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Mission Discussion & Project Reviews

祝飛鴻10/14/93

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TT&C 地面站X-頻段遙測資料接收站

影像資料處理中心 多重任務中心

影像產品 使用者

地面系統

台南TT&C 地面站

中壢TT&C地面站

新竹遙測資料接收站

S/S 頻段通訊

X 頻段影像資料下鏈

遙測酬載科學酬載

衛星本體太陽同步軌道

發射載具

TT&C 地面站TT&C 地面站X-頻段遙測資料接收站X-頻段遙測資料接收站

影像資料處理中心 多重任務中心

影像產品 使用者

地面系統

台南TT&C 地面站

中壢TT&C地面站

新竹遙測資料接收站

S/S 頻段通訊

X 頻段影像資料下鏈

遙測酬載科學酬載

衛星本體太陽同步軌道

發射載具

Satellite System – ROCSAT-2

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Requirement Definition

Mission Requirements

Payload Requirements

Mass/Size

Data Rate

Thermal

Operation Modes

Power

Pointing/Stability

Field of View

Performance

Spacecraft BusRequirements

Mission Needs

Mission Objectives

SMS

System

TCS

RCS

ADCS

EPS

TT&C

C&DH

FSW

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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.

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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)

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How to verify the design?

By Tests

By Analysis

By Inspection

Process of design verification:

Quality Control

Configuration Management

Project Reviews

Design Verification

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Why Project Reviews ?

MistakeIs Costly

MissionFailure

ScheduleDelay

CostIncrease

PerformanceDegradation

IntegratedSystem

AccurateSystem

ReliableSystem

ComplexSystem

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 -

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Spacecraft Development Cycle

RequirementDevelopment

DesignValidation

Operation

Manufacturing

MissionGoal

DesignBaseline

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

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Project Review Objectives

ProjectReviews

RequirementVerification

DesignAdequacy

RiskAssessment

DocumentCompleteness

• 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.

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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.

PDRSDR CDR

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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

SystemEngineers

SubsystemEngineers

• 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

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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

SystemRequirements

PayloadSelection

Orbit Selection

SystemAllocation

SubsystemRequirements