Helios

Helios is a term with multiple meanings, drawn from the Greek word for the sun. It is used in mythology, science, and various cultural contexts.

In ancient Greek religion, Helios is the personification and god of the Sun. He is described as driving a chariot across the sky each day, illuminating the world. In early sources he is a distinct solar deity, later sometimes conflated with or associated to other sun figures such as Helios’ broader mythic context, while his sister Selene represents the Moon and Eos the Dawn. As a divine witness, Helios is a recurring presence in mythic narratives about sight, fate, and daily life on earth.

In space science, Helios refers to the Helios I and Helios II solar probes, a joint project of NASA and the German Space Agency (DLR). Launched in 1974 and 1976, the two spacecraft conducted close approaches to the Sun, studying the solar wind, the corona, and the heliosphere. Their highly elliptical orbits brought them to within about 0.3 astronomical units of the Sun, yielding data on solar radiation, energetic particles, and magnetic fields that informed models of solar-terrestrial interactions.

The name Helios is also used in various contemporary contexts for organizations, products, and fictional works, typically invoking associations with the Sun. The term remains a concise symbol of solar power and illumination in many languages and disciplines.