Author Topic: Preferred Landing Sites  (Read 33990 times)

Offline Zed_Noir

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Re: Preferred Landing Sites
« Reply #120 on: 02/05/2018 04:47 PM »
From Elon's twitter
https://twitter.com/elonmusk/status/960400928225546241


https://pbs.twimg.com/media/DVQHjZ3W4AELWDR.jpg:large


So anyone think Elon is going to staked out Hellas soon?

Offline Ludus

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Re: Preferred Landing Sites
« Reply #121 on: 02/09/2018 01:22 AM »
Itís got thicker atmosphere, probable glaciers, and isnít too bad latitude wise. Probably on the short list.

Online Robotbeat

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Re: Preferred Landing Sites
« Reply #122 on: 02/09/2018 01:29 AM »
Itís got thicker atmosphere, probable glaciers, and isnít too bad latitude wise. Probably on the short list.
Pretty dusty, though. Might not be a showstopper... You could put the city's solar panels on the less-dusty highlands and use a 100km transmission line to bring the power down into the crater.
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Offline redliox

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Re: Preferred Landing Sites
« Reply #123 on: 02/09/2018 02:37 AM »
So anyone think Elon is going to staked out Hellas soon?

I'm slightly surprised, but at the same time it is promotional art.  There are been things made for Olympus Mars and Valles Marineris too, so it is hard to say if Elon is being serious.  The next time he makes a speech about Mars someone needs to ask him this.
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Offline Restless

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Re: Preferred Landing Sites
« Reply #124 on: 02/09/2018 04:57 AM »
My guesses at SpaceX site criteria

0. Low enough below mean datum for sufficient aerobraking for landing (-2Km or lower) & low enough latitude (under ~30 degrees) to minimize landing & takeoff delta V.  Excess landing deltaV makes colony $/ton landed freight bill more expensive. More trips/thousand tons. Excess takeoff deltaV consumes more energy intensive ISRU resources.
1. ISRU: water available in colony need quantities
2. ISRU: solar power available in colony quantities as mining water and especially disassociation eats electrons
3. Given 1&2 sufficient water & solar power available for colony
4. Other ISRU needs: minerals etc. for colonial development
5. Interesting site & nearby attractions that motivate large #s of folks years to a lifetime off planet
Musk is a marketeer; looking cool is important to selling the dream & human satisfaction

NASA Priorities:
0: ~ same as SpaceX
1. Sufficient ISRU to support small base camp for a synod & return propellant
2. Science: geological history of Mars
3. Science search for evidence of past life
4. Science search for existing life.  Base away from but accessible from search site accessed by tele-operated sterilized planetary protection rover

I would insert item 4.a into the list - Resources for large scale agriculture

You can't feed one million people from hydroponics. They are going to want eggs and meat from poultry, milk, beef and dairy products from cattle, pork, bread, vegetables, beer, whiskey and wine. This means several hundred thousand chickens, a 100,000 cows, a 100,000 swine, and about 2 million acres in cultivation as practiced on Earth. High intensity ag might reduce the total land by a factor of, say, 4 to 500,000 acres.

The crops will have to be under at least one psi of pressure, and the livestock about 10 psi which means a lot of pressurized habitat. Assuming plentiful power and water, you still need soil.

So, IMO, the colony site will need to be close to sand and clay deposits.

Clay plus sand equals sandy loam soil. And the sand can be processed into glass panels for construction.
« Last Edit: 02/09/2018 05:07 AM by Restless »

Offline jpo234

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Re: Preferred Landing Sites
« Reply #125 on: 02/09/2018 07:11 AM »
You can't feed one million people from hydroponics. They are going to want eggs and meat from poultry, milk, beef and dairy products from cattle, pork, bread, vegetables, beer, whiskey and wine. This means several hundred thousand chickens, a 100,000 cows, a 100,000 swine, and about 2 million acres in cultivation as practiced on Earth. High intensity ag might reduce the total land by a factor of, say, 4 to 500,000 acres.

I'm reasonably sure that the best Martian colonists can hope for, is lab grown meat and fish from a combined aquaponic system. Anything else would be a huge waste of resources, that the colony won't be able to afford for a very long time.
« Last Edit: 02/09/2018 07:14 AM by jpo234 »
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Offline Restless

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Re: Preferred Landing Sites
« Reply #126 on: 02/09/2018 01:48 PM »
History tells us that poorly resourced colonies fail. We have to think big for a one million person civilization on Mars, and at some point nuclear (or fusion) power will be needed to make it all happen.

Online Robotbeat

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Re: Preferred Landing Sites
« Reply #127 on: 02/09/2018 01:51 PM »
History tells us that poorly resourced colonies fail. We have to think big for a one million person civilization on Mars, and at some point nuclear (or fusion) power will be needed to make it all happen.
Or just huge solar farms. Or, if you prefer, use beamed fusion power. One resource Mars has in abundance is vast expanses of land.
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Offline speedevil

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Re: Preferred Landing Sites
« Reply #128 on: 02/09/2018 01:54 PM »
I'm reasonably sure that the best Martian colonists can hope for, is lab grown meat and fish from a combined aquaponic system. Anything else would be a huge waste of resources, that the colony won't be able to afford for a very long time.

Conversion efficiency for pigs from food to plate is on the order of 10%.
Chickens are broadly similar.
For a diet with 5% of the energy from meat, you only need to add 50% to your garden.
They can also somewhat balance out your habitat, you can in an emergency slaughter many animals to reduce O2 needs.

Offline aero

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Re: Preferred Landing Sites
« Reply #129 on: 02/09/2018 04:40 PM »
And pigs eat potatoes.
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Offline Valerij

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Re: Preferred Landing Sites
« Reply #130 on: 02/12/2018 10:12 AM »
There is one problem that no one mentioned. A large amount of water ice close to the surface of the ground can mean that when heated this ice will melt, and the ground will turn into liquid mud. This is called "permafrost". Permafrost is well known to northern peoples. In such a ground, it is very difficult to build underground structures.
   
For the colony, it is necessary to choose a place where the soil is stable when heated, but where relatively near (maximum tens of kilometers) there is easily accessible water. To search for such places, a heavy (IMHO, at least ten tons) rover will be required, which has a great resource (hundreds or thousands of kilometers without repair), a powerful energy source and equipped with an automatic drilling rig capable of making wells hundreds of meters in depth.
   
I think that such rovers and the information they get will be very interesting for NASA too. Especially in view of their ability to return to the landing site and reload the collected samples for the ITS that is being prepared for return to Earth.
 
PS
I apologize, but it seems to me that the discussion of the landing sites of the "Red Dragon" is now completely meaningless. On the other hand, it is interesting to discuss exactly the places suitable for the creation of the Martian colony, and the requirements for such places.
« Last Edit: 02/12/2018 10:22 AM by Valerij »

Offline speedevil

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Re: Preferred Landing Sites
« Reply #131 on: 02/12/2018 10:23 AM »
There is one problem that no one mentioned. A large amount of water ice close to the surface of the ground can mean that when heated this ice will melt, and the ground will turn into liquid mud. This is called "permafrost". Permafrost is well known to northern peoples. In such a ground, it is very difficult to build underground structures.

This is - somewhat - less relevant than on earth.
On earth, you can get away with less insulated structures that warm the ground noticably.
On Mars, unless you have a fusion plant, underground structures need to be very, very well insulated, as the average subsurface temperature at the equator is about -50C, and 20C colder at middle-latitudes, to under -100C at the polar caps.


Offline Valerij

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Re: Preferred Landing Sites
« Reply #132 on: 02/12/2018 10:41 AM »
This is - somewhat - less relevant than on earth.
In fact, you are wrong. antifreeze, which will melt at minus temperature. However, even a very good heat insulation home is not absolute. And it is also possible local damage to thermal insulation. Therefore, good insulation Martian homes do not negate the need to build it into an array of stable ground.
« Last Edit: 02/12/2018 10:42 AM by Valerij »

Offline John Alan

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Re: Preferred Landing Sites
« Reply #133 on: 02/12/2018 10:43 AM »
There is one problem that no one mentioned. A large amount of water ice close to the surface of the ground can mean that when heated this ice will melt, and the ground will turn into liquid mud. This is called "permafrost". Permafrost is well known to northern peoples. In such a ground, it is very difficult to build underground structures.

This is - somewhat - less relevant than on earth.
On earth, you can get away with less insulated structures that warm the ground noticably.
On Mars, unless you have a fusion plant, underground structures need to be very, very well insulated, as the average subsurface temperature at the equator is about -50C, and 20C colder at middle-latitudes, to under -100C at the polar caps.

Liquid water can not exist on mars unless inside a pressurized space or container,,,
Heating water ice will only see it vanish to vapor as it passes roughly 0*C (32*F)...
There is No Mud on Mars... I assure you...  ;)

Quote
The atmosphere of Mars is the layer of gases surrounding Mars. It is composed mostly of carbon dioxide. The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi; 1.013 bar). It ranges from a low of 30 pascals (0.0044 psi; 0.30 mbar) on Olympus Mons's peak to over 1,155 pascals (0.1675 psi; 11.55 mbar) in the depths of Hellas Planitia. This pressure is well below the Armstrong limit for the unprotected human body
Source...
https://en.wikipedia.org/wiki/Atmosphere_of_Mars

On Edit...
Heating martian permafrost will cause it to dry out... because of the low atmospheric pressure... 
« Last Edit: 02/12/2018 10:53 AM by John Alan »

Offline Lar

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Re: Preferred Landing Sites
« Reply #134 on: 02/12/2018 01:16 PM »
Agree that a water rich but otherwise loosely (sediment) structured substrate won't turn to mud, but as the water sublimes, it may become considerably weaker. So some thought needs to be given to where to build and how deep to excavate, etc.
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Offline rsdavis9

Re: Preferred Landing Sites
« Reply #135 on: 02/12/2018 01:58 PM »
There is one problem that no one mentioned. A large amount of water ice close to the surface of the ground can mean that when heated this ice will melt, and the ground will turn into liquid mud. This is called "permafrost". Permafrost is well known to northern peoples. In such a ground, it is very difficult to build underground structures.

This is - somewhat - less relevant than on earth.
On earth, you can get away with less insulated structures that warm the ground noticably.
On Mars, unless you have a fusion plant, underground structures need to be very, very well insulated, as the average subsurface temperature at the equator is about -50C, and 20C colder at middle-latitudes, to under -100C at the polar caps.

Liquid water can not exist on mars unless inside a pressurized space or container,,,
Heating water ice will only see it vanish to vapor as it passes roughly 0*C (32*F)...
There is No Mud on Mars... I assure you...  ;)

Quote
The atmosphere of Mars is the layer of gases surrounding Mars. It is composed mostly of carbon dioxide. The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi; 1.013 bar). It ranges from a low of 30 pascals (0.0044 psi; 0.30 mbar) on Olympus Mons's peak to over 1,155 pascals (0.1675 psi; 11.55 mbar) in the depths of Hellas Planitia. This pressure is well below the Armstrong limit for the unprotected human body
Source...
https://en.wikipedia.org/wiki/Atmosphere_of_Mars

On Edit...
Heating martian permafrost will cause it to dry out... because of the low atmospheric pressure...

This may be true on the surface but underground the water has no where to sublime to.
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Offline John Alan

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Re: Preferred Landing Sites
« Reply #136 on: 02/12/2018 04:02 PM »
There is one problem that no one mentioned. A large amount of water ice close to the surface of the ground can mean that when heated this ice will melt, and the ground will turn into liquid mud. This is called "permafrost". Permafrost is well known to northern peoples. In such a ground, it is very difficult to build underground structures.

This is - somewhat - less relevant than on earth.
On earth, you can get away with less insulated structures that warm the ground noticably.
On Mars, unless you have a fusion plant, underground structures need to be very, very well insulated, as the average subsurface temperature at the equator is about -50C, and 20C colder at middle-latitudes, to under -100C at the polar caps.

Liquid water can not exist on mars unless inside a pressurized space or container,,,
Heating water ice will only see it vanish to vapor as it passes roughly 0*C (32*F)...
There is No Mud on Mars... I assure you...  ;)

Quote
The atmosphere of Mars is the layer of gases surrounding Mars. It is composed mostly of carbon dioxide. The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's mean sea level pressure of 101.3 kilopascals (14.69 psi; 1.013 bar). It ranges from a low of 30 pascals (0.0044 psi; 0.30 mbar) on Olympus Mons's peak to over 1,155 pascals (0.1675 psi; 11.55 mbar) in the depths of Hellas Planitia. This pressure is well below the Armstrong limit for the unprotected human body
Source...
https://en.wikipedia.org/wiki/Atmosphere_of_Mars

On Edit...
Heating martian permafrost will cause it to dry out... because of the low atmospheric pressure...

This may be true on the surface but underground the water has no where to sublime to.

I would speculate (assuming tunnel not pressurized, only lined) it would sublime out away from the warmth till it reached cold subsoil and refreeze...
My 2 cents on subtopic...  ;)

Offline Ludus

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Re: Preferred Landing Sites
« Reply #137 on: 02/12/2018 09:22 PM »
You can't feed one million people from hydroponics. They are going to want eggs and meat from poultry, milk, beef and dairy products from cattle, pork, bread, vegetables, beer, whiskey and wine. This means several hundred thousand chickens, a 100,000 cows, a 100,000 swine, and about 2 million acres in cultivation as practiced on Earth. High intensity ag might reduce the total land by a factor of, say, 4 to 500,000 acres.

I'm reasonably sure that the best Martian colonists can hope for, is lab grown meat and fish from a combined aquaponic system. Anything else would be a huge waste of resources, that the colony won't be able to afford for a very long time.

While this probably applies for the first few cycles, if Mars is a genuine settlement and settlers are agents in a local free market, this wonít be determined by some planner or central authority. That will probably result in some imports of a wide variety of food plants and animals that would be available to eat  but quite expensive.

Offline Valerij

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Re: Preferred Landing Sites
« Reply #138 on: 02/13/2018 06:22 AM »
Liquid water can not exist on mars unless inside a pressurized space or container,,,
Heating water ice will only see it vanish to vapor as it passes roughly 0*C (32*F)...
There is No Mud on Mars... I assure you...  ;)
...
On Edit...
Heating martian permafrost will cause it to dry out... because of the low atmospheric pressure...
You are right, but only while talking about water in the surface layer of the soil. If the soil layer protects water from direct contact with the atmosphere, permafrost can easily turn into liquid mud when heated. These will be very serious problems for the construction of foundations and buildings, protected by a layer of regolith from above.
   
The composition and the gas pressure at a depth of several meters will be very different from the atmosphere above the ground surface. And we do not know anything about this yet.
   
« Last Edit: 02/13/2018 06:23 AM by Valerij »

Offline Valerij

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Re: Preferred Landing Sites
« Reply #139 on: 02/13/2018 06:57 AM »
Agree that a water rich but otherwise loosely (sediment) structured substrate won't turn to mud, but as the water sublimes, it may become considerably weaker. So some thought needs to be given to where to build and how deep to excavate, etc.
I absolutely agree with you. But I'm talking a little about something else.
   
In my opinion, a significant part of the premises of Martian houses will be under the level of the ground or will be protected by a layer of regolith from above. In permafrost conditions it is very difficult to build such buildings, it is almost impossible to avoid small defects in thermal insulation. If melt water penetrates into these defects, the defects will increase. And if the water will periodically melt and freeze, then the formed ice can cause structural damage. Foundations of buildings thus deformed.
   
Therefore, I believe that it is necessary to survey the soil, including drilling wells. When choosing a location for a colony, you need not only to provide access to water (or ice), but also to find a place for building a colony in an array of heat-stable ground.
« Last Edit: 02/13/2018 07:13 AM by Valerij »