Titan Fly-by - 5 May 2009
5 May 2009
On Tuesday, 5 May, Cassini returns to Saturn's largest moon for the mission's fifty-fifth targeted encounter with Titan: T54. The closest approach to Titan occurs at 22:54:15 UTC at an altitude of 3244 kilometres above the surface and at a speed of 5.8 kilometres per second. The latitude at closest approach is 14.1°S. The encounter occurs on orbit number 110 and just fifteen days after the previous fly-by.This encounter is set up with two manoeuvres: an apoapsis manoeuvre on 27 April, and a Titan approach manoeuvre, scheduled for 2 May. T54 is the third fly-by in a series of eleven inbound encounters and the tenth Titan encounter in Cassini's Equinox Mission. It occurs just under four days before Saturn closest approach.
Science Highlights
- Composite Infrared Spectrometer (CIRS)
CIRS conducts vertical sounding of atmospheric composition, and performs mapping of temperature and aerosol profiles at low latitudes. - Visual and Infrared Mapping Spectrometer (VIMS)
On the inbound, the phase angle is much larger than 90° and VIMS ridealong observations will provide information on Titan's atmosphere composition. After closest approach, VIMS will observe the South Pole region and will look for variations at the surface and in the atmosphere. High resolution images at less than 5 km/pixel will allow imaging of places that may be lakes. VIMS will subsequently monitor the tropical clouds in the Southern hemisphere. - Imaging Science Subsystem (ISS)
ISS will acquire high-resolution imaging of Titan's trailing hemisphere at high southern latitudes and will ride along with VIMS to monitor clouds. - Ultraviolet Imaging Spectrograph (UVIS)
UVIS will obtain an image cube of Titan's atmosphere at extreme ultraviolet (EUV) and far ultraviolet (FUV) wavelengths by sweeping its slit across the moon's 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 coarse of the mission to provide latitude and seasonal coverage of Titan's middle atmosphere and stratosphere. - Magnetospheric Imaging Instrument (MIMI)
MIMI measures energetic ion and electron energy input to Titan's atmosphere. Sun obscures ENA. - Dual Technique Magnetometer (MAG)
T54 is another flank-out, post-dusk, high altitude fly-by that will be a good complement to T52 and T53 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
2 May 2009
| Time UTC | Time wrt T-54 |
Activity |
| 15:02:00 | -03d 08h | OTM #193 prime, Titan-54 targeting manoeuvre |
3 May 2009
| Time UTC | Time wrt T-54 |
Activity |
| 14:46:00 | -02d 08h | OTM #190 backup |
5 May 2009
| Time UTC | Time wrt T-54 |
Activity |
| 07:16:00 | -15h 38m | Start of sequence S50 that contains Titan-54 |
| 07:16:00 | -15h 38m | Start of the TOST segment |
| 07:22:00 | -15h 32m | Turn cameras to Titan |
| 08:02:00 | -14h 52m | New waypoint |
| 08:02:00 | -14h 52m | Deadtime, 9 minutes and 47 seconds long. Used to accommodate changes in fly-by time |
| 08:11:47 | -14h 43m | Titan atmospheric observations - CIRS. Obtain information on the thermal structure of Titan's stratosphere |
| 12:54:16 | -10h 00m | Titan surface observations - ISS. Monitoring for surface/atmosphere changes; attempt to see surface colour variations; monitor limb hazes, 1-3 km/px |
| 13:54:16 | -09h 00m | Titan atmospheric observations - CIRS. Obtain vertical profiles of temperatures in Titan's stratosphere |
| 17:44:16 | -05h 10m | Turn cameras to new waypoint |
| 18:04:16 | -04h 50m | New waypoint |
| 18:04:16 | -04h 50m | Titan atmospheric observations - CIRS. Obtain information on surface & tropopause temperatures, and on tropospheric CH4 |
| 20:39:16 | -02h 15m | Titan atmospheric observations - CIRS. Vertical sounding of stratospheric compounds on Titan, including H2O |
| 21:39:16 | -01h 15m | Titan atmospheric observations - CIRS. Limb scanning for aerosols |
| 22:09:16 | -00h 45m | Titan atmospheric observations - CIRS. Vertical temperature sounding of Titan's tropopause & stratosphere. Slow radial scans |
| 22:38:14 | -00h 16m | Earth occultation, 15 minute duration |
| 22:40:22 | -00h 14m | Solar occultation, 12 minute duration |
| 22:44:16 | -00h 10m | Titan atmospheric observations - CIRS. Hi-res closest approach science |
| 22:54:15 | +00 h00m | Titan-54 fly-by Closest Approach Time Altitude = 3244 km, speed = 5.8 km/s, 146° phase at closest approach |
| 23:13:13 | +00 h19m | Descending ring plane crossing |
| 23:19:16 | +00 h25m | Titan surface observations - ISS. Monitoring for surface/atmosphere changes; attempt to see surface colour variations; monitor limb hazes, 1-3 km/px |
6 May 2009
| Time UTC | Time wrt T-54 |
Activity |
| 00:54:16 | +02h 00m | Titan atmospheric observations - UVIS. EUV/FUV imaging of Titan |
| 07:54:16 | +09h 00m | Titan atmospheric observations - CIRS. Obtain information on CO, HCN, CH4. Integrate on disk at airmass 1.5-2.0 |
| 12:54:16 | +14h 00m | Titan surface observations - VIMS. Global map of Titan |
| 21:21:16 | +22h 27m | Deadtime, 14 minutes and 44 seconds long. Used to accommodate changes in fly-by time |
| 21:36:00 | +22h 42m | Turn to Earth-line |
| 22:16:00 | +23h 22m | Playback of T54 data. Goldstone 70m ground station |
Last Update: 1 September 2019