AXAF CCD Imaging Spectrometer (ACIS)

Configuration Management Plan SMA01

Contract # NAS8-37716

May 7, 1993

Submitted to:
George C. Marshall Space Flight Center
National Aeronautics and Space Administration
Marshall Space Flight Center, AL 35812
Submitted by:
Massachusetts Institute of Technology
Center For Space Research
77 Massachusetts Avenue
Cambridge, Ma 02139

1.0 Introduction

Configuration management requirements for scientific instruments are slightly different than NASA standard practice since generally only one instrument is produced, rather than multiple units where different configurations are possible. The goals of the configuration management effort are to assure a flight worthy instrument is produced at minimum cost, and to assure the scientific value of the data collected. The Center for Space Research has developed its configuration management system to accomplish these goals.

Configuration management is the basis for the control and organization of all projects within the Center for Space Research. As such, a configuration management system has been in existence at CSR since the late 1960's. Over the course of the last 20 years, and the execution of over 10 space flight programs, this configuration management system has become quite refined. We believe our current system meets the AXAF/ACIS Missions requirements. Therefore, this section is not actually a "plan" of what we intend to do, but rather a description of how CSR projects actually operate.

This plan defines the system in use at the Center for Space Research to assure the control of the configuration of the flight hardware, the documentation to describe this controlled configuration, the fabrication of the flight elements to the specified configuration, and the identification (labeling) of the flight components so as to relate each element to a controlled document.

The CSR Configuration Management system shall be used to manage, control and assure both the flight hardware and the ground support equipment configurations. The system provides for the identification of both hardware and documents under configuration control.

2.0 Organization

The Configuration Management function is implemented through a Configuration Control Board (CCB). The CCB consists of the Program Manager, who is ex-officio the Configuration Manager, the Project Engineer, who is ex-officio the Deputy Configuration Manager for Hardware (DCMH), and the Systems Engineer, who is ex-officio the Deputy Configuration Manager for Documents (DCMD). The titles are used interchangeably in this document.

2.1 Internal Approval Requirements

These three people must sign every Engineering Change Order (ECO). Every controlled drawing or document is issued on authority of an ECO. Each member of the CCB uses the ECO process to assure that the new or revised document meets the Project requirements for which he/she is responsible. The DCMD assures that the necessary quality, reliability and safety supporting activities have been performed (e.g., NSPAR's prepared, fracture control classification noted, etc.). The DCMH does the same thing from a technical point-of-new (compliance with external interfaces, instrument specifications, etc.). The Project Manager evaluates the schedule, cost, and manpower impact of the ECO.

For any one ECO, the CCB is expanded to include all staff members who could be affected by the ECO. There are 10 places for signatures at the bottom of the ECO form. The Deputy Configuration Managers act as coordinators for the ECO, and are responsible for assuring that all interested parties have seen and signed the ECO. The DCMD is also responsible for determining which ECO's require prior MSFC Project Office approval, submitting the request for such approval, and assuring that the necessary approval has been received prior to final approval of the ECO. Such approval is referenced in the "Remarks" block of the ECO form.

2.2 MSFC Project Approval

There are certain documents which do not fall under the sole jurisdiction of CSR/MIT. These are referred to as Type 1 and Type 2 documents or changes. Releasing or changing Type 1 documents requires the prior approval of the mission project office. Releasing or changing Type 2 documents requires document submission to the MSFC project office 45 days prior to implementation. Type 2 documents are considered approved if the MSFC project office has not objected before implementation. The Type 1 and 2 documents for ACIS are identified in Data Procurement Document 727. They are generally the Plans and Procedures to be used in the execution of the Phase C/D program (e.g., this Project Management Plan is a Type 1 document). In addition, documents or changes that effect safety, reliability, cost and schedule are considered Type 1. Any proposed change which would force the ACIS to exceed the allocated mission resources (weight, power, telemetry, etc.) are considered Type 1 changes. External interface documents are also Type 1, and therefore require MSFC approval under the MIT Configuration Plan. All proposed class 1 changes will be submitted to the MSFC ACIS Project Office for approval prior to final sign-off of the subject ECO. In the case of Type 1 changes which affect the Interface Control Document (ICD) between MIT and AXAF, copies of the change proposal will also be sent to TRW.

Released documents (schematics, drawings, procedures, etc.) are submitted as specified in the contract Data Procurement Document, typically at formal design reviews, and this establishes a baseline design. Any documents or changes released after CDR will be submitted to the MSFC Project Office on a weekly basis.

3.0 Configuration Identification

3.1 Specification Tree

The project is governed by the AXAF-I Level I Document, AXAF-101, and by the AXAF-I Project Requirements Document (PRD) Level II, MSFC-SPEC-1836A. AXAF-101 is the responsibility of NASA Headquarters. MSFC-SPEC-1836A is the responsibility of the AXAF Project Office at Marshall Space flight Center.

The Contract End Item (CEI) Specification shall be prepared to comply with the above listed documents and with DPD 727, document SCM02. The CEI Specification shall be delivered three weeks prior to the System Requirements Review. The CEI Specification is the responsibility of MIT/CSR, with approval of the MSFC ACIS Project Office.

The ACIS project has been assigned the unique CSR prefix number 36. All CSR documents relating to the ACIS project will bear that prefix, and no other project will use that prefix.

There is only one deliverable flight hardware item, the ACIS assembly, and the quantity to be delivered is one (1). The basic drawing number for this assembly is 36-20000 The assembly consists of three critical component types: the Detector Assembly, 36-21000; the Detector Electronics Assembly, 36-22000; The Digital Processor Assembly, 36-23000; the Power Supply, 36-24000 and the Thermal Control Subsystem, 36-25000. Every component assembly is permanently marked with its serial number.

3.2 Drawing Practices

Drawings are generally generated using a computer aided design and drafting program. The drawings are plotted on a high quality electronic plotter, and have superior legibility. The drawing standards are the minimum required to communicate accurately the form, fit and function of the parts or assemblies represented. As such, they meet the intent of MIL-D-1000 and MIL-STD-100.

CSR does not claim to or intend to comply with the letter of MIL-D-1000 and MIL-STD-100.

CSR places no limitations on the use by the government of any drawings delivered in connection with this procurement.

4.0 Configuration Control

The two main instruments of configuration control are the Engineering Change Order (ECO) and the Configuration Data Base (CDB). Any document to be controlled must be released via an ECO, including the initial release of the document. There are no exceptions to this rule. The CDB is a table maintained by the Systems Engineer which lists every controlled document or drawing, and its current revision letter, release or change date, and the ECO number authorizing the release or change. Since the Systems Engineer signs every ECO, he has the information to maintain the database.

The Configuration Data Base itself is a controlled document. An approved ECO to release or change a document provides the authority to change the Configuration Data Base. If, however, the only proposed change is to modify the Data Base, then an ECO must be approved to do so.

The CSR Configuration Management system also provides the ability to issue pre-release documents. These documents are issued with a configuration number and a numerical revision designator, which distinguishes them from released documents. Released documents have an alphabetical revision designator.

This pre-release feature is used during the early design phase of the flight hardware to enable the various required analyses (fracture control, stress analysis, FMEA, trend analysis, etc.) to be performed on documented, but not yet released, designs. It also allows for the establishment of a baseline which can be used at design reviews for related hardware items which are in a different schedule phase.

The pre-release feature provides a mechanism to correlate the early analyses with a specific design. An ECO is a fairly formal procedure, and hence there is a natural tendency to postpone the release of a document until the design engineer is confident of its accuracy. The multiple (serial) analyses required by satellite scientific instruments could present serious schedule problems. CSR developed this informal pre-release feature to encourage early documentation of designs.

4.1 Configuration Data Base

The Configuration Data Base is maintained as a password protected EXCEL file, as well as in hard copy. Only the Systems Engineer and the Program Manager have access to the password. The drawing number system and revision designation system are described in the following paragraphs.

Every ACIS controlled document shall be identified by the prefix 36- followed by a five digit number - followed by the revision designator. The five digit number may be augmented by the addition of up to 4 additional digits preceded by a decimal point (.). These documents are issued with a configuration number and a numerical revision designator, which distinguishes them from released documents. Released documents have an alphabetical revision designator. Thus, this Configuration Management Plan will be identified as 36-01206-A after it is released. Its current designation as 36-01206-01 indicates that it is not yet released.

The first digit of the five digit number indicates a major assembly. The ACIS project has assigned 2xxxx to the flight assembly. Ground support equipment is assigned the 3xxxx series. ECO's are assigned the 8xxxx numbers. All contractual Data Requirement documents are part of the 0xxxx series.

With the exception of electronic parts, this single data base will be used for all ACIS controlled items, from the Science Requirements documents to the smallest piece part used in the fabrication of the hardware. The numbering system allows the data base to grow as necessary. At the current time, the data base only shows the highest level assemblies and numbers presently assigned to deliverable documents. Hence, this data base is not only a document list and drawing tree, but it is also a parts list. At the part level, the data base contains the part name, specification, quality level, material, fracture control classification, manufacturer, etc. By sorting on the various data fields, the same data base produces a parts listing organized by part type, manufacturer, etc. Electronic parts are controlled in a separate data base.

The Configuration Data Base itself is a controlled document. An approved ECO to release or change a document provides the authority to change the Configuration Data Base. If, however, the only proposed change is to modify the Data Base, then an ECO must be approved to do so.

A controlled copy of the CDB is transmitted to the MSFC ACIS Project Office within one week after each change.

CSR uses only a single Engineering Change Order form. Coordination copies of every proposed ECO are sent to the MSFC ACIS Project Office, and the related contractors. The judgment of the CCB, supplemented by the MSFC ACIS Project Office, is relied on to assure that the ECO is dispositioned appropriately. This procedure is simpler and less expensive than the full Exhibit VI procedure of MM 8040.12A, and this procedure has proven successful on all previous CSR flight instruments.

4.2 Drawing Control

Every project document is marked with the document identifier, including the revision number and the latest revision date. Actual drawings or schematics contain this information at the periphery of the drawing. Textual documents, such as plans or procedures, contain this configuration control page at the front of the document. When the ECO is approved to release a document, the signature blocks are completed and the ECO number is entered in the revision block. The signature page shall bear the signature of the preparer, and the signature of the Configuration Manager. The Configuration Manager's signature indicates that he certifies all necessary approvals have been obtained. The signature block also contains a table listing revision letter or number, the ECO number, a brief ECO description, and the date.

When a document is released the data files representing the original document are made "read only". These files cannot be deleted from the computer system. Backup copies are protected similarly.

When a document is released two copies are made for CSR use. These copies are stamped "Controlled Copy 1" and "Controlled Copy 2". The two copies and a User Log are filed in a Controlled Document File. Users shall complete a line entry on the Log whenever they remove or return a document.

All work on or with the flight components or instruments must be performed from one of the two MIT controlled copies. One of the required R&QA inspections for each fabrication step verifies that work is proceeding according to released documentation.

Proposed changes to a released document shall be indicated by marking "See PECO #XXX" on the front of both controlled prints, and attaching a copy of the Proposed Engineering Change Order (PECO) to the released document. Proposed changes to a released document must be indicated by "red-lining" one of the controlled prints (as well as preparing an ECO form). The originator of a proposed change is required to sign out one of the controlled copies and, if the other copy has been signed out, to inform the other user of a pending change to that drawing.

If the proposed ECO is approved, the DCMD makes a new electronic copy of the document, modifies the copy to incorporate the changes, and makes the new copy read only. The DCMD then prints, files and distributes the required number of paper copies. He collects and destroys all obsolete paper copies. He updates the ECO and Controlled Document databases.

Copies of any newly released or revised documents are sent to the Marshall ACIS project office within one week after release. These copies are labeled "Controlled Copy 3". If MSFC or other contractors require additional copies, they shall be numbered sequentially. The CSR document control procedure makes the MSFC/ACIS document file an extension of the MIT file. Copies of the ECO and Controlled Document databases are sent to MSFC monthly, with weekly updates in the active periods near design reviews. These databases are in EXCEL file format, so they are readily available to all managers.

4.3 Data Requirement (DR) Documents

The data requirements for ACIS are defined in Data Procurement Document (DPD) 727. All deliverable documents listed there will be under configuration control, with the following exceptions:

  1. The Management documents SMA 03, SMA 04, and SMA 05 will not be under configuration control, since they deal with transient data and are reissued periodically.

  2. SSA 03, Mishap Reports are issued in response to unplanned events, and will not be placed under configuration control.

5.0 Configuration Accounting

Since there is only one ACIS being produced, the full indexing system specified in Exhibit XI of MM 8040.12A is overly complex and expensive. For the same reason, configuration control and configuration accounting are functionally equivalent in this case.

The primary instrument of configuration accounting for ACIS is the configuration data base. Procedures for creating and disseminating that information are given in the preceding paragraph.

6.0 Subcontractor and Vendor Configuration Control

Purchase orders for flight hardware or materials will include controlled drawings or specifications as part of the contract.

The Quality Assurance Manager is charged with performing in-process and incoming inspections to assure compliance.

All other materials and components will be certified by the vendor to comply with the purchase order specifications.

7.0 Program Phasing

The Configuration Control Board is already established, well in advance of the requirement to create any controlled documents.

The specifications required are being generated in accordance with the master Project Plan and the Data Requirements Document. The CEI Specification is being generated for release at the Requirements Review, and detailed specifications will be prepared for the PDR and CDR as required.

The configuration baseline is formally established at the CDR. CSR's pre-release documentation provides a strawman for coordination purposes. Strawman design data has been available for at least ten years.

8.0 Reviews

CSR plans to submit documentation in support of the Program Requirements Review, the Preliminary Design Review, and the Critical Design Review three weeks prior to each review, as called out in DPD 727.

The reviews will be held at the approximate dates shown in the master Project Plan. The exact dates will be set by the MSFC Project Office, coordinating with all interested parties.

The Configuration Inspection will be performed on the one ACIS unit produced. This inspection shall be a part of the Acceptance Test of the unit by the government. CSR expects the CI will occur prior to delivery of ACIS to the SIM Contractor.

Phil Gray