Picosat Mission Introduction

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Picosat Mission Introduction
???/??? Date 96/03/08
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??

• ??????
• Picosat/Nanosat????????
• ??????????
• ??????
• ?????????

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Satellite System Architecture
????????
4
??????

• ?????????, ???????
• ??? (large satellite, 1000????),
• ??? (small satellite, 5001000??),
• ???? (mini-satellite, 100500??),
• ???(micro-satellite, 10100??)
• ????? (nano-satellite, 110??),
• ?????????? (pico-satellite, 1????)

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Picosat Examples
P-POD Launcher
CubeSat by radio amateurs
NSPO-YamSat
CubeSat by the University of Tokyo
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Picosat/Nanosat????????
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Picosat/Nanosat????????

• 1. ????????????
• Picosat/Nanosat????????????,??????(???),??????????
  ???????,?????????????
• ?????????????????,??????????????

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Picosat/Nanosat????????(?)

• 2.???????
• Picosat/Nanosat????????????????,?????????????,???
  ?????????????????,??????????????????????,?????????
  ??????
• ??????????,?????????,???????????????,???????????

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Picosat/Nanosat????????(?)

• 3. ???????
• Picosat/Nanosat??????????????,???????????????????
  ???????,???????(MEMS)????????????
• ?????????(??????)???????????,?????????????????,??
  ??????
• ??CalPoly???CP2??,??????????????????????

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Picosat/Nanosat????????(?)

• 4. ????????
• Picosat/Nanosat????,????????????????
• TU Sat 1???????????,?????(Tether)??????????????
• MEROPE????????Van Allen Belts?????????
• QuakeSat????????????????,?????????????

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Picosat/Nanosat????????(?)

• 5. ????
• ???????????,??????????
• TU Sat 1???????????????????????????
• nCube????????????AIS??,????????????????,??????????
  ,?????????????

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Picosat/Nanosat????????(?)

• 6. ????
• ??????XI-IV????CMOS???????,???????????????????CMOS
  ????????,???????????????????

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Picosat/Nanosat????????(?)

• 7. ????
• Picosat/Nanosat????????,????????????,???????,?????
  ???????????
• ICE?????????????,?????100????,?????GPS???????,??GP
  S????????????(scintillation)??,????????????????
• KUTESat?????????????,?????????????????
• ?????,?????????????????

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?? Picosat / Nanosat ???? (1)
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?? Picosat / Nanosat ???? (2)
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?? Picosat / Nanosat ???? (3)
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??????????
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?????????? (1)

• ?????????????

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?????????? (2)

• ????????

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?????????? (3)

• ????????

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?????????? (4)

• ????????

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??????
23
??????
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Spacecraft Development Cycles

• 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.

Mission Need
Requirement Development
Design Baseline
Design Validation
Manufacturing
SDR
System Spec.
Integration Test
PDR
Subsystem Spec.
Operation
CDR
Component Spec.
ITR
Test Procedures
PSR
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Systems Engineering

• A development system capable of meeting mission
  requirements within imposed constraints including
  mass, cost and schedule.
• Trade studies in the system engineering process
  on requirement definition, resource allocation,
  and design integration.
• Feasibility study
• System Requirements
• Specification Breakdown
• Budget Control and Interface Control
• Considering different phases in the spacecraft
  design

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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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Mission Analysis

• To meet Users needs
• Payload Requirements
• Operation Algorithm
• Orbit Launch Selection
• Mission Requirements
• A key aspect of mission analysis is to identify
  critical features of the mission which have an
  impact upon system and subsystem design.

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Payload Performance Requirements

• Communication Payload
• - frequency band
• - link margin
• - BER (Bit Error Rate)
• - Others

• Earth Observation Payload
• - spectral characteristics
• - ground sampling distance
• - swath width
• - Others

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Payload Requirements

• Resource limit of a Picosat/Nanosat
• Example
• Weight 3 Kg (0.751 Kg Payload Weight)
• Size 10cm x 10 cm x 30 cm
• Power
• Actual available power will depend on the solar
  array effective size and selected orbit.
• Typically half of the power will be needed for
  spacecraft bus operation.
• Payload Downlink Data Rate lt1Mbps (limit by
  power requirement)
• Pointing Accuracy 0.30.5 degree (3 axis nadir
  pointing control)

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Spacecraft System Interfaces
Spacecraft System
Ground Segment
Launch Segment
Space Segment
Spacecraft Bus
Payload
FSW
CDH
SMS
TCS
RCS
TTC
ADCS

• All interfaces need to be defined and controlled
  to assure integrity of the final design.

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Spacecraft System Key Interfaces

• Launch Tracking

Space Segment
Launch Segment
Ground Segment

• TTC Frequency
• TTC Format
• Link Budget
• Mission Operation

• Orbit
• Weight
• Size
• Environmental Loads
• Mechanical Interface
• Electrical Interface
• Attitude Control

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Requirements Definition
Payload Requirements
Mission Requirements
Spacecraft Bus Requirements
Mass/Size
Mission Objectives
System
SMS
Pointing/Stability
Mission Needs
TCS
Thermal
RCS
Operation Modes
ADCS
Power
EPS
Data Rate
TTC
Field of View
CDH
FSW
Performance
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Orbit Trade Studies

• Weight
• Size
• Propulsion

• Thermal Control
• Power

Selected Orbit - Altitude - - Inclination -
Thermal Environment
LV Selection
Revisit Time - Taiwan - - Global -
Mission Orbit
Are Mission Needs Met?
No
Coverage Area
Radiation
Yes
Final Mission Orbit

• Antenna
• Operation Mode

• Parts Selection
• Shielding

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Spacecraft Bus Requirements

• Design requirements for each of the spacecraft
  bus subsystem can be expressed by a set of design
  parameters, e.g. link budget, etc.
• Definition of key design parameters for each of
  the spacecraft subsystem and associated analysis
  for design verification will be discussed in
  detail in the subsequent lectures.
• Some of the requirements, however, have overall
  effects across all the subsystems, e.g. weight.
  These requirements are typically classified as
  the system requirements.

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Spacecraft Bus Requirements (cont.)

• System level trade studies are needed to define
  these requirements with proper allocation to
  subsystems.
• Design verification of system requirements may be
  conducted in the subsystem level. Allocation to
  subsystems may need to be adjusted based on the
  subsystem design.
• Typical set of system requirements
• - Orbit - Mission Life -
  Reliability - Mass
• - Power - Link Budget - Pointing
  
• - Memory size/throughput

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Mass
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Power

• Power requirement could be market driven,
  payload driven, and for the case of picosat, size
  and configuration driven.

• Design Drivers
• - Customer/User -
  Target planet, Solar distance
• - Spacecraft configuration -
  Lifetime
• - Attitude control
  - Orbit parameters
• - Payload requirements -
  Mission constraints

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Power Allocation
Orbit Parameters
Attitude Control
Cell Type
Spacecraft Configuration
Body Mounted Solar Cell
Available Mounting Area
Cell Temperature
Available Power (BOL)
Power Allocation
Mission Constraints
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Design Integration
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Design Verification

• All requirements need to be verified either by
  analysis, test, or inspection.
• Test Philosophy
• Acceptance Test Maximum flight prediction and
  duration
• Qualification Test Qualification level and
  duration, i.e. acceptance plus margin
• Proto-flight Qualification level and
  acceptance duration
• Typical Spacecraft System Level Test
• Electromagnetic Compatibility/Interference
  Test (EMC/EMI), Comprehensive
• Performance Test (CPT), Vibration, Shock,
  Acoustic, Thermal Vacuum/Thermal
• Balance Test, Alignment, Mass Property, Leak
  Test, Spin Balance, Deployment,
• etc.

Spacecraft Level
Component Level
Subsystem Level
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?????????
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????2Preliminary Design of Picosat System

• Design a set of picosats which may contain more
  than one satellite for early warning of sand
  storm from Gobi desert in north-west mainland
  China.
• Each satellite shall have weight no more than 3kg
  and size no more than 10cm x 10cm x 30 cm, and
  the design shall include payload suitable for the
  mission, adequate system-subsystem structure and
  elements, and operating sequence to achieve
  mission objective.
• Need to study the characteristics of the sand
  storm in order to formulate a set of mission
  requirements.

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Outline for Program Report

• 1. Program Introduction
• 2. Mission objectives and requirements
• 3. Payload specification and requirements
• 4. Orbit specification
• 5. Power specification
• 6. Structure configuration and specification
• 7. Thermal control specification
• 8. TTC specification
• 9. Command and Data Handling specification
• 10. Attitude specification
• 11. Verification of system
• 12. Power and mass distribute
• 13. Flight operation modes and procedures

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????

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• ????????
• ?????
• ??????
• ROCSAT-1,??????
• YamSat, ?????
• LISA (Lost In Space Algorithm), ??
• ????
• Mission
• Payload
• ????

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47
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Product Tree Example
YamSat System
Structure
Thermal Control
Power
TTC
ADCS
Payload
CDH
X Panel
VHF/UHF Antenna
Battery
Magnetometer
Spectrometer Electronics
OBMU
Black Paint
CW Antenna
Distribution Regulation unit
Magnetic Coil
Optical Parts
-X Panel
Isolator
Transceiver
Y Panel
Solar Array
Receiver
-Y Panel
Harness
Z Panel
-Z Panel
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Flow Chart for Requirements design
50
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• 2.????????
• 3.??????, ????????????
• 4.??????, ????????

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• (7)??????? -2040 degC

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