Exploration
Pioneer 11 flew by Saturn in 1979, and its closest approach to Tethys was 329,197 km on September 1, 1979.
One year later, on 12 November 1980, Voyager 1 flew at the minimal distance of 415,670 km from Tethys. Its twin spacecraft, Voyager 2, passed as close as 93,000 km from the moon on 1 September 1981. While both spacecraft took images of Tethys, the resolution of Voyager's 1 images did not exceed 15 km, and only those obtained by Voyager 2 had a resolution as high as 2 km. The first geological feature discovered in 1980 by Voyager 1 was Ithaca Chasma. Later in 1981 Voyager 2 revealed that it almost circled the moon running for 270°. Voyager 2 also discovered the Odysseus crater. Tethys was the best imaged Saturnian satellite by the Voyagers.
The Cassini spacecraft entered orbit around Saturn in 2004. During its primary mission from June 2004 through June 2008 it performed one very close targeted flyby of Tethys on September 24, 2005 at the distance of 1503 km. In addition to this flyby the spacecraft performed seven non-targeted flybys during its primary and equinox missions in 2004–2010 at distances of tens of thousands of kilometers.
Another flyby of Tethys took place on August 14, 2010 (during the solstice mission) at a distance of 38300 km, when the fourth-largest crater on Tethys, Penelope, which is 207 km wide, was imaged. More non-targeted flybys are planned for the solstice mission in 2011–2017.
Cassini's observations allowed high-resolution maps of Tethys to be produced with the resolution of 0.29 km. The spacecraft obtained spatially resolved near-infrared spectra of Tethys showing that its surface is made of water ice mixed with a dark material, while the far-infrared observations constrained the bolometric bond albedo. The radar observations at the wavelength of 2.2 cm showed that the ice regolith has a complex structure and is very porous. The observations of plasma in the vicinity of Tethys demonstrated that it is a geologically dead body producing no new plasma in the Saturnian magnetosphere.
Future missions to Tethys and the Saturn system are uncertain, but one possibility is the Titan Saturn System Mission.
Read more about this topic: Tethys (moon)
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)
“Typography tended to alter language from a means of perception and exploration to a portable commodity.”
—Marshall McLuhan (1911–1980)
“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)