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paxdan
Launched on August 3rd 2004, NASA's MESSENGER will become the first spacecraft to orbit Mercury.

News and updates are availbale via Johns Hopkins University MESSENGER website and the Kennedy Space Center's MESSENGER website.

There will be an earth flyby in August followed by a couple of swings by Venus and three velocity scrubbing passages past mecury before the craft enters orbit in March 2011.

April 18, 2005 status report from JHU. Extensive JHU FAQs page here.
Buck Galaxy
QUOTE (paxdan @ Apr 20 2005, 11:22 AM)
Launched on August 3rd 2004, NASA's MESSENGER will become the first spacecraft to orbit Mercury.

News and updates are availbale via Johns Hopkins University MESSENGER website and the Kennedy Space Center's MESSENGER website.

There will be an earth flyby in August followed by a couple of swings by Venus and three velocity scrubbing passages past mecury before the craft enters orbit in March 2011.

April 18, 2005 status report from JHU. Extensive JHU FAQs page here.
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I for one can barely wait for Messenger. There is a big section of Mercury we've never seen, and I would love to also see close ups of the huge polar ice deposits.
Jeff7
QUOTE (Buck Galaxy @ May 29 2005, 02:19 PM)
QUOTE (paxdan @ Apr 20 2005, 11:22 AM)
Launched on August 3rd 2004, NASA's MESSENGER will become the first spacecraft to orbit Mercury.

News and updates are availbale via Johns Hopkins University MESSENGER website and the Kennedy Space Center's MESSENGER website.

There will be an earth flyby in August followed by a couple of swings by Venus and three velocity scrubbing passages past mecury before the craft enters orbit in March 2011.

April 18, 2005 status report from JHU. Extensive JHU FAQs page here.
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I for one can barely wait for Messenger. There is a big section of Mercury we've never seen, and I would love to also see close ups of the huge polar ice deposits.
*



"Big section" is putting it mildly.wink.gif If I recall correctly, one of the Mariner spacecraft was the only probe to go past Mercury, and it photographed only a little over a fourth of the planet.

Ugh, searching for Mercury Mariner on Google turns up more matches for some damn new SUV called just that. Of course, it is a hyrbid with mileage about equal to my car, so I guess I can't really complain. smile.gif


Why is it such a long time until Messenger gets to Mercury?

Oh, seems NASA anticipated this question. Link. Orbital insertion around something so small requires a slower speed than, say, something like Cassini.

Should definitely be an interesting mission though. That's a fascinating probe too - all the adaptations needed for flying so close to the sun.
tedstryk
Mariner 10 Photographed 45% of Mercury, or almost half. But only basically one illumination condition was covered - due to orbital mechanics, the same side was illuminated on all three flybys. And the views of many areas were very forshortened on the limb.
MiniTES
MESSENGER = strained acronym. It's even worse than Hipparcos.
JRehling
QUOTE (Buck Galaxy @ May 29 2005, 11:19 AM)
I for one can barely wait for Messenger.  There is a big section of Mercury we've never seen, and I would love to also see close ups of the huge polar ice deposits.
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As others noted, Mariner 10 imaged about 45% of the surface, not all well. Radar has provided some nice additional coverage, not all of which is available publicly.

But we're not going to see the polar ice deposits, at least not in visible wavelengths. They are, if they exist at all, in areas of permanent shade. It wouldn't take much sunlight at 0.4 AU to melt (vaporize) ice.

I suppose it's possible that a crater floor could be imaged in light reflected off of the crater wall, if imaging conditions are just right, and if that kind of lighting isn't enough to make any such parcel of ice disappear.
tedstryk
QUOTE (JRehling @ May 31 2005, 01:27 AM)
As others noted, Mariner 10 imaged about 45% of the surface, not all well. Radar has provided some nice additional coverage, not all of which is available publicly.

  But we're not going to see the polar ice deposits, at least not in visible wavelengths. They are, if they exist at all, in areas of permanent shade. It wouldn't take much sunlight at 0.4 AU to melt (vaporize) ice.

  I suppose it's possible that a crater floor could be imaged in light reflected off of the crater wall, if imaging conditions are just right, and if that kind of lighting isn't enough to make any such parcel of ice disappear.
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I doubt there is reflected light weak enough to not melt ice over eons and bright enough for Messenger to use it to create an image, especially with the glare from whatever is reflecting the light.
edstrick
Uh... doesn't Messenger have a laser altimiter?... that measures reflectance, as well as delay-time which equals range...
I'd have to check, but I thought it did...
Bob Shaw
I'm reminded of the darkside images taken of the Moon by Clementine - I wonder how well Venus will illuminate the shadowed parts of Mercury (obviously, at the right time of the Mercurian year it'll be *much* brighter).
JRehling
QUOTE (Bob Shaw @ May 31 2005, 04:19 AM)
I'm reminded of the darkside images taken of the Moon by Clementine - I wonder how well Venus will illuminate the shadowed parts of Mercury (obviously, at the right time of the Mercurian year it'll be *much* brighter).
*


A full Venus has an absolute magnitude about 4 times that of the Earth, but is 130 times farther from Mercury than Earth is from the Moon. Venusshine onto Mercury should thus be about 1/4200 of the effect of earthshine on the Moon. Depending upon the specs of a camera, that could be used for some imaging, although I suspect that the Messenger camera would not be built for light-sensitivity the way, say, New Horizon's are. The kicker: if the polar areas never see the Sun due to the geometry, they'll never see Venus either.
JRehling
QUOTE (edstrick @ May 30 2005, 10:02 PM)
Uh... doesn't Messenger have a laser altimiter?... that measures reflectance, as well as delay-time which equals range...
I'd have to check, but I thought it did...
*


Yes, the polar ice (if it exists as such) should be detectible through several instruments, and the laser altimeter is one possibility. If they are they, we will end up with image products, I'm sure, mapping them. But we won't have traditional imagery as such (I realize the distinction can be gray -- at what extent does a collection of reflectance data equal an image??).

I'll add that we don't have proof yet that the shadows of the polar craters hold full-fledged surface ice deposits -- only that the areas are highly reflective in radar. They may be dust-covered ice that appear as normal regolith in vis/IR. Whatever is going on there may possibly not involve water ice, but sulfur, for example. Verifying the suspected ice and determining whether or not any such ice is on the surface is something to find out. Finally, the same investigation will be happening with regard to the (presumably similar) phenomenon at the lunar poles. I guess LRO will shed light on the lunar version before Messenger gets to Mercury. (It's quite a coincidence that of the two large airless worlds in the inner solar system, both have large areas of permanent shadow near their poles! -- this wouldn't be true of the Earth or Mars.)
Bob Shaw
Darn - I hadn't thought of that, and it's probably pretty obvious! Not only will libration effects be pretty minimal (unlike the Earth-Moon situation, where something interesting might be a goer), but as Venus and Mercury are probably in all sorts of orbital resonances there's likely to be only a few chances to view the same areas, badly illuminated at best. Oh, well, back to the drawing board.

OK, what about the Zodiacal Light...

Reflections from Comets...

Starlight...
Chmee
QUOTE (Bob Shaw @ May 31 2005, 12:04 PM)
OK, what about the Zodiacal Light...

Reflections from Comets...

Starlight...
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Or how about a high-yield fusion bomb detonated in orbit? Use it like a giant flash-bulb to take a picture! laugh.gif

You could even use the x-rays generated by the explosion to look for hydrogen.
RNeuhaus
Is Mercury atmosphere similar to Moon rather than Mars? What are the composition of Mercury's atmosphere (helllium, hydrogen, oxigen, potassium and sodium)? Wiill the Messengare space answer these questions?
paxdan
Earth from MESSENGER at 29.6 million km

Sunspot
http://messenger.jhuapl.edu/news_room/pres...se_5_31_05.html

"NASA’s Mercury-bound MESSENGER spacecraft – less than three months from an Earth flyby that will slingshot it toward the inner solar system – successfully tested its main camera by snapping distant approach shots of Earth and the Moon."
um3k
No focusing problems on this baby! cool.gif
lyford
I always enjoy these far off shots of Earth. They really drive home how BIG space is and how SMALL our home is...

Anybody seen a higher rez version?
paxdan
QUOTE (lyford @ Jun 1 2005, 07:30 PM)
I always enjoy these far off shots of Earth.  They really drive home how BIG space is and how SMALL our home is...

Anybody seen a higher rez version?
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i think this is the highest we are going to get without image processing.

from the article:

The image is cropped from the full MDIS image size of 1024x1024 pixels
BruceMoomaw
QUOTE (RNeuhaus @ Jun 1 2005, 02:48 AM)
Is Mercury's atmosphere similar to Moon rather than Mars? What is the composition of Mercury's atmosphere (hellium, hydrogen, oxygen, potassium and sodium)? Wiill the Messenger spacecraft  answer these questions?
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It will indeed provide a great deal of additional information on Mercury's atmosphere -- which is incredibly rarified and thus similar to the Moon's atmosphere rather than Mars'. Indeed, both worlds actually have what is described as an "exosphere" -- from which the atoms and molecules escape almost immediately -- rather thann any stable atmosphere. Its surface density is only about one trillion atoms per cubic centimeter. (I'd have to look this up -- I haven't been following the discoveries regarding Mercury's atmosphere closely -- but I think this is an atmospheric density roughly a trillionth of Earth's.)

We also have confirmed recently that Mercury's exosphere contains small amounts of calcium. The exosphere seems to come from atoms "sputtered" off Mercury's surface rocks by the impacting atoms of the solar wind -- a phenomenon much more intense on Mercury than on the Moon, thanks to its closer proximity to the Sun -- and it is suspected that Mercury's magnetic field focuses this activity so that much of the sputtering occurs near the planet's poles.

Messenger's "Mercury Atmospheric and Surface Composition Spectrometer" really consists of two separate, entirely different instruments that might as well count as two separate experiments; they have little to do with each other. Its near-infrared spectrometer will map surface mineral composition, while its ultraviolet spectrometer will specialize in measuring the density, distribution and composition of the exosphere. (I don't know whether it can measure calcium, but I suspect it can -- and one of its goals will be to try to identify additional elements in the atmosphere, such as magnesium, silicon and sulfur.) Messenger's "Energetic Particle and Plasma Spectrometer" also has some ability to directly detect different elements' ions by mass spectrometry -- again, I'd have to do some digging for the details.
Bob Shaw
Bruce:

Can Messenger's instruments detect He on the surface of Mercury? I'm thinking of those old lunar He3 strip-mining plans...

Bob Shaw
JRehling
QUOTE (Bob Shaw @ Jun 2 2005, 02:00 PM)
Bruce:

Can Messenger's instruments detect He on the surface of Mercury? I'm thinking of those old lunar He3 strip-mining plans...

Bob Shaw
*


In principle, He can be detected (quite easily, in fact), but that would only be if it existed in bulk concentrations, which it certainly will not. Lunar Prospector showed no He signal I'm aware of on the Moon. The quantity just isn't much to speak of.
Buck Galaxy
QUOTE (JRehling @ Jun 3 2005, 12:53 PM)
In principle, He can be detected (quite easily, in fact), but that would only be if it existed in bulk concentrations, which it certainly will not. Lunar Prospector showed no He signal I'm aware of on the Moon. The quantity just isn't much to speak of.
*



Huh? I thought the moon's regolith was full of He3?
Phil Stooke
Buck Galaxy said:

Huh? I thought the moon's regolith was full of He3?



No - it has minute amounts of He3. Major strip-mining would be needed to collect the amounts needed for the proposed power schemes.

Phil
BruceMoomaw
Specifically, it's about one part He-3 per 100 million -- which gives you a better idea of the serious problems with mining the Moon for He-3 even if we finally do figure out how to fuse the stuff commercially (which we are absolutely nowhere near right now).
Bob Shaw
Mining the moon for He3 would, of course, give us access to all sorts of other things in the process - not least being meteorites from Earth, Mars, Venus and so on. Possibly even fossils from a certain nearby life-bearing planet (our own!).
Toma B
So there will not be another image of Earth for how long? huh.gif
Why don't they snap a picture at least once a week? blink.gif
BruceMoomaw
Because Messenger is usually too close to Earth to see it as more than a speck -- only during its close flybys of Earth will its camera be able to see Earth clearly. (I believe there is only one more Earth flyby planned before it moves on to using repeated flybys first of Venus and then of Mercury itself to finally put itself into an orbit almost parallel to Mercury, thus allowing it to use an acceptably small amount of fuel to finally brake into orbit around Mercury itself. The Europa Orbiter -- when they finally fly it -- will, after it enters orbit around Jupiter, use repeated flybys of Callisto, Ganymede, and finally Europa itself to match orbits in a similar way with Europa before braking into orbit around Europa.)
BruceMoomaw
"Because Messenger is usually too close to Earth to see it as more than a speck..."

Gaaah. I'm going senile. Make that "too FAR FROM Earth to see it as more than a speck".
gpurcell
QUOTE (BruceMoomaw @ Jun 16 2005, 02:56 AM)
Because Messenger is usually too close to Earth to see it as more than a speck -- only during its close flybys of Earth will its camera be able to see Earth clearly.  (I believe there is only one more Earth flyby planned before it moves on to using repeated flybys first of Venus and then of Mercury itself to finally put itself into an orbit almost parallel to Mercury, thus allowing it to use an acceptably small amount of fuel to finally brake into orbit around Mercury itself.  The Europa Orbiter -- when they finally fly it -- will, after it enters orbit around Jupiter, use repeated flybys of Callisto, Ganymede, and finally Europa itself to match orbits in a similar way with Europa before braking into orbit around Europa.)
*


Bruce, do you know if they are planning to do science during the Venus encounters?
BruceMoomaw
Yes indeedy. Quite a bit (even including using Messenger's laser altimeter to map Venusian cloud top altitudes). The question is whether it will do much of note that Venus Express won't (hopefully) already have done.
JRehling
QUOTE (BruceMoomaw @ Jun 15 2005, 07:57 PM)
"Because Messenger is usually too close to Earth to see it as more than a speck..."

Gaaah.  I'm going senile.  Make that "too FAR FROM Earth to see it as more than a speck".
*


Usually, true, but it's getting closer all the time during these few months. The mission site now has animations depicting the Earth/Venus flybys, and I have some hope that Messenger could produce the "definitive" CCD images of Earth from space. There are darn few good CCD images of the full Earth, but Messenger will have an almost-full Earth for most of its approach, when Earth would fill and more than fill its camera frame. If they got some full-color shots at 6-hour intervals, it would be a wonderful thing, and an unusual photo credit for a Mercury-bound craft.
djellison
Galileo and NEAR both did it - producing movies of the flybys by the time they'd finished

Doug
Toma B
They did it....BUT WHERE ARE THE IMAGES OR MOVIES???
There are only few images...here and there.
djellison
ERmmm..

NEAR - http://near.jhuapl.edu/Images/.Anim.html
specifically - http://near.jhuapl.edu/Voyage/img/earth_swby_lg.mpg


Galileo
http://galileo.jpl.nasa.gov/gallery/earthmoon-all.cfm


Took 60 seconds to find them

Doug
Bjorn Jonsson
And if you want thousands of PDS-formatted Galileo images of the Earth there's always this:

http://pds-imaging.jpl.nasa.gov/cgi-bin/Nav/GLL_search.pl
JRehling
QUOTE (djellison @ Jun 28 2005, 05:27 AM)
Galileo and NEAR both did it - producing movies of the flybys by the time they'd finished

Doug
*


The NEAR stuff is of a half-Earth and looks like it was compressed to the point of severe data loss. You can see lone pixels of red standing out with no other red around them. Maybe there's quality data there somewhere?

Galileo's images are nice, but suffer just a bit for being a very gibbous Earth and (like NEAR) highlighting Antarctica, which misses out on the egocentric "There I am!" potential, but also just looks atypical of any other land mass.

What I'm hoping is that Messenger produces a better product. Galileo's are not bad, but fall shy of canon-level (currently, that one overused Apollo image is about the only such image to have a full Earth and an inhabited continent).
Sunspot
http://messenger.jhuapl.edu/news_room/pres...se_8_02_05.html

NASA’s MESSENGER spacecraft, headed toward the first study of Mercury from orbit, swung by its home planet today for a gravity assist that propelled it deeper into the inner solar system.

Mission operators at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md, say MESSENGER’s systems performed flawlessly as the spacecraft swooped around Earth, coming to a closest approach point of about 1,458 miles (2,347 kilometers) over central Mongolia at 3:13 p.m. EDT. The spacecraft used the tug of Earth’s gravity to change its trajectory significantly, bringing its average orbit distance nearly 18 million miles closer to the Sun and sending it toward Venus for another gravity-assist flyby next year.
dilo
waitng for the movie...
The picture reported in the Messenger site, taken with a telescope from Earth, show some darkening in the central part... look to this enhanced version:
Click to view attachment
Could be due to spacecraft re-orientation?
Myran
Either reorientation or its in a constant slow rotation.
djf
Just noticed this: http://planetary.org/news/2005/messenger_f...movie_0826.html

The movie of the rotating Earth receding in the distance is beautiful. It appears the dark, non-reflective area (i.e. dry land) going into darkness between 07:00-09:00UT is the north coast of Australia. Then near the end of the clip the deserts of the Arabian Peninsula and North Africa are visible through the clouds.
deglr6328
Oh that is just spec-freakin'-tacular! So smooth animation too! Wish there were a higer resolution version though.
hendric
We do have one hell of a beautiful planet. smile.gif

Anyone know of rotation movies of other planets?
JRehling
QUOTE (hendric @ Aug 28 2005, 06:48 AM)
We do have one hell of a beautiful planet. smile.gif

Anyone know of rotation movies of other planets?
*


No links here, but a quick list from memory:

Jupiter is probably the most prolific, with both Voyagers and Cassini having done movie-quality sequences. I think Cassini also did an approach sequence on Saturn, but it is not released yet. The data is out there for partial rotation sequences of Titan and Iapteus, but that will never be full from a single pass.

There's a nice partial rotation movie of Io in Jupiter's shadow.

Pioneer Venus has a few frames for Venus, but nothing movielike.
tedstryk
QUOTE (JRehling @ Aug 28 2005, 04:14 PM)
No links here, but a quick list from memory:

Jupiter is probably the most prolific, with both Voyagers and Cassini having done movie-quality sequences. I think Cassini also did an approach sequence on Saturn, but it is not released yet. The data is out there for partial rotation sequences of Titan and Iapteus, but that will never be full from a single pass.

There's a nice partial rotation movie of Io in Jupiter's shadow.

Pioneer Venus has a few frames for Venus, but nothing movielike.
*


I imagine one could be made from the Mariner '67 Mars images.
hendric
Hmmm...I wonder if they have done any ridiculously high resolution IMAX movies using full resolution shots of these rotations...
djellison
If and when the Messenger data is on the PDS - I'll work it into a WMVHD movie if appropriate. I've been playing with MER imagery at 720p25 format, and it looks fab smile.gif


Doug
Stephen
The MESSENGER team has posted a quite amazing "movie" composed of 358 images they took during their craft's recent flyby showing the spinning Earth during one complete rotation disappearing into the void.

======
Stephen
MizarKey
That movie is one of the most spectacular things I've ever witness...I love the sun's reflection off the ocean and land masses.

To loosely quote "Pale Blue Dot"..."Everyone who has ever lived or died, been written about...was right there" One fragile planet spinning in dark emptiness.

Eric P / MizarKey
BruceMoomaw
It is; it's a lovely piece of work.
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