ESA Science & Technology - Titan Flyby - April 2006

This encounter is set up with two manoeuvres: an apoapsis manoeuvre scheduled for 5 April, and a Titan approach manoeuvre, scheduled for 26 April. Titan-13 is an outbound flyby, with Saturn periapsis occurring (about two days before closest-approach) on 28 April. The navigation team expects to deliver the orbiter to within 30 km of the target altitude at a confidence of 99% (three sigma).

Science Activities

• Imaging Science Subsystem (ISS) - will observe particle properties, vertical distributions (~6 km/px, 0.6 Mbit/frame with 2x2 summing). ISS will also examine wind/cloud motions; (3-12 km/px, 3 images/timestep in CB1 filter to increase SNR), and search for and monitor lightning/aurora (High-resolution imaging, 50-200 m/px, special targets, emission angles < 45° prefer IR-polarizer (phase 45-110)).
• Cassini Plasma Spectrometer (CAPS) - will investigate large-scale and distant aspects of the Titan interaction with Saturn's Magnetosphere by observing during the entire period around an encounter from 10 to 25 R_S.
• Composite Infrared Spectrometer (CIRS) -will obtain information on trace constituents in Titan's stratosphere. Integrate on limb at two positions. Obtain information on CO, HCN, CH₄. Integrate on disk at air mass 1.5-2.0. Pointing: -Y to Titan, X away from Sun.
• Ultraviolet Imaging Spectrometer (UVIS) - will observe the star Beta Ori as it becomes occulted by Titan's atmosphere.
• Visible and Infrared Mapping Spectrometer (VIMS) - will obtain new high resolution images that will help understand Titan's geology and the fate of CH₄. VIMS will also search for and study the evolution of mid-latitude clouds, and search for lightning and hot spots.
• Magnetometer (MAG) - will investigate large-scale and distant aspects of the Titan interaction by observing during the entire period around an encounter from 10 to 25 R_S. (23TI (T13))T13 is an equatorial wake flyby under plasma conditions near Saturnian local midnight with 1852 km altitude at closest approach. Thus it is very similar to T13 even according to local time.
• Magnetospheric Imaging Instrument (MIMI) - will investigate micro-scale and near aspects of the Titan interaction by observing during about one hour period around an encounter. With -Y pointed toward Titan, when within 30 minutes of the targeted flyby, optimise secondary axis for co-rotation flow as close to the S/C -X, ± Z plane as works with the other constraints on Pointing. Also, measure Titan exosphere/magnetosphere interaction by imaging in ENA with INCA (when Sun is not in INCA FOV).
• Ion and Neutral Mass Spectrometer (INMS) - will obtain data regarding Titan's atmospheric and ionospheric composition and thermal structure. INMS will also observe the magnetospheric/ionospheric interaction.
• Radio and Plasma Wave Spectrometer (RPWS) - will perform observations in the immediate vicinity of Titan, including thermal plasma density and temperature measurements with the Langmuir probe, search for lightning and other radio emissions, characterization of plasma wave spectrum, search for evidence of pickup ions. Langmuir probe within 90° of spacecraft ram at closest approach, co-rotational ram outside of ± 15 minutes.
• RADAR - will perform low and high resolution SAR (Synthetic Aperture RADAR) imaging of Titan's surface. Additionally, RADAR will collect Altimetry, Radiometry, and Scatterometry Data. SAR swath cuts right across Xanadu, as well as some areas where there exists good ISS/VIMS hires coverage, enabling useful comparative studies.

Observation Results

Cassini Instrument: Synthetic Aperture Radar (SAR)

Date:   3 May 2006 Credit: NASA/JPL Image Notes: Southwestern area of the Xanadu feature. The prominent circular feature, named Guabonito, is ~90 km in diameter.
Date:   3 May 2006 Credit: NASA/JPL Image Notes: Shikoku Facula, a region that is bright in both radar and visible wavelengths.  Several features are clearly visible in this image, including a circular feature with a radar-dark interior, probably an impact crater. It is seen near the top of the image and is about 35 kilometres in diameter.
Date:   5 May 2006 Credit: NASA/JPL/HST Image Notes: HST map of Titan showing the strips covered by SAR on (from top to bottom) 26 October 2004, 15 February 2005 and 30 April 2006 (next image).
Date:   19 July 2006 Credit: NASA/JPL Image Notes: Roughly 4850 km long strip over the Xanadu region - one of Titan's brightest terrains. The strip width varies between 220 and 490 kilometres.
Date:   5 May 2006 Credit: NASA/JPL Image Notes: Radar-bright western margin of Xanadu, indicating a rough or scattering surface. Narrow, sinuous, radar-bright channels are seen on the right.
Date:   5 May 2006 Credit: NASA/JPL Image Notes: Area in Xanadu with two circular features thought to be degraded impact craters. The one near the top (70 km wide) has a prominent central peak.
Date:   8 May 2006 Credit: NASA/JPL Image Notes: A complex area of hilly terrain and erosional channels, located atop the Xanadu region. The image covers 200 km × 200 km.
Date:   8 May 2006 Credit: NASA/JPL Image Notes: Area atop Xanadu, ~ 400 km × 150 km, with chains of hills or mountains. The darkest areas between the hill chains could contain liquids.
Date:   19 July 2006 Credit: NASA/JPL Image Notes: A network of winding river channels, located atop Xanadu. The imaged area is roughly 340 kilometres long by 230 kilometres wide.