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Mercury, Large quantity water ice


pantheory
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Large quantities of water ice on Mercury.

 

This is an interesting news article about finding large quantities of water ice at Mercury's poles, estimated to be between 100 billion and a trillion tons of water. This seems like a good place for future colonization like the moon, and easier than Mars. We could develop underground colonies in locations near the water sources at Mercury's poles as well as at the lunar poles. Both polar locations could transfer nearby heat from the sun for solar heating, to supply electrical energy for such a colony, and lighting for underground farming. Solar or nuclear power could be provided for manufacturing and mining. Based upon these water resources, its closer proximity, and accessible water supply, it may be easier to colonize Mercury than Mars. Much less fuel would be needed to escape its gravity, where hydrogen and oxygen fuel could be readily manufactured on site. The underground colonies might be able to spread out in all directions from the poles including downward, only limited in its extent by temperature control.

 

Large quantities of ice on Mercury.

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Very interesting. When I had read about the possbility awhile back, I thought it was a bit strange. With very little atmosphere, I would have thought that the ice would sublimate in short order. But I guess at those low temps, it may not happen.

 

So it might be a more ideal first colony when compared to Mars in some ways. But, I think there is still the issue of radiation. The interior of the planet would be protective, but a ship would need to get there, and would be exposed.

Edited by akh
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Very interesting. When I had read about the possibility awhile back, I thought it was a bit strange. With very little atmosphere, I would have thought that the ice would sublimate in short order. But I guess at those low temps, it may not happen.

 

So it might be a more ideal first colony when compared to Mars in some ways. But, I think there is still the issue of radiation. The interior of the planet would be protective, but a ship would need to get there, and would be exposed.

It would probably be easy to build a leading heat and radiation shield of solar cells in front of a ship selectively filtering solar radiation, and using it for the ships electrical needs. Once landed there would by no direct radiation if one lands behind the solar horizon. Polar underground colonies would likewise be shielded from heat and radiation.

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Edited by pantheory
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Emphasis mine:

Based upon these water resources, its closer proximity, and accessible water supply, it may be easier to colonize Mercury than Mars.

Do you realize how hard it is to get to Mercury? There's a reason NASA (and nobody else) has sent all of two missions to Mercury, while practically every space faring nation has sent multiple missions to Mars. Getting even close to Mercury an extremely expensive endeavor. Placing a vehicle in orbit about Mercury is monstrously expensive. Landing on Mercury would be even more than monstrously expensive.

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Emphasis mine:

 

Do you realize how hard it is to get to Mercury? There's a reason NASA (and nobody else) has sent all of two missions to Mercury, while practically every space faring nation has sent multiple missions to Mars. Getting even close to Mercury an extremely expensive endeavor. Placing a vehicle in orbit about Mercury is monstrously expensive. Landing on Mercury would be even more than monstrously expensive.

 

Yeah. Curiosity to Mars - 253 days. Messenger to Mercury - 1260 days. Its not the distance or getting there that is the issue. The issue is slowing down enough to actually orbit or land.

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Emphasis mine:

 

Do you realize how hard it is to get to Mercury? There's a reason NASA (and nobody else) has sent all of two missions to Mercury, while practically every space faring nation has sent multiple missions to Mars. Getting even close to Mercury an extremely expensive endeavor. Placing a vehicle in orbit about Mercury is monstrously expensive. Landing on Mercury would be even more than monstrously expensive.

I think the reason little money has been spent on Mercury is because we never saw any possibilities for human utilization of it someday. Finding water there may change all that. It may be easier to get to Mercury than it is to Mars even though it is twice as distant. Once we get out of the Earth's gravity the sun generally pulls a spacecraft inward toward the sun so less velocity is needed to go to Mercury. Once on Mercury we are in the sun's gravity well and it certainly would take more fuel to return to the Earth but maybe not more than a round trip to Mars. And like Mars and the moon, we could manufacture hydrogen-oxygen fuel there. Once we develop the equipment, designs, and have the experience from lunar colonies, Mercury colonies may be an easier next step than Mars colonies. I think colonies in the asteroid belt where large quantities of water are found, would be even easier for mining colonies. Other than the moon and the asteroid belt, if the west chooses Mars first maybe other countries might choose Mercury as a more likely mining and habitation payoff.

//

Edited by pantheory
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Once we get out of the Earth's gravity the sun generally pulls a spacecraft inward toward the sun so less velocity is needed to go to Mercury.

Learn some orbital mechanics.

 

Every once in a while people come up with the brilliant idea of sending nuclear waste into the Sun. This is just silly. It's silly because it would take less energy to send that nuclear waste on an escape trajectory out of solar system. People just don't understand how expensive it is energy-wise to go down into a gravity well.

 

This also applies to getting to Mercury. It is extremely expensive to get there, extremely expensive to stop there. If it weren't for Venus, we could not do it. The reason it took so long for MESSENGER was that it had to make a very large number of gravity slingshot maneuvers.

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Learn some orbital mechanics.

 

Every once in a while people come up with the brilliant idea of sending nuclear waste into the Sun. This is just silly. It's silly because it would take less energy to send that nuclear waste on an escape trajectory out of solar system. People just don't understand how expensive it is energy-wise to go down into a gravity well.

 

Escaping a gravity well takes a lot of fuel. Going down seemingly could take little fuel if you are willing to wait the time required. There is a continuous acceleration when going toward the sun, and Mercury if it is calculated to be in a direct line with the sun upon arrival :)

 

This also applies to getting to Mercury. It is extremely expensive to get there, extremely expensive to stop there. If it weren't for Venus, we could not do it. The reason it took so long for MESSENGER was that it had to make a very large number of gravity slingshot maneuvers.

 

Because of the distance we had to use gravity assist maneuvers to get there in a timely manner. But relatively little power was required for such maneuvers. Getting back would require a lot more fuel. But refueling there would change that initial fuel requirement in the distant future.

Edited by pantheory
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Escaping a gravity well takes a lot of fuel. Going down seemingly could take little fuel if you are willing to wait the time required. There is a continuous acceleration when going toward the sun, and Mercury if it is calculated to be in a direct line with the sun upon arrival :)

This is completely wrong. Learn some orbital mechanics. I suggest you start with learning about Hohmann transfers, http://en.wikipedia.org/wiki/Hohmann_transfer_orbit.

 

 

Because of the distance we had to use gravity assist maneuvers to get there in a timely manner. But relatively little power was required for such maneuvers.

Trajectories involving gravity assists are not "timely", particularly when the gravity assists involve flying by Earth, then twice by Venus, and then Mercury three times. It took MESSENGER over 6½ years from launch to orbit insertion at Mercury.

 

 

Getting back would require a lot more fuel. But refueling there would change that initial fuel requirement in the distant future.

This, too, is wrong. Gravitation is a conservative force. It takes just as much energy to get there as it does to get back.

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once we have a steady foothold in robotics and its most interesting chapter of nano-robotics, we could send spaceships of them to mars, and they could build a new home for us.

the most interesting part is that they can be monitored and controlled from earth, and incoming radiation can be converted into "photoelectricity" to power themselves.

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once we have a steady foothold in robotics and its most interesting chapter of nano-robotics, we could send spaceships of them to mars, and they could build a new home for us.

the most interesting part is that they can be monitored and controlled from earth, and incoming radiation can be converted into "photoelectricity" to power themselves.

 

A very good idea. But to build a robot which can build homes and all would not be a quick job. It won't be easy.

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DH,

 

This, too, is wrong. Gravitation is a conservative force. It takes just as much energy to get there as it does to get back.

An extreme example is moving toward a galactic black hole from space. You need no fuel or energy to get there because you will eventually get "sucked toward it" if you are close enough to start with. But once very close to the black hole it would take a huge amount of fuel to escape its gravity well where it took no fuel at all to get there to start with. The point is that when in a stationary position relative to the sun, it would take less fuel to go 57 million miles toward the sun than it would take to start from from 36 million miles away from the sun (mean distance Mercury to sun) to 93 million miles away from the sun (Earth) where you are working against strong solar gravity to start with.

 

To go into the same orbit takes the same amount of fuel regardless of your destination. With the same starting velocity, when going toward the sun your craft would be accelerating, and when going away from the sun your craft would be decelerating. Once orbiting Mercury, a craft would need more fuel to go in the direction of Earth, than it would need to go toward the sun.

//

Yeah. Curiosity to Mars - 253 days. Messenger to Mercury - 1260 days. Its not the distance or getting there that is the issue. The issue is slowing down enough to actually orbit or land.

 

Yes, this was a big issue. I think they used ion propulsion for this tricky deceleration- to-orbit maneuver.

//

Edited by pantheory
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How does the science explain this huge quantity of ice in that planet?

 

Isn't it contradict to the current theory of star creation?

I offer one possible explanation. Cometary impact. Four billions years worth. That would be wholly consisten with current theory.

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How does the science explain this huge quantity of ice in that planet?

 

Isn't it contradict to the current theory of star creation?

 

There are many other factors (see post above ^). The "current" theory of star creation (star system creation) looks great and seems plausible for our solar system. However, our earliest discovery of extra solar planets was actually possible only because systems existed that defied the "current" theory. Massive gas giants ("Hot Jupiters") which were very close to their host star, close enough to cause a detectable wobble in the host star.

Edited by akh
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An extreme example is moving toward a galactic black hole from space. You need no fuel or energy to get there because you will eventually get "sucked toward it" if you are close enough to start with.

If you cross the event horizon, yes, there is no escape. Otherwise, no. I strongly suggest you stop reading bad sci-fi and bad pop sci, and start learning some real science instead.

 

But once very close to the black hole it would take a huge amount of fuel to escape its gravity well where it took no fuel at all to get there to start with.

Wrong. Suppose your trajectory takes you close to, but not inside, the event horizon. Sans relativistic effects, you'll just climb right back out of the black hole's gravity well with no energy required. The only energy required would be that needed to overcome those relativistic effects. Black holes are not mythical monsters that suck everything towards them.

 

 

The point is that when in a stationary position relative to the sun, it would take less fuel to go 57 million miles toward the sun than it would take to start from from 36 million miles away from the sun (mean distance Mercury to sun) to 93 million miles away from the sun (Earth) where you are working against strong solar gravity to start with.

That's a pointless point. How exactly are you going to get to that "stationary position relative to the sun"? The Earth is orbiting the Sun at about 30 km/second. You can't get rid of that just by wishing it away. It takes energy, a lot of energy. It takes a lot more energy than is available with any existing technology.

 

Once orbiting Mercury, a craft would need more fuel to go in the direction of Earth, than it would need to go toward the sun.

Wrong again. Going toward the Sun is extremely expensive. Let's go back to my example of sending nuclear waste into the Sun. Starting from a circular orbit about the Sun, a delta V of 25.7 km/sec would be needed to attain an elliptical orbit that just grazes the surface of the Sun if that initial circular orbit was at 1 AU (Earth's orbital radius). It gets more expensive closer in. From Mercury's orbit, the required delta V is 37.5 km/sec. Compare that to a delta V of 9.6 km/sec to put the vehicle on an elliptical orbit with a 1AU aphelion and then a 7.6 km/sec delta V to circularize to 1AU. That's a total of of 17.1 km/sec, which less than half the 37.5 km/sec needed to go toward the Sun.

 

 

I think they used ion propulsion for this tricky deceleration- to-orbit maneuver.

Wrong again. MESSENGER used gravity assists and conventional chemical rockets. BepiColombo will use ion propulsion as well as gravity assists and conventional rockets, but it will still use conventional rockets for that final orbit insertion at Mercury. Ion thrusters don't have near enough oomph to accomplish this task.

 

 

Short of some huge breakthrough in propulsion technology, we will never send people to Mercury. Never. Even if humanity does develop that requisite breakthrough technology, this will not change the huge cost in getting to Mercury. That cost is always present. It is far cheaper to send machinery and people to practically any other place in the solar system.

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I offer one possible explanation. Cometary impact. Four billions years worth. That would be wholly consisten with current theory.

 

Right on. The finding of water on Mercury gives even more credence to this theory. It also says the water here on Earth most likely came from ice-containing comets. And that these comets have hit other planets and moons, which increases the probability of finding some form of life as we know it on them.

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Right on. The finding of water on Mercury gives even more credence to this theory. It also says the water here on Earth most likely came from ice-containing comets. And that these comets have hit other planets and moons, which increases the probability of finding some form of life as we know it on them.

 

Some people have concluded otherwise, although with a caveat.:

 

"That the Earth's water originated purely from comets is implausible, as a result of measurements of the isotope ratios of hydrogen in the three comets Halley, Hyakutake and Hale-Bopp by researchers like David Jewitt, as according to this research the ratio of deuterium to protium (D/H ratio) of the comets is approximately double that of oceanic water. What is however unclear is whether these comets are representative of those from the Kuiper Belt. According to A. Morbidelli [9] the largest part of today's water comes from protoplanets formed in the outer asteroid belt that plunged towards the Earth, as indicated by the D/H proportions in carbon-rich chondrites. The water in carbon-rich chondrites point to a similar D/H ratio as oceanic water. Nevertheless, mechanisms have been proposed[10] to suggest that the D/H-ratio of oceanic water may have increased significantly throughout Earth's history. Such a proposal is consistent with the possibility that a significant amount of the water on Earth was already present during the planet's early evolution." http://en.wikipedia.org/wiki/Origin_of_water_on_Earth

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If you cross the event horizon, yes, there is no escape. Otherwise, no. I strongly suggest you stop reading bad sci-fi and bad pop sci, and start learning some real science instead.

 

........Suppose your trajectory takes you close to, but not inside, the event horizon. Sans relativistic effects, you'll just climb right back out of the black hole's gravity well with no energy required. The only energy required would be that needed to overcome those relativistic effects. Black holes are not mythical monsters that suck everything towards them.

You are missing the point. It takes a great amount of fuel to escape a gravity well such as near a black hole, whereby it takes none to get "pulled in" by gravity, less fuel to go to Mercury than to leave it going back. This is not Sci Fi.

 

That's a pointless point. How exactly are you going to get to that "stationary position relative to the sun"? The Earth is orbiting the Sun at about 30 km/second. You can't get rid of that just by wishing it away. It takes energy, a lot of energy. It takes a lot more energy than is available with any existing technology.

 

We don't have to get stationary relative to the sun. By going opposite the rotation of the Earth the sun's gravity helps pull you toward your destination. 30km/sec is 108,000 Km per hour. We have no problem achieving half that speed. The point is that the pull of the sun's gravity can assist a craft inward toward the sun.

 

Wrong again. Going toward the Sun is extremely expensive. Let's go back to my example of sending nuclear waste into the Sun. Starting from a circular orbit about the Sun, a delta V of 25.7 km/sec would be needed to attain an elliptical orbit that just grazes the surface of the Sun if that initial circular orbit was at 1 AU (Earth's orbital radius). It gets more expensive closer in. From Mercury's orbit, the required delta V is 37.5 km/sec. Compare that to a delta V of 9.6 km/sec to put the vehicle on an elliptical orbit with a 1AU aphelion and then a 7.6 km/sec delta V to circularize to 1AU. That's a total of of 17.1 km/sec, which less than half the 37.5 km/sec needed to go toward the Sun.

 

I agree with your point that presently there is little point to sending nuclear waste inward toward the sun. But with nuclear rockets, or better, less expensive propulsion systems, I expect it will happen someday.

 

....MESSENGER used gravity assists and conventional chemical rockets. BepiColombo will use ion propulsion as well as gravity assists and conventional rockets, but it will still use conventional rockets for that final orbit insertion at Mercury. Ion thrusters don't have near enough oomph to accomplish this task.

 

OK

 

Short of some huge breakthrough in propulsion technology, we will never send people to Mercury. Never. Even if humanity does develop that requisite breakthrough technology, this will not change the huge cost in getting to Mercury. That cost is always present. It is far cheaper to send machinery and people to practically any other place in the solar system.

 

We may be on the same page here but I think the technology of nuclear powered spacecraft is already here. It just needs the political will to do it, and the time to perfect and debug such a system. I also expect positron rocket propulsion is maybe only 50 years away, even though we haven't even started on it in earnest as yet. :)

 

I think we will see serious proposals for man to go to Mercury within the next century. I also think there will be one or more mining colonies there within the next few centuries.

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Edited by pantheory
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It seems more likely to me that water ice on the surface of the Mercury comes from superheated steam blown on it from the Sun rather than comets. Surely, if all ices were deposited by comets , then all the planetoids surfaces throughout the solar system would not have their water ices deposited so uniformly about their surfaces.

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Do you feel that superheated steam is blown off the sun?

 

Are you expecting cometary water to remain in the location of the impact site? That is not going to happen. The comet will vaporise on impact, or earlier if there is a substantial atmosphere.

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Interesting, but not evidence that water molecules constitute a portion of the solar wind, only that water molecules appear to exist on the sun. What evidence do you have that "superheated steam is blown onto Mercury by the sun"?

 

And are you agreeing that the distribution of ice on solar system planetoids is as expected if it is derived from comets?

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