2009 Saturn Tour Highlights
2009 Saturn Tour Highlights
Editor's note: this list was written in January 2009 as a forecast of upcoming events .
Feb. 7 -- Titan flyby (960 kilometers) -- T-50: At closest approach, RADAR will observe across the Tsegihi/ 'Mountains.' T50 is an Ion and Neurtral Mass Spectrometer (INMS) prime observation to measure the boundary between the wake side and inner flank magnetospheric interaction region at mid Southern latitudes.
March 27 -- Titan flyby (960 kilometers) -- T-51: This flyby features a good south polar view for the Visual and Infrared Mapping Spectrometer (VIMS). The Imaging Science Subsystem (ISS) will attempt very high-resolution imaging of the south-polar region, including Ontario Lacus, in ride-along with VIMS.
April 4 -- Titan flyby (4,150 kilometers) -- T-52: The Radio Science Subsystem (RSS) observes an occultation of Titan's atmosphere and ionosphere; this is the only near-equatorial RSS occultation so far. The Ultraviolet Imaging Spectrograph (UVIS) watches Titan occult the star Alpha Eri. Earlier, RADAR gets good northern polar coverage, helping to fill in a gap in the brightness temperature map.
April 20 -- Titan flyby (3,600 kilometers) -- T-53: At closest approach, UVIS observes Titan occulting the sun. The Composite Infrared Spectrometer (CIRS) will obtain high-resolution limb coverage. ISS will ride along with VIMS to image Titan’s trailing hemisphere at high southern latitudes and with CIRS to monitor clouds.
May 5 -- Titan flyby (3,244 kilometers) -- T-54: ISS will acquire high-resolution imaging of Titan’s trailing hemisphere at high southern latitudes and will ride along with VIMS to monitor clouds. The Radio and Plasma Wave Science (RPWS) instrument will measure thermal plasmas in Titan's ionosphere and surrounding environment, search for lightning in Titan's atmosphere, and investigate the interaction of Titan with Saturn's magnetosphere.
May 21 -- Titan flyby (965 kilometers) -- T-55: A RADAR swath sweeps across the northwest Shangri-La dune fields in Titan's southern hemisphere. INMS will be riding with RADAR, obtaining nightside coverage at low Southern latitudes. This provides coverage for the outer flank of the magnetospheric interaction region.
June 6 -- Titan flyby (965 kilometers) -- T-56: This is the only dusk side observation at mid Southern latitudes, and INMS will be taking advantage of that, riding along with RADAR at closest approach. It's the only time in the mission the spacecraft will get simultaneous coverage of the dusk side while in the wake magnetospheric interaction region. VIMS and ride-along ISS will observe eastern Tsegihi.
June 22 -- Titan flyby (955.5) kilometers -- T-57: RADAR and INMS again share prime opportunities near closest approach. The RADAR synthetic aperture radar (SAR) imager observation runs parallel to observatons in the T-55 and T-56 flybys in the southern hemisphere mapping sequence. Earlier, RSS observes an occultation on the inbound leg. T-57 is another flank-out, post-dusk flyby, with a minimum altitude of about 1000 kilometers. As in T-55 and T-56 flybys, magnetometer measurements will provide a description of the draping and the pileup of the external magnetic field around Titan on the nightside hemisphere. The flyby will also be a good complement to T-52, T-53, T-54, T-55 and T-56, in order to characterize the background field for a similar local time with respect to Saturn and different SKR longitudes.
July 8 -- Titan flyby (965 kilometers) -- T-58: UVIS observes a solar occultation while inbound towards Titan, and then a stellar occultation on the spacecraft's outbound trajectory. RADAR's SAR swath runs along the western edge of Xanadu to study its boundary with Shangri-La. The swath runs parallel to the T-55/56/57 mapping sequence and covers Ontario Lacus.
July 24 -- Titan flyby (955 kilometers) -- T-59: The spacecraft's instruments sample Titan's southern mid-latitudes, with the Cassini Plasma Spectrometer (CAPS) controlling pointing at closest approach.
Aug. 9 -- Titan flyby (970) kilometers -- T-60: RADAR takes a South pole pass. The resulting swath links up with the T-13 flyby swath at the edge of Xanadu. ISS will acquire high-resolution, low-phase-angle imaging of western Senkyo.
We will be watching for topographic features in the rings that can only be seen in this special geometry. Any features in the rings that are not exactly in the 'ring plane' will be seen to cast shadows.
Cassini scientists will also be looking at the thermal properties of the rings in this season change. Most rings have seen heating on the north side over the past 14.5 years, but the B ring's densest portions have remained cold with no solar heat penetrating that ring for the past 14.5 years.
This Rings Equinox campaign is a unique opportunity provided by the long duration of the Cassini Mission.
Aug. 25 -- Titan flyby (970 kilometers) -- T-61: RADAR gathers a SAR swath over the Huygens landing site. The swath is near-equatorial, covering Dilmun, Adiri and Belet. As the SAR parallels and overlaps the T-8 flyby, this should provide a good stereo opportunity over the Belet sand dunes. T-61 is the only southern equatorial wake observation in the mission, so the Magnetosphere and Plasma Science (MAPS) instruments take advantage of the opportunity.
Oct. 12 -- Titan flyby (1,300 kilometers) -- T-62: This flyby offers excellent VIMS and UVIS observing opportunities, including a UVIS solar occultation that reaches down to Titan's surface. CIRS takes observations while Titan is in eclipse, measuring the temperature, aerosol density and composition near 75 South. This is the only low altitude in nose side magnetospheric interaction pass in the extended mission.
Nov. 2 -- Enceladus flyby (99 kilometers) -- 120EN: This is the seventh targeted Enceladus flyby of the Cassini mission and will take the spacecraft to the lowest altitude above the active south pole region. This will also be the deepest plume passage of the tour, allowing for sensitive measurements of the geyser-like plume composition and density.
Nov. 21 -- Enceladus flyby (1,603 kilometers) -- 121EN: The eighth targeted Enceladus flyby, this is an approximate 1600 kilometer pass over the south pole enabling imaging of the warm, active tiger stripes.
Dec. 12 -- Titan flyby (4,850 kilometers) -- T-63: CAPS takes advantage of the T-63 flyby being the best wake passage in the extended mission to direct pointing at closest approach.
Dec. 28 -- Titan flyby (955 kilometers) -- T-64: RADAR captures HiSAR SAR over the North polar lakes to perform stereo and/or seasonal change detection. This is the only north polar SAR in the extended mission. Due to the location of the point of closest approach, this is a potentially important flyby in the effort to detect an intrinsic magnetic field within Titan. This is also an opportunity to sample the high northern atmosphere.