Helios 2
Helios 2 — the second West German–American solar probe, launched on 15 January 1976. On 17 April 1976 it passed 43.4 million km from the Sun (0.29 AU) at about 241,000 km/h — the closest and fastest any spacecraft had come, records that stood until NASA's Parker Solar Probe in 2018. Its transmitter failed on 3 March 1980. (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
- January 15, 1976
- Status
- Completed
Trajectory
- Distance from the Sun
- 0.94 AU
- Computed from the cached position
- Distance from Earth
- 1.19 AU
- Computed from cached positions
- Distance from Mars
- 0.648 AU
- Computed from cached positions
Mission
Helios 2, the second West German–American solar probe, was launched on 15 January 1976, with improved systems meant to help it survive longer than its twin. Its orbit was slightly smaller: every 186 days it dropped to 0.29 AU from the Sun. On 17 April 1976 it passed 43.432 million km from the Sun at about 241,000 km/h — the closest approach and the highest speed of any spacecraft at the time, records that stood for 42 years, until NASA's Parker Solar Probe in 2018. Trouble with its high-gain antenna, and competition for tracking time with the Viking missions to Mars, meant it returned fewer high-rate data than Helios 1. Its downlink transmitter failed on 3 March 1980, and controllers shut it down on 7 January 1981. Its orbit is drawn here to the size NSSDCA gives; where it is along that orbit is representative.
- 1976Helios 2 launches on a Titan-Centaur rocketLaunch
The second Helios, built to survive longer.
- 1976Record perihelionMilestone
0.29 AU from the Sun at about 241,000 km/h; unbeaten until 2018.
- 1980Transmitter failsMilestone
Its downlink transmitter stops working.
- 1981Shut downMission end
Controllers switch the spacecraft off.
Images
Images from open archives · credit shown per image