MESSENGER News Thread, news, updates and discussion |
MESSENGER News Thread, news, updates and discussion |
Guest_Sunspot_* |
Jun 1 2005, 08:40 AM
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#16
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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." |
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Jun 1 2005, 05:01 PM
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#17
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Member Group: Members Posts: 345 Joined: 2-May 05 Member No.: 372 |
No focusing problems on this baby!
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Jun 1 2005, 06:30 PM
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#18
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Senior Member Group: Members Posts: 1281 Joined: 18-December 04 From: San Diego, CA Member No.: 124 |
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? -------------------- Lyford Rome
"Zis is not nuts, zis is super-nuts!" Mathematician Richard Courant on viewing an Orion test |
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Jun 1 2005, 07:43 PM
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#19
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Member Group: Members Posts: 562 Joined: 29-March 05 Member No.: 221 |
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? 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 |
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Guest_BruceMoomaw_* |
Jun 1 2005, 07:49 PM
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#20
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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? 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. |
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Jun 2 2005, 09:00 PM
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#21
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Senior Member Group: Members Posts: 2488 Joined: 17-April 05 From: Glasgow, Scotland, UK Member No.: 239 |
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 -------------------- Remember: Time Flies like the wind - but Fruit Flies like bananas!
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Jun 3 2005, 12:53 PM
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#22
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
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. |
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Jun 4 2005, 02:46 AM
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#23
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Junior Member Group: Members Posts: 24 Joined: 6-March 05 Member No.: 185 |
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? |
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Jun 4 2005, 03:05 AM
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#24
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Solar System Cartographer Group: Members Posts: 10229 Joined: 5-April 05 From: Canada Member No.: 227 |
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 -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Guest_BruceMoomaw_* |
Jun 4 2005, 05:55 AM
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#25
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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).
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Jun 4 2005, 05:26 PM
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#26
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Senior Member Group: Members Posts: 2488 Joined: 17-April 05 From: Glasgow, Scotland, UK Member No.: 239 |
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!).
-------------------- Remember: Time Flies like the wind - but Fruit Flies like bananas!
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Jun 15 2005, 04:41 PM
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#27
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Member Group: Members Posts: 648 Joined: 9-May 05 From: Subotica Member No.: 384 |
So there will not be another image of Earth for how long?
Why don't they snap a picture at least once a week? -------------------- The scientist does not study nature because it is useful; he studies it because he delights in it, and he delights in it because it is beautiful.
Jules H. Poincare My "Astrophotos" gallery on flickr... |
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Guest_BruceMoomaw_* |
Jun 16 2005, 02:56 AM
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#28
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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.)
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Guest_BruceMoomaw_* |
Jun 16 2005, 02:57 AM
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#29
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"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". |
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Jun 16 2005, 03:34 PM
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#30
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Member Group: Members Posts: 242 Joined: 21-December 04 Member No.: 127 |
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? |
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