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

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

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.

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

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

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)

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

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)

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)

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.

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

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

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

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

4.Some Main Design Issues Attitude Control Configuration

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.

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.

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