1. Preliminary Platform Design for KuaFu-A
DFH SATELLITE CO., LTD. November , 2010

2. OUTLINES Background Requirements KuaFu-A System Description
Some Design Issues
Summary

3. 1.Background
About DFH
A small satellite provider, till now, DFH has successfully launched more than 20 small satellites;
Three small satellite platforms: CAST100, CAST968, CAST2000;
Product line: from 10kg to 1000kg.

4. Engineering review of KuaFu-A Ground TT&C and Orbit Determination
1.Background
From 2004, DFH has been participating in KuaFu-A project, mainly in satellite engineering.
Supported by CNSA in its Five-Year plan, from 2006 to 2010, A comprehensive review of KuaFu has been done.
Scientific objectives and application review
Engineering review
Key technologies analysis
The achievements of reviews:
Give a solution for scientific objectives and exploration.
Build a basis for further work.
What we discussed base on the prophase results of comprehensive review (payload, requirement, and satellite project).
Input information update, modify satellite project, redesign
Engineering review of KuaFu-A
Carry and Launch
Ground TT&C and Orbit Determination
Ground Data Receiving
Spacecraft Design
Mission Orbit Design

5. 2.Requirements Scientific Objectives
Have been discussed
Mission orbit: Halo orbit around L1 point
Advantages of the Mission Orbit
Allow continuous observation of the Sun
Avoid data transmission to Earth being disturbed by the solar electromagnetic noise
Suffer to a small force and the orbit is easy to be controlled
Lifetime: more than 4 years

6. 2.Requirements Payload Configuration Number Instrument 1
EUV/FUV Disk Imager (EDI) 2
Multi-Order Solar EUV Spectrograph (MOSES) 3
White Light/FUV Coronal Imager (CDI) 4
Solar Wind Instrument Package (SWIP) 5
Radio Burst Instrument (RBI) 6
Solar Energetic Particle Sensor (SEPS) 7
High Energy Electron Detector (HEED) 8
High Energy Proton Detector (HEPD) 9
Ion Composition Detector (ICD) 10
Hard X-Ray /Gamma-Ray Spectrometer (HXGS) 11
Solar Irradiance Measurement (SIM)

7. Attitude Pointing Accuracy Dynamic change: 0.25nT/10min
2.Requirements
Summary of Payload Requirements
Item
Requirement
Comment
Mass
129.5kg
Power
~223w(long-term)
~90w(short-term)
All instruments work during regular phases
Data Rate
~110kbps
Average value
Attitude Pointing Accuracy
10arcsec
Requirement of white-light coronograph
Attitude Stability
5arcsec/5s
Magnetic Cleanliness
Absolute value: 1nT
Dynamic change: 0.25nT/10min
Requirement of magnetometer

8. 3.KuaFu-A System Description
Flight Orbit
Orbit phase: the transfer trajectory and the mission orbit
Coordinate system: the L1 point ecliptic plane rotating frame
Moon
Earth
Sun
Mission Orbit
(Halo orbit)
Transfer Trajectory
(about 100 days)

9. 3.KuaFu-A System Description
System Architecture
On-board Data Handling Subsystem (OBDH)
Telemetry Tracking and Command Subsystem (TT&C)
Attitude and Orbit Control Subsystem (AOCS)
Thermal Control Subsystem (TCS)
Power Supply Subsystem (PSS)
Structure and Mechanism Subsystem (SMS)

10. 3.KuaFu-A System Description
Satellite Preliminary Configuration
In order to reduce the disturbing torque induced by solar light pressure, the exposure area of the satellite should be symmetric about the OXZ plane. Considering the characteristic of “indifferent equilibrium”, the pressure center should be higher than the centroid.

11. 3.KuaFu-A System Description
System Design Parameters
Item
Design Parameters
Mass
Total
722kg
Payload
130kg
Platform
592kg(including 100kg propellant)
Margin
60kg
Power
Supply
Solar array area
3.774m2
Output power
906W (BOL), 752W (EOL)
Battery
Li Ion Battery, 30Ah
Attitude
and Orbit
Control
Mode
3-axis stabilized, sun oriented
Pointing accuracy
10arcsec
Attitude stability
5arcsec/5s

12. 3.KuaFu-A System Description
System Design Parameters
Item
Design Parameters
TT&C
Band
Uplink: S band
Downlink: X band
Antenna
2 S-band omnidirectional receiving antenna
2 X-band omnidirectional transmitting antenna
1 S-band directional receiving antenna
1 X-band directional transmitting antenna
Transmitting Power 1W
Data rate
Uplink 2000bps; downlink 4096bps
Data
Transmission
X band
0.8m parabolic antenna
10W
350Kbps
Designed Lifetime
4 years

13. 4.Some Main Design Issues
Mass budget
Carrying capacity: more than 130kg
The KuaFu-A can satisfy the carrying requirement of payloads.
Item
Mass (kg)
Payload
130
SMS
AOCS
component
145
propellant
100 DT 40
TTCS 20
OBDH 30
PSS 67
Margin 60
Total
722

14. 4.Some Main Design Issues
Power Supply
Primary Power Bus Voltage: 29.5V1V
Output power of Solar Array: more than 700W
The KuaFu-A can satisfy the power supply requirement.
Item
Long term (W)
Short term (W)
AOCS
114 47
TTCS 41 15
OBDH 20
TCS 40 66
PSS 28 DT 26
150
Payload
223 90
Total
492

15. 4.Some Main Design Issues
Attitude Control Configuration

16. 4.Some Main Design Issues
Attitude Control
Attitude Pointing Accuracy: 10arcsec
Attitude Stability: 5arcsec/5s
Solar Guide Telescope: guarantee attitude measurement accuracy
Measurement accuracy: better than 0.5arcsec
Miniaturization Star Sensor: guarantee attitude measurement accuracy
Optical axis pointing accuracy random error: 1.4arcsec~4.7arcsec(3σ)
Three Floating Gyroscope: guarantee attitude stability
Random drift: better than 0.02°/hour(3σ)
Momentum Wheels: guarantee attitude pointing accuracy
Random torque noise: less than 1gcm
Output torque: high accuracy
The KuaFu-A can satisfy the attitude control requirement.

17. 5.Summary KuaFu-A project: Can carry more than 130kg payloads.
The KuaFu-A design has used many spacecrafts flying around L1 point for reference. The project not only has inherited many small satellite technologies, but also charactered the innovative application. So, it has high degree of technological maturity.
KuaFu-A project:
Can carry more than 130kg payloads.
Can supply more than 700W long term power until the end of the lifetime (4 years).
Can provide high attitude pointing accuracy (10arcsec) and high attitude stability (5arcsec/5s).
Use a small satellite (KuaFu-A) can meet the user requirements.

18. Thank You