1. XM Status, Priorities and Plans, XXM Activities Icy Satellite Science
C. J. Hansen, A. Hendrix, D. Shemansky
5 January 2010

2. XM Status, Priorities, Plans
Upcoming icy satellite flybys
Still polishing icy satellite flyby timelines
Rev Rhea 1 March (c/a ~ 900 km)
no UVIS primes
Rev Dione 6 April (c/a ~ 1000 km)
One UVIS prime observation
Close Enceladus flybys on revs 120, 121, 130, 131
Rev November 2 - acquired
Rev November 21 - no close-in prime observations
Rev April 28 - simplified to RSS gravity only
Rev May 18
Rev 120 has high resolution UVIS observation of plume with Saturn in the background, acquired
Solar occ on Rev 131
Continuing to collect icy satellite observations: ICYLONs, ICYMAPs, ICYECLs, ICYATMs, ICYOCCs…

3. Rev 129 Dione ICYMAP

4. XM Enceladus Flybys
March 12, 2008

5. Rev 120
Enceladus’ Plume against Saturn

6. Rev 131, Latest Trajectory
We have the opportunity to observe an occultation of the sun on Rev 131
New trajectory brings the sun much closer to Enceladus’ limb
New results are in the EUV, which gives us access to a different wavelength range than the FUV
The big scientific payoff is the chance to definitively detect / measure nitrogen in the plume - important for models of chemistry-driven dynamics in the interior

7. XXM 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

8. SOST Occultation PIEs 16 occultations requested total
SOST accepted all of these as PIEs
now going through integration process with other TWTs
have gotten 4 of 5 requests to-date
Lost Rhea ring occ on Rev 135 due to trajectory changes
This will remain a hazard for all of XXM
Big question raised at our last UVIS team meeting was whether we were over-subscribing our HSP life
Josh analyzed this collection of occultations and calculates 3 x 108 counts, well within the budget of 1.5 x 109 counts allocated for icy satellite occultations at last team meeting

9. XXM Status (cont.) Enceladus flyby allocations
Requested assignment of Enceladus flyby on 19 October 2011 for dual stellar occultation
No contest
Starting to work on Rev 136 Enceladus

10. Solstice Mission Enceladus Flybys

11. Backup Slides

12. XXM SM7a Tweak
Opportunity for dual stellar occ by Enceladus’ plume tweaked in,
19 October 2011, epsilon Orionis (blue) and zeta Orionis (white)