Exploration
As of 2009 the magnetosphere of Saturn has been directly explored by four spacecraft. The first mission to study the magnetosphere was Pioneer 11 in September 1979. Pioneer 11 discovered the magnetic field and made some measurements of the plasma parameters. In November 1980 and August 1981, Voyager 1–2 probes investigated the magnetosphere using an improved set of instruments. From the fly-by trajectories they measured the planetary magnetic field, plasma composition and density, high energy particle energy and spatial distribution, plasma waves and radio emissions. Cassini spacecraft was launched in 1997, and arrived in 2004, making the first measurements in more than two decades. The spacecraft, which is currently in orbit around Saturn, continues to provide information about the magnetic field and plasma parameters of the saturnian magnetosphere.
In the 1990s, the Ulysses spacecraft conducted extensive measurements of the saturnian kilometric radiation (SKR), which is unobservable from Earth due to the absorption in the ionosphere. The SKR is powerful enough to be detected from a spacecraft at the distance of several astronomical units from the planet. Ulysses discovered that the period of SKR varies by as much as 1%, and therefore is not directly related to the rotation period of the interior of Saturn.
Read more about this topic: Magnetosphere Of Saturn
Famous quotes containing the word exploration:
“I call her old. She has one family
Whose claim is good to being settled here
Before the era of colonization,
And before that of exploration even.
John Smith remarked them as he coasted by....”
—Robert Frost (1874–1963)
“The future author is one who discovers that language, the exploration and manipulation of the resources of language, will serve him in winning through to his way.”
—Thornton Wilder (1897–1975)
“Typography tended to alter language from a means of perception and exploration to a portable commodity.”
—Marshall McLuhan (1911–1980)