ESA Science & Technology - Titan Fly-by - 5 December 2008

This encounter was set up with two manoeuvres: an apoapsis manoeuvre on 27 November, and a Titan approach manoeuvre, scheduled for 1 December. T48 was the twelfth in a series of outbound encounters and the fourth Titan encounter in Cassini's Equinox mission. It occured just over three days after Saturn closest approach.

T-48 was a unique flyby (along with T-47) with low phase and high resolution imaging opportunities for the imaging instruments.

Science Highlights

• Ion and Neutral Mass Spectrometer (INMS)
  T48 is the only dayside pass near Titan's equator in the Prime Mission or the Equinox Mission. This INMS prime observation will measure non-reactive neutrals while simultaneously observing the dayside ionosphere. This fly-by also gives INMS coverage of the boundary between the outer flank and wake magnetospheric interaction regions. Outbound, INMS will collect measurements from closest approach to the ionospheric peak and into the transition from thermal to co-rotating particles
• Cassini Radar (RADAR)
  T48 represents the end of a series of fly-bys that observe territory that may be cryovolcanic. RADAR has the opportunity to look at part of Tui Regio inbound, prior to turning to INMS's preferred attitude. VIMS observations suggest that this region may resemble Hotei Arcus, with an anomalous composition and possible cryolava flow morphologies. Near closest approach, RADAR will observe the dark dunefields of Shangri-La while riding along on the INMS observation. HiSAR in south midlatitudes will look at a possible impact structure feature seen in ISS data.
• Composite Infrared Spectrometer (CIRS)
  CIRS conducts far-IR limb composition measurements, and maps vertical distributions of CO, CH₄, H₂O and others. In addition, CIRS continues its campaign of mapping the planet in the mid and far-infrared to obtain the spatial and temporal variation of temperature and more abundant hydrocarbon and nitrile molecules, which provide information on seasonal changes in weather, climate and chemistry that may be occurring.
• Imaging Science Subsystem (ISS)
  ISS returns to getting much higher resolution observations of the leading hemisphere with a mosaic along a portion of Hotei Arcus. The instrument will also collect global and regional mosaics of Titan's leading hemisphere, including a view of Hotei Arcus in its entirety, as well as southern Xanadu and the western reaches of Tsegihi.
• Visual and Infrared Mapping Spectrometer (VIMS)
  VIMS will conduct global mapping.
• Magnetospheric Imaging Instrument (MIMI)
  T48 is part of the Titan MAPS Campaign, investigating micro-scale and near aspects of the Titan interaction by making observations during about one hour period around an encounter. With the spacecraft -Y pointed toward Titan, when within 30 minutes of the targeted fly-by, optimize secondary axis for corotation flow as close to the spacecraft -X, +/- Z plane as possible with the other constraints on pointing. Also, measure the Titan exosphere/magnetosphere interaction by imaging in ENA with INCA (when the Sun is not in the INCA FOV).
• Ultraviolet Imaging Spectrograph (UVIS)
  UVIS will have its FUV Occultation slit boresite on the star Epsilon CMa as Titan occults the star. Over the course of the nominal mission and extended mission UVIS stellar occultations will sample about 12 latitudes and this sampling will help constrain photochemistry, dynamics and aerosol microphysical processes in the upper stratosphere and mesosphere.
• Dual Technique Magnetometer (MAG)
  T48 is very similar to T47, with a minimum altitude of 1000 km. Therefore, it will be possible to look for temporal effects in response to changes in the upstream conditions (i.e. the fly-by occurring at a different SKR phase). T48 also takes place in Saturn's near-noon sector (10.5 hours Saturn local time), where Titan could be found in the magnetosheath if the solar wind pressure is high.

Table of Events

26 November 2008

1 December 2008

2 December 2008

4 December 2008

5 December 2008

6 December 2008