SSTL satellites to help Nigeria monitor its natural resources

Two British-made satellites that are set to help Nigeria monitor its natural resources and aid disaster relief were launched from Russia yesterday.

The spacecraft, built by Surrey Satellite Technology (SSTL), feature observation equipment that will allow Nigerian authorities to observe the country with a high enough resolution for each image pixel to represent 2.5m on the ground.

They also feature the company’s most advanced solar power collection and data transfer technology, which will enable information to be sent back at 210Mbit/sec — a rate more typical of much larger satellites.

‘NigeriaSat-2 lets you take very high-resolution images, so you can see where all the buildings and roads are and convert them into digital maps — the easiest way of generating new maps,’ Phil Davies, SSTL’s business development manager, told The Engineer.

The other satellite, NigeriaSat-X, takes images that are lower resolution but cover a much wider area, he added. ‘This is actually fine for a lot of applications monitoring agriculture, deforestation and so on.

‘You can monitor the state of crop growth in the individual fields. If there’s deforestation going on, you can monitor that.

‘Some deforestation is legal, but you know where it is happening and then you can spot from the images the illegal deforestation.’

To reduce the power needed to transfer data at higher speeds, SSTL developed a directional system that positions the antenna so it’s pointing at the receiving ground station. This allowed them to more than double the transfer rate from 80Mbit/sec.

SSTL’s engineers also improved the satellite’s solar panels, using triple-junction gallium arsenic cells that have an efficiency of almost 30 per cent.

In addition, they reduced the gaps between cells on the panel, increasing the area given to converting sunlight to electricity, and replaced the previous model’s nickel-cadmium batteries with longer-lasting lithium-ion ones.

NigeriaSat-X was assembled by students from Nigeria at SSTL’s facility in the UK under a Nigerian government-sponsored scheme to help the country develop its own space industry.

‘Having been through that programme, they know how to put a satellite together and it allows them to be much more savvy as a customer,’ said Davies.

‘We’d be very happy if they build more satellites themselves and maybe they’ll just buy equipment from us. A lot of countries want to develop high-tech capability and space is seen as one of the ways you can do that.’

SSTL is already working on the next improvement of its technology with a contract for three satellites to be operated by China. They will be able to capture images with an even higher resolution, with each pixel representing 1m on the ground.