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Venus Express
tedstryk
post Apr 12 2005, 06:56 PM
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If all goes well, Venus Express will be a major topic for discussion in this forum a year from now. Does anyone know how good the surface coverage will be from VIRTIS and VMC? My understanding is that VIRTIS will obtain low resolution multispectral maps, and that VMC will, in addition to cloud monitoring, have one channel that can see the surface, but I don't know at what resolution or at what quality. It will be nice to have some non-radar images of Venus' surface besides the Venera snapshots and the shadowy images from Earth and Galileo's NIMS.

Ted


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Guest_BruceMoomaw_*
post Aug 29 2005, 02:10 AM
Post #2





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Here's my long-promised entry on whatever I've got regarding VIRTIS' possible ability to map Venusian surface composition.

Unfortunately, the two most important documents on this aren't available for free on the Web: the Nov. 2000 Icarus article by Langevin et al ("Detection of Sub-Micron Radiation from the Surface of Venus by Cassini/VIMS"), and the March 2002 article by V.I. Moroz in "Planetary and Space Science" ("Estimates of Visibility of the Surface of Venus from Descent Probes and Balloons"). I have a photocopy of the former, but can't find the copy I thought I had of the latter. Anyway, the former is optimistic about the possibility: "The 5 spectral windows between 0.85 and 1.18 microns now proven to be sensitive to surface spectral sensitivity provide a potentially effective means for remotely mapping the mineralogical composition of the surface of Venus" [something co-author Kevin Baines was saying for previously]... [They] can be effectively used to distinguish ferric (hematite) and ferrous minerals (e.g., the pyroxenes augite and hypersthene, and olivine). The hydrous mineral tremolite -- thought to be stable on geologic timescales on Venus -- also displays a detectable absorption feature...Both wollastonite -- a CO2 buffer mineral thought to be relating the CO2 surface pressure -- and pyrite are spectrally flat, but have distinctly different ablbedos." There's an accompanying graph of these various minerals' near-IR reflectivities, with the Venusian surface spectral windows overlaying it.

The Moroz article is much more pessimistic: "Constraints on the mineral surface composition would be difficult to derive from orbital observations due to multiple reflections between the surface and the atmosphere." The VIRTIS group itself, the Japanese VCO group and the Vernadsky-Brown Venus group are all intermediate in optimism: they think that it will almost certainly be possible to map FeO, thus distinguishing between felsic and mafic minerals and thus between granites and basalts, and also looking for magnetite on the highly radar-reflective mountaintops -- but aren't sure they can go any farther. (The two longest-wavelength windows seem to be the most useful.) Moreover, it seems much more possible to do this in the north polar regions than elsewhere (which, by an agreeable coincidence, is where Ishtar Terra -- Venus' most likely continent -- is located).

As for spatial resolution (including for temperature and near-surface volcanic gases), estimates are all over the place. Moroz sets it at 50-100 km, the VCO group at 100 km, and David Crisp at no better than 250 km (based on Galileo's flyby results). The VIRTIS group itself initially set it as high as 30 km, but now seems to have it pegged at 90-150 km ( http://irsps.sci.unich.it/~luciam/VEX/DOC/...ence_VIRTIS.pdf and the May 2005 report at the VIRTIS site: http://irsps.sci.unich.it/~luciam/VEX/ ).

As for quake detection through sensing pressure waves in Venus' dense CO2 air, they are still very interested in that -- although it will require special observational techniques (see the Dec. 2003 and May 2005 reports at the VIRTIS site).
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- tedstryk   Venus Express   Apr 12 2005, 06:56 PM
- - BruceMoomaw   See my new note on the "Radar on Venus Expres...   Apr 20 2005, 10:31 AM
|- - tedstryk   Actually, VMC will have some limited capabliity to...   Apr 21 2005, 03:16 AM
- - BruceMoomaw   You've caught me -- I was completely unaware o...   Apr 21 2005, 05:34 AM
- - Mode5   To the powers that be, thank you for creating this...   Apr 21 2005, 05:53 AM
- - Gsnorgathon   Ted - do you have a link for the ESA mission doc(s...   Apr 21 2005, 07:08 AM
|- - tedstryk   http://megasn.obspm.fr/VEX_MDR51.doc It is a bit ...   Apr 21 2005, 09:17 AM
- - djellison   I wonder if the effects of looking thru narrow spe...   Apr 21 2005, 09:26 AM
- - tedstryk   Hard to tell. It is sort of like Pre-Cassini Tita...   Apr 21 2005, 09:51 AM
|- - Richard Trigaux   QUOTE (tedstryk @ Apr 21 2005, 09:51 AM)It is...   Jun 26 2005, 08:06 AM
- - BruceMoomaw   I can dig up some stuff on this for you, given a l...   Jun 23 2005, 12:06 AM
- - remcook   I believe the spectral 'windows' are much ...   Jun 25 2005, 08:28 PM
- - edstrick   My understanding is that the topographically relat...   Jun 26 2005, 07:02 AM
- - edstrick   On Cassin, the VIMS is the best instrument we coul...   Jun 26 2005, 10:31 AM
|- - Bob Shaw   QUOTE (edstrick @ Jun 26 2005, 11:31 AM)On Ca...   Jul 8 2005, 01:59 PM
|- - JRehling   QUOTE (edstrick @ Jun 26 2005, 03:31 AM)On Ca...   Jul 8 2005, 02:23 PM
|- - Gsnorgathon   I suppose it's possible, if not easy, to subtr...   Jul 9 2005, 04:10 AM
|- - JRehling   QUOTE (Gsnorgathon @ Jul 8 2005, 09:10 PM)I s...   Jul 9 2005, 05:09 AM
- - maycm   An update....though not much new information. htt...   Jul 8 2005, 12:49 PM
- - TheChemist   Venus Express arrives in Baikonur She's got i...   Aug 10 2005, 04:33 PM
|- - Bob Shaw   QUOTE (TheChemist @ Aug 10 2005, 05:33 PM)Ven...   Aug 10 2005, 07:42 PM
- - BruceMoomaw   Here's my long-promised entry on whatever I...   Aug 29 2005, 02:10 AM
- - BruceMoomaw   Two more notes: (1) The VIRTIS team is fully re...   Aug 29 2005, 02:15 AM
- - tedstryk   http://messenger.jhuapl.edu/the_mission/im...ine_f...   Sep 11 2005, 01:35 PM
|- - 4th rock from the sun   QUOTE (tedstryk @ Sep 11 2005, 02:35 PM)... ...   Sep 12 2005, 08:46 PM
|- - tedstryk   Well, I doubt there would be time-lapse images. T...   Sep 12 2005, 09:59 PM
- - mike   America will just have to make a new probe that re...   Sep 12 2005, 07:08 PM
|- - Bob Shaw   QUOTE (mike @ Sep 12 2005, 08:08 PM)America w...   Sep 12 2005, 09:04 PM
- - TheChemist   QUOTE Oh, and the thing that the ESA Press Office ...   Sep 13 2005, 11:52 AM
|- - tedstryk   QUOTE (TheChemist @ Sep 13 2005, 11:52 AM)...   Sep 13 2005, 03:01 PM
- - RNeuhaus   New update. Now it is less than 14 days from launc...   Oct 12 2005, 04:09 AM
|- - ljk4-1   Preparations for ESA's Venus Express mission p...   Oct 13 2005, 01:50 PM
- - RNeuhaus   The spacecraft Technical details Spacecraft fact...   Oct 13 2005, 02:45 PM
|- - um3k   QUOTE (RNeuhaus @ Oct 13 2005, 10:45 AM)The p...   Oct 13 2005, 03:03 PM
||- - Rakhir   QUOTE (um3k @ Oct 13 2005, 05:03 PM)I'm n...   Oct 14 2005, 08:23 AM
|- - Rakhir   QUOTE (RNeuhaus @ Oct 13 2005, 04:45 PM)The s...   Oct 13 2005, 04:03 PM
|- - RNeuhaus   QUOTE (Rakhir @ Oct 13 2005, 11:03 AM)From ht...   Oct 13 2005, 04:46 PM
|- - tedstryk   QUOTE (RNeuhaus @ Oct 13 2005, 04:46 PM)Thank...   Oct 13 2005, 05:06 PM
|- - ugordan   QUOTE (RNeuhaus @ Oct 13 2005, 06:46 PM)Thank...   Oct 13 2005, 05:09 PM
- - RNeuhaus   The problem was already solved by changing the pro...   Oct 13 2005, 06:25 PM
- - Jeff7   QUOTE (um3k @ Oct 13 2005, 10:03 AM)I'm n...   Oct 14 2005, 04:22 AM
|- - helvick   QUOTE (Jeff7 @ Oct 14 2005, 05:22 AM)I think ...   Oct 14 2005, 08:15 AM
|- - RNeuhaus   QUOTE (Jeff7 @ Oct 13 2005, 11:22 PM)I think ...   Oct 14 2005, 03:59 PM
- - RNeuhaus   According to the VE's pdf document, VE has gre...   Oct 14 2005, 04:22 PM
- - dvandorn   Your diagram shows the most common Hohmann transfe...   Oct 15 2005, 08:59 AM
- - Rakhir   Fairing Installation Today, Monday 17 October 200...   Oct 17 2005, 08:25 PM
- - RNeuhaus   New updates about Venus Express. More details abou...   Oct 19 2005, 10:30 PM
- - Rakhir   New ESA update : summary of the launch, cruise and...   Oct 21 2005, 11:03 AM
- - Adam   Delayed: http://www.esa.int/esaCP/SEM0CV3J2FE_ind...   Oct 21 2005, 06:31 PM
- - Rakhir   Venus Express preliminary investigations bring enc...   Oct 25 2005, 11:33 AM
- - SigurRosFan   Spaceflightnow Mission Status Center: Venus Expres...   Oct 26 2005, 01:27 PM
- - Rakhir   Russian space officials Monday set a Nov. 9 blasto...   Oct 31 2005, 05:21 PM
- - RNeuhaus   Strange news. The postpone of the launch was due...   Oct 31 2005, 09:23 PM
|- - Rakhir   QUOTE (RNeuhaus @ Oct 31 2005, 11:23 PM)Stran...   Oct 31 2005, 10:24 PM
- - Rakhir   Roll Out to Launch Pad http://sci.esa.int/science...   Nov 5 2005, 04:42 PM
- - Rakhir   Pre-launch sequence was executed. 2 days... http:...   Nov 6 2005, 11:24 PM
- - paulanderson   Interesting article: 'Venus Mission May Hold ...   Nov 7 2005, 01:35 AM
- - mike   If Venus is almost exactly like Earth, but much ho...   Nov 7 2005, 03:04 AM
|- - JRehling   QUOTE (mike @ Nov 6 2005, 08:04 PM)If Venus i...   Nov 7 2005, 03:41 PM
- - RNeuhaus   Besides, the other intrigating thing is that Venus...   Nov 7 2005, 03:54 PM
|- - ljk4-1   QUOTE (RNeuhaus @ Nov 7 2005, 10:54 AM)Beside...   Nov 7 2005, 04:03 PM
|- - RNeuhaus   QUOTE (ljk4-1 @ Nov 7 2005, 11:03 AM)A w...   Nov 7 2005, 04:26 PM
|- - ljk4-1   QUOTE (RNeuhaus @ Nov 7 2005, 11:26 AM)Intere...   Nov 7 2005, 04:30 PM
|- - JRehling   QUOTE (ljk4-1 @ Nov 7 2005, 09:30 AM)Act...   Nov 7 2005, 05:26 PM
|- - The Messenger   QUOTE (JRehling @ Nov 7 2005, 10:26 AM)There ...   Nov 7 2005, 05:46 PM
|- - ljk4-1   QUOTE (JRehling @ Nov 7 2005, 12:26 PM)There ...   Nov 7 2005, 10:08 PM
|- - imran   Less than one hour from launch! Live webcast ...   Nov 9 2005, 02:41 AM
||- - jamescanvin   QUOTE (imran @ Nov 9 2005, 01:41 PM)Less than...   Nov 9 2005, 03:11 AM
||- - imran   Both webcasts are working now although you get bet...   Nov 9 2005, 03:22 AM
||- - imran   0327 GMT (10:27 p.m. EDT Tues.) The Venus Express...   Nov 9 2005, 03:30 AM
|||- - imran   QUOTE (imran @ Nov 9 2005, 03:30 AM)0327 GMT ...   Nov 9 2005, 03:32 AM
||- - jamescanvin   QUOTE (imran @ Nov 9 2005, 02:22 PM)Both webc...   Nov 9 2005, 03:33 AM
||- - imran   QUOTE (jamescanvin @ Nov 9 2005, 03:33 AM)Sta...   Nov 9 2005, 03:33 AM
||- - jamescanvin   QUOTE (imran @ Nov 9 2005, 02:33 PM)LIFTOFF...   Nov 9 2005, 03:38 AM
|||- - jamescanvin   QUOTE (jamescanvin @ Nov 9 2005, 02:38 PM)OK ...   Nov 9 2005, 03:39 AM
||- - imran   0336 GMT (10:36 p.m. EDT Tues.) T+plus 3 minutes....   Nov 9 2005, 03:38 AM
|- - JRehling   QUOTE (ljk4-1 @ Nov 7 2005, 03:08 PM)The...   Nov 9 2005, 06:12 AM
- - djellison   Moons tend to orbit their parent planet in the sam...   Nov 7 2005, 04:57 PM
- - BruceMoomaw   Well, as Chesterton said, the most remarkable thin...   Nov 7 2005, 09:20 PM
- - RNeuhaus   Anyway, at the beginning of the planetary formatio...   Nov 7 2005, 09:57 PM
- - Waspie_Dwarf   Alternative link for the live webcast of the launc...   Nov 9 2005, 03:06 AM
|- - jamescanvin   QUOTE (Waspie_Dwarf @ Nov 9 2005, 02:06 PM)Al...   Nov 9 2005, 03:14 AM
- - Waspie_Dwarf   The live feed won't start until 03:28 GMT, at ...   Nov 9 2005, 03:14 AM
- - imran   Cutoff of 3rd stage and separation of nose module.   Nov 9 2005, 03:41 AM
|- - jamescanvin   QUOTE (imran @ Nov 9 2005, 02:41 PM)"Eve...   Nov 9 2005, 03:42 AM
|- - imran   QUOTE (jamescanvin @ Nov 9 2005, 03:42 AM)Thi...   Nov 9 2005, 03:43 AM
|- - imran   There goes the feed. Oh well..guess I'll have...   Nov 9 2005, 03:46 AM
|- - imran   0348 GMT (10:48 p.m. EDT Tues.) T+plus 15 minutes...   Nov 9 2005, 03:51 AM
- - elakdawalla   Argh! Is that second Fregat burn happening or...   Nov 9 2005, 05:02 AM
|- - jamescanvin   From Spaceflightnow.com 0514 GMT (12:14 a.m. EST)...   Nov 9 2005, 05:16 AM
|- - Bricktop   From http://sci.esa.int/science-e/www/object/in......   Nov 9 2005, 05:19 AM
- - jamescanvin   Fregat burn should be underway by now. No word on...   Nov 9 2005, 05:06 AM
- - Waspie_Dwarf   QUOTE (jamescanvin @ Nov 9 2005, 05:16 AM)Fro...   Nov 9 2005, 05:20 AM
- - Rakhir   From http://sci.esa.int/science-e/www/object/in......   Nov 9 2005, 05:20 AM
- - Waspie_Dwarf   QUOTE (Bricktop @ Nov 9 2005, 05:19 AM)From h...   Nov 9 2005, 05:22 AM
- - jamescanvin   Hurrrah! Venus here we come   Nov 9 2005, 05:25 AM
- - elakdawalla   This from Daniel Fischer: "Just to report tha...   Nov 9 2005, 05:48 AM
- - Rakhir   MET: +02h 40m Sun acquisiton and successfully depl...   Nov 9 2005, 06:17 AM
- - Decepticon   QUOTE Venus Orbit Insertion on April 11, 2006....   Nov 9 2005, 07:03 AM
- - edstrick   "Sun acquisiton and successfully deployment o...   Nov 9 2005, 07:06 AM
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