Space is the place: From a locally made satellite to an interview with an American astronaut and a book on the Hubble telescope. Lesley Cowling reports
THE object that will be South Africa’s first satellite to circle the earth is, at first sight, unimpressive. It’s a blueish box with a metal ring on one side and some aerials sticking out of another. Inside, one electronic tray after another is neatly stacked. The box weighs a mere 60kg, is 45cm by 60m (about the size of an apple box) and is dubbed Sunsat I.
#But this humble cube has taken seven years to plan, fund and develop since it was initiated by professors Garth Milne and Arnold Schoonwinkel. It has cost R5-million in hard cash and about R6-million’s worth of expertise, using a range of Stellenbosch University engineers and technicians and the work of 50 post-graduate students.
It has been checked out by Nasa and considered good enough to be given a ride into space on a US Air Force satellite on a McDonnell Douglas Delta II Rocket. And among all the specialised electronic equipment, it contains two experiments by groups of South African school children (see story below).
#So far, it’s unique. But Sunsat I will be far more impressive when it flies. “That’s if it works, of course,” jokes Sias Mostert, development manager of the project. The “I” in the satellite’s name is an optimistic addition by the Stellenbosch engineers, who hope it will lead to more microsatellites.
But Sunsat’s working means more than just circling the earth. Any old rock can do that if it’s taken out into space and dumped into orbit – the earth’s gravity will keep smaller objects circling around it. Whether it works means seeing if Sunsat can do all the things it’s been wired for and whether it will respond to its signals from earth.
#Sunsat I will be relatively near to the earth – between 450 and 850km away – so it will circle the earth quite quickly, once every 100 minutes. There are a few other satellites in that orbit, but the big satellites are further out. At 20 000km away are the Global Positioning System (GPS) satellites. Signals to and from these satellites are used by ships to navigate. The big telecommunications satellites, which give us television programmes from all over the world, telephone calls and the Internet, are even further out at 36 000km.
Sunsat will not be in that league. It will, however, carry a special GPS receiver for the Americans in exchange for Nasa’s free ride into space. Most GPS receivers have an accuracy of about 100m, but this one can pinpoint a position to within four centimetres. Nasa earth scientists will receive messages from this GPS receiver for their research into the dynamics of the earth’s crust.
#The microsatellite’s major functions, though, will be to supply images and relay messages back to Stellenbosch for the various Sunsat projects. Mostert says Sunsat is “a flying fax machine” or, alternately, a “flying postbox”. The faxes will be the pictures – full colour, high-resolution images mostly of agricultural land – that come from the satellite’s camera.
Sunsat also has a sophisticated radio on board which makes it possible to communicate via the satellite, using only a small portable radio.
The Sunsat team has a relationship with a group of amateur radio enthusiasts, and radio hams can use Sunsat to send messages all over the world.
#But apart from the flying faxes and messages (which we could buy from other satellite owners) and the thrill that engineers might get out of being one of the boys with Nasa, what can Sunsat really contribute to a country like South Africa? Is it not presumptuous for a small developing country with so many pressing needs to be playing around in space?
Well, it’s the thrill of space that’s really the important point, according to the Sunsat engineers. They argue that the microsatellite’s most important function is to attract the interest of schoolchildren. Space has a certain romance to it (as the popularity of Star Trek shows), and a project like Sunsat may be exactly the kind of bait to hook more young South Africans into a science degree.
#Mostert says a number of school projects were planned around the development of Sunsat. The one that was most ambitious was called Sunbuild and it encouraged schoolkids to come up with scientific research experiments for the satellite.
To reach more children, Sunsat also includes an electronic “parrot”, so that schoolchildren can “talk” to the satellite. Their voices will be transmitted to the satellite and it will echo them back.
There are some practical advantages to the satellite, too. If all goes well, the pictures that Sunsat produces should be in the same league as the images that come from the French satellite Spot 2. These sell for about R4 000 per processed image to mining and construction companies and government departments. Mostert hopes Sunsat can provide those images more cheaply to South African buyers, serving local needs and earning money for the Sunsat project at the same time.
#Sunsat should be ready for space by the end of the year. The team is putting final touches to the electronics, and the solar panels that will power the satellite with energy have arrived from England. The microsatellite will then be shipped off to Nasa. The launch date was originally set for early next year, but it has been pushed back to August and might be postponed again. But once Sunsat is circling, it will give South Africa the right to call itself one of the world’s nations in space. And, however small and unprepossessing, if a microsatellite with a South African flag on it can’t stimulate some patriotic interest in space technology, very little can. Sunsat team members will give papers at a United Nations conference on Space Technology, which starts next week at the CSIR in Pretoria. See http://www3.un.or. at/OOSA Kiosk/sched/sacall.html or http://sunsat.ee.sun.ac.za/announce/space.htm
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