1. 1 Mission Discussion & Project Reviews 祝飛鴻 10/14/93

2. 2 Satellite System – ROCSAT-2

3. 3 Requirement Definition Mission Requirements Payload Requirements Mass/Size Data Rate Thermal Operation Modes Power Pointing/Stability Field of View Performance Spacecraft Bus Requirements Mission Needs Mission Objectives SMS System TCS RCS ADCS EPS TT&C C&DH FSW

4. 4 Mission Requirements  Mission Objectives:  Communication: Provide communication link between any two locations on earth  Earth Observation: Provide image data of Taiwan island  Science: Grow vegetable in space  Mission Needs:  Communication: coverage area, data type, time latency, etc.  Earth Observation: resolution, revisit time, availability, etc.  Science: type of vegetable, observation time, etc.

5. 5 Payload Requirements  Resource limit of a 3 Kg Picosat:  Weight: 3 Kg (0.75~1 Kg Payload Weight)  Size: 10cm x 10 cm x 30 cm  Power: 12W  4 side body-mount solar panel  GaAs solar cell  45 degree sun angle for the entire orbit, 60 deg C  Actual available power will depend on the selected orbit.  Half of the power will be needed for spacecraft bus operation.  Practically, payload power will be limited to 3~5 W  Payload Downlink Data Rate: ~10Mbps (limit by power requirement)  Pointing Accuracy: 0.3~0.5 degree (3 axis nadir pointing control)

6. 6  How to verify the design?  By Tests  By Analysis  By Inspection  Process of design verification:  Quality Control  Configuration Management  Project Reviews Design Verification

7. 7 Why Project Reviews ? Mistake Is Costly Mission Failure Schedule Delay Cost Increase Performance Degradation Integrated System Accurate System Reliable System Complex System Project Review is an Effective Way to Prevent Problems - Reduce Rework - Increase Reliability - Reduce On-Orbit Malfunctions - - 三個諸葛亮勝過一個諸葛亮 -

8. 8 Spacecraft Development Cycle Requirement Development Design Validation Operation Manufacturing Mission Goal Design Baseline SDR PDR CDR ITR PSR Integration & Test System Spec. Subsystem Spec. Component Spec. Spacecraft development is an iterative process. Major changes in the late stage may cause significant impact to the program. All changes should be evaluated from SYSTEM point of view. Test Procedures

9. 9 Project Review Objectives Project Reviews Requirement Verification Design Adequacy Risk Assessment Document Completeness Requirements are sound and traceable Design meets requirements Design follows good practice with accurate analysis Risks are identified with mitigation plan Documentation is complete, accurate, and adequate Action Items Readiness to proceed next phase MIL-STD-1521B: Technical Reviews and Audits for System, Equipments and Computer Programs.

10. 10 Project Review Definition Review system engineering process and trade studies in deriving the requirements. Demonstrate adequacy of defined requirements. Evaluate optimization, completeness, and risks associated with the requirements. Review preliminary performance specifications and preliminary design details. Evaluate progress, technical adequacy, and risk mitigation of the selected design. Assess compatibility with the requirements. Identify and review long-lead parts and subcontract items. Demonstrate detailed design satisfies the requirements. Review procurement specifications, drawings, analyses, and supporting documents are accurate. Assess producibility, testability, quality, and risk resolution. PDRSDRCDR

11. 11 Project Execution  Project Review is only a mechanism to identify problems. It can not guarantee program success.  Success of the program relies on dedication of the team, good system engineering practice, and timely management decision. Program Manager System Engineers Subsystem Engineers A perfect subsystem design may not produce a workable system. Interface between elements usually present highest risks. Process has to be established to assure quality. - System engineering process needs to be followed for requirement allocation and verification, interface control, configuration control, etc. - System engineering decision needs to be made timely for program execution. How the program got delayed? …….. One day at a time

12. 12 Review of Student Team Report  The goal of student project for this semester is to achieve the level of SDR.  System engineering process should be emphasized in addition to the end results, i.e. requirements should be traceable and trade studies led to the selected solution should be presented.  Details of the requirements will be addressed in the appropriate lecture. Mission Objectives Mission Statement Mission Needs System Requirements Payload Selection Orbit Selection System Allocation Subsystem Requirements