Helios 1
Helios 1 — a West German solar probe launched by NASA on 10 December 1974. On 15 March 1975 it passed 46.5 million km from the Sun (0.31 AU) at about 238,000 km/h, a spacecraft speed record, and it measured the solar wind, magnetic fields, cosmic rays and dust in the inner Solar System until 1985. (Its orbit is drawn to its published size; where it is on it is representative.)
Key facts
Mission & specifications
Mission
- Operator
- DFVLR (West Germany) / NASA
- Launched
- December 10, 1974
- Status
- Completed
Trajectory
- Distance from the Sun
- 0.515 AU
- Computed from the cached position
- Distance from Earth
- 0.589 AU
- Computed from cached positions
- Distance from Mercury
- 0.303 AU
- Computed from cached positions
Mission
Helios 1 was the first of a pair of solar probes built by West Germany, with experiments from German and American scientists and a Titan-Centaur rocket from NASA. It was launched at 07:11 UTC on 10 December 1974 onto an orbit around the Sun that swung in from Earth's distance to 0.31 AU, closer than Mercury's average distance, every 190 days. It reached its first perihelion, 46.5 million km from the Sun, on 15 March 1975, travelling at about 238,000 km/h — a spacecraft speed record at the time. On each pass it measured the solar wind, magnetic fields and waves, cosmic rays, zodiacal light and dust in the inner Solar System. One axis of its long wire antenna failed to deploy, so that antenna worked as a single-ended one, which made its radio-wave measurements harder to calibrate. Controllers deactivated it on 18 February 1985 and last made contact on 10 February 1986. Its orbit is drawn here to the size NSSDCA gives; where it is along that orbit is representative.
- 1974Helios 1 launches on a Titan-Centaur rocketLaunch
West Germany's probe, on NASA's rocket.
- 1975First perihelionMilestone
0.31 AU from the Sun, at a record speed of about 238,000 km/h.
- 1985DeactivatedMission end
Last contact on 10 February 1986.
Images
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