SumbandilaSat (sometimes just Sumbandila, formerly ZASAT-002, AMSAT designation SO-67[3][4]), was a South African micro Earth observation satellite, launched on 17 September 2009 on a Soyuz-2 launch vehicle from the Baikonur Cosmodrome.[5] The first part of the name, Sumbandila, is from the Venda language and means "lead the way".
The University of Stellenbosch, SunSpace and the CSIR (Council for Scientific and Industrial Research) were key players in constructing SumbandilaSat. The CSIR's Satellite Application Centre (CSIR-SAC) was responsible for operations, telemetry, tracking, control as well as data capturing.
SumbandilaSat was part of a closely integrated South African space programme and served as a research tool to investigate the viability of affordable space technology. Furthermore, the data was used to, amongst others, monitor and manage disasters such as flooding, oil spills and fires within Southern Africa.
In June 2011 the satellite was damaged during a solar storm. The damage caused the on-board computer and the camera to stop functioning. This has caused it to stop fulfilling its primary objective and it has been written off as a loss by SunSpace, its builder.[6] The final data packet from the satellite was received on 14 September 2011.[7]
NER < 0.6% with a forward motion compensation (FMC) factor of 4:1
Operational MTF: >= 5% over the full field (excluding orbit motion effects)
GSD = 6.25m @ an orbit altitude of 500 km
6 spectral band (visible range) line scanner
Matrix sensor included for "snapshot" pictures
Image quantisation: 12-bit (data for each pixel stored as 2 bytes)
Image modes
Default scan mode with FMC = 4:1 but system could operate with FMC = 1:1 with consequent degradation in NER
In FMC = 4:1 mode, non-contiguous scenes of 45 km x 45 km could be imaged (max 10 scenes in 6 spectral bands before data downloading was required)
In FMC = 1:1 mode, a contiguous strip with 45 km swath could be imaged (max track length of 450 km could be imaged in 6 spectral bands before data downloading was required)
Imager data store
24 Gbyte
Image data downlink
Expected frequency implemented on satellite exploration S-band
Link margin: 3 dB @ 10° (calculated with 0dBi satellite antenna; 5W Tx power and SAC GS parameters)
Data rate sufficient to download full image data store during two night passes
No real-time downloading of images (all images stored on board the satellite)
Viewfinder
Live downlinking of PAL video images during TT&C ground station passes
PAL images selectable between B&W (narrow FOV) and two wider FOV colour PAL cameras
Satellite bore-sight steerable with "joystick" interface
Viewfinder mode could be interrupted with either image snapshot or image linescan modes upon ground command
The bore-sight direction of the viewfinder was the same as the main imager
ADCS system
The satellite was 3-axis stabilised
System performance was sufficient to maintain pointing accuracy for image downloading
ADCS performance did not degrade image quality
The satellite bore-sight could be controlled to within 3 km on the ground
The intended system implementation used a combination of the following actuators and sensors: Horizon, fine-Sun, coarse-Sun sensors; star camera; magnetometer(s); fibre-optic gyros; reaction wheels and magneto torquers
A satellite slew manoeuvre from one stabilised position to another stabilised position, through an angle of 30°, could be completed in less than 1 minute
Propulsion System
Sufficient propellant included to maintain a satisfactory orbit for 3–4 years
System was to demonstrate orbit constellation deployment as well as orbit maintenance
TT&C Communication Link
Expected frequencies implemented on commercial VHF uplink and UHF downlink
Link margin: 6 dB @ 5° (calculated with -12dBi satellite antenna null; 5W Tx power and 12dBi GS antenna gain)
Satellite Housekeeping
One TT&C GS pass per 24h was sufficient for the purpose of monitoring telemetry and uploading of new command sets and SW
Power
Energy source: solar panel with 65W (EOL) capacity
Mission planning dictated energy requirements per orbit
Experiments
Provision was made for two 1-kg experiments
SU certified the space environmental readiness of the experiments at MC level prior to integration
Average power available per experiment: 1.2W (TBC)
Peak power available per experiment: 10W (TBC)
Orbit lifetime
Design lifetime of 3 years at an orbit altitude of 500 km (subject to average Sun activity)
Given the ultimate unpredictability of the space environment, the operational life varied from the design lifetime
* Courtesy of SunSpace
On-board experiments
It had a number of secondary experimental payloads on board:[3]
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
