Helios (spacecraft)
pair of solar probes operated by NASA and DLR
Helios-A and Helios-B (after launch renamed Helios 1 and Helios 2) are a pair of probes that were launched into heliocentric orbit to study solar processes. As a joint venture between German Aerospace Center (DLR) and NASA, the probes were launched from Cape Canaveral Air Force Station, Florida, on December 10, 1974, and January 15, 1976, respectively.
The Helios project set a maximum speed record for spacecraft of 252,792 km/h (157,078 mph; 70,220 m/s). Helios-B performed the closest flyby of the Sun so far, a record only broken in October 2018 by the Parker Solar Probe. The probes are no longer functional, but as of 2024 remain in elliptical orbits around the Sun.
Construction
The Helios project was a joint venture of West Germany's space agency DLR (70 percent share) and NASA (30 percent share). The Helios probes, built by the main contractor Messerschmitt-Bölkow-Blohm, were the first space probes built outside the United States and the Soviet Union to leave Earth orbit.
Structure
The two Helios probes look similar. Helios-A has a mass of 370 kilograms (820 lb), and Helios-B has a mass of 376.5 kilograms (830 lb). Their scientific payloads have a mass of 73.2 kilograms (161 lb) on Helios-A and 76.5 kilograms (169 lb) on Helios-B. The central bodies are sixteen-sided prisms 1.75 metres (5 ft 9 in) in diameter and 0.55 metres (1 ft 10 in) high.
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