Upcoming Events
C. J. Hansen
13 June 2007
Tour Status
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S31 Sequence is executing, just past periapse of Rev 46
– Period = 16.3 days
– Inclination = 18.40
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Flight s/w update in the fall, Rev 50 apoapsis
– Lost 5 system scans, 4 EUV/FUV’s, and ride-along on ISS ApoMovie
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The s/c is finishing the series of 180 transfer orbits
– 22 July 2006 to 30 June 2007
– Rev 26 to Rev 47
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Next is a pair of near equatorial orbits that enable us to get some icy
satellite flybys and Iapetus
– Rev 48 and Rev 49
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Then we start the series of Titan flybys that take us up to high
inclination
Reference Tour Potential Tweaks
– Enceladus solar occultation
• On the Mission Planning list to be considered (other candidate is EN061)
Just finishing 180 Transfer Orbits
The sun is to the right
Next are the equatorial orbits
Then we start the march to high inclination
Primary Mission Timeline
Titan Flybys in Second Half of 2007
T32
13 June
975
UVIS solar occ ingress, INMS
T33
29 June
1948
RSS earth occultation
T34
19 July
1322
RSS bistatic, VIMS surface coverage
T35
31 August
3302
UVIS stellar occ (sigma Sag), VIMS
T36
2 October
975
Radar, INMS
T37
19 November
1000
CIRS limb scan, INMS, VIMS surface coverage
T38
5 December
1300
ORS southern hemisphere (was RSS gravity)
T39
20 December
970
Radar
T40
5 January
1010
UVIS stellar occ, INMS, VIMS surface
Upcoming Icy Satellite Flybys
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Tethys
Methone
Mimas
Enceladus
Prometheus
Helene
Tethys
Rhea
Iapetus
Dione
Enceladus
Rhea
Mimas
Epimethius
Rev 47
Rev 47
Rev 47
Rev 47
Rev 47
Rev 48
Rev 49
Rev 49
Rev 49
Rev 50
Rev 50
Rev 52
Rev 53
Rev 53
June 27
June 27
June 27
June 28
June 28
July 20
August 29
August 30
Sept. 10
Sept. 30
Sept. 30
Nov. 16
Dec. 3
Dec. 3
15,851 km
12,636
91,806
90,671
41,930
27,920
47,197
5,126
1,229
60,832
83,108
74,327
79,436
6,364
Saturn, Ring Solar Occs
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Saturn, Rings
Saturn
Saturn
Saturn
Saturn
Saturn, Rings
Saturn, Rings
Saturn, Rings
Rev 46
Rev 47
Rev 50
Rev 51
Rev 52
Rev 53
Rev 54
Rev 55
June 11
June 27
Sept. 30
Oct. 24
Nov. 17
Dec. 3
Dec. 19
Jan. 3
At our next meeting I will be previewing the last 6 months of the primary
mission…
Looking Waaayyyy Ahead
Soon it will be time to design the extended extended mission, XXM
– Activity may start as soon as January 2008
• Put on agenda for our next UVIS team meeting
– Kickoff likely to be at the October 2007 PSG!
Serious science choices to be made:
• Do we go after long duration?
– Three Titan flybys / year for 5 years?
• Do we want to come up out of the equatorial plane
occasionally?
• Do we want to fly cyclers to get numerous Enceladus flybys?
What is a Cycler?
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Study led by Ryan Russell (slides are from his analysis), aided by Nathan
Strange and Brent Huffington
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A cycler is a perfectly repeatable orbit that shuttles a s/c between 2 or more
bodies indefinitely with little / no expenditure of fuel
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Delta v is required to match the v-infinity for a given cycler
Periodic orbit in any frame with a repeating geometry between a primary body
and associated orbiting bodies
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Sun - Earth - Mars
Saturn - Titan - Enceladus
Jupiter - Io - Europa
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Can get 3-5 Enceladus flybys per year
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Can get 8-12 Titan flybys per year
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But always see same territory on Titan within a given cycler
Can skip from one cycler to another to get different territory (spend delta-v to change vinfinity)