Help - Search - Members - Calendar
Full Version: Mercury Flyby 2
Unmanned Spaceflight.com > Inner Solar System and the Sun > Mercury > Messenger
Pages: 1, 2, 3, 4
Holder of the Two Leashes
It is time for this new topic.

Round Two
As old as Voyager
One interesting feature MESSENGER will get a good look at during the second flyby is the area of Mercury's surface dubbed 'Weird Terrain.'

This jumbled region of the planet's surface is antipodal to Caloris and marks the focal point of seismic waves generated by the impact.

Mariner 10 only saw half of this disturbed region, so I'm looking forward to seeing just how much havoc Caloris wreaked on the other side of Mercury.

I wonder if a good look at the Weird Terrain will yeild any new info about Mercury's interior? (at least at the time of the Caloris impact).
Decepticon
Do we get any polar regions imaged during any of the flybys?
Dominik
That's something I'm also interested in smile.gif.
CAP-Team
I think you'll have to wait for that till the orbital insertion.
tasp
I recognize there are some controversial views regarding the Deccan Traps and the Yucatan impact on earth.

Perhaps study of Caloris/weird terrain on Mercury might help us understand possible analogous structure(s) on earth ??


I also note, flyby 2 will be flown ~ 1 mile per second slower than flyby 1.

More time for pictures and other goodies!




tty
QUOTE (tasp @ Feb 9 2008, 03:35 PM) *
I recognize there are some controversial views regarding the Deccan Traps and the Yucatan impact on earth.


That idea is simply not on for two good and sufficient reasons:

1. Deccan was not antipodal to Chicxulub 65 MY BP.

2. The Deccan Traps started ereupting well before the K/T boundary as proven by Maastrichtian fossils in the Intertrappan beds.


tty
JRehling
The flybys are all near-equatorial and, moreover, they are so close to the planet that the poles are permanently over the horizon near C/A.

Yet moreover, the interesting thing about the poles, that the bottoms of the craters may contain ice, is by definition something that can't be observed in sunlight, because they're never in sunlight. So far as Mariner 10 showed, there was nothing unusual in the visible areas of the poles.

The interesting thing will be to see the elemental spectroscopy of the north pole where any hydrogen would make a strong signal (as it did on the Moon and Mars). That will have to wait for the orbital mission. The other possibility is that some other element like sulfur is the culprit. I'm betting on ice, though, which would mean that every body in the inner solar system besides Venus has water ice at its poles. Come to think of it, it's probably about a sweep in the outer solar system, too, besides Io.
Mariner9

I was reading an article on Spacedaily, and ran across this real mathematical puzzler:

"Observations during this second Messenger flyby will almost complete the first high-resolution viewing of Mercury, adding another one-third of the planet surface to the 21% of territory not seen by Mariner 10 and first imaged by Messenger in January 2008," says Messenger Project Scientist Ralph McNutt.

I'm scratching my noggin over this one.
He appears to be saying: Mariner 10 + Messenger Flyby 1 = 21% unimaged, aka. 79% coverage.
But if you add another 33% coverage, you get 112% coverage, which can't be correct.

Or, perhaps: Mariner 10 + Messenger Flyby 1 = 79% Coverage. Of the 21% left unimaged, Flyby 2 will get 1/3 of that missing coverage, aka 7%, so the total coverage will go up to 86%.

Anyone want to chime in?

JRehling
Mariner 10 viewed 45% of Mercury. By these numbers, Flyby 1 added 21% and Flyby 2 added 33%, summing to 99%. That works. I think 33% is a bit of an overstatement, but speaking in fractions, 29% could be the real figure, giving a total of 95%.

I still think that's an overstatement, or at least it includes areas on the limb which aren't really being effectively resolved, but the gist is that we'll see more new stuff this time than we did last time. And when it's done, we'll have viewed the great majority of Mercury's surface.

The catch is that it looks totally different depending on phase angle, so we're going to have to see everything at least twice before we've really seen it. But the orbital mission will ace that assignment.
Phil Stooke
I'm pretty sure it means 33% of the blank area. There should still be a sizeable strip left to fill in after Flyby 2, and Flyby 3 will not add anything much to it. That will have to wait until orbit.

Phil
Holder of the Two Leashes
Just one year (88 earth days) to go. smile.gif
Holder of the Two Leashes
MESSENGER is solar sailing its way in to Mercury, according to this article.

Things should start to pick up in earnest soon.
Greg Hullender
Although flyby #2 largely covers territory already imaged by Mariner 10, I think the resolution should be much better. Also, as JR implies, seeing it at a different phase angle ought to tell us a good bit as well.

It's flyby #3 that may be hard to get excited about. A bit slower, a slightly different phase angle, but otherwise pretty much a repeat of flyby #1. But maybe we'll get lucky and see something cool anyway.

--Greg
dilo
QUOTE (Holder of the Two Leashes @ Sep 7 2008, 03:23 AM) *
MESSENGER is solar sailing its way in to Mercury, according to this article.

This is a very exciting navigational technique, at least until a true solar sail will be developed... I wonder if is really new or if someone used it in previous missions?
Holder of the Two Leashes
Apparently this is the first time the technique has been used to steer a spacecraft's trajectory. Mariner 4 had solar pressure vanes as an experiment to help control attitude, with mixed results. Mariner 10 successfully adjusted its attitude with solar pressure, which extended its life. But we are talking here about adjusting course.
dmuller
With the second flyby now just a month away, I have started to dig for events etc for my realtime simulation, and as always I am getting different times for the same events. I guess the closest approach time has not been inked in, but I thought I'd share my initial results anyway.

All times are Spacecraft Event Times in UTC:

Mercury closest approach (altitude 200km) on 6 Oct 2008 between 08:40 and 08:42

Horizons currently has closest approach at 06 Oct 2008 08:41:25, resulting in:
Entry into Mercury Hillsphere: 05 Oct 2008 20:33:55
Exit from Mercury Hillsphere: 06 Oct 2008 20:48:40

Again according to the Horizons information, the flyby changes the orbital elements as follows:
Periapsis: from 47.5 million km to 45.8 million km
Apoapsis: from 102.3 million km to 93.8 million km
Eccentricity: from 0.36 to 0.34
Inclination: from 6.94 deg to 7.03 deg

If anybody has more precise - or updated - information, please share, I will gladly put it on the realtime simulation
elakdawalla
I have from a very reliable source smile.gif the current best estimate (as of Friday, September 5) of flyby time being 08:40:21.4 UTC. At that time it'll be 200.2 km from Mercury.

My source has different orbital information -- is yours measured with respect to the ecliptic? I could also select "with respect to Earth mean equator" or "with respect to Mercury equator".

These are with respect to the ecliptic:

Semimajor axis: 7,596,000 before / 6,975,000 after
Periapsis radius: 4,720,000 before / 4,523,000 after
Eccentricity: 0.38 before / 0.35 after
Inclination: 6.9 before / 7.0 after
dmuller
QUOTE (elakdawalla @ Sep 9 2008, 09:45 AM) *
My source has different orbital information -- is yours measured with respect to the ecliptic?

Mine are the orbital information for Messenger's orbit around the Sun ... the Solar System Barycenter to be precise ... so maybe that is where the difference comes from.

Thanks for the current best estimate. Will work it into the model shortly. Mmmm if your reliable source changes its figures, please post it here :-)
peter59
Press Kit: MESSENGER Mercury Flyby 2 (PDF)
Decepticon
Is there a flyby preview video available?
dmuller
The Messenger website says that there will be (if I read it correctly).

Since I downloaded the images for my realtime simulation anyway (in case that the Solar System Simulator goes down during C/A), here are the images stringed together into a movie for CA +/- 1 hour:
http://www.spaceoutreach.com/display.php?i...8nimdaq15025458

But I know there are people on here who can do much more impressive movies rolleyes.gif
peter59
Mercury Flyby 2 Visualization Tool
http://messenger.jhuapl.edu/encountersm2/
Hurrah! biggrin.gif
peter59
Click to view attachment Click to view attachment Click to view attachment Click to view attachment
NAC Departure Mosaic #2
NAC Departure Mosaic #3
NAC Departure Mosaic #4
WAC Departure Color Mosaic #2
leper
QUOTE (peter59 @ Sep 26 2008, 07:40 AM) *
Mercury Flyby 2 Visualization Tool
http://messenger.jhuapl.edu/encountersm2/
Hurrah! biggrin.gif

Great tool, thanks!
Not quite as good as the Cassini one but gives a great sense of what will take place smile.gif
charborob
This page shows the part of Mercury that will be imaged during Flyby2.
peter59
New: Mercury Flyby 2 Instrument Operations.
http://messenger.jhuapl.edu/the_mission/mo...yby_web_sml.mov (17.8 MB)
PhilCo126
That's great Peter!

The second Mercury flyby is slated for 2:40 a.m. MDT on Oct. 6 and the MESSENGER spacecraft will view areas not seen before by the 1974 & 1975 Mariner X flybys....
Greg Hullender
QUOTE (charborob @ Sep 29 2008, 07:49 AM) *
This page shows the part of Mercury that will be imaged during Flyby2.

Nice! What's great about that link is that it clearly shows what was imaged by Mariner 10 and Flyby 1 and what will be imaged in this flyby. It makes it fairly clear that there will be relatively little unimaged surface after this flyby.

I sent the Messenger team an e-mail about a month ago telling them I wished they'd show us something like this. They never replied, so maybe I'm vain to imagine this is a response to my request, but I was delighted to see it nonetheless!

--Greg
vjkane
I hope that someone eventually publishes a map showing coverage by resolution from the flybys. It would visually show how well flybys can cover a world (useful for considering flybys of Galilean satellites, Triton, etc.).
peter59
First image is here:
Acquired: October 3, 2008
laugh.gif
3488
Enlargement & enhancement of Crescent Mercury.
Click to view attachment

It looks like the Skinakas Basin exists after all, despite being written off, though it is still a bit too soon to jump to that conclusion. The crop & blow up I have just done shows a large feature foreshortened in the northern hemisphere. We will definitely know more tomorrow, as this afternoon's image will be approx 25% closer to Mercury than this one.

There also appears to be another large impact feature in the southern hemisphere. There is clearly a smattering of much smaller craters with bright ejecta blankets in the equatorial region.

Northern horn of crescent Mercury. Looks like there IS a large circular feature foreshortened. I think it is the suspected Skinakas Basin. Obviously we will know much more tomorrow as the second Navigation image will be down, from much closer in.
Click to view attachment

Every feature here is new to human eyes, very interesting & exciting.

Andrew Brown.
Phil Stooke
Here's another version of the new image.

Isn't Skinakas supposed to be a dark area? Nothing on here can be interpreted as a large impact basin or 'mare' from this image. I'm on record saying Skinakas doesn't exist - we will soon know.

Phil

Click to view attachment
Vultur
This spacecraft is really, really exciting!

Please excuse the uninformed question, but what is Skinakas?
TheChemist
QUOTE (Vultur @ Oct 4 2008, 03:25 AM) *
Please excuse the uninformed question, but what is Skinakas?


Skinakas is actually a mountaintop in Crete hosting an observatory.

A short story of the proposed "basin" (unfortunately named after it) is found here :

http://en.wikipedia.org/wiki/Skinakas_Basin
Phil Stooke
The next pic is up - here's an enlarged and processed version. A nice new basin in the south but nothing like that visible in the north.

Phil

Click to view attachment
Phil Stooke
And the next...

Phil

Click to view attachment

The new southern basin's slightly lighter interior and dark spots suggest it might be a mini-Caloris.
3488
Hi Phil,

Certainly Skinakas Does Not exist.

I really hope that the fifth image will be available soon.

That southern basin is impressive. Certainly is reminicent of a mini Caloris.

I've had a go at enlargening & sharpening each hemisphere from the original.

Northern Hemisphere enlarged.
Click to view attachment

Southern Hemisphere enlarged.
Click to view attachment

Andrew Brown.
elakdawalla
QUOTE (Phil Stooke @ Oct 4 2008, 03:45 PM) *
The new southern basin's slightly lighter interior and dark spots suggest it might be a mini-Caloris.


Yeah, looks a lot like Tolstoj (that dark-rimmed bright-centered thing in the southern hemisphere on the limb in the flyby 1 departure images).

--Emily
volcanopele
That's the one I was trying to think of. Thanks, Emily. Nice central peak on that basin too.
n1ckdrake
Getting closer. smile.gif
Click to view attachment
3488
Image # 5.
Click to view attachment


#5 Image Northern Hemisphere.
Click to view attachment

#5 Image Southern Hemisphere.
Click to view attachment

That basin is really coming into its own now. More dark spots are starting to appear on it's floor.

Andrew Brown.
marsbug
To me it looks less like a basin with dark spots, more like a basin with a mottled floor. Thats a bit pedentic I know but I wonder if there's a partial covering of dark lava flows on the basin (mottled) or if later impacts have excavated darker material (spots).
Phil Stooke
Caloris suggests an answer to your question!

Here's the last image in my style of processing.

Phil

Click to view attachment
Phil Stooke
The feature highlighted here may be another old impact basin, overlapped on the north side by a later double-ring basin.

Phil

Click to view attachment
Marz
Click to view attachment

Hoping someone can clue me in on what we're seeing:

Why is the crater pointed to with the green line so bright? Solar glare or is it surface composition?

Is the feature pointed to with the red line perhaps volcanic?



Juramike
The shading on the southern basin towards the terminator looks "not right" (shouldn't it be bright rather than shaded?). Or is that a processing artifact?

-Mike
remcook
i agree. it looks more like the edge of olympus mons like this.
all the other craters seem to have the shadow on the 'right' side.
dvandorn
Hmmm... no Skinakas? I see arc-shaped lobes of dark material, in some areas bounded by what appear to be old, degraded arcs of rimwall massif. I'm not a consummate image manipulator, but look within the crudely drawn red circle below:

Click to view attachment

I really do see a structure there that seems to be roughly concentric with that very roughly drawn red circle. Very degraded, yes -- the southern rim seems to have been obliterated by subsequent large craters. But this might be a basin, after all...

-the other Doug
volcanopele
Looks like a good sized impact basin to me. Though it seems to be a central pit basin, rather than a central peak basin blink.gif

Doug, that looks like an optical illusion to me. I saw what you were talking about earlier, but now I really just see a chance alignment of craters.
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2019 Invision Power Services, Inc.