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Titan Fly-by - 21 May 2009

Titan Fly-by - 21 May 2009

19 May 2009

On Thursday, 21 May, Cassini returns to Saturn's largest moon for the mission's fifty-sixth targeted encounter with Titan: T55. The closest approach to Titan occurs at 21:26:41 UTC at an altitude of 965 kilometres above the surface and at a speed of 6.0 kilometres per second. The latitude at closest approach is 22°S and the encounter occurs on orbit number 111.

This encounter is set up with two manoeuvres: an apoapsis manoeuvre on 13 May, and a Titan approach manoeuvre, scheduled for 18 May. T55 is the fourth flyby in a series of eleven inbound encounters and the eleventh Titan encounter in Cassini's Equinox Mission. It occurs just over three days before Saturn closest approach.

Science Highlights

  • Cassini Radar (RADAR)
    The SAR swath sweeps down across the Shangri-La dunefields and into high Southern latitudes on Titan. This begins a sequence of near-parallel SAR swaths HiSAR north of Xanadu and over southern polar regions.
  • Ion and Neutral Mass Spectrometer (INMS)
    On T55, INMS will be riding with RADAR, obtaining unique nightside coverage at low Southern latitudes. This fly-by provides unique coverage for the outer flank of Titan's magnetospheric interaction region.
  • Composite Infrared Spectrometer (CIRS)
    During T55 CIRS will perform surface temperature mapping; continued composition integrations and obtain stratospheric temperature maps.
  • Visual and Infrared Mapping Spectrometer (VIMS)
    On the inbound leg, the phase angle is much larger than 90° and VIMS ridealong observations will provide information on Titan's atmospheric composition. After closest approach, VIMS will observe from great distances Titan's South Pole region, riding along with CIRS. Only cloud monitoring will be possible.
  • Imaging Science Subsystem (ISS)
    ISS will acquire a full-disk mosaic of eastern Tsegihi at high southern latitudes and ride along with CIRS to monitor clouds.
  • Ultraviolet Imaging Spectrograph (UVIS)
    UVIS will obtain an image cube of Titan's atmosphere at extreme-, and far-ultraviolet wavelengths by sweeping its slit across the disk. These cubes provide spectral and spatial information on nitrogen emissions, H emission and absorption, absorption by simple hydrocarbons, and the scattering properties of haze aerosols. This is one of many such cubes gathered over the course of the mission to provide latitude and seasonal coverage of Titan's middle atmosphere and stratosphere.
  • Magnetospheric Imaging Instrument (MIMI)
    MIMI will measure energetic ion and electron energy input to Titan's atmosphere.
  • Dual Technique Magnetometer (MAG)
    T55 is another flank-out, post-dusk fly-by, with a minimum altitude of 965 kilometres. Therefore, the measurements will provide a description of the draping and the pileup of the external magnetic field around Titan on the nightside hemisphere. It will be also a good complement to T52, T53 and T54 in order to characterize the background field for a similar local time with respect to Saturn and different SKR longitudes.
  • Radio and Plasma Wave Science (RPWS)
    RPWS 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.

Table of Events

5 May 2009

Time UTC Time wrt
Titan-55
Activity
07:16:00 -16d 14h Start of sequence S50 that contains Titan-55

18 May 2009

Time UTC Time wrt
Titan-55
Activity
13:45:00 -03d 08h OTM #196 prime.
Titan-55 targeting manoeuvre

19 May 2009

Time UTC Time wrt
Titan-55
Activity
13:44:00 -02d 08h OTM #196 backup

21 May 2009

Time UTC Time wrt
Titan-55
Activity
06:14:00 -15h 12m Start of the TOST segment
06:14:00 -15h 12m Turn cameras to Titan
06:54:00 -14h 32m New waypoint
06:54:00 -14h 32m Deadtime, 15 minutes and 49 seconds long. Used to accommodate changes in fly-by time
07:09:49 -14h 17m Titan atmospheric observations - CIRS. Obtain information on the thermal structure of Titan's stratosphere
08:26:41 -13h 00m Titan surface observations - VIMS.
Cloud mapping
12:26:41 -09h 00m Titan atmospheric observations - UVIS. Several slow scans across Titan's visible hemisphere to form spectral images
18:56:41 -02h 30m RADAR. Inbound scatterometry
20:14:41 -01h 12m Transition to thruster control
20:15:41 -01h 11m RADAR. Inbound HiSAR
20:56:41 -00h 30m RADAR. Inbound altimetry
21:08:41 -00h 18m RADAR. Inbound and outbound SAR
21:11:06 -00h 15m Earth occultation, 18 minute duration
21:12:01 -00h 14m Solar occultation, 17 minute duration
21:26:41 +00h 00m Titan-55 Fly-by Closest Approach Time. Altitude = 965 km, speed = 6.0 kms-1, 141° phase at closest approach
21:44:41 +00h 18m RADAR. Outbound altimetry
21:46:45 +00h 20m Descending ring plane crossing
21:56:41 +00h 30m RADAR. Outbound HiSAR
22:16:41 +00h 50m Transition off of thruster control
22:38:22 +01h 12m RADAR. Outbound scatterometry
23:56:41 +02h 30m Titan atmospheric observations - CIRS. Obtain information on surface & tropopause temperatures, and on tropospheric CH4. Scan or contiguous steps across disk

22 May 2009

Time UTC Time wrt
Titan-55
Activity
02:26:41 +05h 00m Titan atmospheric observations - CIRS. Integrate on Titan's limb with arrays parallel to limb, paired detector mode, to maximize S/N for detection and characterization of trace gas species and isotopes
06:26:41 +09h 00m Titan atmospheric observations - CIRS. Obtain information on CO, HCN, CH4. Integrate on disk at airmass 1.5-2.0
09:26:41 +12h 00m Titan surface observations-ISS.
Monitoring for surface/atmosphere changes; attempt to see surface colour variations; monitor limb hazes, 1-3 km/px
11:26:41 +14h 00m Titan atmospheric observations - CIRS. Obtain information on the thermal structure of Titan's stratosphere.
19:26:41 +22h 00m Deadtime 52 minutes and 18 seconds long. Used to accommodate changes in fly-by time
20:19:00 +22h53m Turn to Earth-line
22:04:00 +01d 01h Playback of T55 data with Goldstone 34m ground station

23 May 2009

Time UTC Time wrt
Titan-55
Activity
00:20:00 +01d 03h Playback of T55 data with Goldstone 70m ground station

 

Observation Results

Cassini Instrument: Cassini Radar (RADAR) 

Release Date: 10 June 2009

Credit: NASA/JPL

Image Notes: This 225 by 636 km view shows a pattern of dunes likely consisting of sand-sized particles made of organic material, shaped by local weather/terrain.

Release Date: 10 June 2009

Credit: NASA/JPL

Image Notes: A 335 by 289 km view of a complex canyon system, likely carved into older terrain by the ample flow of liquid methane rivers; centred at 71°S, 240°W.


Cassini Instrument: Imaging Science Subsystem (ISS)
 

Release Date: 1 July 2009

Credit: NASA/JPL/Space Science Institute

Image Notes: Wide-angle camera image over Titan's northern hemisphere, taken in violet light, revealing the hazes in the upper atmosphere as a thin halo around the moon

Release Date: 23 July 2009

Credit: NASA/JPL/Space Science Institute

Image Notes: Near-infrared view of Titan with a 938 nm filter, looking toward Fensal and Aztlan, two dark areas near the equator. North is up, 38° counter-clockwise.

Last Update: 1 September 2019
30-Jul-2021 03:01 UT

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