1. XXM Status, Priorities, Plans, and Activities Icy Satellite Science
C. J. Hansen, A. Hendrix
January 2014

2. XXM Status Icy satellite observations executed since last team meeting
Enceladus plume observations
Low phase observations of Mimas, Enceladus, Tethys and Dione
Iapetus gamma Ori occultation
We have no PIEs in 2014

3. Satellite Flyby Hiatus

4. Proximal Mission Phase Priorities
Two more potential Enceladus stellar occs in the future
One is equatorial
22 June :19 Rev 280 Mean anomaly = 116
The other requires a trajectory tweak – occ rayheight is currently 3000 km)
11 March :57 Rev Mean anomaly = 220
Approved
The other main priority for UVIS are the Dione stellar occ opportunities
MAG sees mass-loading in the magnetosphere at ~7 kg/sec (Enceladus supplies ~200 kg/sec)
Dione plume won’t go as high or lose as much gas (escape velocity is higher because Dione is larger, gravity higher)

5. Locations to-date plus planned
Circles are ~250 km radius; red is new data

6. Solstice Mission Enceladus Flybys
All Enceladus flyby’s in XXM have executed except E21
E20 and E22 are relatively distant flybys on Rev 223 and Rev 228, resp., in 2015

7. Case 7a

8. Occultations in F Ring and Proximal Orbits
24 Dione occultation opportunities
12 Rhea occultation opportunities
When will we start scheduling PIEs?

9. Backup

10. Reference Trajectory Schedule
April 2013 Discuss Enceladus occultation with scientists May 2013 Gather initial feedback from science teams June 2013 Release of Enceladus occultation study for Summer PSG June/July 2013 Release of proximal orbits trade space October 2013 PSG decides on proximal orbit and approves Enceladus occultation trajectory January 2014 Preliminary release of reference trajectory March 2014 Final release of reference trajectory; covers remainder of tour

11. System Scans - Summary of Request
June 2012
OR August hr
August hr
August hr
January resume 4 per year 64 hr cadence

12. Hello Helene!
Helene is Dione’s leading co-orbital; one of 4 of Saturn’s moons in the Lagrangian L4 point
Phoebe-size: 36 x 32 x 30 km
Sub-Saturnian side
36x32x30 km (like Phoebe), imaged June 18 from 7000 km

13. XXM Planning Status Requested PIEs for all occultations by:
Dione and Tethys
Look for volatiles being released, supplying E ring
Rhea
Look for rings or other evidence of volatile release
15 occs requested
8 in as occ PIEs
2 “in” SOST but in conflict
4 out
1 not scheduled yet
Iapetus in apoapsis Rev 196
Now looking at occs in proximal orbit