While solar power in the form of solar cells was first observed in 1876, it was not until 1953 that the first usable silicon solar cell was invented. Calvin Fuller, Gerald Pearson and Daryl Chaplin invented the first silicon solar cell. It could effectively power small electrical machines.
The first commercial solar cells that were sold in 1956 were not affordable for the general public. At that time, a power cell capable of generating one watt of energy was priced at $300. During the 1960s and 1970s, solar cells saw widespread use in the space programs of both the United States and Russia.