Why are unmanned spacecrafts sent into space?
Many unmanned spacecrafts like Pioneer 10, Voyager 1, Voyager 2 etc. have been sent into space to study the parts of the solar system. They take photographs and measurements not only for scientific knowledge but also to pre-pare the way for the manned landings on other planets and moons. There are probes which have landed on Venus and Mars sending back vital information about their surface, atmosphere etc. Apart from carrying out their assigned tasks of studying other heavenly objects, they also contain information about us and our planet. In case they are found by extra terrestrial life forms, they can get information about Earth and its people. They contain photographs and recordings that offer peaceful greetings in 53 languages, and sounds of a baby crying, a human heartbeat, roar of ocean waves, chirping of birds etc.