Company from São José dos Campos develops technique to manufacture solar panels used in artificial satellites
The manufacture of solar panels that capture energy from the Sun to supply electrical energy to satellites that revolve around our planet is a technological innovation produced in the city of São José dos Campos. The merit goes to Orbital Engenharia, a small company that since last year has dominated the complete production cycle of these artifacts. “In addition to Brazil, only countries such as the United States, France, Germany, Japan, Russia and China have the capacity to manufacture these panels”, says mechanical engineer Célio Costa Vaz, director of Orbital. To acquire knowledge and join the select group of space solar panel producers, the company received funding from FAPESP, through the Technological Innovation Program in Small Businesses (PIPE).
Also known as photovoltaic generators, the panels are the most efficient way of generating energy for satellites and stratospheric balloons. They transform the solar radiation found in space into electricity, energy essential for the operation of these space vehicles. The explanation for why only a small number of nations master the production technology of these generators lies in the difficulty of assembling their basic unit, a part called a Solar Cell Assembly (SCA), or assembled solar cell, in a free translation. “If we compare a panel to a battery box, each cell would be a battery”, says Vaz. It is made up of three components: the solar cell, the interconnector and a protective cover, known as a cover glass.
Solar cells can be made from various materials, including silicon and gallium arsenide. They are usually 0.2 millimeters (mm) thick and typically have widths ranging from 2 centimeters (cm) by 4 cm to 4 cm by 7 cm. Interconnectors are tiny pieces of silver, 0.012 millimeters thick, used to make electrical contact between cells. Ocover glass, in turn, is very thin glass (between 0.1 mm and 0.2 mm thick), similar to a microscope slide, equipped with an anti-reflective layer. It is glued onto the solar cell and protects it from radiation in space such as protons and electrons.
Essential tools
These three components – solar cell, interconnector and cover glass – can be easily purchased, but the problem is assembling the cell. “At first glance, it may seem like a simple challenge, but it is not. There are several quality requirements that make this assembly very complex. In the past, we tried to develop and qualify it, but we failed”, says engineer Célio Vaz, who worked for 18 years at the National Institute for Space Research (Inpe), based in São José dos Campos. The complicating factor is the fact that the tooling needed to produce the SCA is not found on the market, unlike the components. “We had to develop the equipment, devices and tools to manufacture the Solar Cell Assembly. This was only possible with PIPE funding.”
During the first phase of the project, the researcher designed the equipment for producing the cells and the solar panel, defined the manufacturing processes and procedures, outlined the product warranty plan, inspection programs and qualification tests. This work, which began in April 2001, took around six months.
In the second phase, lasting two years, the equipment was effectively produced, the processes were developed and the test specimens were manufactured and tested. “The results obtained demonstrate that we have technological quality and qualified manufacturing means to meet the demand for equipment for the aerospace sector”, says Célio Vaz.
