Landing on Mercury on equator at perihelion Options

[helvick]

I hope that the link work

Nope but this should do the trick :

[edstrick]

Note that we *DO* know there's polar volatile <ice, probably> deposits on Mercury. Due to the orbital tilt of the planet, we can look down into the permanently shadowed craters at the poles with earthbased radar and see intense, depolarized radar returns from the shadows that have identical properties to the martian residual polar caps and the surfaces of the icy galilean moons.

[JRehling]

Nope but this should do the trick :

The old version of that mosaic with visible seams where the brightness changes has had a long lifetime on the web, but the corrections have been made and can be found, with other Mariner 10 imagery, here:

http://cps.earth.northwestern.edu/M10/TXT/encounters.html

[edstrick]

I note that that page has ONE (the first) of the Mariner 10 WIDE angle camera images of Venus.

[Rem31]

The old version of that mosaic with visible seams where the brightness changes has had a long lifetime on the web, but the corrections have been made and can be found, with other Mariner 10 imagery, here:

http://cps.earth.northwestern.edu/M10/TXT/encounters.html

Why has the (large) image an brighter and lighter colour than the smaller image of the link i have posted?

[efron_01]

about Mercury having been a moon of Venus..
I have seen several articles that asume that Mercury did experience a terror impact itself
early in it's history, blowing a lot of the material of the original planet away.

therefor the iron core is too big for the size of the planet and it would explane it's orbit

Any moons that came from this impact fell down to the planet, or into the sun
It could also explain the sudden rise in impacts on the moon and the earth 4by ago

http://www.space.com/scienceastronomy/0601...it_and_run.html

http://www.spacedaily.com/reports/Early_Me...ered_Earth.html

[nprev]

As I recall, the Arecibo radar images of Mercury's North Pole seem to indicate the same cratered terrain typical of most of the planet. In fact, the ice repositories are thought to primarily reside in some of the deeper craters because they avoid direct exposure to sunlight.

Sure would be a great surface mission...that material has to be virtually primordial...whether it originated via ancient outgassing from Mercury or from cometary impacts is the main question to answer!

[Alan S]

This might be a topic for a new thread, but since I'm new, I'll just ask my question here.

Apollo Astronaut has advocated an idea of mining Helium-3 from the lunar surface, since we believe that the solar wind impacting the surface of the moon for billions of year should implant this material into the surface matarial. I've done some reading at it appears the certian minerial are more likely to contain the Helium-3 then others (illiment being one that I recall.)

So, here is my question. Assuming engineers can develop a Helium-3 fusion reactor and mining He-3 becomes worthwhile, wouldn't Mercury --being closer to the sun-- contain much more Helium-3 then the moon? I've not seen anything writen about this. Is this a correct idea. Could we mine He-3 from Mercury?

[edstrick]

The helium 3 is a fraction (in very approximate primordial proportion) of the total helium in the sun and thus the solar wind. (Earth's traces of helium are almost entirely "new" atoms from alpha-particle decay of uranium and thorium and their decay-chains of nucleids. Earth lost most of its helium 3 and only traces show up in certain natural gas wells that contain some primordial gas leaking from inside the Earth)

The solar wind impacts the soil and high velocity nucleii in the wind are "implanted" some micrometers into the impact glass and mineral grains of the regolith. As the regolith gets repeat-pounded by small meteor impacts, it's progressively re-re-re-re shock melted and mixed with regolith glass and mineral fragments. As it gets older, it approaches a steady state where most of the soil is glass and it's just reprocessed in-place, slowly getting thicker from random larger impacts as it gets older.

On mercury, impact gardening may be somewhat faster than on the moon, while solar wind impact will be significantly larger, but the higher surface temps (baking out the soil) at low latitude and the nature of the re-processing of regolith may result in an only modest increase in the helium-3 content per kilo of regolith.

Helium 3 mining is a fantasy for the near and intermediate term future. Fusion power is always 50 years in the future <who said that?>, and deuterium/helium-3 fusion is harder than deuterium/tritium or deuterium/deuterium fusion due to the presence of 2 protons in the He-3 nucleus.

[ljk4-1]

Dr. Robert Bussard of the Bussard ramjet interstellar vessel concept fame,
has been promoting a new type of fusion engine called inertial electrostatic
confinement fusion (IEC).

IEC involves "a fusion process that converts hydrogen and boron directly
into electricity producing helium as the only waste product."

See this video of a talk Bussard gave on the IEC for the details:

http://video.google.com/videoplay?docid=1996321846673788606

The Advent of Clean Nuclear Fusion: Superperformance Space Power and Propulsion

By Dr. Robert W. Bussard

57th IAC, Valencia, Spain, October 2-6, 2006

http://www.askmar.com/ConferenceNotes/2006...IAC%20Paper.pdf

So there may be no point in going to Mercury to mine Helium 3. Speaking
of mining Mercury, what minerals might the planet have that would make
going there for that purpose worth it? No doubt mining the planetoids would
be much easier and cheaper. Perhaps Mercury would make a good solar
observation station.

[JRehling]

So there may be no point in going to Mercury to mine Helium 3. Speaking
of mining Mercury, what minerals might the planet have that would make
going there for that purpose worth it? No doubt mining the planetoids would
be much easier and cheaper. Perhaps Mercury would make a good solar
observation station.

I'm not sure if it would be worth going to Mercury for Helium 3 even if that were the only form of fusion and it worked great. In fact, I doubt it. By no means is there anything else on Mercury would going to get and bring back. You'd lose money bringing diamonds back from Mercury even if they were already pre-cut and in fireproof burlap sacks.

This may be hard to believe, but the minimum-energy path to Mercury is greater than that to any other solid object... in the universe. And there's no atmosphere to brake your descent. And the escape velocity is nontrivial for your trip home, with the same delta-v on the way back to Earth. A muscular there-and-back mission could take place FASTER than one to Pluto, but far more expensively.

There would be no reason to send a (visual) solar observatory to Mercury. Why not just orbit the Sun at the same distance -- what use is it to have the ground beneath you, at an alarming increase of delta-v (and spending ~50% of the time unable to see your target) for the privilege?

I'd go back to the start here and opine that it wouldn't be worth going to Mercury for Helium 3 even if the only other form of energy available to the human species was burning wood and scaling back our population to pre-industrial levels. Basically, I don't think it's a break-even no matter what. Mercury is not economically viable.

[Bob Shaw]

The helium 3 is a fraction (in very approximate primordial proportion) of the total helium in the sun and thus the solar wind. (Earth's traces of helium are almost entirely "new" atoms from alpha-particle decay of uranium and thorium and their decay-chains of nucleids. Earth lost most of its helium 3 and only traces show up in certain natural gas wells that contain some primordial gas leaking from inside the Earth)

In fact, there's hardly a drop of He to be had on Earth bar from a couple of US sources - and that's not exactly a renewable commodity. Nazi Germany tried to buy helium from the US before WWII for their airship programme, but were refused access as even then it was deemed to be a strategic asset. Thus we got the Hindenberg disaster (actually, barely a hiccup in terms of aeroplane crashes) but equally there were no Nazi nukes. (Yes, I know, it's more complicated than that!)


Bob Shaw

[nprev]

I think that JR's analysis was right on, if nihilistic (reality can be that way! ) The only use I can think of for Mercury is something like what's happening to the California desert right now. Mercury may be colonized if there's literally no place else left to go in the Solar System in the distant future.

This would of course depend heavily on three rather unlikely background conditions: high-speed economical interplanetary space transportation (propulsion method unknown), one or more extremely prosperous human cultures that have already colonized everywhere else, and truly fearsome population pressure.

EDIT: Heck, let me add one more precondition: Human interstellar travel must be utterly infeasible. If it were, then better real estate would surely be accessible...

[edstrick]

"...what minerals might the planet have ..."
We dont' really know about low abundance mineralogy, but the bulk of the crust is made from similar rather refractory <high temperature melting and vaporising> minerals as the lunar surface, more specificially the lunar highlands. Calcium feldspar and pyroxenes, and some olivine <maybe> More interesting and unknown in composition are the polar crater volatiles. But they're of science interest, not anything else except very long term value as resources.

Seriously high performance ion drive missions... solar electric will do just fine... can do the hard transport to and form Mercury fairly easily, though not descent/ascent for sample return.