Helios

Helios-A and Helios-B (also known as Helios 1 and Helios 2) are a pair of probes that were launched into heliocentric orbit to study solar processes. As a joint venture of West Germany’s space agency DLR (70 percent share) and NASA (30 percent share) the probes were launched from Cape Canaveral Air Force Station, Florida, on December 10, 1974, and January 15, 1976, respectively. As built by the main contractor, Messerschmitt-Bölkow-Blohm, they were the first space probes built outside the United States and the Soviet Union to leave Earth’s orbit.

The probes set a maximum speed record for spacecraft of 252,792 km/h (157,078 mph; 70,220 m/s). Helios-B flew 3,000,000 kilometres (1,900,000 mi) closer to the Sun than Helios-A, achieving perihelion on April 17, 1976, at a record distance of 43.432 million km (26,987,000 mi; 0.29032 AU), closer than the orbit of Mercury. Helios-B was sent into orbit 13 months after the launch of Helios-A. The Helios space probes completed their primary missions by the early 1980s but continued to send data up to 1985.

The probes are no longer functional yet remain in their elliptical orbits around the Sun.