
3 1 c m
40cm
actual image size: 32cm x 23cm
Description
Solar cells convert sunlight directly into electricity. They are usually made from sheets of silicon to which a small quantity of boron has been added. One side is also coated with small quantities of phosphorus. They have a different atomic make-up to silicon, and when sunlight falls on the phosphorus-rich side, the phosphorus gives up electrons, which flow to the boron-rich region, constituting an electric current. Each cell only produces a small amount of electricity and so thousands, arrayed on a panel, are needed to power a large satellite. The Landsat satellites (originally Earth Resources Technology Satellites) can be used to provide information for map making, studies of land use, pollution monitoring and mineral prospecting.
Image Details
Image Ref.
10278459
© Science Museum / Science & Society Picture Library