A satellite is an object that has been intentionally placed into orbit. These objects are called artificial satellites to distinguish them from natural satellites such as Earth's Moon. On 4 October 1957 the Soviet Union launched the world's first artificial satellite, Sputnik 1. Since then, about 8,900 satellites from more than 40 countries have been launched. According to a 2018 estimate, some 5,000 remain in orbit. Of those about 1,900 were operational, while the rest have lived out their useful lives and become space debris. Satellites are now being used for a variety of purposes such as military, telecommunications, GPS, agriculture, data collection, weather monitoring and so on. This test is generic in nature and as such figures such as number of questions in actual exam and passing percentage in actual exam are just arbitrary.