Cassini Spacecraft Zips Close By Saturn's Moon Titan

A NASA spacecraft flew close by Saturn's largest moon, Titan, yesterday (Sept. 24) to take a close look at the moon's atmosphere and observe how its seasons change.

Cassini swung high over Titan, taking a long, sustained look at the hazy moon. At its closest approach — which occurred at 2:38 p.m. EDT (1838 GMT) — the spacecraft flew 5,080 miles (8,175 km) above Titan's surface.

This close look is the first in a new series of high-altitude Titan flybys Cassini will make over the next year and a half. The spacecraft has flown by Titan many times in the past as part of other science campaigns.

Scientists have long been interested in Titan, which has a thick, nitrogen-rich atmosphere and a methane-based weather cycle. Some researchers think Earth resembled Titan before life took hold here. [Photos of Titan's surface.]

Cassini's composite infrared spectrometer instrument will be probing Titan's stratosphere to learn more about its vertical structure as the seasons change. Titan's equinox, when the sun shone directly over the equator, occurred in August 2009, and the northern hemisphere is now in spring.

Another instrument, the visual and infrared mapping spectrometer, will be mapping an equatorial region known as Belet at a resolution of 3 miles (5 km) per pixel. These images will complement the mosaics that were obtained from earlier Titan flybys in January and April. This spectrometer will also look for clouds at northern mid-latitudes and near the poles.

Cassini's visible-light imaging cameras will also be taking images of Titan's trailing hemisphere, or the side that faces backward as Titan orbits around Saturn. If Titan cooperates and has a cloudy day, scientists plan to analyze the images for cloud patterns.

Cassini launched in 1997 with a mission to study Saturn and its many moons. The craft reached the ringed planet in 2004. In February of this year, its mission was extended to May 2017.

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