We're now just one Mercury year (88 days) from flyby #3, which happens on September 29, 2009, so this seems like a good time to start a thread about it.
http://messenger.jhuapl.edu/index.php
For comparison purposes, it'd be nice if someone (probably someone on the Messenger team) put together a Mercury Map showing what areas will get better coverage from this flyby than from the previous ones. I realize it'll be very similar to flyby #1, but it won't be exactly the same.
After that, it's a long wait until MOI on March 18, 2011. Curiously, that's the same date the New Horizons crosses the orbit of Uranus.
http://pluto.jhuapl.edu/mission/passingplanets/passingPlanets_current.php
--Greg
From a global point of view I don't think there will be any significant extension of coverage this time. The important thing will be the chance to extend the area covered by the highest resolution images shortly before and after closest approach. Things happen so fast near closest approach that only a small area can be seen in the highest resolution images. This time it will be possible to image areas not covered at highest resolution before, or to plan images to give good stereo viewing when combined with the earlier images. So, lots of opportunity to do good things, but not really any chance of increasing coverage.
Phil
Yes, I understand that. I was hoping someone might make a map that indicated which areas would get improved coverage though. That is, if one were trying to make a Mercury map, which existing areas should one expect to upgrade as a result of this flyby.
Of course, that'll all be obsoleted when Messenger goes into orbit, but that's still a long time from now.
--Greg
There's no public information on coverage yet, but it will come.
Phil
It will also be interesting if any stereo-pair frames are shceduled.
Any further word on the search for "Vulcanoids"?
--Mark G.
Probably a dumb question, but what are Vulcanoids - Mercury-crossing asteroids?
There is an article about vulcanoids in Wikipedia.
By the way, this year marks the 150th anniversary of the publication of Le Verrier's first study of the "intramercurial planet" and of Lescarbault's observed transit of Vulcan across the Sun http://en.wikipedia.org/wiki/Vulcan_(hypothetical_planet)
Just half an orbit away now. (Messenger's orbit is currently 116 days). Even if the coverage largely duplicates flyby #1, the phase angle might be different enough to be useful. Does anyone remember how close to the other flybys the Messenger team started posting information for the public?
--Greg
Just got an email with a 5-year milestone press release:
http://messenger.jhuapl.edu/news_room/details.php?id=127
That suggests they might be able to have quite the extended mission, when the time comes. I wonder if this counts as the first successful solar sail application? :-)
--Greg
http://messenger.jhuapl.edu/news_room/details.php?id=128
Does anyone know of a detailed diagram of the flyby (#3). I actually want not just the inner stuff, but the stuff from a couple million KM out, to show the interactive dance of the 3-body problem to my son.
You could download Celestia and the MESSENGER add-on with it. It's a wonderful tool for visualising such things.
The page outlining the plans for the third flyby is up.
http://messenger.jhuapl.edu/mer_flyby3.html
Haven't been able to find much information yet. According to the site, closest approach is 29Sep2009 17:54:58 EDT, presumably that translates to 29Sep2009 22:54:58 UTC but it doesn't state if it's Earth received time (ERT) or spacecraft event time (SCET). Does anybody know the answer to this?
The latest SPICE kernel I could find was updated on 30 Mar 09 and implies closest approach on 29Sep09 22:53:00 SCET ET at 199.7km altitude and a relative speed of 19,094km/h. That time translates to 29Sep09 22:58:32 ERT UTC. (66 leap seconds and one-way light time of 6min38sec)
EDIT: Assumed that time given is ERT and have updated MESSENGER realtime simulation (http://www.dmuller.net/messenger) accordingly
Thanks for the tip on Celestia -- I'm working with it now.
At 8 million km distance today, the crescent of Mercury would be barely resolved by a human eye traveling with Messenger (~2 arc minutes).
Some new diagrams showing picture plans were put up on the main website today.
http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&image_id=325
In the related link, showing the simulated position of Messenger relative to Mercury and the sun
http://messenger.jhuapl.edu/whereis/index.php#current_orbit
Messenger seems to be cruising almost "parallel" with the planet while approaching from the night side.
It's hard to tell the relative sizes of things from the sim diagrams, but in the fourth picture it looks like
even now the planet is directly between the spacecraft and the sun. I'd be curious to know - about how
much total time will the spacecraft be spending in Mercury's eclipse during this approach?
Well then it seems like for the moment I should put aside my hopes of an eclipse picture taken at some point
from which the angular diameter of the planet just about matches that of the Sun. I don't know what the science
value of such a shot would be, but it would definitely be a memorable sight to see. Perhaps the orbital phase
will present opportunities for this kind of a photograph.
Hmm - I wouldn't fancy that observation too much - being THAT close to the sun and then you're pointing the entire instrument deck sunward? No thanks.
That would be the shot:
http://messenger.jhuapl.edu/news_room/details.php?id=129
They still have not released a press kit for this. It looks like it won't be released until the 23rd when they have the teleconference.
The mission website discussion of the orbital phase does not say much about how the mission will end.
http://messenger.jhuapl.edu/the_mission/orbit.html
Maintaining the orbit will require continued fuel consumption.
The page does not reveal if, after 12 months or 2 solar days they expect to simply run the tank dry and
lose contact with the spacecraft, or what other sort of ending will follow. I have heard no
proposals for extending the mission, but somewhere near the end - after completion of all the major objectives
a moment may come when otherwise unacceptable risks can be considered. My little suggestion represents just one
possibility - maybe not a very strong candidate, but if the mission can end with an attention-grabbing "goodbye" shot,
there would be some value in that.
Dmuller, thanks for pointing out the big advantage in apparent size still enjoyed by the sun at the present time.
While we are waiting, I have added my Mariner 10 set to my blog http://planetimages.blogspot.com/2009/09/mariner-10-at-mercury.html
ExcellentMariner 10 images! And a very nice job of bringing out the subtle color differences from a very limited dataset. They match very well with the Messenger global views.
Thanks. I made them just before the first Messenger flyby. The correlation isn't perfect, but the filter combinations here are much more blue-shifted. The south pole view is just a rough overlay based on the color seen in the first two images.
James Leary has discussed a possible extended mission:
http://www.nasa.gov/missions/highlights/webcasts/elv/messenger/event2-QandA-transcript.html
However, all he said was that they mght get the spacecraft into a slightly lower orbit so as to get slightly better pictures. He didn't suggest that Messenger would ultimately impact Mercury.
Solomon's "Mercury After Messenger" is a very cool read all by itself, and he suggets an XM for Messenger might be just a single Earth year:
http://www.spacepolicyonline.com/pages/images/stories/PSDS_IP1_Solomon_MESSENGER.pdf
Despite the title, it's mostly about what Messenger will do at Mercury, but it suggests that after Messenger and Bepi-Colombo, there won't be a lot gained by another orbiter. The next step would have to be a lander or sample-return mission.
--Greg
The Messenger team will be doing a press conference tomorrow to discuss next week's flyby:
http://messenger.jhuapl.edu/news_room/details.php?id=130
There is a nice map, just posted today, showing the planned imaging coverage:
http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&image_id=326
Note that this suggests that Flyby #3 will cover more than half of the never-seen terrain.
I also note that the areas marked for Flyby #1 and Flyby #2 are backwards. Flyby #1 coverage is actually the area outlined in red on the image and Flyby #2 is outlined in blue, as we can see from the Flyby #2 coverage plan:
http://messenger.jhuapl.edu/gallery/sciencePhotos/pics/M2_new_coverage_Sep08.jpg
We knew that this flyby would be very similar to Flyby #1 -- so much that some of us had worried there would be nothing new to see at all. What's surprising (to me, anyway) is that the coverage on approach is much larger and significantly shifted compared to flyby #1 (and this is where almost all the new coverage comes from) but the coverage on departure is almost the same as for Flyby #1. Wonder why so much difference between the two?
--Greg
Does anybody have the flyby timeline in spreadsheet form? Going through the encounter sim just drives me nuts, plus it doesn't match with any other info i have :-(
Another press release today:
http://messenger.jhuapl.edu/news_room/details.php?id=132
A couple of things I hadn't realized before:
1) This is their last chance to study the magneto tail in the equatorial plane.
2) The flyby images are higher-resolution near the equator than any pictures Messenger will take later.
3) They are still looking for possible moons, down to radius 100m.
--Greg
Another Messenger update, this one has a new photo.
http://messenger.jhuapl.edu/mer_flyby3.html
Given the approach image we saw before, I think that means the lighted part of this crescent is mostly terrain that has never been imaged before, so that's kind of cool. Interesting-looking bright crater near the top.
--Greg
I have uploaded http://www.planetary.org/news/2009/0923_MESSENGERs_Final_Flyby_of_Mercury_Old.html onto my realtime simulation at http://www.dmuller.net/messenger. Less than 4 days to go.
This is the first Mercury 3 image release enlarged and with the terminator brightened. The bright crater was seen last time too.
Phil
The latest image, enlarged, terminator brightened and sharpened.
Phil
Latest image from the website, showing essentially the same thing as Phil Stooke was able to get by sharpening the image before.
http://messenger.jhuapl.edu/gallery/sciencePhotos/pics/CN0162589824M_RA_3_web.png
And here's what he gets by enlarging, selectively brightening and sharpening this new image:
My own sharpenning of the last picture of Messenger.
Just a wavelett sharpen
Surprised no-one has commented on this glitch here:
http://www.planetary.org/blog/article/00002128/
I am hoping that whatever it was wasn't caused by something in the space environment close to Mercury, but was rather a purely internal programming thing that can be avoided by adjusting procedures. If it was a totally random event the timing is extraordinary (but not unprecedented - remember Iapetus). Anybody know anything more?
Better view into new territory.
http://messenger.jhuapl.edu/gallery/sciencePhotos/pics/CW0162741055G_RA_3_web.png
That's reassuring, thanks Doug.
I think the latest image via peter59 already closes the gap at low latitudes. If I'm not mistaken the bright crater on the limb near the equator with the prominent northward trending ray is on the other side of 'terra incognita'. Also we can already see converging E-W rays in the southern hemisphere from the very prominent crater up ahead.
This is the new view converted to an (approximate) stereographic projection. That makes craters near the limb circular so you can interpret features more easily. Very extensive smooth plains in the north.
Phil
The latest, via Twitter, is that MESSENGER safed just before closest approach. No high-res images on departure But since the flyby didn't involve any thruster firing, the gravity assist should have been successful. All approach imaging should have been done, so that last gore should be filled.
New, nice image.
http://messenger.jhuapl.edu/gallery/sciencePhotos/pics/CN0162744001M_RA_3_web.png
That just clinches it: there's an alien ship out there, tailing our spaceprobes, with a load of mischevious, drunk, giggling ET teenagers inside it, just waiting to fire their "Put little toy alien spacecraft into safe mode at just the worst possible moment!" ray at them...
Pesky alien kids!!!
Yes, back in the old days, we didn't know to fear safe modes during flybys. But this time I did...
Was it actually first safe mode event for MESSENGER?
Some nice crater chains approx radial to that double ringed basin.
Does it have a name?
P
Great reprojs, Phil!
Noticed a crater that's apparently been buried by a lava flow (arrowed).
Yes, and a similarly buried big double-ring basin near the top of the same image.
Phil
I was struck by this one's symmetry...didn't have much time to melt down the rim walls, did it? Interesting.
it will be nice when the images get here
http://pds-imaging.jpl.nasa.gov/Admin/resources/cd_messenger.html
and i can remove the stripe from my map
OK, no serious harm done this time but I sure hope there won't be a flyby #4 in March 2011.
Maybe this story can shed some light on it? http://science.nasa.gov/headlines/y2009/29sep_cosmicrays.htm More cosmic rays.
Yeah -- fault handling on gravity assist flybys or opportunistic encounters is way, way different than for planned science flybys. Remember how OSIRIS on Rosetta safed before the Steins flyby, and how Dawn safed during its Mars flyby. On such encounters science is way, way down the list compared to spacecraft health. If the flyby is just for science, as with NH at Pluto and Mariner 10's Mercury flybys, then they disable a lot of the fault protection.
--Emily
Galactic cosmic rays could have impacted the spacecraft at any time, regardless of its position relative to the planet.
The fact that this event came just as Messenger entered Mercury's shadow offers a strong hint that it was somehow
related to that transition. That said, I guess some of those 7000+ stored flyby commands could have been corrupted
by a CR incident, and we would not have discovered it until it came time to execute them.
Note - This was WRT Sunspot's earlier post. The subsequent posts are acknowledged with some relief.
Here's a version of my map with the Flyby 3 sliver added in. This uses WAC and NAC images. I plan to add the Mariner map & radar data back in and then try adding one of VP's mosaics.
Steve great work!
Do you have a Messenger Map Only version? (A strange request from my father)
I can understand Decepticon's father's request. With all this wonderful MESSENGER data, the Mariner 10 imagery seems... undesired.
The Mariner 10 data that really looks different is the south polar mosaic because it is a 1970s creation. Making a clean, modern version of it is on my to-do list.
Greetings, here is a MESSENGER only version that Decepticon's father may want to look at:
...and an updated version of the one including Mariner and radar data for comparison:
WOW! Thanks scalbers!
The latest release, a distant view - enlarged and the terminator brightened.
Phil
apologies for resurrecting this old thread, but Science express had yesterday three new preprints on scientific results from M3 (as usual, full papers are available only to subscribers)
http://www.sciencemag.org/cgi/content/abstract/science.1188186
http://www.sciencemag.org/cgi/content/abstract/science.1188067
http://www.sciencemag.org/cgi/content/abstract/science.1188572
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