In the past few decades, solar cell technology has evolved from powering calculators to powering emergency road signs, parking lot lights and satellites to providing all of the electrical power for houses.
This is all possible due to the power of the sun, which on a bright sunny day can provide up to 1,000 watts of energy per square meter of the Earth's surface. NASA's Mars Rovers are currently being powered by the sun. The two rovers have functioned for nearly a year on solar power alone; this is far more time than the originally anticipated 90-day period. Advancements in technology, primarily through research conducted by NASA, have made harnessing the power of the sun and using it to generate power a relatively simple task.