Titan Flyby - March 2006
17 March 2006
Only 19 days after Titan-11, Cassini returns to Titan for its thirteenth targeted encounter. The closest approach to Titan occurs on Sunday, 19 March, at 00:06 UT at an altitude of 1951 km above the surface and at a speed of 5.8 kilometres per second. The latitude at closest approach is 0° (equator) and the encounter occurs on orbit number 22.This encounter is set up with two manoeuvres: an apoapsis manoeuvre that was scheduled for 5 March, and an approach manoeuvre, scheduled for 15 March. However, the apoapsis manoeuvre was so small that it was cancelled. This inbound encounter occurs about 2 days prior to Saturn closest approach.
Science Activities
- For the Radio Science Subsystem (RSS), Titan-12 provides the first Cassini tour opportunity to observe Titan's ionosphere and neutral atmosphere using radio occultation, and Titan's surface using bistatic scattering. The radio occultation is the second ever of Titan, the first being a sole Voyager 1 occultation in 1980. The three Cassini radio signals (Ka/X/S) are planned to probe the ionosphere and atmosphere of Titan on both the ingress and egress sides. The measurements provide important high-spatial-resolution information about the large-scale structure of the ionosphere and atmosphere of Titan. The strength and polarization properties of the reflected signals, if detectable, provide important information about the dielectric constant of the surface region probed (physical nature) as well as the surface roughness.
- Imaging Science Subsystem (ISS) is to create a 32-frame global-scale mosaic extending over Shangri-La, Tui Regio, and western Xanadu, including a frame over Ontario Lacus to look for possible cloud activity and potential stereo with T44.
- Visible and Infrared Mapping Spectrometer (VIMS) will search for and characterize mid-latitude clouds, aurorae, hotspots, and changes in surface properties. VIMS will also characterize the geologic features, haze and composition of Titan's equatorial region.
- Composite Infrared Spectrometer (CIRS) will continue its global mapping of trace species (CO, H2O, HCN) via rotational lines in the far-infrared by conducting inbound and outbound composition integrations.
- RADAR will add to the radiometry and scatterometry coverage of Titan.
- Radio and Plasma Wave Spectrometer (RPWS) will make 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, and search for evidence of pickup ions.
- Cassini Plasma Spectrometer (CAPS) will make observations of Titan's interaction with Saturn's magnetosphere.
- Ion and Neutral Mass Spectrometer (INMS) will determine atmospheric and ionospheric composition and thermal structure.
Table of Events
11 March 2006
| Time UTC | Time wrt Titan-12 | Activity |
| 00:35:00 | -07d 23h | Start of Sequence S19 which contains Titan-12 |
15 March 2006
| Time UTC | Time wrt Titan-12 | Activity |
| 22:50:00 | -03d 01h | OTM #55 Prime, Titan-12 minus 3 day targeting manoeuvre |
16 March 2006
| Time UTC | Time wrt Titan-12 | Activity |
| 22:50:00 | -02d 01h | OTM #55 Backup |
18 March 2006
| Time UTC | Time wrt Titan-12 | Activity |
| 07:49:00 | -16h 16m | Start of the TOST segment |
| 08:19:00 | -15h 46m | Turn cameras to Titan |
| 08:19:00 | -15h 46m | Deadtime, used to accommodate changes in flyby time |
| 08:41:00 | -15h 24m | Infrared (IR) global mapping; search for and characterize clouds |
| 10:05:00 | -14h 00m | IR limb stare; stratospheric studies; obtain information on CO, HCN, CH4 |
| 17:05:00 | -07h 00m | Narrow Angle Camera (NAC) global map; global mosaic looking for cloud activity |
| 20:55:00 | -03h 10m | Transition to thrusters; 22 min duration |
| 21:16:00 | -02h 49m | Visible & IR Regional map; characterize geologic features, haze, and composition of Titan's equatorial region |
| 22:40:00 | -01h 25m | Radio Science (RSS) bistatic; determine physical properties of Titan's surface |
| 23:56:00 | -00h 09m | Titan wake crossing |
| 23:59:00 | -00h 06m | RSS atmospheric occultation; understand atmospheric and ionospheric structure |
19 March 2006
| Time UTC | Time wrt Titan-12 | Activity |
| 00:05:57 | +00h 00m | Titan-12 flyby closest approach time; altitude=1951 km, speed=6.0 kms-1, 148° phase at closest approach |
| 01:02:57 | +00h 57m | Transition back to reaction wheels; 21 min duration |
| 01:24:00 | +01h 19m | RADAR scatterometry and radiometry; surface composition and roughness measurements |
| 05:35:00 | +05h 30m | Visible & IR observations of dark side; cloud and aurorae search; WAC photometry |
| 12:25:00 | +12h 20m | Far IR limb stare; obtain information on CO, HCN, CH4 |
| 14:06:00 | +14h 01m | Deadtime, used to accommodate changes in flyby time |
| 14:22:00 | +14h 17m | Turn to Earth-Line |
| 14:44:00 | +14h 39m | Begin playback of Titan-12 data, Madrid 70M |
20 March 2006
| Time UTC | Time wrt Titan-12 | Activity |
| 00:04:00 | +23h 59m | End playback of Titan-12 data |
| 19:57:00 | +01d 20h | Saturn Periapsis |
Last Update: 1 September 2019
