The experience of 22 years developing small satellites in South Africa. Prof Herman Steyn University of Stellenbosch

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1 The experience of 22 years developing small satellites in South Africa Prof Herman Steyn University of Stellenbosch

2 GreenSat Military space program Included a launcher program Produced test facilities (vacuum, vibration, anechoic, acoustic, etc) Satellite was not fully completed when program stopped in 1994 University involvement defined in 1989 with Kleinsat (Smallsat) idea Sponsorships for MSc at Univ of Surrey in the UoSAT unit (1990/91) Junior lecturer of Stb Univ send to ISU in Japan (Kitakyushu in 1992)

3 SUNSAT Birth Chair of Satellite Systems in 1990 Prof Garth Milne Prof Schoonwinkel father of Kleinsat idea joined Stb Univ 1993 SUNSAT student project in Elec Eng department of Stb Univ started in 1992 Aims were to:» Train engineers for SA space industry» Challenge graduate students» Inspire school kids in science» Have international cooperation» Get sponsorships from SA industry

4 SUNSAT Project Africa s first indigenous (locally built) orbiting satellite Satellite was designed and developed without any technology transfer help Developed by graduate students and staff in period First microsatellite (64kg) with SPOT-5 type 3-band multispectral resolution 3456 pixel pushbroom sensor giving a 52 km swath and 15 m GSD from 800 km 64 Mbyte SRAM disk with 40 Mb/s QPSK S-band data downlink capability 3-Axis stabilised with reaction wheels during imaging, passive gravity gradient

5 SUNSAT Launch NASA Turbo-Rogue GPS and laser reflectors for occultation research Free piggyback launch with Danish Oersted microsatellite and USA Argos satellite as primary payload Launch 23/2/99 on Delta II USAF Orbit altitude 640 to 850 km Successfully commissioned in 3 months Radio amateur payload was huge success (store & forward, voice repeater) Orbital useful life almost 2 years, last contact made in January 2001 Possible collision with space debris or more probable a battery malfunction

6 SUNSAT Imaging

7 SUNSAT Hardware

8 SUNSAT Achievements Schools outreach program reached about children with electronic kits More than 100 graduates were involved in the program (Masters & PhD degrees) Over 90 journal and conference papers Large participation by AMSAT community Significant international contact» Germany: FG Magnetometer for SAFIR-2» South Korea: 15m GSD imager for KITSAT-3» Australia: Star imager & Boom for FEDSAT» NASA USA: Atmospheric occultation and gravitational studies Established an university spin-off company SunSpace, to exploit SUNSAT s satellite technology commercially

9 Stellenbosch Satellite Eng Group Stellenbosch University AISS Sun Space and Information Systems SAC Electrical and Mechanical Engineering ESL ISSA Optics Teaching and Research Research and Development System Development and Deployment Strategic Partners

10 SunSpace Partnership Research support» Space radiation testing & fault tolerant design methods» Propulsion/thermal/material analysis» Formation flying/constellation control» Small GEO platforms» Imaging applications/data handling» ADCS algorithms/simulation support Product development» New ADCS sensors and actuators» New OBC and MMU architectures» Spaceborne GPS receiver» Sunsat-2004 microsatellite bus ESL Ground Station Satellite Research US

11 Typical Masters Topics Satellite Engineering: An AIS for ship surveillance and tracking from a satellite Development of an onboard computer for a nanosatellite Low-power communications bus and protocol for a nanosatellite An infra-red based earth horizon sensor for a LEO satellite GPS based orbit propagation/estimation for a LEO satellite A real time operating system and housekeeping software for a satellite An attitude control system for a nanosatellite Onboard image classification to grade images for downloading An arcjet propulsion system for a nanosatellite Integrated CMOS star tracker and MEMS inertial rate sensor Visual approach and docking mechanism for a satellite pair Satellite Research US

12 SS-3 Satellite Project 200 kg Minisatellite Technology transfer training 650 km sun-sync orbit Main imager payload:» 6.5 meter/pixel» 3 Spectral bands 3-Axis reaction wheel stabilised Video view finder capability Design and built in South Africa by SunSpace Dnepr Launch in April 2007 Commissioned in 8 weeks Still fully operational to date

13 SS-3 Hardware/Testing

14 SS-3 Imaging Example

15 SS3 - View Finder - Aden Satellite Research US

16 Sumbandila Satellite Project 83 kg Microsatellite for DST» 505 km 9 am/pm sun-synchronous orbit» 6.25 m GSD Imaging in 6 spectral bands» Communication system for DOC» Propulsion system for drag compensation» Expected orbital life 5 years Satellite build by SunSpace in 15 months Stellenbosch University did project management 20 Masters and 2 PhD students and 8 interns in satellite engineering trained Launch 17 Sept 17h55:07 from Baikonur Kazakstan on a Soyuz/Fregat

17 Sumbandila Imaging: FMC4 scanning with X & Y wheel Pitch forward 13 deg Roll = required amount for off-track image target Increase pitch rate to -0.6 deg/sec Scan image for 34 sec at constant rate for a 60 km image strip through target Stop at pitch -13 deg Return to nadir pointing Pitch & roll = 0 deg Satellite Research US

18 Image Data download: Target Tracking towards SAC Satellite Research US

19 Imaging Product Tokyo Haneda Airport Area ( 12 km x 8 km)

20 Tsunami Damage Sendai 05/04/11 (rightside image)

21 Decay (Meter) Propulsion: Orbit Maintenance On 26 th January 2010 the butane propulsion fired for a total of 75 sec to lift the orbit 250 m m Decay of semimajor axis 3250 m On 9 to10 th March 2010 a total of 20 x 30 sec firings was used to lift the orbit another 1650 m On 27 to 30 th April 2010 a total of 34 x 60 sec firings was used to lift the orbit another 5000 m On 14 to 16 th April 2011 a total of 20 x 60 sec firings was used to lift the orbit another 3250 m Current orbit perigee and apogee: 498 x 502 km m 1650 m X: 8732 Y: Orbits since launch

22 ADCS Product Examples

23 Satellite Imagers

24 RSA EO Satellite Roadmap Performance ARM-C - 2m5 GSD Panchromatic - 5m GSD Multispectral - 15m GSD Hyper spectral ZA-004 Very High Resolution - < 2m GSD MS - < 5m GSD SAR SumbandilaSat - 6m25 GSD Multispectral - 6m25 GSD Viewfinder SUNSAT - 15m GSD Multispectral Mass

25 Next SA Satellite(s) ARM Constellation

26 MSMI Camera Core innovative concept:» Dissimilar sensors on focal plane of a single telescope Multi-spectral (VNIR) and panchromatic Hyperspectral: VNIR & SWIR Video (Snap shot or real time motion)» Included Selectable combinations of EO data for storage/downloading On board mass memory & data compression Bore sight motion detection to assist ADCS» Compact & light for micro/mini-satellites More affordable revisits by small satellite constellations

27 Camera Components

28 Mission Requirements Track crop production for predicting final yield» about once every 10 days => Multi-spectral data Provide statistical estimates of cultivated areas» especially small field sizes typical of developing countries» estimate population density => High resolution panchromatic data Identify crop variety planted» using unique spectral signatures => Hyper-spectral data

29 1 Pan chromatic channel = 2.5m 6 Multi- Spectral channels = 5m MSMI Imager: Baseline for ARM Constellation 200 channels Hyper-spectral 15m Blue Green Red NIR SWIR

30 University CubeSat programs CPUT / F SATI program:» 40 Master students working on ZACube-1 and ZACube-2» University of Stellenbosch contributing the ADCS design» Human capital development for SA space engineering needs Univ Stellenbosch FP7 project:» Participant in European Union FP7 Deorbit Sail project» Develop an ADCS for a solar sail 3U Cubesat

31 ZACube-2 Objective: Student satellite project 3U CubeSat - Matrix 5.2 Mpix colour camera - HF beacon for SANAE radar antenna calibration - UHF store/forward system - L-band transponder - Novel 3-axis ADCS ADCS - 3-axis Nanowheels - CubeSense Sun & Earth sensor - 3-axis Torquerods - Passive aerodynamic control

32 Questions?