How will it be to make a manned landing at Mercury at its closest to the sun (perihelion) on its equator when the sun is in the zenith ,what are the dangers of a landing then? Do we need to be protected against the sunheat and radiation then? How strong is the heat and radiation of the sun then ,and is it dangerous when the solaractivity is high then? What kind of spacesuits do we need then? Better protected suits than we have used on the apollo moonlandings i think. Can you explain how a landing on Mercury will be when it is at perihelion and land on its equator with the sun directly overhead? I hope it will ever happen. Lets start discuss about it.
But how will a (hypothetical) manned landing on Mercury be at its perihelion on the equator with the sun in zenith? Can you give an idea of how that looks like ,like i have written in the beginning of this thread? And i really dont understand why we dont put a lander or rovers like on mars on Mercury. We have landed a lander on Venus,Mars,but why not on Mercury? I and a lot of people on earth are waiting for the moment that a lander is on its way to Mercury and that is going to land on this planet to send the first images of the surface of Mercury back to earth ,like the venera,s did on Venus and the vikings and pathfinder did on Mars. The only thing i can say is that we forgot 1 planet ,And that is Mercury. Thanks.
A manned landing on Mercury at perihelion -- or an unmanned one, for that matter -- would be difficult as Hell (which may be appropriate). The problem wouldn't be as severe as that on a Venus lander, but it would be plenty hard -- you would not only need to have an extremely efficient reflecting shield to fend off the heat radiation from the Sun, but also another to deal with that being reflected and emitted from Mercury's surface. (This, in fact, is one reason why the Messenger orbiter will be put into a highly elliptical orbit around Mercury: to give it time to cool off again from each of its low-altitude periapses over Mercury's surface.) As for the design of any EVA walking suit that could cope with that heat: I shudder even to think about the problem. The high-energy particle radiation and X rays from the Sun at that range would also pose a very difficult problem for any manned mission that close to the Sun -- we'll have enough danger from those during long-duration manned trips to Mars and near-Earth asteroids.
However, temperature-wise, there are plenty of other places that either an unmanned or manned lander could touch down on Mercury that would be a cinch. Its near-polar regions are quite tolerably cool -- which is why it has ice as its poles -- and its nightside very quickly cools down after sunset, stays cold, and even stays within modest temperature ranges for a short time after sunrise again.
A polar or nightside landing on Mercury is entirely feasible with the technology we have right now. The trouble, as usual, is simply money. Europe's BepiColombo, which consists of a large and low-altitude European orbiter and a small secondary Japanese one for magnetospheric studies, was originally also supposed to include a very small lander to touch down within about 3 degrees of the pole -- but, since Mercury is an airless world with a gravity field considerably stronger than the Moon's (and therefore requiring a larger mass of braking fuel), in the end the cost and mass of the lander was just too much for ESA's already-strained budget to endure and they cut it out of the mission. At some point it certainly will be done by someone; Mercury's surface almost certainly looks almost indistinguishable from the Moon's, but there are a great many interesting geophysical and compositional instruments they could land there on even a single lander. But that's likely to be a couple of decades off (at least), just for monetary reasons.
Exploring Mercury is difficult. While it's relatively easy to use a single Venus flyby to fly a spacecraft past Mercury, it passes the planet at high speed. Such high speed that it would take an enormous propulsion system to simply get into orbit around the planet. The Mercury Messenger orbiter mission does multiple Mercury flyby's to reduce the spacecraft's aphelion and make it possible to get into orbit with a "reasonable" sized rocket system. And it will take many years to get there.
Landing on Mercury is harder. You are orbiting a planet with a deeper gravity well than the moon, and with no atmosphere to reduce speed from orbital velocity. You have to do it ALL with rockets. Bigger rockets than needed to land on the Moon.
When you get there, you will find an impact generated regolith, made of basaltic to anorthositic (we think) rock, very similar -- indeed visually identical -- to lunar highlands plains and cratered terrain sites.
If Mariner 10 had found a truely exotic planet, as un earth-like or un moon-like than Venus or Titan, we'd have a much greater interest in exploring the planet. Certainly, Mercury has been neglected, as has Venus in many ways. But for good reason, I'm afraid.
At least, and orbiter with high resolution mapping and imaging, and IR spectrum analysis, perhaps radar probing, would be fine. We know little about Mercury and we may find unexpected/unexplained things. And the big mystery is why Mercury has no volcanoes. As far as we know. Another thing would be to detect dust storms (from static electricity, as believed on the Moon) or Transcient "Lunar" Events.
After, a lander would have to check isotopes ratios and place a seismometre, so that we have an idea of Mercury inner structure. After?
Robert Strom (I think) and subsequent researchers have pretty clearly shown that Mariner 10 images show some volcanic flows and deposits. Their geologic morphology is poorly preserved due to considerable primary and secondary impact cratering, and many of the features were observed at such high sun angle that morphology is poorly if at all visible. What they do see is some crater and inter-crater plains with flow fronts and ponded morphology that is rather unlike basin ejecta deposits that fooled Apollo era geologists into thinking Apollo 16 was going to explore highland volcanism. They also see color boundaries in high sun angle data that look like flows with different color and thus chemistry from adjacent plains and crater deposits.
Everything seems to be pretty seriously old. Relatively young volcanics like on the Moon seem to be absent or very scarce, and "constructional" volcanic features are scarce or absent.
One long recognised factor is that the entire crust has scattered lobate escarpments, apparently compressional thrust faults that indicate the crust has been under compression during most of the visible geologic record. This makes it much harder for magma to find a route to the surface as all the channels and fissures are squeesed tightly shut, as compared with a crust under extension.
hey, that is interesting, and fairly different of the Moon. Maybe Mercury has a completelly different history. Worth sending a visible light mapper and IR spectrometre.
The compression of Mercury crust (and perhaps mantle too) is often explained as the result of the cooling and contraction of its huge iron core. This contraction would have created all the compression faults (perhaps following the Mare Caloris impact). The Mare caloris itself produced considerable destructions, for instance at the antipodes all the mountains were thrown into the air by the shockwave.
An interesting job too for a probe would be sensing Mercury's gravitation field. For this it requires a trajectory coming from afar and going as close as possible from the ground. For this, the probe would perform a very close passage, perhaps some kilometres, which would place it on a very elliptic orbit.
From this orbit, it could make a global map of Mercury.
After, the orbit would be circularized at lowered, so that the probe could make high resolution views.
Ideally, on an airless world, the orbit could be lowered at will, theoretically some kilometres, lower than an airliner. But from a previous discution on a lunar orbiter, it appeared that, due to the presence of mascons on the Moon, such orbit is not stable and it ends up crashing on the ground. A similar problem may exist on Mercury, limiting the lowest altitude.
An interesting prediction, from the crust compression model, is that it could exist many underground tectonic cavities. If there is yet any form of volcanism or outgassing, it would take place here, and the cavities may have a complete atmosphere (with a pressure gradient and all). Eventually this could lead to some outgassing at very low pressure, if there are exit points.
Come on, guys - just land at night!
How about landing on the terminator (where the temperature is balanced,
right?) and having the mission follow just ahead of sunrise. The planet takes
59 days to rotate, so it should be slow enough for the explorers.
I saw them do this on the Chronicles of Riddick, so it must be true.
To summarize what other posters have written: Mercury is the hardest place in the solar system to land.
It takes more delta-v to get from the Earth to Mercury than to any other planet. Including Pluto. In fact, a minimum-energy voyage to Alpha Centauri would cost less delta-v than a minimum-energy voyage to Mercury! (Of course, the former would take millions of years.)
Among the solid bodies in the solar system, Mercury is unique in terms of having a pretty high escape velocity (roughly a tie with Mars for third-highest, behind Earth and Venus) but NO atmosphere to assist in the deceleration from cruise to landing. So it requires the most hardware to undertake a soft-landing of any solid body in the solar system! That's two categories in which Mercury is THE hardest!
Those two difficulties combine: You have to take all of that soft-landing hardware to Mercury, which means that the launch will involve a very large rocket for a given payload.
The other difficulty, thermal, makes Mercury more difficult than almost anywhere else: Venus is worse in this respect, but only because Mercury has cooler poles and night. Landing on the equator in daytime would make Mercury very hard in that respect too. We don't have any hardware that could survive those surface conditions unless it involved a nuclear-powered refrigerator, and now we've tripled the (not just additive but multiplicative) mass problem.
Takeoff from Mercury would be as difficult as from Mars, and then the cruise back to Earth would be VERY hard: again, the biggest delta-v leap of any planet for a back-to-Earth trajectory.
All told, I'm not sure if anything less than a Saturn V could launch a Mercury equivalent of a MER, assuming that we could build a rover that could survive Mercurian conditions. It's safe to say that the Mercury equivalent of Apollo would involve technology far beyond anything yet developed. Imaginable, perhaps, but not yet developed. And the long cruise to Mercury would mean that a solar storm would have an excellent chance of killing the crew. If you utilize gravity assists from Venus, the cruise gets longer.
It's got sort of a joke-like difficulty to it. I'll predict that by the time we had the rocketry to perform a Mercury human mission, the state of robotics would make any such mission purposeless. But I won't live long enough to collect on that bet.
Even Arthur C. Clarke, the Keeper of the Holy of Holies, said in "Odyssey Three" that, at a time when humans were routinely poking around comets and the like, only two manned landings had ever been made on Mercury -- and neither of them got much attention. The place has certainly got plenty of interest for geologists, but as Ed said it just isn't distinctive enough to have any pizzazz for people not intensely interested in science.
Are there space artist impressions to find on the web of Mercury,s surface? and other planets? And which are the best and most real and the most beautifull? Can somebody help to find that stuff? Thank you.
The Mercury atmospheric composition:
It has stupendously less than that -- its atmospheric pressure is, I believe, about one-trillionth that of Earth. That is, it is an "atmosphere" only by the strictly scientific sense of the word, like that of Io. Its list of constituents still seems to be growing -- potassium and calcium atoms have now been identified in it, and there may be others. (For instance, there is surely a faint trace of argon-40 in it, decaying naturally out of the potassium-40 in Mercury's rocks.) But it is entirely an "exosphere"; the incredibly faint trace of gas making it up has all been baked out of Mercury's surface crust by meteoroid impacts and/or sputtering of Mercury's surface rocks by high-speed particles of solar radiation.
Niven may or may not have been aware of the really weird anomalous data on Mercury that the 3/2 synchronous rotation explained.
Earthbased radio astronomy measurements of the radio (thermal, they presumed, correctly) emission of the disk as a function of phase angle showed that the nightside subsurface was warm, as if the planet wasn't in 1:1 synchronous rotation, instead of at cryogenic temperatures.
D'oh!... turnes out that side faces the sun half the time, too.
He surely wasn't aware of that, or he wouldn't have called it "the coldest place in the Solar System", now would he? Hmmm? (Come to think of it, though, I remember seeing a little reference to it in an issue of Science Digest back in 1964-65 before the radar discovery broke.)
I'm assuming he wasn't. It was pretty obscure science at the time. Planetary radio was barely able to measure whole-disk brightness temperatures of planets as a crude function of wavelength and phase angle, and maybe some indication of limb darkening at the shortest wavelengths.
It was a *** THIS IS WEIRD *** type of observation leaving them wondering about calibration and the like.
There was in another thread a discution on the possibility of a http://www.unmannedspaceflight.com/index.php?showtopic=1647&st=30, understand a lander which would be able to withstand the tremendous heat on Venus. On mercury, the conditions are in fact easier, as there is not the tremendously oxydizing Venus atmosphere (but solar radiations instead).
The discutions revolved around things such as using high temperature semicionductors (there are many, even more than at current temperature) or more innovative things such as electrostatic micro-relays, or micro sized vacuum tubes (with performances comparable to transistors). With a few cheap experiments, we could quickly know if really an electronics working at 460°C is feasible. If yes, little development is needed, as most of the technology already exists.
So the idea of a long lived lander on Mercury can be envisioned seriously, not just as a dreamy prospect.
As I explained ealier, an orbiter around Venus with high resolution imaging and IR spectrometre mapping would be the very least to do. To have some small landers with seismometres and an isotopic analysis too. But, as Bruce Moomav explains above, we need several seismometres in the hot zone, not just on the poles.
A long lived Mercury lander would have decidedly different objectives from a short-lived one. Also is the landing terrain: normal regolith versus polar ice deposits.
A short life lander could do Surveyor type imaging of the local regolith, but with real UV to mid IR specteral capability. You might have a slow-scan imaging spectrometer that wouild build up a few complete pans at good resoluton over a lander's life. Then you'd have an instrumentation suite that would do Hydrogen to Uranium elemental abundances of samples, isotope measurements, and precision mineralogy.
A long life lander would have to characterize the landing site with imaging and the like, but it's primary goals would be geophysical: Seismic, Magnetic fields, atmosphere, solar-wind interaction.
Mercury has massive polar ice deposits in permanently shadowed crater bottoms and other locations. Radar data show the deposits are 1) thick, and 2) non-atennuating, with high internal scattering. We see exactly the same type radar return from the exposed permanent martian ice caps (*not* the ice under dirt surrounding the poles), and on Ganymede, Callisto, Europa. Lunar polar ice, which is probably present in small amounts, nowhere has shown the strong depolarized return of these other deposits, and probably consist of some percent of ice mixed with regolity in the cold traps. A Mercury Polar Ice explorer will be of great scientific interest, but it's a very long term priority.
An ion drive would do well on a trajectory to Mercury. Plenty of solar energy.
I cannot calculate if such a trajectory is feasible, but I well see a probe launched at 11km/s from Earth on a sun orbit, spiraling closer an closer from Mercury orbit, until it is caugh in orbit around it. Then it continues braking with its ion drive untill it is on a low orbit. After of course a classical chemical rocket is necessary to land.
Such a mission would need much less fuel than braking all the speed from a direct approach with only a chemical rocket. So it removes part of the cost problem.
I feel that Mercury is not just the grey and boring world we currently imagine. Interesting and unusual geology may exist near the poles if there are sulphur deposits. And where this sulphur would come from? Volcanoes! Oh, better: sulphate rocks from an ancient ocean!!!
I think it is simply incredible that Mercury just stopped any large scale geologic activity sooner than the much smaller Moon. There is a mistery, worth at least an orbiter. With ion drive, it would not be so costy.
Mariner 10 did have a tiny infrared radiometer. It trailed 2 beams across the terminators and nightside, one on final approach and one beam as it was exiting from behind the planet. Interestingly, the nightside of the "departure" hemisphere had more thermal variety than the very bland "approach" hemisphere nightside.
What kind of experience will it (possibly) be when you land on Mercury ,when it is at perihelion its (closest) distance to the Sun ,and the Sun is overhead in the zenith. How will the heat of the Sun feel then? Does it really feel burning through the glasses of your helmet of your spacesuit? I really love the thought of how it will be to be on Mercury then.
All I can say is you like hot weather a lot more than I do, Rem...
I have vague memories of reading, years ago, some document that said that in that particular place at that particular time, Mercury's surface temperature actually does rise to significantly above that of Venus. It's an extremely fuzzy memory, though, and I could be wrong. (I do know that Caloris Basin got its name because its center is pretty close to one of the two points of maximum equatorial surface temperature on Mercury on such occasions -- alternating with another point 180 degrees away, of course.)
What are the kind of dangers of a (manned) landing on Mercury at the equator when it is at perihelion (closest to the Sun)? will the astronauts need Sunprotection then?
God, yes. We've mentioned all this before. A manned landing under such conditions presents huge problems even if you don't try to get out of your ship and walk around -- it presents staggering problems for any space suit design. Very large-scale daytime surface exploration of Mercury, whenever the human race ever gets around to it, is yet another opportunity to utilize remote-control robots controlled from a nearby, non-landed and Sun-shielded manned ship (which could be hundreds of thousands of km from Mercury, thus avoiding the emitted IR heat from the planet's surface itself).
And on a manned landing on Mercury at (perihelion) at the equator with the Sun in zenith at Caloris basin ,how hot does the Sun feels then? Will it be a burning Sun or just not. The Sun is even burning hot at (this) moment in my backyard in the Netherlands ,how will that be when compare it with a equatorial Sun on Mercury? What is the kind of protection that the astronauts need against the Sun when they land and walk on Mercury at perihelion at Caloris basin? And my last question ,what kind of cooling will the spacesuits need then? Can you try to answer this questions? Lot of thanks. Rem 31.
As I recall, Mariner 10's discovery of a magnetic field at Mercury was something of a surprise. That, plus the more accurate determination of the planet's density (which turned out to be much higher than all but Earth's) provided by Mariner 10's measurement of the size and mass of the planet, led scientists to posit a large iron core for Mercury. That alone is worthy of study, and while Messenger and BepiColumbo orbiters will constrain the models of the planet's interior, there's nothing like a seismic network of landers to really study the planet's geology. A number of people posting here have suggested that such a network could be emplaced at the poles or at high latitudes, but I see nothing far-fetched about a low-latitude seismic network of landers. All the probes would have to do is land early in the Mercurian night, as others have suggested, and dig into the regolith a few dozen meters! (We are already developing automated drilling technology for Mars exploration.) There is no need for the spacecraft to be "cooked"; a few meters down, there is bound to be a benign temperature regime. Such landers could function for a very long time, whether powered by RTGs or some sort of suitably-hardened solar panels. (And if the latter are developed, SEP would make even the daunting task of reaching and orbiting Mercury not so far beyond present technology, I would think.) But the automated drilling is an enabling technology, no?
- John Sheff
John:
The trouble with Mercury is, that although the environment *could* be coped with at a pinch, the sheer cost in terms of rocketry is worse than enormous. Getting to Mercury at all other than (slowly) by way of multiple Earth-Venus gravity assists is hideously impractical - and landing on it is literally the 'worst-case' scenario in the entire Solar System, what with it's reasonably high gravity and no atmosphere for braking purposes.
To put men there is even more difficult as you'd almost certainly want to do it *quickly* because of Solar flares!
To get to Mercury you really need some major set of breakthroughs in propulsion technology, even above and beyond the few speculative technologies we have some promise of!
Bob Shaw
A comparative view of Sun between Mercury and Earth.
I know how horrendous the delta-vee requirements are for landing on Mercury, but they're not, even with present technology, impossibly high. If you remember, the lander portion of Beppi-Columbo was not nixed for technological reasons - it was simply deemed too expensive for the program's budget!
I agree that manned landings, when they happen, will probably not occur within our technological horizon, i.e., this century, and only as a "mopping-up" exercise after the rest of the solar system has been thoroughly explored.
I remember as a kid reading a SF novel by Alan E. Nourse, called, I think, "Brightside Crossing" (You might want to look it up, Rem31, if you can find a copy; it might answer your questions). It may even have been written before Mercury's true rotation period was known. His characters mounted a surface-crawling manned expedition to traverse Mercury's dayside, timed to arrive at the center right when the planet was at perihelion! The expedition was mounted not for the sake of science, but for the glory, as it was "the last great challenge left in the solar system". This was science-fiction, I know, but I wonder ...
Today you have people willing to pay $60,000 and put their lives at great risk to climb Mt. Everest. They do it not for science, nor for the sake of being as high up as they can. (You can, after all, get higher in a aircraft or spacecraft!) They do it for the sheer challenge of it, "because it was there". So the fact that Mercury is, as you say, the most difficult place in the solar system to get to, may not repel people, but may be precisely what makes it an irresistable draw for some. Funny things, these humans...
Absolutely agree with you on this but people are strange as Jsheff pointed out. At some stage some human will just do it so they can say they did it first.
Well, all the way back in the 1950s -- when he was still an unabashed hack SF writer rather than a fairly good stylist -- Robert Silverberg wrote a story about an attempt to drive all the way across Mercury's dayside (which ends in failure and the deaths of a couple of the participants). More recently we've had stories about a guy deliberately jumping into that gigantic cleft on Miranda (20 km deep, if I remember correctly), and -- so help me God --another one about the first successful bungee jump from orbit into the atmosphere of Jupiter.
Do you need also Solarheat and radiation protection when you land on Mercury when it is at (aphelion)? greatest distance from the Sun. I know that you need protection when landing at perihelion ,closest to the Sun. And what will be the best place on Mercury to put a lander down on the Surface?
I don't have detailed numbers for you, but my gut feeling is that the proximity of the Sun is such, aphelion or perihelion, that you'd run into a similar harshness of environment (and need about the same level of protection) either way.
After all, what difference does it make if the heat outside is just about enough to melt lead, or just more than enough to melt lead? Well, except for maybe needing lead-pond floats on your spacecraft... though I will note that there is no evidence of liquid-ponding of *any* materials in the Mariner 10 images.
-the other Doug
In spite of the fact Mercury has extermes temperatures between day and night: 427°C and -173 °C and its mean surface temperature of 179 °C, the best place for human supervivence is on the poles. At the poles might have some water ices. But, the problem is that every 44 days (one orbital period is close to 88 days), the North and the South of poles will have alternate soft summer and winter due to its small orbital inclination of 7 degrees.
However, Mercury has own a small magnetic field that is 1% as strong as Earth. This does not help much to protect from solar wind and energetic particles.
Finally, Mercury's Perihelion is 46,001,272 km and Aphelion is 69,817,079 km, difference of 23.8 millions kilometers is much difference than the Earth with its about 3 millions kilometers. That will induce, I seems, a small greater variations of temperatures between the seasons.
All at all, Stephen Hawking recently has told to the press that there is no any an adequate biosphere place for human in our solar system unless we have to travel inter-stars searching for a similar Earth biosphere.
Rodolfo
Good tought ermar!
I haven't percated that its 7 degree inclination orbital implies a 0.01 degree for sol inclination orbital. Hence, the poles might have some permanent ice since they might be always in the shadow. Not yet sure if there are any volcan or mountain on the poles. Anyway, the climate of Mercury is similar to Moon only for the night side and much harsh for the day side.
Rodolfo
Here is one of the most beautifull photographs of Mercury i can found on the web Taken by the Mariner 10. Mercury was at near (ap)helion ,its greates distance from the Sun. You can see the sharp dark shadows on the picture. One thing is sure ,it will be hot on the dayside areas on the time the pictures were taken. I hope that the link works
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.
I note that that page has ONE (the first) of the Mariner 10 WIDE angle camera images of Venus.
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/060111_hit_and_run.html
http://www.spacedaily.com/reports/Early_Mercury_Impact_Showered_Earth.html
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!
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?
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.
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/2006-9%20IAC%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.
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...
"...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.
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