Helios probes

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The Helios deep space probes were launched in the mid 1970s by the Federal Republic of Germany and NASA, using US Air Force launch vehicles.

There were two in the series, Helios I and Helios II. They were launched to orbit and measure the Sun. They set a speed record for spacecraft at 252,792 km/h (70.2 km/s). They also set the record for closest approach to the Sun, at about 45 million kilometres, slightly inside the orbit of Mercury. The Helios 2 was sent into orbit 3 months after the launch of the Helios 1. Both probes orbited around the sun in an ellipse, with their farthest distance from the sun being almost 1 AU (Astronomical Unit - the distance from the Earth to the Sun) and their closest distance to the Sun at 0.3 AU. The Helios space probes completed their primary missions by the early 1980's, but they continued to send data up to 1985. Presently, these probes are no longer functional, but they still remain in their elliptical orbit around the sun.

The name Helios has also been used for a NASA experimental aircraft, the Helios Prototype, and for a series of French military photo-reconnaissance satellites, Helios 1B & Helios 2A.

[edit] External links

• NASA - Helios

Sun Spacecraft Missions v • d • e
Orbiters: Pioneer 6, 7, 8 and 9 | Helios probes | Ulysses probe | Solar and Heliospheric Observatory (SOHO) | Reuven Ramaty High Energy Solar Spectroscopic Imager | Hinode | STEREO | TRACE | ACE
Sample return: Genesis (spacecraft)
Future: Solar Dynamics Observatory | Solar Orbiter
See also: Sun | Exploration of the Sun