Helios-A and Helios-B (also known as Helios 1 and Helios 2), were a pair of probes launched into heliocentric orbit for the purpose of studying solar processes. A joint venture of the Federal Republic of Germany (West Germany) and NASA, the probes were launched from the John F. Kennedy Space Centre at Cape Canaveral, Florida, on Dec. 10, 1974, and Jan. 15, 1976, respectively.
Helios 2 flew three million kilometres closer to the Sun than Helios 1, achieving perihelion on 17 April 1976 at a record distance of 0.29 AU (or 43.432 million kilometres), slightly inside the orbit of Mercury.
