Mercury Flyby 1 Options

[Juramike]

are you gonna tell me THIS looks like newspaper?

http://messenger.jhuapl.edu/gallery/scienc...0108826105M.png

WOW. WOW.

Wow.

Any good explanation why there are pocket clusters of little craters surrounded by relatively smoothed over terrain in this image?

[antipode]

Any guesses about the total relief we are seeing here between crater rim and crater bottom? Pretty subdued? Maybe only a few Km???

P

[JRehling]

[...]

[nprev]

Never thought of that, JR...Mercury is already teaching us about general planetary processes, then, as promised!

[MarsIsImportant]

This may be a little premature, but I'm going to ask it anyway...because of all the excitement. When will we have a rover on Mercury and where should we land it?

I know that the poles should have some moderate temperatures, so it might be possible.

[JRehling]

[...]

[tasp]

Can we expect a percentage of Hermian crater chains to be resultant from freshly solar disrupted comets ?

[nprev]

I dunno, Tasp; they'd have to be pretty small comets, IMHO. Maybe, if we find some that have no discernable relationship to larger craters, but doubt that they''d be tidally disrupted impactors; more likely thermal breakup.

A good-sized comet from the Oort Cloud's gonna have a tremendous relative velocity at impact (in fact, that's the horse I'd bet on for Caloris). Additionally, most comets don't seem to calve until well after perihelion, and usually they're beyond the orbit of Mercury by then.

Hmm. Almost makes me wish that Mercury was rotationally locked to the Sun 1:1 instead of 3:2. The differential crater densities between the two sides might have been most instructive.

[dvandorn]

Tasp raises a good point, though, Nick. Mercury's orbit sees more objects cross its path than any other planetary orbit in the system. First, it's the smallest piece of real estate in the system occupied by a planetary orbit, and second, ever since we've seen several comets *per year* glide directly into the Sun, we know that there are a lot of bodies infalling through its orbit.

A lot of those bodies will be the result of fragmentation of larger comets, so a lot of the Hermean impactors would expected to be relatively small (less than a km in widest dimension, most fist-sized or smaller) and travelling at very high speeds relative to Mercury.

From that, I would expect the impact flux to be higher (at this point in time) on Mercury than on any other Solar System body.

I'd also point out, to those who were contemplating the possibility of cometary or asteroidal debris finding its way into a Mercury orbit, that with the largest flux of potential impactors, Mercury would also see the largest flux of near-misses. And that while it can be difficult for a fly-by object to achieve an orbit if you consider it as a two-body problem, the proximity of the Sun makes any such trajectory a three-body problem, which opens up all sorts of otherwise unlikely-sounding possibilities for orbital insertions.

-the other Doug

[nprev]

Tasp raises a good point, though, Nick.

Oh, no doubt about it! That's why I was wishing for orbital/rotational 1:1 synchronicity; would be fascinating to compare the density of inbounds on the dark side vs. outbounds on the light side, since the latter would presumably be mostly from comets rounding the Sun. As is, it's gonna be a normal distribution, though.

[JRehling]

[...]

[elakdawalla]

This may be a little premature, but I'm going to ask it anyway...because of all the excitement. When will we have a rover on Mercury and where should we land it?

I dunno about rovers, but Alan Stern mentioned to me that one of the mission scenarios proposed under the what-if-you-could-have-a-nuke-powered-Discovery-mission call for proposals was a Mercury dark side lander.

--Emily

[MarsIsImportant]

It's interesting that you mentioned the Stirling generator in that article. I heard about it in this article concerning a possible Venus Rover. http://space.newscientist.com/article/dn12...line-news_rss20 I thought it might be possible for Mercury too.

Any who, I didn't mean to take things off topic. I mentioned a desire for a Mercury Rover because...well, look at those images we have seen of Mercury over the past few days! I cannot help but want a closer look.

[Gladstoner]

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[edstrick]

General observation on high resolution imagery of Mercury.

Mercury has been ***CHEWED*** on. The bulk of the surface is "functionally" older than lunar mare terrains, regardless of absolute dates. Most of the surface is like lunar highlands or impact basins and craters (Apollo 15, 16 and 17, Surveyor 7) and basin-ejecta-plains (like Apollo 14's Frau Mauro site). What lava plains there are, are hard to tell from welded basin ejecta blankets (Cayley Plains @ Apollo 14). Many existing lava plains may have basin ejecta blankets on top. Very-high to Ultra-high resolution imagery, and there was a little very high resolution data from Mariner 10 (the closest in approach and flyaway frames), will mostly show sharp features in recent craters and their ejecta secondary terrains, and "tree-bark" textures on rounded and quite blurry highland terrains.

Look at that new image near the terminator from the flyout sequence. Aside from fresher primary impacts and secondaries, ALL the terrain is rather rounded at the resolution of the image. At 10 times more resolution, there simply won't be much more data, just blurrier, softer terrains with sharp features of recently imposed disturbances on it. This is not like Mars, where crucially important processes primarily occur at sub-meter to meters scale, forming essentially important geologic features that can not be understood at all at hundred meter scales. Yes, high resolution will be important, will help, but don't expect the sort of "my-ghod" reactions you get from Mars or Europa or Io or (will get) from Titan. At least not nearly as many of them on as grandiose a scale.