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Ask OCE — January 12, 2006 — Vol. 1, Issue 2
Helios 2, a joint venture between West Germany and the United States, was launched on a Titan-Centaur rocket on January 15, 1976. The second in a pair of nearly identical interplanetary probes sent to observe the sun and its solar wind, it carried the first instrument capable of exploring linear time profiles of gamma-ray bursts.

Because the Helios satellites were equipped with special heat-dispersal systems, the spacecraft were able to withstand extremely high temperatures, which reached an estimated 700 F (370 C). Their elliptical orbits took them 28 million miles from the sun, with their perihelions well within the orbit of Mercury, aphelions at the orbit of Earth, and orbital periods of about 190 days. They returned useful data about the sun’s magnetic field, the solar wind, the relative strength of cosmic rays, and measurements of meteoroid loss from the solar system.

Gamma-ray bursts detected by Helios 2 suggested some similarities in the fine time resolution structures of different bursts. The Helios 2 data, when added to the information provided by other satellites, provided new tools to scientists trying to discover the nature and origin of gamma-ray bursts.

The Helios 2 mission ended in 1981.


Read more about the Helios 2 mission.

In This Issue

Message from the Chief Engineer

The View from Outside: Japan Delays Return of Asteroid Probe

This Week in NASA History: Helios 2

Jeff Bauer on Data Memos

NASA on the Hill: House Reaches Agreement on NASA Authorization Bill

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