Introduction. Satellite Research Centre (SaRC)

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1 SATELLITE RESEARCH CENTRE - SaRC Introduction The of NTU strives to be a centre of excellence in satellite research and training of students in innovative space missions. Its first milestone satellite development, X-SAT, in collaboration with DSO National Laboratories has been successfully launched on 20 April X-Sat is the first Singapore-built satellite. Nine thousands of high resolution earth images have been captured since May The centre has also completed two 1.3kg pico-satellite (named VELOX-P and VELOX-PII) in 2012 and a 4.28kg nano-satellite (named VELOX-I) in VELOX-PII was lifted off on board Russia s RS-20B rocket (Dnepr) on 21 November VELOX-PII is Singapore s second indigenous satellite in space. VELOX- PII conducted experiment to validate the viability and robustness of NTU s satellite technology, including hardware and software built in-house by students. This includes the fine sun sensor; attitude determination and control algorithms; and a power management system with peak power tracker and fault tolerant feature using in-house built solar panels. VELOX-I was successfully launched on 30 June Various inhouse developed technologies such as extensible mechanism, radiation harden imaging sensor, GPS based precision navigation, advanced attitude control, short range inter-satellite communication have been validated in orbit. The centre is now working on a tropical climate satellite (VELOX-CI) using radio occultation technique which is funded by EDB and a nano-satellite (VELOX-II) for evaluating new engineering payloads.

2 X-SAT X-SAT (experimental Satellite) is the first Singapore-built satellite. It is an experimental satellite in collaboration with DSO national laboratories. The satellite was completed in Dec 2009 and was finally launched on 20 April To date, it has been in orbit for close to 4 years. More than 9000 high resolution images have been captured. Applications include haze, flooding and environmental monitoring etc. X-SAT flight model To develop a low cost micro-satellite bus capable of performing remote sensing operation in near real-time scenarios To build-up country capability (resources and facilities) in satellite engineering To promote academic interest for R&D in this area 0.8m height, 0.6m x 0.6m 105 kg 3 years Orbit Sun-synchronous LEO,817 km altitude, launched on 20 April 2011 Battery Solar panels Primary Payload Secondary 3-axis stabilized and controlled with 1 GPS receiver, Fine sun sensors, 3 magnetic torquers and 4 Reaction Wheels TT&C: S-band (CCSDS), Data downlink: X-band 13.5Ah Li-ion battery 2 deployable GaAs panels and 1 fixed for 247W at EOL Multi-Layer Insulation (MLI) 3 band multi-spectral (0.52~0.60, 0.63~0.69, 0.76~0.89 μm), 12m GSD (a) Parallel Processing Unit: for experimentation of COTS electronics and FPGAs to perform reliable imaging algorithmic functions (image selection, classification, compression) in space. (b) DLR GPS: A GPS receiver provided by DLR for on-board experimentation using XSAT micro-satellite mission. 6.1m dish antenna ground station in NTU campus

3 VELOX-P & -PII VELOX-P & -PII are the first two Singapore-built pico-satellites. They were completed in 2012 and VELOX-PII was the first to have the opportunity to be launched on 21 Nov 2013 in Yasny, Russia. The satellite has been functioning well since then. Besides educational objective, the pico-satellite is used to qualify the in-house built solar panels, power subsystem, attitude determination & control system, and fine sun sensor. VELOX-PII subsystems stack (left) & flight model (right) To launch the first Singapore s pico-satellite VELOX-PII, which is designed, built, and operated by students from different schools in the College of Engineering, NTU. To test an in-house dual-fov sun sensor, based on new position sensitive device and calibration techniques to achieve an accuracy of less than 0.5 degree. To qualify the solar panels, power subsystem, attitude determination & developed by NTU. 100mm x 100mm x 113.5mm 1330 grams 12 months Orbit Sun-synchronous LEO, km altitude, launched on 21 Nov axis stabilized with 1 GPS receiver, 2 IMUs, 1 dual-fov sun sensor, 5 coarse sun sensors, and 3 magnetic torquers Mainboard with 100 MHz 8051 MCU, 2Gb SD card, UART and I 2 C data interfaces 9600bps BPSK downlink / 1200bps AFSK uplink, UHF & VHF dipoles 5 GaAs panels for 2.4W peak, 2600mAh Li-ion battery Al chassis, with stainless steel load bearing parts Battery heaters Dual-FOV sun sensor, fault tolerant power subsystem Ground station in NTU campus with UHF/VHF high-gain cross-yagi antennas Kay-Soon Low, Director of SaRC ekslow@ntu.edu.sg

4 VELOX-I VELOX-I is the first Singapore-built nano-satellite. It is part of NTU s Undergraduate Satellite Program, which provides an opportunity for engineering students to participate in a multidisciplinary handson space project. The satellite was completed in It is also the fourth indigenous satellites built in Singapore. Besides educational objective, VELOX-I also contributes to the nano-satellite research with its technology demonstration and scientific payloads. VELOX-I in flight configuration To launch the first Singapore s nano-satellite VELOX-I, which is designed, built, and operated by undergraduate and postgraduate students from different schools in the College of Engineering, NTU and supported by research staffs. To acquire images of Earth and transmit them back to the ground station. An experimental narrow angle camera with tele-optics is used to provide remote sensing images. To carry out experiments relevant to technology demonstration. include a vision system, and intersatellite short range communication system. Technology validation includes fine sun sensors and ADCS hardware/algorithm. 100mmx100mmx340mm (VELOX-I), 60mmx70mmx30mm (VELOX-PIII) 4281 grams (VELOX-I) including a 193 grams pico-satellite VELOX-PIII 12 months (VELOX-I), 6 months (VELOX-PIII) Orbit Sun-synchronous LEO, km altitude, launched on 30 June axis stabilized and controlled with 1 GPS receiver, 2 IMUs, 2 dual-fov sun sensors, 8 coarse sun sensors, 3 magnetic torquers and 3 RWs Mainboard with 100 MHz 8051 MCU, 2Gb SD card, UART and I 2 C data interfaces 9600bps BPSK downlink / 1200bps AFSK uplink, UHF & VHF dipoles 4 deployable GaAs panels for 28.8W peak, 5200mAh Li-ion battery Al chassis, with stainless steel/ti-6al-4v load bearing parts; springloaded separator, solar panel deployer, and optics extension mechanism Multi-Layer Insulation (MLI) and battery heaters Vision system with 30m GSD, zigbee communication system, GPS Ground station in NTU campus with UHF/VHF high-gain cross-yagi antennas

5 VELOX-CI TROPICAL CLIMATE SATELLITE Kay-Soon Low, Director of SaRC

6 VELOX-II VELOX-II is an advanced nano-satellite with 6U cubesat dimensions. It carries an advanced intersatellite communication payload that allows VELOX-II to perform data downlink anytime anywhere in the orbit even it is not in line of sight of the ground station. This project is in collaboration with Addvalue Innovation Pte Ltd. Besides the primary payload, VELOX-II also carries a GPS payload for precision navigation and a fault tolerant electronic circuit. VELOX-II in flight configuration To design, build and launch the first 6U nano-satellite in the world with inter-satellite communication capability between a LEO and a geosynchronous orbit satellite. To demonstrate data downlink anywhere anytime in orbit without passing the ground station. To demonstrate precision navigation and fault tolerant electronics. 120 x 246 x mm (stowed) 12kg 12 months Orbit Near equatorial LEO orbit, km altitude, launched in axis stabilized and controlled with 1 GPS receiver, 2 IMUs, fine and coarse sun sensors, 3 magnetic torquers and 3 reaction wheels Mainboard with 100 MHz 8051 MCU, 2Gb SD card, UART and I 2 C data interfaces 9600bps BPSK downlink / 1200bps AFSK uplink, UHF & VHF dipoles 2 deployable GaAs 6U panels (2s5p x 4 channels) for 40.8W peak, 2 fixed 3U panels (6W per channel), 7.2V nominal Li-ion battery Al chassis, with stainless steel/ti-6al-4v load bearing parts; springloaded separator, solar panel deployer, and optics extension mechanism Multi-Layer Insulation (MLI) Inter-satellite communication system, GPS & fault tolerant electronics Ground station in NTU campus with UHF/VHF high-gain cross-yagi antennas Kay-Soon Low, Director of SaRC ekslow@ntu.edu.sg

7 AOBA VELOX-III Aoba Velox-III is the first satellite jointly developed by Nanyang Technological University (NTU, in Singapore) and Kyushu Institute of Technology ( Kyutech, in Japan). Besides educational objective, the satellite is used to demonstrate the operation of PPT for attitude control and orbit maintenance, wireless communication of OBDH subsystem and evaluate radiation effect on commercial off-the-shelf microprocessors in space. This satellite was launched by Kounotori-6 (HTV6) on 9 th December 2016, and was deployed from the International Space Station (ISS) in Aoba Velox-III flight model Demonstration of Pulsed Plasma Thruster(PPT)on orbit for attitude control and orbit maintenance. Evaluate radiation effect on commercial off-the-shelf microprocessors in space. Implement a 2.4 GHz wireless communication for OBDH subsystem. Establishment of fundamentals of a satellite project conducted by Kyutech undergraduate students. 227 mm x 100 mm x 100 mm 2300 grams 6 months Launch Date 9th Dec 2016 Orbit LEO, 400 km altitude, 51.6 o inclination Permanent magnet, Gyro sensor PIC16LF877A micro controller, UART and I2C data interfaces Down link: UHF MHz (1200bps) Up link: VHF MHz Li-ion battery (1series, 3 parallels, 3.6V, 3200 mah Al chassis, with stainless steel load bearing parts Battery heaters Pulsed Plasma Thruster, 2.4 GHz Zigbee module, 3 COTS MCUs Ground station in Kyutech with UHF/VHF high-gain cross Yagi-Uda antennas Mr Lim Wee Seng, Director LimWS@ntu.edu.sg School of Electrical & Electronic Engineering