South Africa's R25-million satellite has partially broken down, less than two years after launch - meaning that years of effort by some scientists have gone to waste.

The news that several projects are unlikely to take place is a blow to researchers who prepared hi-tech experiments to be launched by the spacecraft, SumbandilaSat.

The satellite's stabilisers have malfunctioned, causing SumbandilaSat - launched at the end of 2009 - to tumble in space, and radiation from the sun has damaged the high-resolution camera.

In a written reply to questions in parliament recently, the Minister of Science and Technology, Naledi Pandor, said engineering troubles were likely to last until the end of the satellite's life.

"Owing to SumbandilaSat's physical condition, the forced- vibrating-string experiment (Nelson Mandela Metropolitan University) and the very-low-frequency radio experiment (University of KwaZulu-Natal) payloads have not yet been turned on and have not had a chance to download information ... This will probably last until the end of SumbandilaSat's life," Pandor said.

"Due to the tumbling effect of the satellite and its battery capacity, priority has been given to SumbandilaSat's multi-spectral imager, its main payload."

Andrew Collier, head of the University of KwaZulu-Natal's project, said he had given up inquiring about his experiment.

"It is quite disappointing, because a lot of time and effort went into designing those experiments. We have been waiting for the results ... because I have students who will then go ahead and work on the analysis of the data that comes back. "

Eugene Avenant, spokesman for the SA National Space Agency, labelled the satellite project a success. "We are downloading useful images on a daily basis that are being used by students and other researchers in studying natural phenomena."

He said SA had also gained valuable experience in building satellites.