What were the names of the early artificial satellites launched into orbit?

The early artificial satellites launched into orbit were indeed Sputnik, Explorer, and the Mariner series. Sputnik was the first artificial satellite, launched by the Soviet Union in 1957, marking the beginning of the space age and initiating the space race between the United States and the Soviet Union. Following Sputnik, the United States launched Explorer 1 in 1958 as its first successful satellite. The Mariner series included various missions aimed at exploring Mars and Venus, further broadening our understanding of planetary science. These efforts were foundational in establishing satellite technology and exploration, which are critical elements of modern space exploration today.

The other choices refer to different aspects of space exploration; for instance, the Apollo missions focused on crewed lunar landings rather than initial satellite launch efforts, and the Gemini program was designed to develop and test technologies for the Apollo missions. The Hubble Space Telescope, launched much later, is not considered among the early artificial satellites but rather a significant advancement in astronomical observations after satellites had become more prevalent.