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Space Forum / Space History / July 2004Cassini orbit
Anywhere I can find information on the Cassinni orbit? How will it avoid the rings? Or is it entirely outside the rings? -- Gene Seibel Space Ship One - http://pad39a.com/gene/ss1.html Because I fly, I envy no one - except Mike Melvill. > Anywhere I can find information on the Cassinni orbit? How will it > avoid the rings? Or is it entirely outside the rings? In the public domain, you can download the Cassini-Huygens Saturn Arrival Press Kit at http://saturn.jpl.nasa.gov/news/press-kits/cassini-arrival.pdf Note the Periapsis Raise Maneuver baselined for August 23, 2004.  SignatureAlex R. Blackwell University of Hawaii > Anywhere I can find information on the Cassinni orbit? How will it > avoid the rings? Or is it entirely outside the rings? Go to http://saturn.jpl.nasa.gov/news/press.cfm and download the PDF "Cassini-Huygens Saturn Arrival". On page 39 there's a diagram that charts the first few orbits. It will be outside the rings. They plan to make 77 orbits over the next 4 years, giving an _average_ orbital period of almost 3 weeks. _Average_ is the operative word here since they'll be tweaking almost every orbit individually. It's highly elliptical. Signaturebp Proud Member of the Human O-Ring Society Since 2003 (brucepalmero at gmail dot com (remove last 'o')) http://www.esa.int/SPECIALS/Cassini-Huygens/SEMD6E2VQUD_0.html shows all the orbits for the next 4 years > Anywhere I can find information on the Cassinni orbit? How will it > avoid the rings? Or is it entirely outside the rings? > -- > Gene Seibel > Space Ship One - http://pad39a.com/gene/ss1.html > Because I fly, I envy no one - except Mike Melvill. > http://www.esa.int/SPECIALS/Cassini-Huygens/SEMD6E2VQUD_0.html shows all the > orbits for the next 4 years Thanks, Vic, but where exactly? After clicking dozens of links for an hour the closest thing I found was a chart that listed the flybys of the moons and the orbits where they occur. Were you referring to something else? Signaturebp Proud Member of the Human O-Ring Society Since 2003 > Thanks, Vic, but where exactly? After clicking dozens of links for an > hour the closest thing I found was a chart that listed the flybys of the > moons and the orbits where they occur. Were you referring to something > else? Are you looking for, say, a petal plot graphic of the T18-5 tour? There are a few available publicly; however, the ones I've seen are not annotated. I've seen several other types of graphical representations of the tour, with different perspectives, including 3-D animations, that simultaneously show the targeted and non-targeted encounters, though I don't believe these in the public domain. SignatureAlex R. Blackwell University of Hawaii >>Thanks, Vic, but where exactly? After clicking dozens of links for an >>hour the closest thing I found was a chart that listed the flybys of the [quoted text clipped - 4 lines] > are a few available publicly; however, the ones I've seen are not > annotated. I was responding to Gene primarily but when I saw Vic's post I thought it might be worth checking out. > I've seen several other types of graphical representations of the tour, > with different perspectives, including 3-D animations, that > simultaneously show the targeted and non-targeted encounters, though I > don't believe these in the public domain. For the last few years I checked the JPL page that tracked "Where Is Cassini Now?" maybe once a week or so. Now that you mention it, it would be nice to have a 3D representation of where it is with respect to the planet itself, its rings and the larger moons. I've had bad experiences in the past with VRML. My last foray into that area was during Mars Pathfinder I think. The issue might have been the speed of my computer (or lack thereof). In contrast, I've had good experience with STSPlus for following Shuttle flights. With the relatively long orbital period it shouldn't be too resource intensive to track Cassini around Saturn. Hopefully they'll release more data on their websites in the next few months. Signaturebp Proud Member of the Human O-Ring Society Since 2003 > For the last few years I checked the JPL page that tracked "Where Is > Cassini Now?" maybe once a week or so. Now that you mention it, it > would be nice to have a 3D representation of where it is with respect to > the planet itself, its rings and the larger moons. Since the Cassini orbital tour is so complex, an annotated 3-D simulation is probably the best, if not easiest, way to understand it. While not for public consumption, at least yet, Cassini Mission Planning also makes flyby movie animations for significant milestones; indeed, the one for the Phoebe flyby was about 45 Mb in size and showed the FOVs of the ISS NAC, ISS WAC, CIRS, and RADAR. It was pretty cool and really imparted a sense of the intricate ballet (rolling and slewing) to accommodate the various observation requirements. BTW, the T0 observations are underway. The real time plot shows the VIMS observing Titan's south polar regions. SignatureAlex R. Blackwell University of Hawaii > BTW, the T0 observations are underway. The real time plot shows the > VIMS observing Titan's south polar regions. I'm really looking forward to the Titan images! Pat >> BTW, the T0 observations are underway. The real time plot shows the >> VIMS observing Titan's south polar regions. > >I'm really looking forward to the Titan images! ...Who isn't? OM Signature"No bastard ever won a war by dying for | http://www.io.com/~o_m his country. He won it by making the other | Sergeant-At-Arms poor dumb bastard die for his country." | Human O-Ring Society - General George S. Patton, Jr > I'm really looking forward to the Titan images! I am, too. The ISS NAC IRP0/CB3 filter (centered on the 938nm bandpass - a "methane window") should offer much higher resolution of Titan surface features (2-3 km/pxl) than was had during the approach phase. Already, many of my colleagues feel that the predictions of a global Titan ethane ocean are being laid to rest, since there is too much heterogeneity in the imagery to make that plausible. "Seas" or "lakes" are still a possibility, and a good explanation for the specular reflections in the Arecibo radar data (Campbell et al., 2003) is still needed. Maybe the first close flyby of Titan (Ta) on October 26, 2004 will answer this. At least Cassini RADAR will join in on the fun ;-) BTW, CIRS is now viewing the terminator on Titan; earlier the instrument was trained on Titan's south polar limb. SignatureAlex R. Blackwell University of Hawaii > I am, too. The ISS NAC IRP0/CB3 filter (centered on the 938nm bandpass > - a "methane window") should offer much higher resolution of Titan [quoted text clipped - 4 lines] > "lakes" are still a possibility, and a good explanation for the > specular reflections in the Arecibo radar data I sure hope so, those would be fascinating to study... the weather patterns on the moon would be interesting to observe also ...although the weather might not be too dynamic given the fact that it orbits with one face perpetually facing Saturn in a area of the solar system with little solar energy to heat its surface and atmosphere. > (Campbell et al., 2003) is still needed. Maybe the first close flyby > of Titan (Ta) on October 26, 2004 will answer this. At least Cassini > RADAR will join in on the fun ;-) > > BTW, CIRS is now viewing the terminator on Titan; earlier the > instrument was trained on Titan's south polar limb. If you are going to see and cloud movement, the terminator would be a very good place to start looking. I hope that Titan gives us as many surprises as Io and Triton did. Given those Arecibo radar images, and the recent Very Large Telescope optical images of it, that may very well be the case. It will be fun to see how the Cassini imaging relates to the VLT map of the surface: http://www.rednova.com/news/images/1/2004/04/14/titan_16big_surface_features_eso.jpg Pat > I hope that Titan gives us as many surprises as Io and Triton did. It looks like it might. The T0 ISS imagery are on the ground and being processed, and I believe the raw ISS data are online. There's a great deal of haze in the atmosphere, which is complicating processing, even in the spectral "windows" to the surface, though some of my colleagues are pulling out some interesting surficial details. No rest for the weary, I'm afraid. After the T0 downlink, Cassini went back to work with distant observations of the icy satellites. In fact, as I write this, the ISS NAC is trained on Mimas. SignatureAlex R. Blackwell University of Hawaii >> I hope that Titan gives us as many surprises as Io and Triton did. > > It looks like it might. The T0 ISS imagery are on the ground and being > processed, and I believe the raw ISS data are online. They are indeed. Any guesses on what the big white blotches are? http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS02/N00006548.jpg > There's a great > deal of haze in the atmosphere, which is complicating processing, even > in the spectral "windows" to the surface, though some of my colleagues > are pulling out some interesting surficial details. Best of luck to them. > No rest for the weary, I'm afraid. After the T0 downlink, Cassini > went back to work with distant observations of the icy satellites. In > fact, as I write this, the ISS NAC is trained on Mimas. More than I ever managed, as an undergraduate... two months in a freezing dome until after closing time, two photographs of Mimas, maybe, if you squint... bah. Much easier on the fingers this way ;-) Signature-Andrew Gray andrew.gray@dunelm.org.uk > They are indeed. Any guesses on what the big white blotches are? Yes ;-) And there are more than a few friendly wagers being made by members on various Cassini science teams, though I'm not sure when the winners are supposed to collect. Maybe at the next Project Science Group meeting. At any rate, I'm still waiting to collect from a bet I won regarding the *Jupiter* flyby. SignatureAlex R. Blackwell University of Hawaii >> They are indeed. Any guesses on what the big white blotches are? > [quoted text clipped - 3 lines] > Group meeting. At any rate, I'm still waiting to collect from a bet I > won regarding the *Jupiter* flyby. If the guys over at the Large Optical Telescope are right, they could be ice deposits on the tops of mountains. (methane ice?) Pat > If the guys over at the Large Optical Telescope are right, they could be > ice deposits on the tops of mountains. (methane ice?) I don't understand all the chemistry of the hydrocarbon mix, but wouldn't the ice be at a lower temperature than the surrounding areas? I ask because many of the recent pictures were taken with infrared filters and I thought the whiter areas would indicate warmer material. They do look like snow-covered mountain peaks though. They could also be upwellings of liguid from the interior. A slushy volcano maybe. Signaturebp Proud Member of the Human O-Ring Society Since 2003 >I don't understand all the chemistry of the hydrocarbon mix, but >wouldn't the ice be at a lower temperature than the surrounding areas? >I ask because many of the recent pictures were taken with infrared >filters and I thought the whiter areas would indicate warmer material. >They do look like snow-covered mountain peaks though. They could also >be upwellings of liguid from the interior. A slushy volcano maybe. Here's where I got the ice idea from: http://www.rednova.com/news/stories/1/2004/04/14/story003.html Pat > I don't understand all the chemistry of the hydrocarbon mix, but > wouldn't the ice be at a lower temperature than the surrounding areas? > I ask because many of the recent pictures were taken with infrared > filters and I thought the whiter areas would indicate warmer material. > They do look like snow-covered mountain peaks though. They could also > be upwellings of liguid from the interior. A slushy volcano maybe. Yes, it "light" and "dark" interpretations of Titan surface features seems to be, shall we say, in a state of flux and uncertainty at the present moment. Indeed, I've seen no less than three different models proposed in the last two days ;-) SignatureAlex R. Blackwell University of Hawaii > Yes, it "light" and "dark" interpretations of Titan surface features > seems to be, shall we say, in a state of flux and uncertainty at the > present moment. Indeed, I've seen no less than three different models > proposed in the last two days ;-) Anyone had a peek at those Voyager shots of Cassini Regio on Iapetus yet? If the dark features are primarily on the leading hemisphere of Titan, then the Iapetus images might be interesting. Pat > Anyone had a peek at those Voyager shots of Cassini Regio on Iapetus > yet? If the dark features are primarily on the leading hemisphere of > Titan, then the Iapetus images might be interesting. Interestingly, Cassini performed some long distance observations of Iapetus yesterday before beginning the first solar conjunction of the tour (July 4-11, 2004). However, the best views of Iapetus since Voyager should come next New Year's Day when Cassini performs a non-targeted flyby at ~55,219 km, which, of course, is only an appetizer before the main course, an ~1,407 km targeted encounter on September 10, 2007. SignatureAlex R. Blackwell University of Hawaii > Interestingly, Cassini performed some long distance observations of > Iapetus yesterday before beginning the first solar conjunction of the [quoted text clipped - 3 lines] > before the main course, an ~1,407 km targeted encounter on September 10, > 2007. The Voyager 2 Iapetus flyby was just under 1 million km. The Cassini B/C flyby should return much higher resolution images than Voyager. From the Cassini flyby geometry, the flyby speed appears to be lower, affording more time for observations by all the instruments. One thing I really miss from the Voyager flybys was the "live" monitor on NASA TV of raw images after reception and processing. It was just image after image sans commentary. At Saturn, they came in at around 1 image every 40 seconds, IIRC. I remember sitting in a Pasadena civic auditorium meeting room with about 20 other space junkies at 4:30 AM watching the Triton "cantelope" images come in. (This was at the Planetary Society "Planetfest" event for the Neptune encounter.) Being among the first humans to see a new world was a treasured experience. We can get the raw images today on the web, but they are posted in batches and don't convey the immediacy that "live" TV did with images appearing serially after they were received and processed. The working press probably still get to see this presentation. NASA should re-consider putting the raw images on NASA TV. BTW, is there an online reference for the non-targeted flybys with dates and distances? > BTW, is there an online reference for the non-targeted flybys with > dates and distances? Cassini Mission Planning (MP) may release a new tour reference trajectory that might change some of the values slightly, but below are two tables. One is for non-targeted icy satellite flybys, the other for non-targeted "rock" satellite flybys. Reading from left to right, the columns are: Orbit, Satellite, Flyby Date, Flyby Distance (km), and Flyby Altitude (km). Non-targeted Icy Satellite Flybys 00 Enceladus 2004 JUL 01 233900.18 233647.84 00 Tethys 2004 JUL 01 215224.98 214689.53 00 Dione 2004 JUL 01 300671.72 300111.72 00 Rhea 2004 JUL 01 441329.41 440565.41 00 Hyperion 2004 JUL 03 755965.95 755828.04 0A Mimas 2004 OCT 28 333037.59 332832.33 0A Tethys 2004 OCT 28 246015.38 245487.35 0A Rhea 2004 OCT 28 865974.60 865210.60 0B Tethys 2004 DEC 13 711404.40 710871.74 0B Enceladus 2004 DEC 14 634152.97 633899.76 0B Mimas 2004 DEC 15 115554.78 115347.24 0B Rhea 2004 DEC 15 239200.36 238436.36 0C Hyperion 2005 JAN 14 902678.41 902528.87 0C Mimas 2005 JAN 15 757729.30 757521.78 0C Tethys 2005 JAN 15 669490.08 668957.64 0C Enceladus 2005 JAN 16 189871.86 189624.63 0C Rhea 2005 JAN 16 144130.54 143366.54 0C Dione 2005 JAN 17 847151.91 846591.91 03 Dione 2005 FEB 15 772534.17 771974.17 03 Mimas 2005 FEB 16 607734.08 607527.31 03 Rhea 2005 FEB 17 281052.98 280288.98 03 Tethys 2005 FEB 17 161788.63 161259.62 04 Mimas 2005 MAR 08 403501.75 403296.70 04 Rhea 2005 MAR 09 594790.73 594026.73 04 Dione 2005 MAR 11 843763.57 843203.57 05 Dione 2005 MAR 28 707465.56 706905.56 05 Tethys 2005 MAR 29 116750.02 116221.64 05 Mimas 2005 MAR 30 152380.72 152182.91 05 Rhea 2005 MAR 30 141553.35 140789.35 06 Hyperion 2005 APR 10 718397.77 718254.30 06 Tethys 2005 APR 13 739977.34 739444.39 06 Rhea 2005 APR 14 243051.28 242287.28 06 Enceladus 2005 APR 14 355596.85 355342.45 06 Dione 2005 APR 15 208391.49 207831.49 06 Mimas 2005 APR 16 758014.88 757807.24 07 Hyperion 2005 MAY 01 792799.56 792677.31 07 Mimas 2005 MAY 02 319679.95 319480.77 07 Rhea 2005 MAY 02 445766.69 445002.69 07 Enceladus 2005 MAY 02 258833.46 258583.40 07 Dione 2005 MAY 04 903482.95 902922.95 08 Dione 2005 MAY 19 862025.90 861465.90 08 Rhea 2005 MAY 20 385093.60 384329.60 08 Mimas 2005 MAY 21 438810.17 438605.17 08 Hyperion 2005 MAY 22 992400.65 992263.32 08 Tethys 2005 MAY 22 795270.33 794736.52 09 Rhea 2005 JUN 08 318194.57 317430.57 09 Dione 2005 JUN 08 132325.76 131765.76 09 Mimas 2005 JUN 08 157755.05 157557.64 09 Enceladus 2005 JUN 08 386164.46 385910.93 09 Tethys 2005 JUN 08 206768.29 206239.65 09 Hyperion 2005 JUN 10 166644.29 166504.06 10 Rhea 2005 JUN 26 245693.99 244929.99 10 Mimas 2005 JUN 26 255777.28 255579.00 10 Tethys 2005 JUN 26 187232.32 186703.19 10 Enceladus 2005 JUN 26 407436.74 407182.35 10 Dione 2005 JUN 28 963640.46 963080.46 11 Dione 2005 JUL 13 836471.68 835911.68 11 Rhea 2005 JUL 14 179561.55 178797.55 11 Mimas 2005 JUL 15 422028.57 421823.36 11 Tethys 2005 JUL 16 823579.63 823045.71 12 Mimas 2005 JUL 31 788085.12 787880.42 12 Rhea 2005 AUG 01 204995.35 204231.35 12 Dione 2005 AUG 02 145053.35 144493.35 12 Enceladus 2005 AUG 02 373995.60 373742.53 12 Tethys 2005 AUG 02 238960.20 238430.96 13 Hyperion 2005 AUG 17 601809.84 601648.10 13 Mimas 2005 AUG 19 393168.77 392967.72 13 Rhea 2005 AUG 20 253314.53 252550.53 13 Tethys 2005 AUG 20 133592.82 133064.20 13 Enceladus 2005 AUG 20 407813.19 407558.78 13 Dione 2005 AUG 22 936189.96 935629.96 14 Tethys 2005 SEP 04 751538.87 751006.68 14 Mimas 2005 SEP 04 443035.17 442832.00 14 Enceladus 2005 SEP 05 324812.52 324559.62 15 Dione 2005 SEP 22 735295.16 734735.16 15 Mimas 2005 SEP 22 737078.42 736870.77 15 Enceladus 2005 SEP 23 264905.55 264654.92 16 Tethys 2005 OCT 11 274729.68 274199.23 16 Dione 2005 OCT 13 664649.77 664089.77 16 Hyperion 2005 OCT 17 936584.64 936449.66 17 Dione 2005 OCT 27 967950.22 967390.22 17 Mimas 2005 OCT 28 862520.01 862311.95 17 Enceladus 2005 OCT 29 190888.41 190640.84 17 Tethys 2005 OCT 30 375577.76 375046.41 17 Iapetus 2005 NOV 12 415474.98 414756.98 18 Tethys 2005 NOV 26 647391.79 646859.38 18 Mimas 2005 NOV 26 435900.62 435694.54 18 Enceladus 2005 NOV 27 108820.09 108572.48 18 Dione 2005 NOV 28 580597.98 580037.98 18 Hyperion 2005 NOV 29 748527.28 748388.47 19 Hyperion 2005 DEC 23 225135.86 224990.77 19 Dione 2005 DEC 24 153179.71 152619.71 19 Rhea 2005 DEC 24 200337.85 199573.85 19 Tethys 2005 DEC 24 177975.24 177446.84 19 Mimas 2005 DEC 25 412815.79 412610.11 20 Hyperion 2006 JAN 13 786743.54 786617.08 20 Dione 2006 JAN 15 987722.69 987162.69 20 Mimas 2006 JAN 16 396759.43 396553.15 20 Enceladus 2006 JAN 17 146760.09 146508.82 20 Rhea 2006 JAN 17 183987.88 183223.88 20 Tethys 2006 JAN 19 958740.67 958206.81 20 Iapetus 2006 JAN 25 877438.52 876720.52 21 Hyperion 2006 FEB 23 580865.10 580707.70 21 Mimas 2006 FEB 24 724438.65 724231.44 21 Rhea 2006 FEB 24 224946.01 224182.01 21 Tethys 2006 FEB 25 130500.20 129971.87 21 Dione 2006 FEB 26 657753.15 657193.15 22 Hyperion 2006 MAR 16 811526.15 811394.56 22 Dione 2006 MAR 19 900643.56 900083.56 22 Mimas 2006 MAR 21 192777.83 192570.33 22 Tethys 2006 MAR 22 754083.84 753550.56 23 Iapetus 2006 APR 11 605167.65 604449.65 23 Hyperion 2006 APR 27 469839.52 469670.74 23 Enceladus 2006 APR 28 479293.34 479040.89 23 Mimas 2006 APR 28 387566.46 387360.81 23 Rhea 2006 APR 28 452823.90 452059.90 23 Dione 2006 APR 30 781716.86 781156.86 24 Hyperion 2006 MAY 17 881860.83 881704.41 24 Dione 2006 MAY 20 792294.26 791734.26 24 Mimas 2006 MAY 21 307140.64 306935.35 24 Rhea 2006 MAY 22 197747.07 196983.07 24 Enceladus 2006 MAY 23 589872.46 589619.17 25 Hyperion 2006 JUN 28 291652.11 291482.02 25 Tethys 2006 JUN 29 758957.52 758424.72 25 Rhea 2006 JUN 30 650003.54 649239.54 25 Enceladus 2006 JUN 30 169579.83 169330.09 25 Mimas 2006 JUL 01 812130.69 811922.59 25 Dione 2006 JUL 02 892083.81 891523.81 26 Hyperion 2006 JUL 18 966380.89 966201.20 26 Dione 2006 JUL 22 680707.41 680147.41 26 Rhea 2006 JUL 23 166146.51 165382.51 26 Tethys 2006 JUL 23 120223.14 119695.91 26 Enceladus 2006 JUL 23 269979.32 269729.89 26 Mimas 2006 JUL 24 315775.53 315572.86 27 Dione 2006 AUG 16 134497.36 133937.36 27 Enceladus 2006 AUG 16 411627.84 411374.72 27 Rhea 2006 AUG 17 164330.67 163566.67 27 Mimas 2006 AUG 17 696158.34 695952.19 27 Tethys 2006 AUG 18 732742.65 732210.42 28 Mimas 2006 SEP 09 347042.24 346832.70 28 Rhea 2006 SEP 09 633127.46 632363.46 28 Dione 2006 SEP 11 971323.61 970763.61 29 Hyperion 2006 SEP 19 789915.97 789771.81 29 Mimas 2006 SEP 25 480223.85 480019.68 29 Tethys 2006 SEP 25 367243.01 366712.62 29 Enceladus 2006 SEP 25 283781.03 283531.97 29 Rhea 2006 SEP 25 296937.01 296173.01 30 Dione 2006 OCT 09 873852.85 873292.85 30 Hyperion 2006 OCT 10 774779.28 774634.09 30 Tethys 2006 OCT 10 546943.17 546411.25 30 Mimas 2006 OCT 13 881903.02 881705.43 31 Enceladus 2006 OCT 27 475144.77 474895.94 31 Dione 2006 OCT 28 476424.35 475864.35 31 Rhea 2006 OCT 28 274858.91 274094.91 32 Rhea 2006 NOV 08 359751.12 358987.12 32 Dione 2006 NOV 08 522231.82 521671.82 32 Tethys 2006 NOV 09 197049.02 196519.90 34 Dione 2006 NOV 30 821705.64 821145.64 34 Rhea 2006 DEC 03 220248.02 219484.02 35 Hyperion 2006 DEC 12 740559.62 740400.35 35 Rhea 2006 DEC 14 552978.48 552214.48 35 Dione 2006 DEC 15 279401.50 278841.50 36 Rhea 2006 DEC 27 895679.02 894915.02 36 Enceladus 2007 JAN 01 623936.91 623684.11 39 Rhea 2007 FEB 22 670770.38 670006.38 41 Enceladus 2007 MAR 22 474822.18 474566.65 41 Dione 2007 MAR 22 295376.91 294816.91 41 Rhea 2007 MAR 25 591179.40 590415.40 42 Tethys 2007 APR 08 343802.01 343270.52 42 Mimas 2007 APR 08 414677.49 414470.17 42 Dione 2007 APR 08 142071.40 141511.40 42 Hyperion 2007 APR 11 724525.02 724387.67 43 Rhea 2007 APR 24 263707.01 262943.01 43 Dione 2007 APR 24 101426.05 100866.05 43 Tethys 2007 APR 25 448352.74 447822.64 43 Hyperion 2007 MAY 02 923158.13 923002.38 44 Tethys 2007 MAY 09 710439.40 709912.16 44 Dione 2007 MAY 10 235264.55 234704.55 44 Mimas 2007 MAY 10 235356.78 235159.54 45 Hyperion 2007 MAY 24 806676.22 806546.67 45 Mimas 2007 MAY 26 125268.34 125070.49 45 Rhea 2007 MAY 27 177100.34 176336.34 45 Dione 2007 MAY 28 833203.80 832643.80 46 Tethys 2007 JUN 10 773783.48 773251.61 46 Rhea 2007 JUN 11 251913.80 251149.80 46 Mimas 2007 JUN 11 103968.85 103770.70 46 Enceladus 2007 JUN 12 303287.40 303035.20 46 Hyperion 2007 JUN 14 589227.48 589103.63 47 Rhea 2007 JUN 28 106501.29 105737.29 48 Mimas 2007 JUL 19 767251.75 767044.40 48 Tethys 2007 JUL 20 117129.23 116600.79 48 Rhea 2007 JUL 21 610352.18 609588.18 48 Enceladus 2007 JUL 21 470385.71 470133.17 48 Dione 2007 JUL 22 687137.51 686577.51 48 Hyperion 2007 JUL 23 329380.02 329251.51 49 Dione 2007 AUG 28 734785.97 734225.97 49 Mimas 2007 AUG 29 227555.19 227349.51 49 Enceladus 2007 AUG 30 482764.79 482512.17 50 Tethys 2007 SEP 30 125175.52 124647.34 50 Mimas 2007 SEP 30 139749.08 139544.33 50 Rhea 2007 SEP 30 189210.62 188446.62 51 Hyperion 2007 OCT 21 117106.77 116970.00 51 Enceladus 2007 OCT 23 557388.48 557136.03 51 Mimas 2007 OCT 23 428797.38 428592.59 51 Tethys 2007 OCT 25 782016.68 781483.21 51 Dione 2007 OCT 26 864560.43 864000.43 52 Hyperion 2007 NOV 11 870159.39 870025.15 52 Mimas 2007 NOV 16 718722.65 718515.63 52 Tethys 2007 NOV 16 600523.67 599991.77 52 Enceladus 2007 NOV 17 119186.51 118939.14 53 Hyperion 2007 DEC 01 444348.31 444209.72 53 Dione 2007 DEC 01 946132.17 945572.17 53 Tethys 2007 DEC 03 166688.25 166159.15 53 Enceladus 2007 DEC 03 361164.86 360910.16 53 Rhea 2007 DEC 03 429836.77 429072.77 54 Rhea 2007 DEC 19 296359.46 295595.46 54 Enceladus 2007 DEC 19 190141.76 189894.00 54 Tethys 2007 DEC 19 172714.22 172186.57 54 Dione 2007 DEC 19 155048.11 154488.11 54 Mimas 2007 DEC 19 359983.61 359780.67 54 Hyperion 2007 DEC 21 551813.86 551684.23 55 Dione 2008 JAN 03 123460.53 122900.53 55 Tethys 2008 JAN 05 754575.50 754041.61 56 Hyperion 2008 JAN 11 796497.10 796352.94 56 Tethys 2008 JAN 15 156335.05 155803.94 56 Mimas 2008 JAN 15 168230.16 168031.41 56 Enceladus 2008 JAN 16 404202.06 403948.05 56 Dione 2008 JAN 16 304672.52 304112.52 56 Rhea 2008 JAN 17 547664.27 546900.27 57 Enceladus 2008 JAN 27 200062.79 199812.51 57 Tethys 2008 JAN 28 256999.34 256471.91 57 Dione 2008 JAN 29 884337.54 883777.54 57 Hyperion 2008 JAN 31 375293.75 375145.08 58 Dione 2008 FEB 08 182951.24 182391.24 58 Enceladus 2008 FEB 08 181223.59 180973.80 58 Rhea 2008 FEB 09 361189.46 360425.46 58 Tethys 2008 FEB 10 793715.91 793181.58 59 Rhea 2008 FEB 20 331341.30 330577.30 59 Hyperion 2008 FEB 22 605256.72 605135.54 60 Rhea 2008 MAR 02 363395.94 362631.94 61 Hyperion 2008 MAR 14 625723.23 625585.62 62 Mimas 2008 MAR 23 142492.35 142296.20 63 Hyperion 2008 APR 04 363890.00 363753.92 65 Enceladus 2008 APR 21 451755.36 451502.36 65 Rhea 2008 APR 21 465655.32 464891.32 65 Hyperion 2008 APR 24 462414.26 462235.67 68 Hyperion 2008 MAY 15 889338.10 889165.89 70 Dione 2008 JUN 01 400312.69 399752.69 71 Hyperion 2008 JUN 05 469260.60 469106.96 74 Hyperion 2008 JUN 26 436182.75 436013.38 Non-targeted "Rock" Satellite Flybys 00 Calypso 2004 JUN 30 46986.72 46978.66 00 Pandora 2004 JUL 01 97557.84 97513.04 00 Janus 2004 JUL 01 67782.84 67687.31 03 Pandora 2005 FEB 16 93072.57 93024.34 03 Epimetheus 2005 FEB 17 69828.03 69760.29 03 Calypso 2005 FEB 17 83650.14 83636.02 04 Helene 2005 MAR 09 75923.51 75907.51 05 Epimetheus 2005 MAR 29 61157.93 61097.97 05 Telesto 2005 MAR 30 77969.02 77954.20 06 Epimetheus 2005 APR 15 38277.77 38212.42 06 Calypso 2005 APR 15 72796.93 72788.65 07 Epimetheus 2005 MAY 02 93969.62 93901.40 09 Calypso 2005 JUN 08 97466.39 97455.02 10 Telesto 2005 JUN 26 84229.80 84215.45 11 Epimetheus 2005 JUL 14 76659.72 76595.74 12 Prometheus 2005 AUG 02 89852.99 89787.25 14 Pandora 2005 SEP 05 31510.01 31459.57 15 Calypso 2005 SEP 23 67706.07 67697.99 16 Telesto 2005 OCT 11 10143.55 10131.50 18 Helene 2005 NOV 27 86979.88 86963.88 19 Telesto 2005 DEC 25 18894.00 18880.87 19 Helene 2005 DEC 25 76664.69 76648.69 21 Helene 2006 FEB 25 70853.37 70837.37 26 Telesto 2006 JUL 24 49020.77 49008.26 27 Helene 2006 AUG 17 48602.67 48586.67 43 Telesto 2007 APR 24 98246.01 98233.70 45 Epimetheus 2007 MAY 26 61018.85 60950.29 46 Prometheus 2007 JUN 12 47861.25 47797.83 46 Epimetheus 2007 JUN 12 86470.68 86412.99 47 Prometheus 2007 JUN 28 59221.26 59167.76 47 Epimetheus 2007 JUN 28 96316.52 96260.35 48 Helene 2007 JUL 20 29101.70 29085.70 50 Telesto 2007 SEP 30 81998.03 81986.03 51 Helene 2007 OCT 24 35688.58 35672.58 52 Pandora 2007 NOV 17 88366.72 88314.50 52 Epimetheus 2007 NOV 17 90150.30 90081.70 52 Calypso 2007 NOV 17 94325.17 94313.38 53 Epimetheus 2007 DEC 3, 6249.41 6187.88 57 Prometheus 2008 JAN 27 86092.97 86033.02 59 Prometheus 2008 FEB 20 70971.48 70910.01 59 Pandora 2008 FEB 20 67221.45 67171.25 59 Janus 2008 FEB 20 99240.82 99150.50 60 Prometheus 2008 MAR 02 94562.85 94495.31 62 Epimetheus 2008 MAR 23 83591.65 83536.37 65 Telesto 2008 APR 20 63417.19 63404.08 66 Telesto 2008 APR 30 43699.98 43687.18 69 Janus 2008 MAY 25 72087.48 71998.11 70 Janus 2008 JUN 01 13691.23 13595.89 72 Prometheus 2008 JUN 16 97096.99 97049.65 73 Epimetheus 2008 JUN 23 82155.06 82091.68 74 Prometheus 2008 JUN 30 45232.90 45185.70 74 Janus 2008 JUN 30 66151.36 66060.19 SignatureAlex R. Blackwell University of Hawaii [snip] > Non-targeted Icy Satellite Flybys Impressive lists. Thanks for posting them. The non-targeted icy satellite flybys list contains flybys at distances greater than 100,000 km. I misused the term "non-targeted" in my earlier query for a reference on flybys that are farther than the few thousand km distance for the "close" targeted flybys, but less than 100,000 km. ("Passage to a Ringed World" had a statment that flybys of satellites other than Titan at distances greater than a few thousand km are considered nontargeted flybys. The same reference also states there were 27 such flybys. The reference is old, but is in line with the Cassini-Huygens Saturn Arrival press kit statement of "at least two dozen distant flybys".) I don't have a reference at hand for the Voyager satellite flyby distances, but my recollection is that they were in the range of the two dozen or so Cassini "distant flybys". I am guessing that these Cassini distant flybys will yield observations comparable in quality to Voyager, and may cover satellite regions not well observed by Voyager. Hence, my interest in the dates. To a first order, I understand they must be within a day or two of the Titan flyby dates since all the icy satellites except Iapetus are inside of Titan's orbit. But the objects and distances of the flybys would be of interest in setting the expectations. If you have a list of such flybys and can post the list, it would be greatly appreciated! > Impressive lists. Thanks for posting them. > [quoted text clipped - 3 lines] > the few thousand km distance for the "close" targeted flybys, but less > than 100,000 km. [...] > If you have a list of such flybys and can post the list, it would be > greatly appreciated! Perhaps the table below, which from the latest tour reference trajectory (040622-ref) released by Cassini Mission Planning, may be of help. Reading from left to right the columns are: Encounter, Body, Date (UTC), Altitude [km], and Vinf [km/s]. 0Ph Phoebe 11-Jun-2004 19:33:34 2,068 6.35 0Mi Mimas 01-Jul-2004 00:30:14 76,471 22.32 BDi Dione 15-Dec-2004 02:06:09 80,626 5.26 CIa Iapetus 01-Jan-2005 01:36:33 55,219 2.06 3En Enceladus 17-Feb-2005 03:32:44 1,172 6.73 4En Enceladus 09-Mar-2005 09:06:41 500 6.62 4Te Tethys 09-Mar-2005 11:42:29 83,232 6.92 5En Enceladus 29-Mar-2005 20:36:09 52,354 9.54 6Mi Mimas 15-Apr-2005 01:29:52 84,722 14.26 7Te Tethys 02-May-2005 21:58:59 49,586 9.15 11En Enceladus 14-Jul-2005 19:58:30 1,000 8.12 12Mi Mimas 02-Aug-2005 03:57:01 46,912 6.36 15Te Tethys 24-Sep-2005 01:27:44 32,765 7.66 15Hy Hyperion 26-Sep-2005 01:42:21 1,010 5.62 16Di Dione 11-Oct-2005 18:01:43 500 9.01 16En Enceladus 12-Oct-2005 03:40:55 40,086 6.60 18Rh Rhea 26-Nov-2005 22:40:38 500 7.27 22Rh Rhea 21-Mar-2006 07:32:47 76,014 5.38 28En Enceladus 09-Sep-2006 19:58:23 39,930 10.32 32En Enceladus 09-Nov-2006 01:48:55 94,860 14.14 33Di Dione 21-Nov-2006 02:34:05 72,365 12.28 45Te Tethys 26-May-2007 20:57:11 97,187 11.74 47Te Tethys 27-Jun-2007 19:50:58 15,838 10.22 47Mi Mimas 27-Jun-2007 22:53:36 92,146 16.33 47En Enceladus 28-Jun-2007 01:09:44 90,652 9.42 49Te Tethys 29-Aug-2007 11:22:51 47,355 4.65 49Rh Rhea 30-Aug-2007 01:27:52 5,087 6.71 49Ia Iapetus 10-Sep-2007 12:33:53 1,407 2.36 50Di Dione 30-Sep-2007 06:46:01 60,869 5.54 50En Enceladus 30-Sep-2007 10:58:54 82,941 5.91 52Rh Rhea 16-Nov-2007 19:58:08 74,276 9.04 53Mi Mimas 03-Dec-2007 05:28:32 79,484 14.76 61En Enceladus 12-Mar-2008 19:06:31 100 14.54 74En Enceladus 30-Jun-2008 08:30:40 89,947 21.42 SignatureAlex R. Blackwell University of Hawaii [snip] > Perhaps the table below, which from the latest tour reference trajectory > (040622-ref) released by Cassini Mission Planning, may be of help. [quoted text clipped - 35 lines] > 61En Enceladus 12-Mar-2008 19:06:31 100 14.54 > 74En Enceladus 30-Jun-2008 08:30:40 89,947 21.42 Thanks again for posting this info. I notice the 61En flyby has changed from 995 km in the presskit list to 100 km. I think this will be a new record for closest flyby (non-orbit) of a solar system body. The flyby velocity appears relatively high. Will Cassini be able to slew fast enough to take images without smear at closest approach? (Recalling the Galileo Europa 12 flyby was at 200 km, but the closest image was at ~500 km.) As it appears from having Cassini orbit apoapsis graze Iapetus orbit during the Iapetus flybys, the flyby velocities are low. For a few minutes, I wondered if Cassini could crank the Saturn orbit periapsis up via Titan flybys, then do a really close Iapetus flyby and burn at closest approach to put itself into a highly elliptical orbit around Iapetus. Given that SOI was a 626 m/s delta-v on a 96 minute burn, and the low mass of Iapetus being of little help, there isn't enough propellant to make it. So it can't get there even if it spotted something like a monolith. :) There was a good Mimas flyby just prior to SOI. Too bad Cassini was in its quiet operation period. It's tax day 2005 for close ups of that battle station, er, moon. > I notice the 61En flyby has changed from 995 km in the presskit list > to 100 km. I think this will be a new record for closest flyby > (non-orbit) of a solar system body. The flyby velocity appears > relatively high. Will Cassini be able to slew fast enough to take > images without smear at closest approach? (Recalling the Galileo > Europa 12 flyby was at 200 km, but the closest image was at ~500 km.) 61En will be quite challenging and pixel smear, which happened with some of the Phoebe imagery, is a definite risk. However, colleagues on the ISS team feel confident they can handle it, especially since they got a good handle on Cassini's pointing stability and target tracking characteristics during the Phoebe flyby. SignatureAlex R. Blackwell University of Hawaii >I notice the 61En flyby has changed from 995 km in the presskit list >to 100 km. ...I heard a squeak about this one. It may be a typo, with the actual flyby having been rounded off to 1000km and not 100. OM Signature"No bastard ever won a war by dying for | http://www.io.com/~o_m his country. He won it by making the other | Sergeant-At-Arms poor dumb bastard die for his country." | Human O-Ring Society - General George S. Patton, Jr > ...I heard a squeak about this one. It may be a typo, with the actual > flyby having been rounded off to 1000km and not 100. No, it's not a typo. 100 km is the current estimate for C/A during 61En. SignatureAlex R. Blackwell University of Hawaii > I notice the 61En flyby has changed from 995 km in the presskit list > to 100 km. I think this will be a new record for closest flyby > (non-orbit) of a solar system body. Actually, the Viking 2 orbiter flew by Deimos at ~22 km. SignatureAlex R. Blackwell University of Hawaii > As it appears from having Cassini orbit apoapsis graze Iapetus orbit > during the Iapetus flybys, the flyby velocities are low. For a few [quoted text clipped - 4 lines] > and the low mass of Iapetus being of little help, there isn't enough > propellant to make it. True enough. Interestingly, though, while Iapetus' mass is too low to give any type of useful gravity assist, it is large enough that the non-targeted flyby on January 1, 2005 (13 days before the Hugyens Probe entry at Titan during Tc) is expected to perturb the Probe trajectory. > There was a good Mimas flyby just prior to SOI. Too bad Cassini was > in its quiet operation period. That particular Mimas pass (~76,801 km) was inbound to SOI just prior to the ascending ring plane crossing. SignatureAlex R. Blackwell University of Hawaii > Indeed, I've seen no less than three different models >proposed in the last two days ;-) ...Jeez, just go with the model who has big tits and still knows how to cook, Alex :-) OM Signature"No bastard ever won a war by dying for | http://www.io.com/~o_m his country. He won it by making the other | Sergeant-At-Arms poor dumb bastard die for his country." | Human O-Ring Society - General George S. Patton, Jr >>> They are indeed. Any guesses on what the big white blotches are? >> [quoted text clipped - 6 lines] > If the guys over at the Large Optical Telescope are right, they could be > ice deposits on the tops of mountains. (methane ice?) The blurb on some pictures I saw last night - though I forget where - seemed to have them labelled as a large cluster of (methane?) clouds... Ah, here we are: http://photojournal.jpl.nasa.gov/catalog/PIA06112 http://photojournal.jpl.nasa.gov/catalog/PIA06109 http://photojournal.jpl.nasa.gov/catalog/PIA06110 The next interesting question is, if so, what can be figured out about the winds from that dispersion... Signature-Andrew Gray andrew.gray@dunelm.org.uk >The next interesting question is, if so, what can be figured out about >the winds from that dispersion... If the clouds are hanging over the south pole, then we have a clue about the weather circulation pattern; Titan only rotates once every 15.94 days (its orbital period) but the atmosphere is supposed to be around half again as dense as that of Earth on its surface (given that, and its low gravity -only around 1/7 that of Earth- this is the place where jumping off of a building cartoon style...with an umbrella for a parachute... might actually work.), so that atmospheric density might account for the cloud producing weather pattern around the pole. Pat > http://www.esa.int/SPECIALS/Cassini-Huygens/SEMD6E2VQUD_0.html On the page above just press the play button on the graphic of Cassini's orbit. > Anywhere I can find information on the Cassinni orbit? How will it > avoid the rings? Or is it entirely outside the rings? Thanks for the responses. -- Gene Seibel Hangar 131 - http://pad39a.com/gene/plane.html Because I fly, I envy no one. >Anywhere I can find information on the Cassinni orbit? How will it >avoid the rings? Or is it entirely outside the rings? It'll be operating well outside the rings, where the moons are. It went down low for the insertion burn because such burns are more efficient at low altitude, but low-altitude ring-plane crossings are risky, so it won't be doing them unnecessarily. Signature"Think outside the box -- the box isn't our friend." | Henry Spencer -- George Herbert | henry@spsystems.net |
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