ESA Science & Technology - Titan Flyby - 20 December 2007

This encounter is set up with two manoeuvres: an apoapsis manoeuvre on 13 December, and a Titan approach manoeuvre, scheduled on 17 December. T39 is the fourth in a series of outbound encounters that will last until the end of the prime mission (mid 2008), and occurs less than two days after Saturn closest approach. This is also the fourth in a series of seven Titan southern hemisphere encounters.

Science Activities

• Cassini Radar (RADAR)
  RADAR uses this opportunity to obtain South Pole coverage, including the first SAR coverage south of 70° south. The inbound leg features radiometry of unique terrain at high latitudes, scatterometry of Titan's southeast terrain, altimetry, and low rate SAR. Outbound observations include radiometry of unique northwestern terrain contiguous with that to be observed on the T43 flyby and scatterometry near the Huygens landing site. RADAR will return to the south pole area in the proposed extended mission, two years after this flyby; this allows the science team to look for changes over time; for instance, are Titan's lakes filling up?
• Imaging Science Subsystem (ISS)
  ISS monitors for surface and atmosphere changes of the bright area just to the north of the Adiri region, and it will be attempting to see surface colour variations and monitoring limb hazes. The instrument will also perform a full disk colour sequence at 1.4 km/pixel, and will take spectrophotometric low phase angle measurements of Rhea.
• Composite Infrared Spectrometer (CIRS)
  CIRS will obtain information on trace constituents in Titan's stratosphere and stratospheric temperatures. Vertical temperature and compositional profiles will be obtained via limb measurements.
• Visible and Infrared Mapping Spectrometer (VIMS)
  VIMS will create a regional and global map for continued monitoring of cloud formation and evolution.
• Dual Technique Magnetometer (MAG)
  T39 is a very close flyby over the southern polar region, passing through the outer flank. Good outer flank (away from Saturn) flybys have been missing until now. The outer flank feature will be an aspect of all coming flybys.

Table of Events

14 December 2007

18 December 2007

19 December 2007

20 December 2007

21 December 2007

Titan Ground Trace

Image courtesy NASA/JPL/Space Science Institute

The above image shows the ground trace of the Titan-39 flyby on a mosaic of Titan's surface, for a period of 32 hours around closest approach. The colour of the trace indicates Cassini's altitude above the surface. Blue: > 100 000 km, green: < 100 000 km, light blue: < 50 000, yellow: < 10 000 km, orange: < 5000 km, red: < 2000 km. The point of closest approach (CA) is marked T39 (Cassini at 970 km altitude).

Observation Results

Cassini Instrument: Imaging Science Subsystem (ISS)

Date: 25 January 2008 Credit: NASA/JPL/Space Science Institute Image Notes: Titan's organic haze layers as seen by the narrow angle camera at the wavelength of 338 nm (ultraviolet) from a distance of 190 000 km

Cassini Instrument: Cassini Radar (RADAR)

Date: 8 January 2008 Credit: NASA/JPL Image Notes: Radar swath over Titan's south pole (< 84°S), revealing two radar-dark features in an area dominated by smooth valleys and rugged terrain.
Date: 8 January 2008 Credit: NASA/JPL Image Notes: Radar image of Titan, revealing evidence of flowing liquids. From sinuous, wide river channels to shorter, more chaotic drainage patterns.