University of Tokyo CubeSat Project CRITICAL DESIGN REVIEW

1
University of TokyoCubeSat ProjectCRITICAL
DESIGN REVIEW

• April, 6, 2001
• Intelligent Space Systems Laboratory
• University of Tokyo

2
Contents

• Project Overview
• CubeSat program, Organization, Management,
  Schedule
• Mission Overview
• Design Assumption, Mission Objective, Mission
  Profile, Success Level
• System Design
• Design Strategy Concepts
• Subsystem Details
• Electronics, Power, Communication, Structure,
  Environment, Ground Segment
• Concerns

3
Project Overview
4
CubeSat Program
Proposed in University Space Systems Symposium.
(Nov. 1998, Hawaii) International educational
program to improve students skill of space
engineering and project management. Quick and
low cost development policy. 10cm cubic
satellite weighing less than 1kg.
5
Project Constraints
10cm cubic shape, weight less than
1kg. Installed in the carrier called P-POD,
developed by CalPoly. P-POD is to be installed
in MPA (Multiple Payload Adopter), developed by
One Stop Satellite Solutions Inc. Launched by
Russian rocket Dnepr from Baikonur in November,
2001. Orbit 600-800km circular, 60 degree
inclination HAM band operation
6
CubeSat Developers
California Polytechnic State U Dartmouth
CollegeFlorida Space InstituteLeland High
SchoolMontana State UniversityStanford
UniversityStellar Innovations
Taylor University Tokyo Institute of
TechnologyUniversity of ArizonaUniversity of
TokyoWilcox High School
7
CubeSat Program Organization
Russia
Launcher Provider
OS2 Mission Organizer
OSSS Inc.
Stanford U
Carrier Provider
CalPoly
U.S.A.
Japan
Japan-side Agency
Astro Reserch Co.
CubeSat Developers
JapanU of TokyoTokyo Inst. of Tech.
U.S.A.10 Facilities
8

• Payload Configuration

MPA Mass lt 300kg Isogrid Spaceframe Deploys
Payload Satellites Three-axis Stabilization
Dnepr LV Launch weight 211 t Propellant
amyl heptyl Number of stages 3 LV diameter 3m
LV length 34m Reliability 0.97 Payload 400kg
(800km) 1400kg (600km) (inclination 65deg)
P-POD Deployes 3 CubeSats
CubeSat
9
UTs Project Organization
21 active membersGeneral meeting every 1-2
week(s)Subsystem meeting every week
10
Development Milestone
Development code XI sai (X-factor
Investigator)
Communication test model, Mass model, CDR
11
Mission Overview
12
XI Outlook
Solar cells are to be attached on whole surface
Antenna Latch Mechanism
Antenna
Flight Pin Hole
Camera Hole
photo XI-II (BBM model)
13
Mission Description
Mission Statement "To acquire the indispensable
technology in developing super-small satellite
system" Mission Gathering the satellites
health information via beacon signal. Command
uplink data downlink. Telemetry data
broadcasting service. On-orbit verification of
the commercial-off-the-shelves (COTS)
components. Imaging experiment as an extended
mission. (TBD) Sending everyones message into
space.
14
Success Level (1)
Projects Minimum Success --- Acquiring the
important technology and knowledge through
designing and fabricating the spacecraft.
Establishing overall work flow of the satellite
development project. Establishing a methodology
of spacecraft design. Raising the fabrication
technique. Conducting several kind of testing
and feeding back its results to the design.
Keeping the project progressing smoothly so as
to bring it to be the launchable
condition. Mission Success --- Receiving
signals from the spacecraft. Surviving in the
actual launch environment. Successfully
verifying the function of the communication
system. Gathering house keeping data.
15
Success Level (2)
Full Success --- Succeeding in uplink
downlink. Successfully commanding the
spacecraft by uplink. Getting downlink data as
a reaction to the command uplink. Advanced
Success --- Successfully verifying the function
of the advanced mission components. Verifying
that sensors planned to be equipped as advanced
mission components should work normally.
16
Mission Profile (1)
Launched by Dnepr from Baikonur in Nov.
2001. MPA is put in 600-800km circular orbit
with 60 degree inclination.
MPA deploys some of its payloads activates
P-POD. P-POD deploys CubeSats.
CubeSat starts operation after a certain elapsed
time.
17
Mission Profile (2)
Post Ejection Stand-by Main OBC is activated
while the other components are off.
Nominal Operation Antenna is deployed. All
components including beacon are activated except
telemetry transmission system.
Telemetry Transmission This mode occurs as a
reply to the uplink command from ground station.
18
System Design
19
Basic Specifications
?Structure 10cm cubic, 1kg, Aluminum A7075
body ?Main Processor OBC PIC16F877 4MHz(Program
memory 8k, RAM 368) Data Recorder EEPROM 32k
224k ?Communication System Downlink 437.490MHz,
FSK, AX.25, 1200bps, 600mW Uplink 145.835MHz,
FSK, AX.25, 1200bps Beacon 436.8475MHz, CW,
100mW ?Power System Battery Manganese type
lithium-ion battery, 8 parallel Solar
Cells Single crystal silicon, 60 cells Bus
Voltage 5V ?Attitude Control Passive
stabilization using permanent magnet ?Sensors Vol
tage, Current, Temperature, Area sensor
20
Structure
PWR5V
Power
OBC
Com1
Main
DC-DC1
TX
ROM
TX TNC
TX
RX TNC
Analog SW
DC-DC2
TLM
TLM
OBC
Com2
DC-DC3
OBC
CMD
RX TNC
RX
uSW
Flight Pin
ACK
TLM
Charge Circuit
CW Gen
CW
PWR5V
Flight Pin
Important Analog Sensors
Digital Sensors Antenna Latch
Solar Cell
Analog Sensors
Battery
21
Internal Function Design Strategy
Mother board intervenes inter-subsystem signal
power flow.
Structure Subsystem
Camera Module
Electronics Subsystem
Battery
Mother Board
Power Subsystem
Solar Cell
Communication Subsystem
22
Structure Subsystem
23
Structure Subsystem
24
Body of CUBESAT
a) Assembly b) Weight and Center Of Mass c)
Material d) Size
25
Assembly of XI-II

• First, Subsystem Boards are attached to Mother
  Board.
• Then,that module is attached to 4 pillars.
• Finally,Solar Cell panels covered CUBESATs
  surface.

26
Construction of subsystem board

• Each subsystem board is attached to Mother Board.
• Battery and I/F connectors are also attached to
  Mother Board.

27
Center Of mass

• The difference of geometric center between center
  of mass is 7.8mm (within 20mm)
• Total mass is 990g (within 1kg)

28
Material

• A7075 is the same material of P-POD which means
  that thermal expansion is equal.

29
Front view of XI-II

• Solar cells mounted on EXTERNAL MOUNTING SURFACE
  do NOT exceed 6.5mm
• Antennae are also mounted on EXTERNAL MOUNTING
  SURFACE.

30
Bottom view of XI-II

• Antennae are mounted within 6.5mm.
• 2 Kill Switches are mounted on this plane.

31
Interface
a) Flight Pin b) External Input/Output c)
Connector d) Kill Switch
32
Installation of CUBESAT

• 3 CUBESATs can be installed in a P-POD carrier.
• We can get some experimental data from I/F hole
  before launch.

33
Interface System
V up
Subsystem
Micro Switch
Flight Pin
Switch Unit
V down
Plunger
Antenna Deployment Order
Charge up
Switch Unit
Charge down
Flight Pin 2
GND
1 2 3 4 5 6 7 8
External Interface RJ-45
Battery V
DCDC 5V for electronics
DCDC 5V for communication
DCDC 10V
V operate 4V
External Tx
External Rx
34
Mother Board

• All Subsystem Boards are attached to Green
  connector.

35
Interface Board

• All External I/F is allocated to Interface Board
• Interface Board has some module as follows.
• Kill Switch
• Before-Flight Pin
• External I/O Connector

36
External Interface

• We use RJ-45 connector.
• Even if CUBESAT is installed in the P-POD , we
  can get the data witch the table shows.

37
Kill Switch
Kill Switch

• We use 2 Kill Switches in parallel for
  redundancy.
• When one of 2 switches is ON , all system can get
  power.

38
Flight Pin

• Switch1Supplying power to the system.
• Switch2OPEN/CLOSE battery charging circuit.

39
Antennae Deployment Mechanism
a) Magnetic Plunger b) Folding Method
40
Antenna Deployment System

• Antenna is deployed using Electromagnetic Plunger

fa
fb
V is impressed
The piece is captured by the magnet
Magnetic Power decreases And the piece is released
Electromagnetic Plunger fa 3.5 N min.
fb 0.8 N
41
Antenna Deployment System
Antenna Deployment Video
42
Strength Analysis
a) Behavior as Cantilever Beam b) Ceiling panels
vibration c) Load Estimation d) Countermeasure
for vibration(Antennae)
43
Behavior as Cantilever Beam1

• If CUBESAT experiences very strong vibration, it
  may behave as a cantilever beam.
• In this case , the Harmonic Frequency is around
  20kHz (witch is enough high, comparing to the
  launch vehicles frequency)

44
Ceiling panels vibration1

• Harmonic Frequency is around 1 - 2 kHz
• The Harmonic Frequency largely depends on the
  thickness of the panel.
• The thicker the panel is designed , the higher
  the Harmonic Frequency becomes.

45
Ceiling panels vibration2

• To avoid ceiling panels vibration we have to
  design it as possible as thick.
• For this design , Total Mass is large problem
• Eventually,we have to choose around
  1.0-1.5mm

46
Load Estimation
P-POD

• The 3rd CubeSat experiences maximum load while
  2nd stage flight
• The maximum stress is 0.011kgf/mm2
  (enough for Aluminum use)

Maximum Stress
47
Countermeasure for vibration(Antennae)

• To complete any mission , fastening and deploying
  antennae is very important.
• It is difficult to simulate the behavior of the
  antenna , so we conduct some experiments to
  confirm the feasibility of this design.
• Fixing antennae with several points.

48
Electronics Subsystem
49
Function of Electronics
50
Block Diagram
51
Command Data-Handling
OBC
Tx-TNC
CW-TNC
Ground Station in UT
52
Command Data-Handling(2)
Command from Ground Station
?Antenna deployment ?Requesting current data
(Total , Solar Array , C-DCDC , E-DCDC)
?Resetting C-DCDC ?Resetting charging circuit
?Requesting EEPROM data ?Requesting temperature
data (Battery , Solar Array , FM-Transmit)
?Requesting voltage data (Battery , Solar
Array)
53
Command Data-Handling(3)
Data to Tx-TNC
?Current ----- 9 bytes
(Total , Solar Array , C-DCDC , E-DCDC) ?EEPROM
Data ----- Undecided?Current
Temperature of Solar Array ----- 12
bytes ?Temperature ----- 8 bytes
(Battery , Solar Array , FM-Transmit) ?Voltag
e ----- 2bytes (Battery ,
Solar Array)
54
Command Data-Handling(4)
Data to CW-TNC 17 bytes
Time
3 bytes
Status
1 bytes
Picture
1 bytes
Voltage
2 bytes
9 bytes
Current
Additional Data
1 bytes
55
Components of Electronics
XI-II model
56
Components of Electronics-(2)
XI-II model
57
Components of Electronics-(3)
ROM (24LC256)

• I2C serial EEPROM
• Memory 256Kbit(32Kbyte)
• Max erase/write cycles100,000
• Max write-cycle time 5ms
• Max clock frequency 400kHz

58
Thermal Monitoring
Thermal Sensor ( LM335Z ) Power
consumption5mW Measuring range -40100?
Characteristic 10mV/? Precision
1?
59
Function of Reset-(1)
60
Function of Reset-(2)
For SEL tolerance, reset function is
needed. Reset system requires high reliability so
as not to shut off continuously even in CPU
malfunction case.
CPU
Two wire AND reset system using FET
61
Communication Subsystem
62
Communication System Diagram
OBC
Telemetry data
Beacon data
Up-link command
Sensors
AD Convert
Tx TNC PIC16C622
Rx TNC PIC16C711
Negotiation
Morse encoder PIC16C716
AX25 Coded data with Parity
AX25 Coded command
PLL Control
PLL Control
Demodulator MX614
Morse Coded data PTT Control
Modulator MX614
PLL Control
FSK modulated command
FSK modulated data
Nishi RF Lab. Custom made FM transmitter
Nishi RF Lab. Custom made CW transmitter
Nishi RF Lab. Custom made FM receiver
switching
Half wave length dipole antenna
Half wave length monopole antenna
Antenna SW
63
Telemetry Transmission System
64
Tx TNC (AX.25 encoder)

• Tx TNCMicro controller PIC16C622
• program memory(EPROM) 2 kbyte
• data memory(RAM) 128 byte
• clock 4 MHz
• I/O port 13 (4 AD Converters)
• power consumption 2.0 mA _at_ 5V
• Tx TNC receives telemetry data from OBC
• Puts Parity byte for error detection
• Encodes the telemetry data with AX.25 protocol
• Sends encoded data to FSK modulator

• AX.25 Protocol
• This protocol is mainly used for data
  transmission by HAM
• Every Amateur Radio Station all around the world
  can decode our telemetry data!!!

AX.25 frame structure(with Parity)
65
Tx TNC Program
Start Initialization
data from OBC ?
No
Yes
Receive data from OBC
Packetize into AX25 format
Send packet to FSK modulator
66
FM Transmitter

• FM Transmitter is used to transmit telemetry data
• Nishi RF Laboratory custom made transmitter

• frequency
• band width
• RF output power
• input power
• operative temp.
• volume
• (including CW transmitter)

437.490MHz 20kHz 1W under 6W -30?60? 906010cm
FM transmitter
FM transmitter System Diagram
67
Beacon Transmission System
68
CW Generator (Morse encoder)

• Morse encoderMicro controller PIC16C716
• program memory(EPROM) 2 kbyte
• data memory(RAM) 128 byte
• clock 4 MHz
• 4 AD Converters (8bit)
• power consumption 2.0 mA _at_ 5V
• CW generator receives beacon data from OBC
• Monitors sensor data independently from OBC
• (Countermeasure of OBCs hang up)
• Generates Morse code
• Controls the KEY of CW transmitter
• Data rate human decodable speed
• Beacon data format

69
CW Generator Program
Start Initialization
No
OBC ready to send data?
Yes
Data Sampling
Counter lt 10sec
Yes
Receive data from OBC
No
Data sensing (AD Convert)
UT1 www.space.t.u-tokyo.ac.jp
UT2 AA BB CC
UT3 DD EE FF
Data Sending
UT4 GG HH II
UT5 JK LM NO
UT6 PQ RS TU
70
Command Receiving System
71
Rx TNC (AX.25 decoder)

• Rx TNCMicro controller PIC16C711
• program memory(EPROM) 1 kbyte
• data memory(RAM) 64 byte
• clock 4 MHz
• 4 AD Converters (8bit)
• power consumption 2.0 mA _at_ 5V
• Rx TNC receives AX.25 encoded command
• from FSK demodulator
• Decodes it and sends command to OBC
• OBC Reset System
• If the command is Reset Command, resets OBC
• Monitors OBCs current and resets OBC in case of
  SEL
• (Countermeasure of OBCs SEL)

PIC16C711
72
Rx TNC Program
Main Routine
Start Initialization
Interruption Routine
Receive Uplink command
A/D convert Total I
set Receiving flag
Total I gt Threshold ?
Command rset or flag_rst 1 ?
No
Yes
Yes
flag_rst 1
No
OBC ready to receive?
Reset OBC
Yes
Wait 10 ms
Send serial data to OBC
flag_rst 0
clear Receiving flag
73
FM Receiver

• FM Receiver is used to receive up-link command
• Nishi RF Laboratory custom made receiver

• frequency
• input power
• receive sensitivity
• receive output
• operative temp.
• volume

145.835MHz under 100mW under -16dBµ 16dBV
typ. -30?60? 506010cm
74
Antenna Configuration
Antenna for Transmitters 430MHz band Half
wavelength dipole antenna
Antenna for Receiver 144MHz Half wavelength
monopole antenna
75
Antenna Pattern (Transmitter)
The gain which we can decode the data in our
ground station
76
Antenna Pattern (Receiver)
77
Link Budget (Telemetry Tx)
CUBESAT Comm. System
UTs Ground Station
78
Link Budget (Command Rx)
UTs Ground Station
CUBESAT Comm. System
79
Power Subsystem
80
Power Subsystem
Charge Circuit
A
A
OBC
TNC
OBC
Batteries
Switching Regulator
Switching Regulator
DCDC Converter
Communication Subsytem
Electronics Subsystem
Tx
81
Power Subsystem(CONTD)

• Supply a continuous source of electrical power to
  loads.
• Power source is solar panels.
• Batteries are used for storage
• Regulated DC power and unregulated power is
  supplied for loads.
• Power consumption is monitored for SEL.

82
Power Regulation Control

• Bus voltage main 5V
• Regulated to 5V using switching regulators and
  DCDC converter
• Elect. subsystem power line Comm. subsystem
  power lines are independent so that they monitor
  each other and shutdown in case of SEL

83
Source

• Power is supplied by body mounted solar cells.
• Cells are arranged on all 6 CubeSat surfaces.
• Average power 1228 mW (typ _at_ 80?)

84
Solar Panel
Bass bar

• Cell type Si Crystal (SHARP)
• Efficiency 16
• 10 cells in series / panel
• Cell size
• X 28.25x13.8mm
• -X,Y,-Y47.75x13.8mm
• Z,-Z 47.75x15.8mm

Photo3 cells in series
85
Solar Array Layout (X panel)
X panel 4.5V x 172mA 774mW (typ. _at_ 25
?) 4.5V x 162mA 727mW (typ. _at_ 80 ?)
86
Solar Array Layout (-X,Y,-Y panel)
-X,Y,-Y panels 4.5V x 297mA 1336mW (typ. _at_
25 ?) 4.5V x 279mA 1256mW (typ. _at_ 80 ?)
87
Solar Array Layout (Z,-Z panel)
Z,-Z panels 4.5V x 340mA 1530mW (typ. _at_ 25
?) 4.5V x 319mA 1438mW (typ. _at_ 80 ?)
88
Energy Storage

• Batteries will be used during eclipse and
  downlink
• Liion secondary batteries are selected.
• 8 batteries are set in parallel.
• DOD is 3
• Batteries only lifetime is 38 hrs

89
Liion battery
Cathode Material Lithium Manganate Anode
Material Carbon Operating Voltage 3.8V Discharg
e Capacity 780 mAhr
Single Cell Spec.
90
Battery Charger

• 3 candidates for Battery Charge Circuit

MM1485

• Small power dissipation
• Const. Voltage Current Charge Mode
• Pre-charge Temperature protection
• Large package (16 pins) and may be difficult to
  assembly

91
Energy Consumption
Components PowermW Frequency in use
OBC 20 All times sensors 20 All times Tx TNC
20 During downlink Tx 6000 During
downlink CW 300/125 All times (ON / OFF) CW
TNC 20 All times Rx 125 All times Rx TNC
20 All times Camera 150 Sometimes Magnetic
Plg. 800 Antennae deployment
92
Power Balance

• Points
• Beacon can be sent by solar panels direct drive
• Source and consumption must be balanced
• Solar cell average output 1228mW gt Consumption
  at beacon use 900mW
• Maximum average supply power 669mW gt Average
  consumption 616mW

OK
OK
93
Attitude Control

• Objectives
• To make CubeSat tumble in order to smooth thermal
  input
• Point antennae to the ground station
• Methods
• Use a permanent magnet and a libration damper

94
Control Mechanism

• Torque will be generated to align earth magnetic
  direction and CubeSats dipole moment.
• Libration is damped by energy dissipater.

Dipole Moment
Ground Station
Antennae
95
Torquer Sizing
Required Torque 1.0E-6 Nm
Disturbance
TorqueNm
AirDrag
2.26E-10
Solar Pressure
1.38E-9
Gravity Gradient
1.25E-8
At 800km magnetic field
To follow the change of magnetic field
1.0E-6
Required Magnetic Dipole Moment 0.046 Am2
96
Permanent Magnet
97
Libration Damper

• Libration damper dissipates energy to stable
  attitude change.
• Dissipation caused by hysteresis loss and eddy
  current loss
• High permeability iron is used for the damper
• 3days are expected (8 days for worst case) to
  damp oscillation

98
Environment Subsystem
99
Environmental Tests (outline)
Tried and Tested
Future Works
Heavy ion testing (PIC16F877 F84 C622
C774) Heavy ion testing (PIC16F877 C774
C622) Li -ion battery testing (in a
vacuum) C-MOS Camera testing (in a vacuum)
Thermostat EM-Plunger , Li -ion battery ,
C-MOS camera,Solar Panels SEL testing
DCDCs,OP-AMPs,Tx,Rx etc Vibration testing
Solar Panels , EM-Plunger,EM Thermal Vacuum
Chamber XI-II a , EM , FM1 , FM2
100
Analysis (outline)
thermal analysis We construct a model of heat
transfer by means of the node point method using
C-programming. We will complete building 50nodes
model and fixing the value of every parameter
from XI-IIa testing. SEE analysis We
calculated SEE rate using the CRÈME software and
provided reset functions to XI-IIa. (
http//crsp3.nrl.navy.mil/creme96/ )
101
Tried and Tested
Heavy ion testing ( at NASDA) 2000.09.12 source
Calfornium (Cf252)
(for quick look)
102
Tried and Tested
Heavy ion testing ( at JAERI Takasaki) 2000.10.09
source 20Ne4, 40Ar8, 84Kr17
Using CREME96 Results,We decided to use
PIC16F877.
(height 600km,incrination60)
cf. LETMeV/(mg/cm2),SEUcm2/bit
103
Tried and Tested
Vacuum chamber testing - Li ion battery test
(2001.01.21 - 23 at UT-Arakawa Lab.) No
deterioration observed in 10-5 Torr evacuated
chamber.
104
Analysis
Quick look
Height600km incrination 60 6 nodes (CUBE
planes) mass density Al density specific
heat9209J kg-1K-1 conductivity240W
m-1K-1 e0.825 a0.805
105
Future Works
We have a plan to execute EM-Plunger and XI-II a
test with thermal vacuum chamber. (2001.04.10. -
at ISAS Ohnishi Lab.)
106
Future Works
107
Future Works
108
Outgas Examination
We choose following products from out-gas point
of view.
?However, they are not fixed yet.
109
Work Room
Work Room Environment
We will construct isolated work space to
manufacture EM,FM1,FM2. (aiming at 1000-level
clean room)
?Air conditioner HEPA Unit(SS-MAC) YAMATO science
co.
110
Ground Segment
111
When can we contact?(1)
Pass time for 1 week
1000
900
800
700
600
Pass timesec
500
400
300
200
100
0
0
5.2
12.4
27.1
34.3
49.0
56.1
61.3
76.1
97.8
97.8
106.7
121.3
130.1
144.7
151.7
166.3
Simulation passage timehr
112
When can we contact?(2)

Maximum elevation angle (deg)
Pass
113
When can we contact?(3)

• There are 49 passes.
• which means we can contact with our CubeSat
• 6 or 7 times per day.
• In those passes, 22 passes have an elevation over
  20deg.
• The longest pass time is about 900sec.
• We have 1 or 2 chances to contact for 900sec
  everyday.

114
Necessary Time for Communication

• CW Beacon Downlink
• CW Beacon is consist of 73 words.
• If duty ratio is 0.3, it takes about 240sec to
  send 73 words.
• (60 words per minute )
• FM Packet Telemetory downlink
• Packet length is about 80 bytes.
• Baud rate is 1200 bps , so it takes 0.54sec
  to receive a packet.

115
Operation Plan
If we can receive the CW Beacon, we send Uplink
Command once or twice a day.
116
How to handle Downlink Data
We expect it may be difficult for us to receive
and decode downlink data perfectly, so we prepare
backup system to get something of traces of
downlink data.

• Recording CW Beacon Telemetry Packet to Mini
  Disk.
• Original TNC skipping CRC (check sum).

117
Ground Station Equipment(1)
144MHz/430MHz Antenna
Transceiver, TNC, etc.
118
Ground Station Equipment(2)

• 144MHz/430MHz cross Yagi antenna WHS32N, MASPRO
• 430MHz cross Yagi antenna (TBD)
• Antenna rotator controller for azimuth
• 750FX, EMOTATOR
• Antenna rotator controller for elevation
• EV800, EMOTATOR
• VHF/UHF multi band all mode transceiver IC-970J,
  ICOM
• VHF/UHF multi band all mode transceiver
• (Equipped for 9600bps packets) IC-910D, ICOM

119
Ground Station Equipment(3)

• TNC TNC505,TASCO
• TNC (With function to co-decode CW signal)
  TNC555, TASCO
• TNC (Skipping CRC)
• handmade
• Signal converter I/F between PC and rotators
• Level converter CT17, ICOM (I/F between PC and
  Tranceivers
• PC (OSWindow98)
• MDLP mode MD recorder (TBD)
• MDS-S50, SONY2

120
Ground Station Configuration
Command
TNC-505
144MHz uplink
IC-970J
Telemetory
TNC
430MHz Telemetory downlink
MD recorder
PC (Windows98)
MD recorder
IC-910D
TNC-555
430MHz CW downlink
CW beacon
EV-800
Signalconverter
CT17
750FX
Frequency, Azimuth, Elevation
121
http//www.space.t.u-tokyo.ac.jp/cubesat
122
Message Mission

• Message from all over the world will be
  microfilmed and packed in CubeSat
• Themes are
• Dreams for space
• CubeSat mission proposal etc.
• Messages are accepted by postal cards.
• Details are uploaded to WebPages

123
Program Timeline
FM Shipment (8/15)
Launch
TCDR
FM Deadline
Mass Model Shipment
CDR(3/19)postponed
Long Range Comm. Experiment
EM Deadline
red char. contract matter
124
Concerns (Electronics)

• We made a reset system for countermeasure against
  SEL, but still do not decide the SEL threshold
  current. How do we decide it and how much should
  we have a margin for it?
• For countermeasure against SEU, we will set only
  Watch Dog Timer. Is it enough? How can we detect
  SEU?

125
Concerns (Communication)

• When and by whom will our CubeSats call sign be
  distributed?
• Only one frequency band is allocated for up-link
  command.
• If some developers uses the same protocol (ex.
  AX.25), how
• each Cubesat distinguishes its GSs command from
  other
• GSs command? Are there any regulations?
• Does our Cubesat require an impedance matching
  circuit
• between transceiver and antenna?
• Is it necessary to conduct a radiation
  environment test to FSK modulator-demodulator?
• Must our Cubesat equip space rated coaxial cable?
  Now, we are planning to use normal one (1.5D2V).

126
Concerns (Environment)

• the thermal vacuum testing regulation for Flight
  Model
• TML,CVCM limits
• the Vibration testing on Flight Model.

127
Concerns (Power)

• Is the use of a permanent magnet permitted?
• When can we charge batteries last?

128
Concerns (Ground)

• How can we get the orbital information of our
  CubeSat?