Landing on Mercury on equator at perihelion |
Landing on Mercury on equator at perihelion |
Mar 21 2006, 12:18 AM
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#1
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Junior Member Group: Members Posts: 40 Joined: 20-March 06 Member No.: 720 |
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.
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Guest_Richard Trigaux_* |
Mar 21 2006, 11:18 AM
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#2
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Guests |
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. |
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Mar 21 2006, 03:20 PM
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#3
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
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. -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Mar 21 2006, 05:37 PM
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#4
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
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. |
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