The Work Breakdown Structure 

The work breakdown structure is a view of the project in terms of a hierarchy of tasks. 

For Tinkerbell, the development work is in two main parts:

  1. Analysis & Design (A&D) 
  2. Implementation & Test (I&T)
  3. . . . And there are two top-level, ongoing processes that support the project:

  4. Promotion & Funding (P&F) 
  5. Management (M) 
These types do not appear as tasks in the Network or Gantt charts, but all of the work that is planned and performed for Tinkerbell will be classified at the top level into one of these four types.  Work is further broken down into subtypes of a granularity that is fine enough for the developers to use in identifying all of the work. 

As work proceeds, the approaching detail tasks become visible, and are added to the work breakdown and to the Network and Gantt views.  All developers have management responsibility, and must report any needed changes as they are discovered.
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11000   Initial Analysis & Design
11010       Develop Use Cases
11020       Build/Use Propulsion Testbed
11030       Prototype the Operator Interface
11040       Simulate Spacecraft Flight Operations
11050       Simulate the Camera View Window
12000   Detailed Analysis & Design
12010       Tug
12020       Main Video Camera
12030       Remote Control Unit
12040       Berthing Unit
12050       System
21000   Implementation
21010       Tug
21020       Main Video Camera
21030       Remote Control Unit
21040       Berthing System
22000   System Test
23000   Flight Test
31000   Create a Website
31010       Prepare Pages
31020       Set Up Newsgroup
31030       Publicize Website
32000   Seek Funding
32010       Prepare a Business Plan
32020       Seek Institutional Partners
32030       Approach Potential Funding Sources
33000   Promote Science and Technology
41000   Form the Development Team
41010       Form the Seed Team
41020       Recruit Teams for All Top-Level OBS
42000   Develop a Project Plan
42010       Work Breakdown
42020       Dependency Net
42030       Gantt (Bar) Chart
42040       Organizational Breakdown
90000   Initial Design Complete

WBS Code Structure:

    1 10 10 __ __
    | |  |  |  |
    | |  |  |  |
    | |  |  Third (and fourth) pairs are appended for
    | |  |  finer granularity sub-tasks, as needed.
    | |  Second pair designates the task.
    | First pair designates the super-task.
    First digit designates the task type (A&D, I&T,
    P&F, M)

    The 90000 series is reserved for milestones, and
    has no hierarchy.
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11000 Initial Analysis & Design 

This task begins the iterative process of analysis and design (often associated with object-oriented methods) that will be used for the entire development.  It concludes with the delivery of: 
  1. the initial document set of Use Cases, Tradeoff Studies, and Functional Requirements, and 
  2. the Tinkerbell system prototype (operator interface, flight simulator, camera view simulator). 

11010 Develop Use Cases 

The development team will identify and describe a set of Tinkerbell use cases (object-oriented). The use cases will cover typical applications and failure modes of all four Tinkerbell subsystems. 

11020 Build/Use Propulsion Testbed 

The development team will build a low-cost propulsion testbed (probably an air-bearing frame on a flat-floor) for testing prototypes and mathematical models. 

11030 Prototype the Operator Interface 

The development team will prototype the operator interface software that runs on the Remote Control Unit.  This prototype will run on any compatible PC, and is intended as the testbed for display and control panel concepts and implementation.  The operator interface prototype will control the flight and camera view simulations.  Eventually, the operator interface prototype will be accepted as the flight operator interface, and the simulations will be replaced by flight hardware and software. 

11040 Simulate Spacecraft Flight Operations 

The development team will simulate spacecraft propulsion, guidance, and manipulator control operations, by developing software modules that run on the display and control panel testbed PC. The control interfaces between these simulation modules and the display and control prototype are built as prototypes of the interfaces to the actual flight systems. 

11050 Simulate the Camera View Window 

The development team will simulate the camera view that appears in the display and control panel, by developing software modules that run on the display and control panel testbed PC. The control interfaces between these simulation modules and the display and control prototype are built as prototypes of the flight  video display and control systems.
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12000 Detailed Analysis & Design 

This task continues the iterative process of analysis and design into the details of  design for each sub-system of Tinkerbell.  It concludes with the delivery of: 
  1. the detailed document set (to be described), and 
  2. refined physical and software prototypes and simulations (to be described). 

12010 Tug 

(to be described) 

12020 Main Video Camera 

(to be described) 

12030 Remote Control Unit 

(to be described) 

12040 Berthing Unit 

(to be described) 

12050 System 

At the system level, the development team will perform detailed analysis and design of the major sub-systems interfaces.  (to be described)
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21000 Implementation 

(to be described) 

21010 Tug 

(to be described) 

21020 Main Video Camera 

(to be described) 

21030 Remote Control Unit 

(to be described) 

21040 Berthing System 

(to be described)
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22000 System Test 

(to be described) 

23000 Flight Test 

(to be described) 

31000 Create a Website 

This task covers the preparation and initial offering of a website, to serve as a means of communicating within the developer teams and to involve both the general public and the aerospace professionals in the Tinkerbell project. 

31010 Prepare Pages 

The developer team will prepare pages for inclusion in the website.  This work covers the general introduction of Tinkerbell concepts, general scientific information, technical information, and membership information.  The objective is to make the development process open to anyone who wants to know, in order to generate support and attract new development team members. 

31020 Set Up Newsgroup 

The developer team will set up a newsgroup, or a private news service, that allows subscribers to read mail distributions and have their inputs distributed.  This service probably gets a small yearly fee from subscribers, to defray the cost of maintaining the site. 

31030 Publicize Website 

Upon approval of the initial pages, the developer team will publicize the website, by submitting to the popular search engines, notifying space-interest sites about an exchange of links, notifying other space newsgroups, etc.
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32000 Seek Funding 

This task covers efforts aimed at securing the resources needed to actually build and fly Tinkerbell. 

32010 Prepare a Business Plan 

The developer team will prepare a business plan, describing the market and the financial plan. 

32020 Seek Institutional Partners 

The developer will make contact with institutional partners, among business, government, and academia.  These partners will participate in Tinkerbell development by supplying use of technical or logistic resources, directly working on Tinkerbell design and implementation, or designing Tinkerbell into their own  future missions. The effects of these partnerships will be worked into the business plan.  The team and partners may choose to form a consortium. 

32030 Approach Potential Funding Sources 

The developer team will identify and approach potential funding sources with the website and business plan.  The team will follow up contacts as needed.
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33000 Promote Science and Technology 

This task covers encouraging support and popularity of the Tinkerbell website by creating pages that promote science and technology relevant to Tinkerbell and space exploration.   For example, this effort includes: 
  • Creation of pages designed to support discussion of control interfaces for space applications, and to promote acceptance of our control interfaces as international standards. 
  • Creation of pages covering general science and technology relevant to Tinkerbell and other spacecraft (human factors, development methodologies, orbital mechanics, propulsion, guidance, structures, telemetry, thermal control, etc.) 

41000 Form the Development Team 

This task covers all efforts to attract needed team members and to organize appropriate sub-teams as the project progresses. 

41010 Form the Seed Team 

An initial seed team of ten or fewer people will be recruited to perform the initial analysis and design of Tinkerbell and to support the publicizing and funding efforts. 

41020 Recruit Teams for All Top-Level OBS 

Using the Organizational Breakdown Structure (OBS) developed as part of the project plan, the developer team will reorganize and recruit to form sub-teams for the various parts of the project.
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42000 Develop a Project Plan 

This task includes all work to create a project plan to good, modern project-engineering standards. 

42010 Work Breakdown 

The developer team will prepare a breakdown of the work into a hierarchy of tasks and sub-tasks. 

42020 Dependency Net 

The developer team will prepare a network diagram of the project, indicating the dependency relationships between sub-tasks (predecessors and successors). 

42030 Gantt (Bar) Chart 

The developer team will prepare a Gantt chart diagram of the project, indicating the sequence of tasks and sub-tasks on the timeline. 

42040 Organizational Breakdown 

The developer team will prepare an Organizational Breakdown Structure (OBS) for the project, indicating the organization of teams and developers needed to perform the project plan. 

90000 Initial Design Complete 

This milestone indicates completion of task 11000. 

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