The goals of the Design Phase are to:
Under the leadership of the Project Scientist, the design process begins in the Science Advisory Committee (SAC). The Project Scientist assembles the SAC from representatives of all the partners with scientific expertise in the various science areas of interest to the partners. The SAC begins the design process by describing what science the telescope will perform in the Science Cases Document. The Science Cases define the scientific goals and the actual observations required to achieve them. They make no assumptions about the telescope system, because they are used to define the telescope system. This document should be relatively short, only a few pages, and need contain only representative samples of each type of observation that is anticipated. A single science case might include a short explanation of the science and a step-by-step explanation of the observation to be performed.
Examples of NEO science cases to be included are:
The Science Cases will contain typical magnitudes, colors, and rates of motion of the target, but will not mention specific requirements, such as the telescope's field of view, the imager's pixel size or number of pixels, or specific scheduling features of the control system.
After the Science Cases are defined, the Project Scientist leads the SAC in defining the Science Requirements. These are specific statements about what the components of the telescope system must do to perform the observations detailed in the Science Cases, and how quickly or how well they must perform to make these observations. For example, the Science Requirements Document will contain specifications for the telescope (e.g., field of view, its slew, set, and guide rates, tracking accuracy), the imager (e.g., pixel size, well depth, quantum efficiency vs. wavelength, readout time), and the control system (e.g., robotic operation capabilities, ability to access ephemerides from the NEO Confirmation Page, integration of the imager with the telescope).
The Science Requirements will have a traceability matrix or table that details how each requirement can be traced back to a Science Case that justifies its existence or the specific values it contains. It will not contain design information, that is, details on how the design components of the telescope system implement the requirements.
Following the development of the Science Cases and Science Requirements documents, the primary work of the SAC is complete. The SAC will participate in design reviews of telescope system components and will receive periodic progress updates from the Project Scientist. If the project encounters a major decision, the Project Scientist may choose to seek the advice of the SAC before advising the Project Manager concerning the decision.
The next step in the design process is the development of the Operations Concept Definition Document (OCDD). This document details how an observation will be made within the environment of the Winer Observatory facility. The Project Scientist will write this document with the assistance of the Systems Engineer and the Project Manager. The Project Manager may choose to have one or more members of the SAC review the OCDD to ensure that all components of making an observation have been covered. Again, the OCDD contains a traceability and compliance matrix to ensure that all science requirements are covered.
Winer's Scientific Director, Mark Trueblood, has managed projects of a similar nature with far larger dollar values as an employee at Ford Aerospace and at NOAO. His experience shows that early cost estimates are not accurate until specific requirements are defined, a design to those requirements is completed, and cost estimates to that specific design are made by the vendors responsible for actually doing the work.
A major product of the Design Phase is a set of requirements in the form of a document that specifies the functions each part of the telescope system will have and the performance each will achieve. This Functional and Performance Requirements Document (FPRD) will be used to derive vendor specifications that will be sent to vendors near the end of the Design Phase to obtain quotations. The FPRD will enable both (a) an informed decision on whether there are adequate funds in hand to proceed with the project based on vendor quotations for performing the work required to build the system we need to make the observations for the science we wish to pursue and (b) the selection of vendors based on these same quotations.
The Systems Engineer and the Project Manager will develop the FPRD in parallel with the development of the OCDD. The FPRD is an engineering document that specifies in engineering terms all of the requirements that each component of the telescope system must meet. It is quantitative and comprehensive, and serves as the basis for writing the Acceptance Test Plans and Procedures. This document also contains a detailed table tracing each requirement back to the Science Requirements Document. The FPRD contains specific engineering requirements for the inputs, outputs, and internal components of the telescope system. It may repeat the Science Requirements but also extend them to include additional requirements derived from them.
A key activity of the Systems Engineer is to maintain the error budgets. If the FPRD specifies, for example, a certain tracking accuracy, the Systems Engineer will allocate portions of this error to the telescope, imager, and control system to ensure that the requirement is met. If different vendors are then chosen for each of these components, and each meets its individual requirements, the overall telescope system will perform correctly. After error budgets are developed for each major component, they will be compared to, and fed back into the FPRD. The OCDD, FPRD, and error budgets are living documents that are iterated during the project lifetime to ensure that they are mutually consistent and, simultaneously, consistent with what the vendors are building and delivering.
Optical design will begin as the Operations Concept Definition Document (OCDD) and Functional and Performance Requirements Document (FPRD) are being completed, and early optical design results will be fed back into both documents. This effort will include ray-tracing the optics, analyzing the performance using ray tracing (spot diagrams with encircled energy plots and computed Strehl ratios), performing tolerance analysis, giving a final optical prescription and writing a complete procurement specification for each optical component in the telescope system.
If a telescope vendor can be identified early enough, the optical designer will also perform a stray light and ghosting analysis and will work with the vendor to design the telescope baffling. Otherwise, these activities will be performed during the Construction Phase, as will adjusting the mechanical design (e.g., element spacing) for the as-built optical design.
After the OCDD and FPRD have been developed, reviewed, and approved, the Project Scientist and Project Manager will write the procurement specifications for each component of the telescope system. The Project Scientist may wish to have the SAC review the procurement specifications before they are sent to vendors for quotes.
After review and approval, the procurement specifications will be sent to a list of pre-qualified vendors in accordance with Winer Observatory procurement procedures. The quotations and proposals will be reviewed by the Project Manager and Project Scientist, and may be discussed with the SAC before vendors are selected. In the end, responsibility for selecting the vendors will rest with the Project Manager, who will take his decisions to the partners and the Winer Board of Directors for approval.
During this period of waiting for vendor quotations in response to our requests, the Project Manager and the Project Scientist will write a detailed Commissioning Plan that defines the activities to be performed at the Winer Observatory after the telescope system is installed and tested.
After all components (telescope, instrumentation, and control system) pass their Final Acceptance Test (described below in Phase 2) at the observatory site, the Construction Phase ends and the Commissioning Phase begins. We will need a plan of how to understand the capabilities of each component, not simply whether each component meets its requirements, and how the telescope system performs as a whole. The Commissioning Plan will be structured to permit us to understand these characteristics. It will include a description of all the observations and tasks needed to effect the Commissioning Plan, and a schedule for implementing the Plan. This document is another candidate for review by the SAC.
After receiving the vendor quotations and proposals, the Project Manager will review his assessment of which vendors to use to build the telescope system with the Project Scientist, the Winer Board of Directors, and the SAC. After obtaining approval of vendor selections, the Project Manager will assemble a detailed Project Budget and Construction Schedule and will present the results to the same bodies. If possible, he may present draft versions of top-level budgets and schedules to these bodies during their initial assessment to assist them in comparing alternatives.
The decision to proceed with the project will be a decision of the partners. For Winer Observatory, the Winer Board of Directors will make this decision after the Project Manager has prepared and presented the detailed Project Budget and Construction Schedule, and they have been approved by the Winer Board.
Last modified: March 24, 2013.