The commissioning of South Africa’s Sumbandila microsatellite (SumbandilaSat) has been progressing well, despite a couple of glitches.

“We are well on track to complete the commissioning process within the planned timescales,” reported Sun Space and Information Systems (SunSpace) chief systems engineer Jan-Albert Koekemoer.

The R26-million, 81-kg, microsatellite was launched by a Russian Soyuz rocket from the Baikonur Cosmodrome last September. It is in a low Earth orbit at an altitude of 500 km.

“We had a pause in the commissioning process over the Christmas and New Year period, although we continued to operate the satellite,” he said. “This week, we started the commissioning of the Star Tracker.”

SunSpace is the company which designed and built SumbandilaSat, and the commissioning process, which is being carried out from a control centre at the University of Stellenbosch, has to be completed by the end of March, when the spacecraft will be handed over to the Satellite Applications Centre (at Hartebeeshoek, west of Pretoria) for operation.

SumbandilaSat is equipped with a magnetometer, a horizon sensor, a coarse Sun sensor, a fine Sun sensor, a star tracker, a global positioning system (GPS) and three laser ring gyroscopes, which all serve its attitude determination and control system.

For manoeuvreing, the spacecraft has magnetic torquer rods, three reaction wheels, and a propulsion system with a small thruster.

The microsatellite’s main payload is a multispectral imager which operates across six spectral bands. It also carries a lower resolution video camera.

In addition, SumbandilaSat is carrying four experimental payloads – three from South African universities while the fourth is a South African amateur radio payload – and a Department of Communications (DoC) sponsored store-and-forward communication payload.

By November, the on-board computers had been activated and new software uploaded to them, the magnetometer and the fine Sun sensor had been calibrated, the video camera and the horizon sensor had been brought into operation and the SA Amsat payload switched on.

Since then, the SunSpace team has successfully refocused the multispectral imager. “The focus shifted as a result of the thermal environment the satellite is experiencing in space,” explained Koekemoer.

Key systems still to be commissioned are the GPS receiver and the propulsion system.

“SumbandilaSat’s orbit has already deteriorated by about 400 m since launch,” he reveals, “this is less than 0,1%, and we hope to lift the orbit soon using the thruster.” Also still to be commissioned are the DoC payload and the university experiments.