Pending NSF.” When the Project Manager receives the agency’s decision, he or she will
upload the returned, completed approval form to the appropriate LCR-specific collection in DocuShare
and advance the workflow to “Approve” or “Denied” as appropriate.
The LCR’s lifecycle ends either when the LCR has been “Denied” or follow-up
action items have been
completed and the workflow administrator advances the workflow status to “Fully Implemented.”
5 Voting
CCB members shall record their votes using the workflow’s
voting mechanism.
Members need not attend a CCB meeting to record a vote nor do they need to wait until after a CCB
meeting to record a vote. At any time the member is comfortable with his/her vote (until the voting
deadline lapses), the vote can be recorded. Therefore, there is no need for proxies.
Members may vote
Recommend
agreeing the proposed change(s) should be approved,
Not Recommend
voting for the proposed change(s) to be denied, or
No Objection
having insufficient stake in the issue to either recommend or object to approval.
In balance, “No
Objection” is considered a favorable vote.
The Chair sets the voting deadline during the associated CCB meeting, and the workflow administrator
registers a comment to each LCR to be voted on, thereby triggering an email notification to all CCB
members, including any who were unable to attend the CCB meeting. Any votes not registered by the
deadline are
assumed to be “No Objection.”

LSST Change Control Process
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The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
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8
6 Change Control Board Meetings
Change Control Board meetings are called by the Chair, who is responsible for preparing the agenda and
material for the meetings and documenting the comments and recommendations of the Board, as well
as the potential action items requested by the Board. The Chair is assisted in these functions by the
Document Specialist.
The Change Control Board meets regularly to consider proposed changes to the technical, cost, and
schedule baselines. CCB meetings occur the third Wednesday of each month. If a change request is
urgent, a special meeting of the CCB can be called. If in a particular month, no change requests are ready
to be voted on by the membership, the Chair may cancel the meeting for that month.
The CCB meetings are run by the Chair. At least one (1) week in advance of the CCB meeting, the chair
will notify the CCB membership by email of the change requests on which votes will be expected.
Regular agenda items include
Setting voting deadlines for LCRs ready for a CCB decision,
Introducing new requests,
Reviewing the status of action items and ongoing impact studies,
Reporting on the implementation of approved changes, and
Reporting and discussing subsystem level changes.
Minutes of each CCB meeting will be taken as necessary to augment the approval, rejection, impact
assessment, and notification comments that are recorded on the Change Request Form. Minutes are
posted to the CCB website, uploaded to DocuShare, and emailed to the membership for review.
LCR processing is administered through a web-based system that imposes the appropriate workflow and
captures and archives (i) the change request with references to relevant documents, (ii) the comments
and recommendations of CCB members, and (iii) the decision. Upon concluding the change control
action, the web site generates a document file equivalent to the current Change Request Form that will
be posted in the DocuShare collection of the request.
All documents under formal change control must be designated as such in their respective databases.
7 Change-Controlled Document Archiving
When a document has been placed under change control, the Document Specialist will apply the LSST
standard controlled document formatting as demonstrated in Document-9224. He or she will (i) locate
the document within the appropriate sub-collection of DocuShare Collection-1821, (ii) ensure that
permissions are properly set, and (iii) notify the Subsystem Managers that the document has been
placed under change control.
Change-Controlled documents are archived in one of four sub-collections of DocuShare Collection 1821.
1. Design Documents (Change-Controlled)
Collection 2809
2. Interface Control Documents (Change-Controlled)
Collection 2807

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3. Plans, Policies, Procedures (Change-Controlled)
Collection 2806
4. Requirements Documents (Change-Controlled)
Collection 2808
Collection 1821 is the home collection for change-controlled documents; however, the Documents may
be co-located in other collections. If this is the case, the permissions settings for Collection 1821 prevail
regardless of the co-location.
Permissions to upload new versions, change the preferred versions, or edit any of the change-controlled
documents’ DocuShare properties are restricted to members of the Controlled Documents Membership
group. The members of this group are
CCB Chair,
Project Manager,
Project Director, and
Document Specialist.

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