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Fifth Close Titan Flyby

Fifth Close Titan Flyby

14 April 2005

Titan-5 is Cassini's fifth close flyby, and sixth targeted flyby of Titan. The flyby occurs on Saturday 16 April at 19:12 UT. The closest approach will be at an altitude of 1025 km above the surface at a speed of 6.1 kms-1. Titan has a diameter of 5150 km, so the spacecraft passes within 1.4 Titan radii. The Titan-5 flyby is also the first near-polar pass - the orbiter reaches a latitude of 74 deg at closest approach.

This encounter is set up with two manoeuvres: an apoapsis manoeuvre performed on 9 April, and a Titan approach manoeuvre, also successfully performed on 13 April. The flyby occurs about 2 days after Saturn periapsis on 14 April, and is therefore an outbound flyby.

Science Activities

Titan-5 represents the first Titan flyby with dedicated magnetospheric pointing for a large portion of the flyby. The combination of the low altitude of the Titan-5 flyby, along with CAPS (Cassini Plasma Spectrometer) controlling the pointing starting near closest approach, will allow CAPS to take measurements near the polar (latitude 74°) ionosphere. The high latitude of closest approach means Cassini will be flying through the Alfven currents which couple Titan to Saturn's magnetosphere. CAPS will continue to take high resolution data out to 120 Titan radii observing distant signatures of Titan's interaction with Saturn's magnetosphere.

  • Composite Infrared Spectrometer (CIRS)
    CIRS will attempt to detect new species in the far-infrared at high latitude (55°). It will also map CH4, CO, HCN, etc. using long wavelength rotational lines.
  • Ion and Neutral Mass Spectrometer (INMS)
    INMS will perform a critical first step in sampling the global composition of the thermosphere and ionosphere. Around closest approach, INMS will measure the minor ion and neutral densities.
  • Imaging Science Subsystem (ISS) 
    For the ISS, T5 provides a second good look (after T4) of the sub-Saturn hemisphere, including the first high-resolution (< 250 metres/pixel) coverage of the sub-Saturn region. This will be the first good look at the quasi-circular, approximately 1000 km diameter, feature, perhaps associated with an impact structure.
  • Dual Technique Magnetometer (MAG)
    For MAG, T5 is the most important flyby among all the Titan encounters of the mission. It is close to optimum for electromagnetic studies of Titan's interior via induction effects. The flyby geometry is also well suited for the study of the origin of Alfven wings and slow mode wings. The low altitude of closest approach is very favourable for studies of an internal magnetic field with a dipole near the rotation axis.
  • Magnetospheric Imaging Instrument (MIMI)
    MIMI will investigate detailed aspects of the Titan's interaction with Saturn's magnetosphere by observing through closest approach with a desirable spacecraft orientation.
  • Radio and Plasma Wave Science (RPWS)
    RPWS will measure large-scale and distant aspects of Titan's interaction with Saturn's magnetosphere by observing during the entire period around closest approach and from 10 to 25 Saturn radii.
  • Ultraviolet Imaging Spectrograph (UVIS)
    UVIS will continue spectral imaging to map Titan's atomic emissions, acetylene distribution, and haze properties.
  • Visual and Infrared Mapping Spectrometer (VIMS)
    VIMS will map a portion of the northern hemisphere, study cloud formation and dissipation, and attempt to correlate composition with geological features.

Table of Events 

09 April 2005

Time UTC Time wrt
Titan-5
Event
05:15:00 -07d 14h Start of Sequence S10 which contains T5

13 April 2005

Time UTC Time wrt
Titan-5
Event
20:40:00 -02d 23h OTM #22 Prime; T5 minus 3 day targeting manoeuvre

15 April 2005

Time UTC Time wrt
Titan-5
Event
02:14:00 -01d 17h OTM #22 Backup

16 April 2005

Time UTC Time wrt
Titan-5
Event
06:25:00 -12h 46m Turn cameras to Titan
06:55:00 -12h 16m Deadtime, used to accommodate changes in flyby time
06:17:46 -11h 54m Infrared stare at high latitude, attempt to detect new molecular species
10:41:46 -08h 30m Titan atmospheric & surface observations. Multi-filter, wide- and narrow-angle-camera images of Titan's atmosphere and surface
11:11:46 -08h 00m Spectral imaging of visible hemisphere, several slow scans across Titan
16:11:46 -03h 00m High resolution surface imaging by ISS & VIMS. Twelve ISS NAC footprints (some along the T3 SAR swath) with pixel scales 725-250 m
18:11:46 -01h 00m Transition to thrusters
18:32:46 -00h 39m Turn to MAPS attitude. Studies of Titan's interaction with Saturn's magnetosphere
18:52:46 -00h 19m INMS attitude through closest approach. Composition sampling of thermosphere and ionosphere
19:11:46 +00h 00m T5 flyby closest approach. Altitude=1025 km, velocity=6.1 kms-1, 126° phase
19:23:46 +00h 12m Return to MAPS attitude for next 16 hours. High resolution measurements of Titan's interaction with Saturn's magnetosphere. This activity continues through closest approach and out beyond 120 Titan radii.
19:48:46 +00h 37m Transition to Reaction Wheels. Duration = 24 minutes
19:51:00 +00h 40m Descending ring plane crossing

17 April 2005

Time UTC Time wrt
Titan-5
Event
11:48:47 +16h 37m Deadtime, used to accommodate changes in flyby time
11:59:00 +16h 48m Turn to Earth-Line
12:31:00 +17h 20m Begin playback of T5 data to Madrid 70M
21:25:00 +01d 02h End playback of T5 data

23 April 2005

Time UTC Time wrt
Titan-5
Event
23:10:00 +07d 04h Saturn apoapse 007, r=40.6 RS, phase=65°

Times last updated on 11 April 2005 - subject to change.
The time is in UT of the event. After this it takes about 1 hour and 8 minutes for the signal to reach Earth.

Titan Surface Coverage

Credit: NASA/JPL/Space Science Institute

This map of Titan's surface illustrates the regions that will be imaged by Cassini during the spacecraft's close flyby of the smog-enshrouded moon on 16 April 2005. At closest approach, the spacecraft is expected to pass approximately 1025 kilometres above the moon's surface. The coloured lines delineate the regions that will be imaged at differing resolutions.

Images from this encounter will add to those taken during the 31 March 2005 flyby and improve the moderate resolution coverage of this region. The imaging coverage will include the eastern portion of territory observed by Cassini's radar instrument in October 2004 and February 2005, and will provide a way to compare the surface as viewed by the different instruments. Such comparisons will provide insight into the nature of Titan's surface.

The higher-resolution (yellow boxes) have been spread out around a central mosaic in order to maximize coverage of this region by the visual and infrared mapping spectrometer which will be observing simultaneously with the cameras of the imaging science subsystem.

The map shows only brightness variations on Titan's surface (the illumination is such that there are no shadows and no shading due to topographic variations). Previous observations indicate that, due to Titan's thick, hazy atmosphere, the sizes of surface features that can be resolved are a few times larger than the actual pixel scale labelled on the map.

The images for this global map were obtained using a narrow band filter centred at 938 nanometres in the near-infrared. At this wavelength, light can penetrate Titan's atmosphere to reach the surface and return through the atmosphere to be detected by the camera. The images have been processed to enhance surface details.

It is currently northern winter on Titan, so the moon's high northern latitudes are not illuminated, resulting in the lack of coverage north of 35 degrees north latitude.

Observation Results

Cassini Instrument: Visual and Infrared Mapping Spectrometer (VIMS)

Date: 27 April 2005

Credit: NASA/JPL/University of Arizona

Image Notes: One of Titan's most prominent - 80 km diameter - impact craters, seen at 2 µm (left), in radar (center) and in a false-colour multi-wavelength image (right).

Cassini Instrument: Ion and Neutral Mass Spectrometer (INMS)

Date: 25 April 2005

Credit: NASA/JPL/University of Michigan

Image Notes: Mass spectrum of Titan's ionosphere near 1200 km altitude, in the mass range which includes compounds with 1 through 7 C-atoms as the base structure.

Cassini Instrument: Imaging Science Subsytem (ISS)

Date: 2 May 2005

Credit: NASA/JPL/Space Science Institute

Image Notes: Wide-angle camera natural colour image of Titan's upper atmosphere, created by combining images obtained with red, green and blue filters.

Date: 2 May 2005

Credit: NASA/JPL/Space Science Institute

Image Notes: Narrow-angle camera mosaic at 938 nm, centred on 27° W, 11° N. The outline of the bright/dark boundary in some places suggests fluvial activity.

Date: 2 May 2005

Credit: NASA/JPL/Space Science Institute

Image Notes: This image reveals more complex patterns of bright and dark regions, including a dark, ~20-km-wide circular feature surrounded by bright terrain.

Date: 2 May 2005

Credit: NASA/JPL/Space Science Institute

Image Notes: Narrow-angle camera view at 938 nm of a bright spot and the southern boundary of the dark terrain in the equatorial region of Titan's Saturn facing hemisphere.

Date: 2 May 2005

Credit: NASA/JPL/Space Science Institute

Image Notes: Narrow-angle camera view at 938 nm of terrain on Titan with several narrow, dark and branching features, which are suggestive of channels.

Date: 2 May 2005

Credit: NASA/JPL/Space Science Institute

Image Notes: Narrow-angle camera view at 938 nm of a brighter area with a complex pattern of small, 40-km-wide, dark features within it.

Date: 22 April 2005

Credit: NASA/JPL/Space Science Institute

Image Notes: Image of Titan's surface, obtained with the wide-angle camera at 938 nm, penetrating the cloud deck. North on Titan is up and tilted 30° to the right.

Date: 22 April 2005

Credit: NASA/JPL/Space Science Institute

Image Notes: Naturel colour composite of wide-angle camera images taken through three filters (red, green and violet), of Titan's orange atmosphere and bluish haze.

Date: 22 April 2005

Credit: NASA/JPL/Space Science Institute

Image Notes: False-colour composite from two infrared images at 938 and 889 nm and a visible light image (at 420 nm). Same orientation as the above two images.

Last Update: 1 September 2019
28-Nov-2021 20:36 UT

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