Science and technology


South Africa's satellite 'leads the way'

21 December 2010

South Africa's micro-satellite, SumbandilaSat, is living up to its Venda name as it "leads the way" in providing free, frequent high-resolution images capable of revolutionising local earth observation in various fields.

During August and September, SumbandilaSat produced five high-resolution images of the south-western part of the Kruger National Park and neighbouring Bushbuckridge, where the Council for Scientific and Industrial Research (CSIR) and SA National Parks (SANParks) are conducting various research projects.

These images would have cost over R40&nbps;000 each from a commercially operated satellite, but SumbandilaSat is able to deliver such images, each covering an area of 50 by 60 kilometres, to local projects at no cost.

So far, the satellite has delivered 800 images of targets worldwide, of which approximately 54% have been cloud-free translating to four images on average per day. Three to five images of southern African targets can be captured per week.

Setback, solution

Earlier in the mission, a setback was experienced with the performance of the altitude stabilisation system on the satellite.

A design team from satellite builders SunSpace were able to rectify the problem, however, by means of a unique manoeuvre that involved guiding the satellite to tumble "head-over-heels" in order to scan an image from south to north while orbiting from north to south.

The provision of free, frequent high-resolution satellite images of specific areas of interest has the potential to revolutionise local earth observation capabilities in many fields, with natural disasters (like fires and floods) and human activities (like mining, settlements, forestry) being accurately monitored on a regular basis.

Managing Kruger Park fires

The SumbandilaSat images can also be used to map burnt areas, for example, in the Kruger National Park, where fire is part of the natural ecology and is used by SANParks as a management tool to manipulate vegetation to promote biodiversity and influence the balance between grass, shrubs and big trees.

SANParks currently has to rely on very coarse-resolution satellite images of 500m pixel size for regular mapping of burnt areas. SumbandilaSat provides images at 6.25m pixel resolution and covers an area of 50 by 60 kilometres per image.

The satellite imagery can also be used to monitor the recovery of the vegetation in the burnt area and the long-term influence of fire on tree and grass cover.

Affordable micro-satellite technology

Although the imaging capacity of SumbandilaSat is much less than that of commercial high-resolution satellites, the satellite has demonstrated the viability of affordable micro-satellite technology, which is its primary stated mission.

A constellation of similar satellites is planned to increase the availability of such satellite data for diverse applications. Several African countries will participate in this joint venture, and will eventually share in the data produced by the African Resource Management Constellation, especially for disaster monitoring applications.

The South African National Space Agency will be tasked with ensuring that society benefits from investments in space-based earth observation technology.

SumbandilaSat images are available via the CSIR Satellite Applications Centre catalogue. New image requests can be directed to sales and customer services at the CSIR Satellite Applications Centre (SAC).

SAinfo reporter

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