a novel satellite concept “panel extension satellite
TRANSCRIPT
PETSAT Projectwith PETSAT Project team
A Novel Satellite Concept “Panel Extension Satellite (PETSAT) ” Consisting
of Plug-in, Modular, Functional Panels
PETSAT Project
Shinichi Nakasuka and Hironori SaharaUniversity of Tokyo, Japan
Yoshiki SugawaraAoyama Gakuin University, Japan
Kanichi Koyama, Takanori Okada, Hideaki Kikuchi, and Chisato Kobayashi
SOHLA
PETSAT Project
Plug-in of Panels having different functions deal with variety of mission requirements just like a “Lego Block”
→ Mass production of panels lead to low cost/high reliability→ Plug-in makes system level test simple and less time consuming→ Open architecture to allow participation of new companies → Extending panels makes it possible to use small satellite as “large sat”
PETSAT(Panel ExTension SATellite)Mission panel 1
Mission panel 2
Attitude Control panel 1
Attitude Control panel 2
Attitude Control panel 3
Communication panel 1
CPU panelBattery panelCommunicationpanel 2
extension
PETSAT Project
Before Separation(Launch Locked)
PETSAT Project
Important Considerations• How to distribute various satellite functions into
different functional panels• Design of standard interfaces between panels in
four aspects:– Mechanical– Electrical– Information– Thermal
• Standardization of components– Standard panel structure for different functional panels– Equipment should be installed into flat, standard panels
• Fault tolerance and graceful degradation
PETSAT Project
(1) Architectural Study
PETSAT Project
PETSAT Project
Function Distribution into PanelsHow to distribute OBC, memory, attitude control, power, communication, etc, into (how many) different panels
• Each panel has “Common compo.” + “Special compo.”– Inter-panel communication controller is indispensable– How about solar cell, battery, CPU ?– Each panel is powered by components in each panel ?
• Easy plug-in of any quantity of panels should be possible– Distributed architecture like “Personal Computer on Internet”
• Fault tolerance required including panel interface failure– Tolerant against electric or information line failures– Graceful degradation and reconfiguration capability
• Should deal with variety of mission requirements by changing types and quantity of panels– Ex) Two communication panels should have double capacity
PETSAT Project
PETSAT Project
Overall Architecture of Functional Panels• Types of Functional Panels:
– (1)OBC+memory (2)communication(COMM-P) (3)attitude control(ACS-P) (4)thruster(PROP-P) (5)battery (6)mission panel (MISN-P)
• Common components to be implemented on each panel:– Power control module including solar cells/battery – Information module:inter-panel communication and in-panel
information management • Other important considerations:
– Power demands and generations are not balanced in each panel(e.g., Mission, communication panels require lots of power)→Real time power distribution between panels is indispensable
– Many CPU exists including local CPUs and main OBC →System management by multi-CPUs
PETSAT Project
PETSAT Project
Common Components
Interpanel comm.
Solar Cell
Small Battery
Local CPU
Other panels
Other panels
Power
PETSAT System Configuration
Tx/Rx・Antenna
Comm. Panel
Large Battery
Battery Panel
Actuator
Sensor
Control Panel
MemoryMissionSystem
Mission PanelOBC Panel
OBC
Memory
PETSAT Project
OBC Panel
Comm. Panel
Battery Panel
Control Panel
Mission Panel One Panel
PETSAT Project
Requirements as to Four Interfaces• Mechanical Interface
– Reliable folding/extension in space environment– Low shock extension and latch in several angles
• Electrical Interface– Self-supply within each panel in principle– Autonomous power re-distribution between panels
• Information Interface– Plug-In simplicity and system extensibility – Fault tolerance in distributed agent architecture
• Thermal Interface– Suppress temperature difference between/within
panels
PETSAT Project
PETSAT Project
(2) Design of Each Subsystem
PETSAT Project
PETSAT Project
(1) Structure: stowed and deployed configuration
PETSAT Project
Deployment Sequence should be controlled
PETSAT Project
Standard Panel Structure
Model 1(FY16) Model 2(FY17) Model 3(FY18)weight@space (3kg@2ℓ) ([email protected]ℓ)
Cost65.6Hz
Thermal pass
1st Frequency 400Hz 137.5HzThermal. cond.
FY16: FY17: FY18:Press
1.5mm thickness
PETSAT Project
Equipment weight ratioBase-unit BASE-U
SAPHING-M
PROP-CONTIG-CONT
THRTNKSUP
PROPELLANT 0.5kg 6.7%Panel structure PNL 1.0kg 13.3%
8%Solar cell plate
0.6kg0.6kg0.3kg
0.2kg0.4kg0.4kg1.5kg2.0kg
8%inter-panel hinge 4%
2.7%5.3%5.3%
7.5kg
Propulsion module
20%26.7%
total
Packing Components into PanelsExp) PROP panel
CUBE-P COMM-P ACS-P MISN-P
350 mm one side
Base Unit Bay
Local Unit Bay
PETSAT Project
1) Cutting wire of launch rock triggered by signal from rocket
3) Cutting nylon wire to deploy panels sequentially triggered by bus-panel or timer
Release and Deployment Sequence
2) Release from Rocket
PETSAT Project
(2) Power System1. Distributed power system
to realize high reliability2. Consisting of Solar cell, BCR, PDM3. Compact standard platform
Independent power system for each panelThe battery output line is connected between panels to obtain redundancy(12.6v)Independent PDM for each panel (for 5v,12v)Minimum inter-panel connection
Panel Module 3
Panel Module 2
Panel Module 1
Panel Module n
PDM+5V+12VVOLT
REG
PDM+5V+12VVOLT
REG
PDM+5V+12VVOLT
REG
SeparationRelay
PDM+5V+12VVOLT
REGActivation
Switch
SeparationRelay
SeparationRelay
SeparationRelay
BCR
BCR
BCR
BCR
PETSAT Project
(3) Information System: Concept
HCAN1HCAN2
… …
CPU1 CPU2
COMPO1
COMPO2
COMPO3
CPU1 CPU2
COMPO1
COMPO2
COMPO3
CPU1 CPU2
COMPO1
COMPO2
COMPO3
Panel #1 Panel #2 Panel #3
Comparator
I2C
- Two Layered
PETSAT ProjectPCM(パネルコントロールマネージャ)
CPUI(CPU統合器)
PWR(電力制御モジュール)
PANELBASEunit
INFO-U
PCM
CPUI
PCM
CAN(Inter-panel)I2C
(Intra-panel)
I2CCAN CAN@750[kbps]
I2CMemory Bus
PWR(Power Control Module)
Local Component
Memory Bus
Information Management System
PETSAT Project
Common Information Unit (INFO-U)
CAN bus500 [kbps] (debug)700 [kbps] (release)
EEPROMMax 512 [kB]
External bus selection to isolate failed bus
Bus selection
Arbitration FUnctionInter-panel Comm.
Data storage/telemetry data
ArbitrationIntra-panel Comm.
I2C bus100 [kbps] --- 400 [kbps]
DIPSW3 x 8bit
Panel ID/Mode change
Power control for local components
SCI bus56.4 [kbps]
Intra-panel comm.
GPIOLocal components power
control and monitoring
CompareReliability
Redundancy of CPUs
MeasurementsADC / 8ch8ch x 12 bit
PETSAT Project
(4) Thermal Interface• Orbits (thermal environment) usually cannot
be decided until the last moment
• Suppress inter-panel and intra-panel temperature difference under as little level as possible
• Preparation of design freedoms for thermal control to be used to deal with variety of missions and orbits
PETSAT Project
(3) SOHLA-2
- In-orbit Demonstration Model -
PETSAT Project
PETSAT ProjectSOHLA-2 Configuration
Launch will be in 2008 - 2009
PROP
ACS
BOOM
COMM
MISN
CUBE
LF Antenna for Lighting Observation Gravity Gradient
Boom
Earth
- Gravity gradient stability- Maximum solar power in
worst case- Importance of each panel
PETSAT Project
Overview of SOHLA-2• Mission: Test and demonstration of PETSAT
technologies and lightning observation experiment• Bus panel: as similar as possible to University of
Tokyo’s CubeSat “XI-IV” and “XI-V”• Attitude control panel: 3-axis gyros, sun sensor
magnetic torquers• Communication panel: S-band, max 256kbps.• Propulsion panel: mono-/bi- propellant using H2O2,
Isp=60/120s, F=100mN/1N• Mission panel: Three channel LF receiver, 5m
antenna
PETSAT Project
Direction Estimation
Data Storage and Preprocessing
Ground Observation System
Wide band Antenn+Filter+Amp
A/D Converter
Signal Processing
5m
5m
Satellite Observation System
Difference of arriving RF phases has information about the relative direction of the RF source
Location of lightning
Mission: Lightning Observation
Research by Prof. Kawasaki, Osaka University
PETSAT Project
2 9 4 . 5 2 9 5 . 0 2 9 5 . 5 2 9 6 . 0 2 9 6 . 5
- 0 . 0 0 0 4
- 0 . 0 0 0 2
0 . 0 0 0 0
0 . 0 0 0 2
0 . 0 0 0 4
0 . 0 0 0 6
E-F
ield
[V/m
]
T i m e [ μ s e c ]
衛 星 観 測
0 . 0 0 . 5 1 . 0 1 . 5 2 . 0 2 . 5
E-F
ield
T i m e [ μ s e c ]
地 上 観 測
VHF Radiation from LightningObserved at Ground
Observed at Satellite
PETSAT Project
ADC board
AMP board
< RF Performance >- 30MHz~100MHz- 45dB
1st model will beDemonstrated onSOHLA-1/BMW(2008.8 launch)
< ADC Performance >
- 200MHz,7-bit,
- 16kpts,100 pulse
Configuration of Interferometer
BPF
ADC
FPGA
BPF
ADC
FPGA
BPF
ADC
FPGA
200MHz
memory memory memory
Trigger detect
DSP RAM FLASH
IIC I/F
AMP AMP AMP
FLASH
PETSAT Project
University of Tokyo’s CubeSat Project “XI”
XI-IV (Launched in 2003.6) XI-V (Launched in 2005.10)
PETSAT Project
Bus panel (heritage from CubeSat “XI-IV”)
Thermo Sensors
CUBE-ModulePower
Com1Main
Com2
Battery
Solar Cell
DCDC
DCDCOBC
ROM TX TNC
RX TNC
CW Gen
TX
RX
CWCharge Circuit
OBC
RX TNC
uSWFlight PinFlight Pin
PWR5V
TLMTLM
CMD
TLM
DCDC
OBC
PWR5V
Info.Power
BASE-Module
POWER UNIT
I/F CPU
INFO UNITInfo.
PETSAT Project
Design Policies of Propulsion for Microsatellite
• We set the following 6 policies for the propulsion:– SAFETY FIRST, but DECENT PERFORMANCE– MODERATE PRICE due to STANDARDIZATION– also, GOOD HANDLEABILITY and REDUNDANCY
In order to keep the policies,performance degradation is tolerated to some extent.
• We started development of the propulsion as follows:– Mono-Propellant
• Hydrogen Peroxide solution (< 60 wt%)• High-performance catalysts used.
– Bi-Propellant• Flammable fuel such as Ethanol• Oxygen derived from decomposition
of Hydrogen Peroxide.
• Propulsion System for common use ofboth of Mono- and Bi-Propellant desired.
Conventional
Promising
PETSAT Project
Propulsion System for Microsatellite• Configuration should be simplified to be installed into small capacity.• Effective Commercial-Off-The-Shelf (COTS) is adopted.
• We conducted captive tests of Mono- and Bi-Propellant,and attained 60 and 120 seconds of specific impulse, respectively.
Mono-Propellant:Isp=40~60sec100mN-class thrust
Bi-Propellant:Isp=120~150sec1N-class thrust
PETSAT Project
Propulsion System for Microsatellite• Now we are manufacturing a Flight-Model of the Propulsion.• Demonstration will be conducted by using SOHLA-2 microsatellite in
2008 or 2009, and BOTH operations of Mono- and Bi-Propellant are made possible.
PETSAT Project
2003 04 05 06 07 08 09
CubeSat XI-IV’03/6
CubeSat XI-V ‘05/10(Sister-Sat with XI-IV launched with SSETI-EXPRESS)
PRISM(Remotesensing) ‘08
PETSAT(PanelSatellite) ’08-‘09
Nano-JASMINE(AstrometrySatellite) ’08-‘09
PETSAT and University of Tokyo’s Nano-Satellite Projects
30 m Ground Resolution
Multi-purpose4 km Ground Resolution
Development Launch
Space Science
PETSAT Project
PETSAT for Small Industries• Development under way by SOHLA (group of
small industries), Univ.of Tokyo, Aoyama-gakuin, Osaka Univ. and Doshisya Univ.
• Fusion of technological competence in small industries with system design/analysis capability of universities
• Contribution to technological and management training for non-space engineers and young students
PETSAT Project
PAF to be hard-attached to the rocket
Wire
Rocking using volt
Launch Rock Mechanism
PETSAT Project
Items Values CommentsOVERALLWeight < 50kg
Size (stowed) 350x350x500 mm
Size (deployed) 350x50x1400 mm (Antenna length is 5m)
Size (one panel) 350x350x50 mm350x350x100 mm
(four panels)(mission panel)
BUS FUNCTION PANEL (BUS-P)Configuration Same system as CubeSat “XI” Space proven for over
3 yearsCommunication Uplink: (FM)
145MH 1200bpsDownlink: (FM,CW)437MHz 1200bps437MHz CW
Amateur Frequency Band
LOCAL CPU PIC16F877
PETSAT Project
Items Values CommentsATTITUDE CONTROL PANEL (ACS-P)Sensors Magnetometer
3-axis mechanical gyros6 sun sensors
Accuracy is roughly 0.5°
Actuators Magnetic TorquerReaction Wheel (TBD)
Local CPU H8/3694F (Renesas)THRUSTER PANEL (PROP-P)Fuel Ethanol (C2H5OH) can be othersOxidizer H2O2 (stabilizer included) middle-level
concentration (<60%) Thrust 500 mN / 1 N For mono / bi-
propellantTotal ΔV 50sec / 120sec mono- / bi-Local CPU H8/3694F (Renesas) (Hitachi)