South Africa’s Expanding Space Frontier
Segue abaixo mais uma notícia em inglês postada dia (30/04) pelo site sul-africano "http://www.engineeringnews.co.za/” destacando que a África do Sul estará expandindo nos próximos quatro anos sua fronteira no setor espacial com o desenvolvimento e lançamento dos dois satélites previstos no Programa IBSA de Satélites.
Wheels within Wheels
South Africa’s Expanding Space Frontier
By: Keith Campbell
30th April 2010
Edited by: Martin Zhuwakinyu
Only months after South Africa returned to space, with the launch of the Sumbandila microsatellite, that success has opened new opportunities for the country. The recent India Brazil South Africa Dialogue Forum (Ibsa) summit in the Brazilian capital of Brasília resulted in an agreement to build and launch two Ibsa satellites over the next four years. And the satellite bus for the first will, it was agreed, be designed and built in South Africa, while the bus for the second will most probably also be South African.
The satellite bus is the basic spacecraft – the framework, the control, navigation and manoeuvring systems, and the power generation and distribution system. On this are mounted the various instruments and systems, whether scientific experiments, telecommunications transponders, cameras and other imagers, and so on, which turn it into an operational satellite.
Ibsa satellites are planned to be small satellites, in order to make them more affordable. And South Africa’s Sun Space & Infor-mation Systems (SunSpace), a spin-off company from the University of Stellenbosch and based in that lovely town, specialises in such satellites.
The specialists involved in SunSpace have now designed and built three small satellites which have been placed in orbit. The first of these was the 64-kg-mass SunSat-1, an acronym for Stellenbosch University Satellite, which was produced by staff and students at the university and launched, free of charge, by the US National Aeronautical and Space Administration in February 1999, and performed well in orbit. It was the success of SunSat-1 that led to the creation of SunSpace. Following SunSat-1, SunSpace designed and built a microsatellite for another country and this was successfully launched and is still operational today. SumbandilaSat is thus the third complete small satellite (it has a mass of 81 kg) to be produced by the team in Stellenbosch.
The result is that the Brazilians, for example, now see this country as being an expert in this segment of the satellite market. And that is why at least one, if not both, Ibsa satellite buses will be designed and built in Stellenbosch. (SunSpace can offer designs ranging in mass from 50 kg to 400 kg).
There is also a very strong possibility that the second Ibsa satellite, which will be devoted to earth observation and food security, will be fitted with another SunSpace product – the multispectral microsatellite imager, which was developed in cooperation with a Belgian university. (SunSpace also designs, builds, and has exported, systems for satellites as well as complete satellites.)
It is true that, during its commissioning process, SumbandilaSat was hit by a number of ‘anomalies’, to use space jargon. Radiation seems to have caused these, which include the loss of two of the satel- lite’s three reaction wheels, which form part of its manoeuvring system. As a result, SumbandilaSat’s ability to manoeuvre has been severely restricted and, should the third wheel also be lost, these restrictions would become most severe. But, even with no operational reaction wheels, the satellite would remain operational and useful.
Likewise, three of the six spectral bands in SumbandilaSat’s imager have also been lost – fortunately, the less important trio. And again, the imager is still operational and transmitting valuable imagery.
These anomalies should not be grounds for dismay. What is really important is the skill and success of the South African ground team in working around these events and keeping the satellite operationally effective.
It should never be forgotten that SumbandilaSat is a prototype for South Africa and one of its most important functions is to teach South Africans how to operate a satellite in orbit and deal with the many problems that can arise. Moreover, precisely because it is a prototype, the satellite carries no backups for its systems – these would have added weight and cost to the programme. But production satellites usually have backup as well as primary systems. When the primary system fails, the backup replaces it.
In addition, it cannot be stressed too much just how hostile an environment space is, even the space that is just above our atmosphere. There are still many imponderables up there and things can go very wrong, very easily and very fast.
All spacefaring nations know this, which is why anomalies on SumbandilaSat do not bother Brazil or India – they have had plenty of experience of their own with anomalies. For example, India’s $100-million, 1 380-kg, Chandrayaan-1 moon probe, launched in October 2008, was meant to operate for 24 months but actually lasted only ten – and suffered from many problems even before its final failure. Yet it was undoubtedly a scientific success.
Source: Website http://www.engineeringnews.co.za /
Comentário: Fica claro aqui na opinião do blog os motivos de tanta empolgação por parte dos sul-africanos com este programa de satélites que até o momento não teve a mesma repercussão no Brasil e ao que parece também na Índia. No entanto, a desinformada imprensa brasileira parece não entender o grande significado deste programa para o Programa Espacial Brasileiro, principalmente se o mesmo for realizado nos quatro anos defendidos pelo jornalista sul-africano Keith Campbell em todas as matérias escritas por ele até agora sobre este programa de satélites, o que sinceramente não acreditamos. O Brasil não é um bom parceiro na questão de cumprimento de prazos no setor espacial, especialmente em relação a satélites (vide o CBERS, SABIA-Mar e a lista é enorme). No entanto a realização desse projeto além de ter um ganho muito significativo para imagem política do país, e dos esperados ganhos científicos e tecnológicos desta empreitada, o envolvimento exitoso principalmente com a Índia poderá abrir portas para projetos mais ousados com esta nação de reconhecida competência espacial.