The first solar cell design, from the US laboratory Bell, was tested in 1955. The Bell system uses 3,600 solar cells to power the Telstar satellite in 1962, and since then it has been a standard in aeronautical design, especially in space technology . However, it took decades for the cost of solar cells to compete with other forms of energy. They are still slowly adopted in regions where sunshine is strong. The efficiency of solar technology has also improved considerably in recent years.
