HELIOS

(Greek: "Sun"), in Greek religion, the sun god. He drove a chariot daily from east to west across the sky and sailed around the northerly stream of Ocean each night in a huge cup. In classical Greece, Helios was especially worshiped in Rhodes, where from at least the early 5th century BC he was regarded as the chief god, to whom the island belonged. His worship spread as he became increasingly identified with other deities, often under Eastern influence. From the 5th century BC, Apollo, originally a deity of radiant purity, was more and more interpreted as a sun god. During the Roman Empire the sun itself came to be worshiped as the Unconquered Sun. either of two unmanned solar probes developed by West Germany in cooperation with the U.S. National Aeronautics and Space Administration (NASA). Helios 1 and Helios 2 were launched by NASA from the John F. Kennedy Space Center in Cape Canaveral, Fla., on Dec. 10, 1974, and Jan. 15, 1976, respectively. Both traveled closer to the Sun than any other spacecraft: Helios 1 passed within 45,000,000 km (28,000,000 miles) and Helios 2 within 43,400,000 km. Equipped with special heat-dispersal systems, the probes were able to withstand extremely high temperatures, which reached an estimated 700 F (370 C). Both returned useful data about the Sun's magnetic field, the solar wind, the relative strength of cosmic rays, and measurements of meteoroid loss from the solar system.