Cassini Diving over Enceladus

Cassini is a spacecraft currently in orbit around Saturn.

Enceladus is the 6th largest moon of Saturn (~500 km in diameter).

On March 12, 2008, this man-made moon met the natural moon… at closest approach of 50 km! That was very close!

PIA08409 Enceladus_sm

This 3-image mosaic is the highest resolution view yet obtained of Enceladus’ north polar region during Cassini’s March 2008 flyby of Enceladus.  Credit: NASA/JPL/Space Science Institute.  More photos of March 2008 flyby of Enceladus.

Once upon a time, in year 2005, Cassini performed several close flybys of Enceladus and discovered evidence for geyser-like jets.  These continuous eruptions of ice water create a gigantic halo of ice dust and gas around Enceladus, which are the source of the material in Saturn’s tenuous E-ring.

enceladus_plume

This false-colour view taken on Nov. 27, 2005 identify the source locations for individual jets spurting ice particles, water vapour and trace organic compounds from the surface of Saturn’s moon Enceladus. Credit: NASA/JPL/Space Science Institute.

On March 12, 2008, this was what happened: Cassini, flying at about 15 km/s, dived through the icy water geyser-like jets, snatching up precious samples that might point to a water ocean or organics inside the little moon.  The geysers emanate from fractures – casually referred to as “tiger stripes” – running along the moon’s south pole, spewing out water vapour at ~400 m/s.

The close encounter by Cassini provides a much more detailed look at the “tiger stripes” that modify the surface.  New images show that compared to much of the south polar region on Enceladus, the north polar region is much older and pitted with craters of various sizes.

enceladus tiger strips

This close-up view of Enceladus taken on July 14, 2005 shows a distinctive pattern of continuous, ridged, slightly curved and roughly parallel faults within the moon’s southern polar latitudes. These surface features have been informally referred to by imaging scientists as “tiger stripes”.  Credit: NASA/JPL/Space Science Institute.

This was the first of 4 Cassini flybys on Enceladus this year.  During this flyby, the spacecraft came within 50 km of the surface at closest approach and 200 km while flying through the plume.  Future trips may bring Cassini even closer.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.

Source: CICLOPS Press Release

Another interesting article from The Planetary Society Weblog

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~ by thChieh on March 14, 2008.

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