Author Topic: When you can land anywhere on Mars where’s the best place?  (Read 32175 times)

Offline DAZ

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When you can land anywhere on Mars where’s the best place?

Much has been discussed about the increase in payload weight that you can land on Mars using retro propulsive landings, like being used on the proposed Red Dragon.  Increasing the payload weight is an extremely important consideration for manned missions and future colonization of Mars.  A secondary consideration that has been discussed, to a lesser extent, has been the greatly increased accuracy that these landings also afford.  One thing that seems to have not been discussed too much is the 3rd and possibly more important aspect which is that you can now land almost anywhere on Mars using retro propulsive landing instead of parachutes.

The landing system that NASA has used for its science missions have not only been limited by the weight they can land and the accuracy but also they are limited to only low-lying areas of Mars.  This is due to the fact that they need as much air as possible for their parachutes.  This has limited the missions to pretty much these areas in the northern hemisphere.  The heavier the mission the more they have been limited for their landing locations.

These missions to date have been targeted for the scientifically interesting areas within the limits of what could be reached.  They really haven’t been used to explore the areas that might be the most interesting for a future manned mission.  Only to a very limited extent have there been discussions on the possible locations of future Mars colonies.  It would definitely seem to be advantageous to send future red Dragon missions to these possible locations.

Now these colonial locations would most definitely need to be located were certain natural resources could be found such as possibly water.  But the question I’m proposing is that the very geographical location be as high if not a higher priority then what geological resources are available?  To illustrate a possible location we could take the example of inside the crater of Olympic Mons.  It is closer to the equator so the day would be longer for work, solar energy collection, possible direct communications to earth and temperature extremes may not be as high.  It has an extremely high altitude so the less air could also possibly be advantageous for launching rockets and may contain less dust to settle on your solar energy collection system.  Being closer to the equator could also help not only landings but also takeoffs.  There could be other advantages and also disadvantages but this is only an example to illustrate the intent of the question.

Offline the_other_Doug

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Just one major point -- high-altitude sites literally poke up through Mars' sensible atmosphere.  Even the MCT/BFS will rely on shedding speed via aerodynamic breaking, and for such a high-altitude site like the Olympus Mons caldera, you lose most of that.  You'd need to increase the speed shed by propulsive braking by so much more than the fuel you could possibly carry, it would never come out on the right side of the equation.

In terms of using aerodynamic breaking, the centers of the great basins, like Hellas or Argyre, are best.  They provide more time through denser layers of air, and thus more aerodynamic breaking.  Unfortunately, they're not as seemingly rich in subsurface water as other sites, the theory I've seen being that the great impacts that generated the basins dried out the remnant rock beds, and there was less water intrusion subsequently into these basins than you saw in other areas, especially the current northern hemisphere, after the end of the LHB.

So, in short, Hellas and Argyre are easier to land in, but not necessarily the best landing sites when it comes to finding easy-to-mine water resources.

Trust me, NASA has been looking into this for decades, and SpaceX has been looking into it for years.  I'm positive that SpaceX has already come up with extensive lists of candidate sites and even more extensive lists of the many, many factors which play one against the other when it comes to making the final decision.

And, heck, there's no way to tell if the first Red Dragon will go to the final landing site for the first crewed landings.  I bet we get a better idea of the plans after September's IAC meeting, though... ;)
-Doug  (With my shield, not yet upon it)

Offline Hotblack Desiato

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Well, one of the most crucial parts of any colonization effort is water.

So SX needs to find a glacier. NASA already found some of them. Another crucial part will be the availability of sunlight and moderate temperatures.

Therefore Arsia Mons could be a very interesting spot to investigate. Close to the equator (just 8° south), and there are hints that there are glaciers.

And Arsia Mons is 16 km high (not as high as Olympus Mons, but 16 km isn't bad either. Having a launch platform at the peak of Arsia Mons sounds like a good idea to me.

However even with a powered landing, Arsia Mons will be challenging to land on or close too (the surrounding plains are still at 7km above average height). From what I have gathered so far, more atmosphere is always better, especially for a spacecraft like MCT, which enters atmosphere at above 7km/s.

EDIT: maybe there are glaciers in Vallis Marineris, but if there are any, they are good at hiding ;-)
« Last Edit: 06/10/2016 10:13 pm by Hotblack Desiato »

Offline philw1776

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I still think you want to select the lower areas.  More CO2 pressure, more atmosphere for water extraction from the atmosphere.  Lots of mist in Marinaris Valles.  High latitude areas are low but tend to have KNOWN subsurface ice, but are also less human vista interesting.

Here is a recent NASA workshop on the Best Mars Sites.  NASA is biased towards looking for Mars life, present & past which I think is not a SpaceX priority.  But these NASA sites also had a water, in-situ resources requirement.

Peruse for your enjoyment.
The Sites Map...

http://www.nasa.gov/sites/default/files/atoms/files/exploration-zone-map-v10.pdf

and now page after page of specific site evaluation by its advocates...

http://www.nasa.gov/sites/default/files/atoms/files/mars-c-abstracts_in_order_of_presentation10242015_0.pdf

I welcome discussion by advocates of specific sites.
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Offline CuddlyRocket

I still think you want to select the lower areas.  More CO2 pressure, more atmosphere for water extraction from the atmosphere.

Though thin the Martian atmosphere does provide significant radiation shielding compared with being in space (~50% reduction). It might well be wise to maximise that effect, implying favouring lower areas.

Offline DAZ

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All good points. 

The reason I used Olympic Mons as an example is it pretty much illustrates an extreme.  Another extreme could be landing at the pole where most of the ice in the world is located.  At the poll you have a lot of the resources you’re looking for but you obviously have a large number of drawbacks.

I’m not convinced that the thin air at the top of Olympic Mons is not an advantage for landing as opposed to a disadvantage.

As I understand it the EDL use presently is something like this.  The vehicle enters the Mars atmosphere at a high altitude and use the lift it have available to essentially try to stay as high up as long as possible.  You then fall through the atmosphere slowing a little more and open your parachute at supersonic speeds at a relatively high altitude so as to reduce the force on the parachutes.  You could use retro propulsive at this point but the associated losses from using engines at this high-altitude make this unpractical/unusable.  You then slows much as you can and cut away from your parachutes at the last moment and use your landing method to affect your landing.

For retro propulsive EDL it is a little bit different.  Instead of trying to stay high you dive down into the lower thicker (for Mars) atmosphere.  Use your lift to pull out of the dive and fly roughly parallel at this relatively low altitude (something like 10,000 feet) parallel to the ground.  You then use your lift to stay at this altitude for about as long as you can and as slow as you can.  You could open parachutes at this point but the forces generated at this low altitude would shred any reasonable obtainable parachute design.  You will be relatively close to your landing site at a relatively low altitude.  At this point using retro propulsive to affect your landing becomes much more practical and more desirable.  So yes, low and thicker atmosphere is still desirable for this landing method but it assumes that your landing target is still below you.

To land on Olympic Mons mostly it’s the same retro propulsive EDL the difference is at a certain point you will use your available lift to put the vehicle in a climbing arc.  Near the top of this arc you will need to be near your intended landing zone.  In fact using this method you could be considerably going slower and at a lower altitude (relative to the distance you will be traveling) than for the above described retro propulsive EDL.  If you try to use this method on the above described retro propulsive EDL you would of course be going slower but would also be much higher above your landing point and would lose much of the advantage of doing the retro propulsive landing.

Offline AC in NC

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All good points. 

The reason I used Olympic Mons as an example is it pretty much illustrates an extreme.  Another extreme could be landing at the pole where most of the ice in the world is located.  At the poll you have a lot of the resources you’re looking for but you obviously have a large number of drawbacks.

I’m not convinced that the thin air at the top of Olympic Mons is not an advantage for landing as opposed to a disadvantage.

To land on Olympic Mons mostly it’s the same retro propulsive EDL the difference is at a certain point you will use your available lift to put the vehicle in a climbing arc.  Near the top of this arc you will need to be near your intended landing zone.

DAZ:

Love this post

Although OM seems like a gimmick choice and acknowledging the amazing people geek attraction of the site, I was looking at it with the 3D Explorer.  I was hoping there might be something to mitigate the drag loss at that altitude.  While that landing approach seems like one hell of a modelling/verification challenge, it seems like it would be worthy of some kind of look.

Beside capturing the imagination, I think there are a goodly number of natural advantages.  I don't know where to go to find the topographical details to hunt around for others with those.  But the many hundreds of years vision of some kind the Domed Caldera with a lake, agriculture, and shirt sleeve habitation for millions of people served by infrastructure of the rim of the caldera is pretty cool.  It's probably the case there's somewhere else similar but lower but man, it's Olympus Mons.

Seeing some of the problems on some of the threads discussing 30-day transits I wonder if there might be an ability to bleed deltaV with a variety of maneuvers of this sort including multiple passes.
« Last Edit: 06/11/2016 01:37 am by AC in NC »

Online Bob Shaw

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Olympus Mons is a high basaltic desert, hard to land on and with few resources. Hellas is well below the Mars datum, Marineris Vallis is low and misty, the Northern Plains are icy and the poles are ice(s). All of the latter are better options!

Offline AC in NC

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Killjoy!!!   :D   

Thanks for the details.  For us outsiders, it's hard to know how to sort through the material that is out there.

Offline meekGee

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 isn't the kinetic energy lost by aerobraking much higher than any altitude difference?

So if you aerobrake while moving towards (and below) your high altitude target, and then use your engines to gain a few km, you're stlll ahead of the game?
ABCD - Always Be Counting Down

Offline AC in NC

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Olympus Mons is a high basaltic desert, hard to land on and with few resources. Hellas is well below the Mars datum, Marineris Vallis is low and misty, the Northern Plains are icy and the poles are ice(s). All of the latter are better options!

Thanks again Bob.  Was fascinating exploring Hellas Planitia with Mars 3-D Explorer.  Clearly was a lot of water flowing into that area in the past.
« Last Edit: 06/11/2016 02:47 pm by AC in NC »

Offline Lar

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I expect we will land folk at Olympus Mons, or they will trek there, but not for a while.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Online Bob Shaw

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I expect we will land folk at Olympus Mons, or they will trek there, but not for a while.

The trafficability of the Olympus slopes is an interesting thought. Little or no erosion on the shield portion, with gradually reducing dust deposits, and a slope measured in single figures of degrees. Cotton wool filled with a fractal razor blade surface? Walking might be challenging, but driving vehicles with *BIG* wheels might be practical. Remember, though, that the view will be far from spectacular en-route, though the caldera will be a hit, as will be the cliffs at the base of the mountain.

Offline Robotbeat

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I used to be a Hellas Basin guy, but now I've converted to Valles Marineris, particularly Melas Chasma. Very deep, -5km. Has water in a couple different forms, both hydrated sulfates and nearby reoccuring linea. It has tall hills sticking up off the plane but still low craters and also a lot of flat area to land and build on. And it's not too far from high altitudes (+3km? +5km?) since it's near the cliff walls of Valles Marineris, so if you want thinner air for some reason, you're close to it. It's geologically interesting and has access to plenty of resources.

And the view is incredible.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Retired Downrange

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"…What does Mars smell like?

What may seem to be a frivolous question at first is actually quite interesting once your intellectual curiosity is engaged. The Martian atmosphere itself is much different than Earth’s. Our various robotic visitors to Mars have revealed an atmosphere rich in carbon dioxide (96%). Not much to smell there. But the surface of Mars is also much different than Earth, and contains sulfur, acids, magnesium, iron and chlorine compounds. What might that smell like?"

"Obviously, colonists wouldn’t be breathing the Martian atmosphere. But some essence of Mars would be present in their living quarters, most likely."

http://www.universetoday.com/129386/mars-stink-duplicated-earthbound-humans/
« Last Edit: 06/12/2016 04:23 am by Retired Downrange »

Offline Robotbeat

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One of the sulfa tea common on Mars is gypsum. Our walls are made of gypsum, but don't smell like sulfur, I'm not sure Mars would, either. But I kind of like the smell of gunpowder.
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Offline philw1776

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I used to be a Hellas Basin guy, but now I've converted to Valles Marineris, particularly Melas Chasma. Very deep, -5km. Has water in a couple different forms, both hydrated sulfates and nearby reoccuring linea. It has tall hills sticking up off the plane but still low craters and also a lot of flat area to land and build on. And it's not too far from high altitudes (+3km? +5km?) since it's near the cliff walls of Valles Marineris, so if you want thinner air for some reason, you're close to it. It's geologically interesting and has access to plenty of resources.

And the view is incredible.

Could. Not. Agree. More.
Especially with your selection criteria which I believe is close to Musk's criteria for his base.
Including the last one.  You want people motivated to stay.  The Northern Highlands are rich in water, etc. resources but are mostly featureless landscapes.

Thinking ahead to late 21st century, a narrow offshoot canyon site with adjoining walls would be great for initial "roof over the whole thing" settlement expansion.  Gonna need lots of living space for the numbers of folks he talks about.
« Last Edit: 06/12/2016 03:48 pm by philw1776 »
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Offline the_other_Doug

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I used to be a Hellas Basin guy, but now I've converted to Valles Marineris, particularly Melas Chasma. Very deep, -5km. Has water in a couple different forms, both hydrated sulfates and nearby reoccuring linea. It has tall hills sticking up off the plane but still low craters and also a lot of flat area to land and build on. And it's not too far from high altitudes (+3km? +5km?) since it's near the cliff walls of Valles Marineris, so if you want thinner air for some reason, you're close to it. It's geologically interesting and has access to plenty of resources.

And the view is incredible.

Could. Not. Agree. More.
Especially with your selection criteria which I believe is close to Musk's criteria for his base.
Including the last one.  You want people motivated to stay.  The Northern Highlands are rich in water, etc. resources but are mostly featureless landscapes.

Thinking ahead to late 21st century, a narrow offshoot canyon site with adjoining walls would be great for initial "roof over the whole thing" settlement expansion.  Gonna need lots of living space for the numbers of folks he talks about.

Absolutely agreed in re Valles Marineris, except for one pesky problem: weather.

Winds are strong and sometimes unpredictable in the whole Marineris rift valley system, there are frequent landslides and dustslides along the walls which increase the amount of dust in the air (a bad thing from a variety of aspects), and the thicker air comes with the price of far more frequent cloud and fog events.

All of which makes access really dicey, and sunlight less reliable for both power and farming.

Not insurmountable problems, but significant challenges.  I wouldn't look for the first attempts at landings and colonies to add more challenges than are absolutely required, just for the sake of a really, undeniably great view...
-Doug  (With my shield, not yet upon it)

Offline raketa

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What they need:
Level one requirement
1/Water... fuel, O2
2/Energy(if solar primary, than open space)
3/Shelter(cave system will be good beginning, radiation shield)
Level 2 requirement
3/Food(at beginning the could rely on Earth supply)


Offline RobLynn

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What about the North pole?
-continuous sunlight for 220 days - increasing PV output, saving battery mass, and getting a lot more bang for your buck from energy systems over the 6 month long summer.
-communications with earth and other space craft all the time
-Lots of frozen CO2 and almost certainly H2O available (potentially in large quantities underground) - making processing for fuel and water easier as don't have to waste energy on compression.  Large quantities of water enable substantial nuclear reactors - poles could be a good source
-Can use ice for radiation shielding (easier to dig into or move, and possibly even liquefy and pump unlike rock)
-Relatively low elevation.
-Very little dust or wind
-Possibility of making ice runways for winged planes, spaceplanes, (atmospheric augmented ramjets?) to land on or take off from at high speed.

downsides might be boring and difficult to propulsively land on frozen CO2
 
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Offline the_other_Doug

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I see caves mentioned frequently as good locations for initial Mars settlements.  And there's a problem with that idea.

Most caves on Mars, at least the ones we've been able to identify, are evacuated lava tubes.  They're located on the great Tharsis lava sheets, which cover a good quarter of the planet.

As near as anyone can tell, the Tharsis volcanism period occurred after the early, wetter Noachian period.  While not bone-dry, these lavas were not overlain at any obvious point with glaciers or significant bodies of water.

So, while Martian lava tubes can provide natural radiation protection, they tend to be found almost exclusively in big, boring sheets of basalt that don't have much in the way of ice or water deposits, either frozen into the regolith or in big buried glaciers.

There will be trade-offs, but I think it's easier to dig into the ground for radiation protection where there is more water, than it is to go any appreciable distance to find abundant water and transport it back to your safe-but-dry lava tube...
-Doug  (With my shield, not yet upon it)

Offline philw1776

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What about the North pole?
-continuous sunlight for 220 days - increasing PV output, saving battery mass, and getting a lot more bang for your buck from energy systems over the 6 month long summer.
-communications with earth and other space craft all the time
-Lots of frozen CO2 and almost certainly H2O available (potentially in large quantities underground) - making processing for fuel and water easier as don't have to waste energy on compression.  Large quantities of water enable substantial nuclear reactors - poles could be a good source
-Can use ice for radiation shielding (easier to dig into or move, and possibly even liquefy and pump unlike rock)
-Relatively low elevation.
-Very little dust or wind
-Possibility of making ice runways for winged planes, spaceplanes, (atmospheric augmented ramjets?) to land on or take off from at high speed.

downsides might be boring and difficult to propulsively land on frozen CO2

VERY far away from the equator sites require more delta V, reducing payload and requiring more propellant for return to Earth.
FULL SEND!!!!

Lava tubes are only accessible via the pit craters that form from collapse of weak roof areas. The feature that occurs most frequently next to a pit crater is another pit crater, which tells me that lava tubes, accessed by pit craters, are intrinsically prone to instability. I would only send a robotic explorer down into a pit crater. My housing preference, once a colony is in its self-sufficiency phase, would be to excavate into tested bedrock or ice. The glacier-rich regions in or adjoining a deep (for landing) crater like Gale or Jezero seem to be good base choices to me.
--
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Offline oiorionsbelt

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Online ZachS09

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Hasn't Acidalia Planitia or the Schiaparelli Crater been discussed before? I'm new to this specific thread, so let me know if these places have already been covered.
Liftoff for St. Jude's! Go Dragon, Go Falcon, Godspeed Inspiration4!

Offline philw1776

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Hasn't Acidalia Planitia or the Schiaparelli Crater been discussed before? I'm new to this specific thread, so let me know if these places have already been covered.

Fortunately it's a meager 2 pages long so you can read it.

Here's a discussion of sites from a NASA symposium

http://www.nasa.gov/sites/default/files/atoms/files/mars-c-abstracts_in_order_of_presentation10242015_0.pdf


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Offline gospacex

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What about the North pole?
-continuous sunlight for 220 days - increasing PV output, saving battery mass, and getting a lot more bang for your buck from energy systems over the 6 month long summer.
-communications with earth and other space craft all the time
-Lots of frozen CO2 and almost certainly H2O available
...
downsides might be boring and difficult to propulsively land on frozen CO2

And a questionable pleasure of temperatures of -78 Celsius almost year-round.

Offline Ludus

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I see caves mentioned frequently as good locations for initial Mars settlements.  And there's a problem with that idea.

Most caves on Mars, at least the ones we've been able to identify, are evacuated lava tubes.  They're located on the great Tharsis lava sheets, which cover a good quarter of the planet.

As near as anyone can tell, the Tharsis volcanism period occurred after the early, wetter Noachian period.  While not bone-dry, these lavas were not overlain at any obvious point with glaciers or significant bodies of water.

So, while Martian lava tubes can provide natural radiation protection, they tend to be found almost exclusively in big, boring sheets of basalt that don't have much in the way of ice or water deposits, either frozen into the regolith or in big buried glaciers.

There will be trade-offs, but I think it's easier to dig into the ground for radiation protection where there is more water, than it is to go any appreciable distance to find abundant water and transport it back to your safe-but-dry lava tube...


Not for initial settlements but very interesting for large settlements and cities. Analysis seems to be that they are very stable over millions of years.

That would be the search criteria I'd put in, are there lava tubes near water sources? If there's a vision of really settling Mars, Lava tube cities are the only way to produce a pleasant environment on a human time scale.

Offline Dalhousie

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I see caves mentioned frequently as good locations for initial Mars settlements.  And there's a problem with that idea.

Most caves on Mars, at least the ones we've been able to identify, are evacuated lava tubes.  They're located on the great Tharsis lava sheets, which cover a good quarter of the planet.

As near as anyone can tell, the Tharsis volcanism period occurred after the early, wetter Noachian period.  While not bone-dry, these lavas were not overlain at any obvious point with glaciers or significant bodies of water.

So, while Martian lava tubes can provide natural radiation protection, they tend to be found almost exclusively in big, boring sheets of basalt that don't have much in the way of ice or water deposits, either frozen into the regolith or in big buried glaciers.

There will be trade-offs, but I think it's easier to dig into the ground for radiation protection where there is more water, than it is to go any appreciable distance to find abundant water and transport it back to your safe-but-dry lava tube...


Not for initial settlements but very interesting for large settlements and cities. Analysis seems to be that they are very stable over millions of years.

That would be the search criteria I'd put in, are there lava tubes near water sources? If there's a vision of really settling Mars, Lava tube cities are the only way to produce a pleasant environment on a human time scale.

I have been in a number of lava tubes.  They are very awkward places to get into and move round it.  It will be far easier to make suitable habitats at better locations.
Apologies in advance for any lack of civility - it's unintended

Offline philw1776

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FORGET lava tubes.
They're nowhere near where water is to be found underground.
Simply use backhoes, etc. to pile regolith over your habs and you're shielded.
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Online docmordrid

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Bring along expandable hab segments  based on Quonset huts, then put them in a trench and cover them. The below was used in the Vietnam era.
DM

Offline RobLynn

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What about the North pole?
...

And a questionable pleasure of temperatures of -78 Celsius almost year-round.

low temperatures wouldn't be much of a problem given very low rates of convective heat transfer in thin atmosphere - and are easily insulated against - thick walls are a requirement anyway for radiation protection. 

Low temps might be a real advantage through reducing size of radiators required to dissipate concentrated energy sources (saving a lot of cooling system mass), improving efficiency of electrical machinery and computers etc, storing cryogenic fuels for rockets and giving simpler options for some chemical processing jobs (only 50-70K above critical point for CO and O2), it also makes it more feasible to utilise superconductors for various applications which might save significant mass on deliveries to Mars.
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Offline gospacex

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What about the North pole?
...

And a questionable pleasure of temperatures of -78 Celsius almost year-round.

low temperatures wouldn't be much of a problem given very low rates of convective heat transfer in thin atmosphere - and are easily insulated against - thick walls are a requirement anyway for radiation protection.

I'm more worried about people and machines doing outside work. Any Mars location, even equatorial one, is quite cold by Earth standards. Working in -78 C conditions while atmosphere freezes out into CO2 snow? Not much joy.

Quote
Low temps might be a real advantage through reducing size of radiators required to dissipate concentrated energy sources (saving a lot of cooling system mass), improving efficiency of electrical machinery and computers etc, storing cryogenic fuels for rockets and giving simpler options for some chemical processing jobs (only 50-70K above critical point for CO and O2)

Such wonderful conditions, ask yourself why we don't build datacenters and liquid O2 plants on South Pole of Earth? Is it easy to have a base there?

Achieving cold is not going to be a problem on Mars. Dig in some 3 meters below ground on equator and you get at least -40C year round.
« Last Edit: 06/17/2016 01:47 pm by gospacex »

Offline Robotbeat

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What about the North pole?
...

And a questionable pleasure of temperatures of -78 Celsius almost year-round.

low temperatures wouldn't be much of a problem given very low rates of convective heat transfer in thin atmosphere - and are easily insulated against - thick walls are a requirement anyway for radiation protection.

I'm more worried about people and machines doing outside work. Any Mars location, even equatorial one, is quite cold by Earth standards. Working in -78 C conditions while atmosphere freezes out into snow? Not much joy.

Quote
Low temps might be a real advantage through reducing size of radiators required to dissipate concentrated energy sources (saving a lot of cooling system mass), improving efficiency of electrical machinery and computers etc, storing cryogenic fuels for rockets and giving simpler options for some chemical processing jobs (only 50-70K above critical point for CO and O2)

Such wonderful conditions, ask yourself why we don't build datacenters and liquid O2 plants on South Pole of Earth?...
...we do build data centers near the North Pole in order to take advantage of the low temperature for cooling:
http://www.cnet.com/news/facebook-turns-on-data-center-at-edge-of-the-arctic-circle/
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Robotbeat

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By the way, if you have access to a plentiful low-temperature cold sink, your nuclear reactor can produce more power (and/or can be lighter) and needs less fuel to do so.

The cold of the north pole is, in fact, an advantage. PARTICULARLY if you can somehow exchange heat with the ground or the ice instead of just the air.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline guckyfan

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The cold of the north pole is, in fact, an advantage. PARTICULARLY if you can somehow exchange heat with the ground or the ice instead of just the air.

But you are in the dark for much of the Mars year. A large glacier near the equator would be a good heat sink too. If you want to use it that way. Better have a heat exchanger in the loop so no radiation gets there, even in case of an accident.

Offline DAZ

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It would seem what is needed here is some information on the difficulty of launching from different locations on Mars.  How much more difficult is it to launch from the pole as opposed to the equator or from a lower altitude as opposed to a higher altitude?  If you launch from the pole for example does this limit your available orbits and does this affect your logistics?  Even though I know there is a difference to the difficulties of launching from these various locations it is outside of my skill set to determine what these variations are.

Offline guckyfan

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The disadvantage of launching far from the equator is much smaller on Mars. If it turns out that Phobos and Deimos can provide fuel launch from near the equator is necessary however, because access to the moons from polar launch sites is not viable.

Offline Vultur

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What about the North pole?
-continuous sunlight for 220 days - increasing PV output, saving battery mass, and getting a lot more bang for your buck from energy systems over the 6 month long summer.

Problem is the huge battery mass you need for the winter (and half the year on Mars is a lot longer than 6 months...)

Also, solar intensity at the pole is going to be low even though it's 24-hours, since the sun is low in the sky - that's why the poles don't get hot in summer on Earth, and Mars' axial tilt is similar.

...we do build data centers near the North Pole in order to take advantage of the low temperature for cooling:
http://www.cnet.com/news/facebook-turns-on-data-center-at-edge-of-the-arctic-circle/

And commercial/profit-making activities in the Antarctic IIRC have major legal issues.

I used to be a Hellas Basin guy, but now I've converted to Valles Marineris, particularly Melas Chasma. Very deep, -5km. Has water in a couple different forms, both hydrated sulfates and nearby reoccuring linea. It has tall hills sticking up off the plane but still low craters and also a lot of flat area to land and build on. And it's not too far from high altitudes (+3km? +5km?) since it's near the cliff walls of Valles Marineris, so if you want thinner air for some reason, you're close to it. It's geologically interesting and has access to plenty of resources.

And the view is incredible.

I don't have a good mental picture of the proportions of Valles Marineris; are the walls going to block enough of the sky that solar power will be limited, or is the canyon/valley so wide that the cliffs don't loom huge from the middle?

Offline Hotblack Desiato

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By the way, if you have access to a plentiful low-temperature cold sink, your nuclear reactor can produce more power (and/or can be lighter) and needs less fuel to do so.

The cold of the north pole is, in fact, an advantage. PARTICULARLY if you can somehow exchange heat with the ground or the ice instead of just the air.

Usually yes. A reactor usually runs at 200 - 230°C, they could go higher but that would add risk to it. This way, nuclear power plants are usually at 25-35% efficiency (electrical), whereas other thermal powerplants can reach 50%. On Mars, there is the more pressing need for heat. Heat can be either generated with electrical heaters, or by directly using the station as the heat-sink for the reactor, lowering its electrical efficiency yet generating more useful heat for the station. Depending on the distance between reactor(s) and station, aswell as the heat-demand of it, it might be even interesting to drive the reactor at a point with even lower efficiency. If there is excess heat, it could be radiated away, and a cold atmosphere will be helpful for that. But I don't think that this is even required, they will leak enough heat even without a big radiator.

Offline gospacex

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By the way, if you have access to a plentiful low-temperature cold sink, your nuclear reactor can produce more power (and/or can be lighter) and needs less fuel to do so.

The cold of the north pole is, in fact, an advantage. PARTICULARLY if you can somehow exchange heat with the ground or the ice instead of just the air.

Usually yes. A reactor usually runs at 200 - 230°C

More like 300°C

Offline CuddlyRocket

I don't have a good mental picture of the proportions of Valles Marineris; are the walls going to block enough of the sky that solar power will be limited, or is the canyon/valley so wide that the cliffs don't loom huge from the middle?

At its widest, the cliffs are below the horizon from the middle; though widths vary of course, especially in the side canyons. And there is often hilly terrain in the middle.

An additional consideration is that 'blocking the sky' provides radiation protection. Also, the orientation (North-South v East-West) of the valley affects how much direct sunlight there is. Further, given cabling your solar panels and base need not be co-located (though, added mass and transmission losses). Plus, a shadowed base will be colder due to reduced passive solar heating.

An interesting set of engineering trades!
« Last Edit: 06/20/2016 11:30 pm by CuddlyRocket »

Offline Long EZ

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Find a spot that has plenty of iron/nickel meteorites lying around. Then you are ready to melt them for raw materials. Hopefully the chunks are not too large to handle. A glancing impact could fragment the meteorite and not bury the pieces.   

Offline john smith 19

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By the way, if you have access to a plentiful low-temperature cold sink, your nuclear reactor can produce more power (and/or can be lighter) and needs less fuel to do so.

The cold of the north pole is, in fact, an advantage. PARTICULARLY if you can somehow exchange heat with the ground or the ice instead of just the air.

Usually yes. A reactor usually runs at 200 - 230°C

More like 300°C
I'm guessing you're talking about a PWR. That also needs a 200atm pressure vessel to hold it.

Most space nuclear reactor designs run considerably hotter and use a liquid metal heat pipe system for heat transfer.

Such designs are much more compact and lighter (but then they don't generate the 100s of MW that PWRs generate.

Realistically anything whose outlet temperature after power generation had been done is over 0c can be used to melt ice.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline john smith 19

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The "best" place depends as always on your goals.

For NASA that may be more to do with "interesting" science locations. Bottoms of cliffs, deep ("high" atmospheric pressure) canyons, possible ice etc.

For SX their end game is human settlement. ISRU is viewed as essential for their Methane based propellant system so water is also essential. Access to deposits of some other raw materials would be good (not sure which).

Deep canyons deliver higher atmospheric pressure, making ISRU more efficient and giving some more radiation pressure. Note there are pockets of higher magnetic field which also (slightly) increase radiation protection. Tunneling into the base of a cliff (or even a big hill) can give you the necessary 3m of radiation protection .

So the ideal site is
a)Close to easily accessible water
b)Close to other mineral resources
c)In a deep canyon
d)Near the wall or near a fair sized hill that can be tunneled into.
e)With an above Mars average magnetic field.

In roughly that order.

I haven't included places where winds can clean PV panels because a crewed site will have people who can go out and do that when necessary.

I've no idea how many sites actually meet all the criteria. I'm betting water surveys are now a more important part of probe design than they were.

SX have been sharing data with NASA on various subjects. I'd be surprised if they don't have access to most, if not all of NASA's mapping of these issues for Mars. Where you have 2 sites that are neck and neck I'd say the tie breaker will be which one can you land the most payload at.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline the_other_Doug

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...SX have been sharing data with NASA on various subjects. I'd be surprised if they don't have access to most, if not all of NASA's mapping of these issues for Mars. Where you have 2 sites that are neck and neck I'd say the tie breaker will be which one can you land the most payload at.

Anyone who wants to look at the publicly-available data in the Planetary Data System (PDS) has access to all of NASA's mapping data on Mars.  Heck, you have access to them.  And if you don't want to go through the hassle of figuring out how to deal with the PDS data products, there are tons and tons of reduced versions of those data available on the internet.

Keep in mind that neither NASA, nor anyone else, has an orbital sensor system that directly says "Hey, there's water here!"  What they have is the ability to sense abundances of hydrogen.  Since large hydrogen abundances in (or over) the surface you are looking down upon can only mean one of a few things, composition-wise, a lot of reputable planetary geologists have concluded that areas on Mars that show high hydrogen abundances indicate either frozen water very slowly sublimating up through regolith cover layers, or hydrated minerals (i.e., rocks which contain water bound into them) right on the surface.

The only ground truth that confirmed the presence of water ice on Mars where orbital assets (primarily, but not limited to, Mars Odyssey) indicated it might be found came from the Phoenix lander.  That's a good start, and it means that the theories about easily accessible permafrost in the high polar latitudes are likely correct, overall.  This doesn't mean that equatorial locations which show high hydrogen abundances are necessarily indicative of subsurface water ice -- those may be indicating hydrated rocks.  (Maybe not likely, but that particular "water or bust" bust condition may still end up being the case).

Of course, it's possible in many situations to extract water from hydrated minerals, as well, but it's energy-intensive, and nowhere near as easy as finding permafrost, or even relatively pure ice deposits.  For an ample water supply, you're looking for ice, not just hydrated minerals.  At least at first, anyway.  And, of course, if it's possible to tap into a still-liquid system of briny aquifers that may yet exist on Mars, so much the better -- just dig some wells, and then treat the resulting water to remove the salts.

But, to my main point -- let's not be tossing around concepts like "What is NASA going to want from SpaceX for them to share their water mapping data?"  It's just not a question, the data is freely available to anyone who wants to look at it...
-Doug  (With my shield, not yet upon it)

Offline philw1776

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Along these find & follow the water ideas, SX needs to make orbital deep radar water ice surveying followed by ground truth validation high proirity
FULL SEND!!!!

Offline BobHk

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I used to be a Hellas Basin guy, but now I've converted to Valles Marineris, particularly Melas Chasma. Very deep, -5km. Has water in a couple different forms, both hydrated sulfates and nearby reoccuring linea. It has tall hills sticking up off the plane but still low craters and also a lot of flat area to land and build on. And it's not too far from high altitudes (+3km? +5km?) since it's near the cliff walls of Valles Marineris, so if you want thinner air for some reason, you're close to it. It's geologically interesting and has access to plenty of resources.

And the view is incredible.

Could. Not. Agree. More.
Especially with your selection criteria which I believe is close to Musk's criteria for his base.
Including the last one.  You want people motivated to stay.  The Northern Highlands are rich in water, etc. resources but are mostly featureless landscapes.

Thinking ahead to late 21st century, a narrow offshoot canyon site with adjoining walls would be great for initial "roof over the whole thing" settlement expansion.  Gonna need lots of living space for the numbers of folks he talks about.

Absolutely agreed in re Valles Marineris, except for one pesky problem: weather.

Winds are strong and sometimes unpredictable in the whole Marineris rift valley system, there are frequent landslides and dustslides along the walls which increase the amount of dust in the air (a bad thing from a variety of aspects), and the thicker air comes with the price of far more frequent cloud and fog events.

All of which makes access really dicey, and sunlight less reliable for both power and farming.

Not insurmountable problems, but significant challenges.  I wouldn't look for the first attempts at landings and colonies to add more challenges than are absolutely required, just for the sake of a really, undeniably great view...

Wind is a bonus...add wind turbines and you have a good source of energy.

Offline gospacex

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I don't have a good mental picture of the proportions of Valles Marineris; are the walls going to block enough of the sky that solar power will be limited, or is the canyon/valley so wide that the cliffs don't loom huge from the middle?

At its widest, the cliffs are below the horizon from the middle; though widths vary of course, especially in the side canyons. And there is often hilly terrain in the middle.

An additional consideration is that 'blocking the sky' provides radiation protection.

A note on hills/canyon walls 'blocking the sky' shielding. It is likely to be less significant than it seems - at those low angles (5-10 degrees tops) atmosphere itself is much thicker and would block a lot more than at zenith. I estimate 10-15 more air mass at least.

Offline gospacex

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By the way, if you have access to a plentiful low-temperature cold sink, your nuclear reactor can produce more power (and/or can be lighter) and needs less fuel to do so.

The cold of the north pole is, in fact, an advantage. PARTICULARLY if you can somehow exchange heat with the ground or the ice instead of just the air.

Usually yes. A reactor usually runs at 200 - 230°C
More like 300°C
I'm guessing you're talking about a PWR. That also needs a 200atm pressure vessel to hold it.

That's only because of "no boiling" requirement.
BWR go only a tad below 300°C (say 290°C) and they operate at ~70atm.

Offline john smith 19

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By the way, if you have access to a plentiful low-temperature cold sink, your nuclear reactor can produce more power (and/or can be lighter) and needs less fuel to do so.

The cold of the north pole is, in fact, an advantage. PARTICULARLY if you can somehow exchange heat with the ground or the ice instead of just the air.

Usually yes. A reactor usually runs at 200 - 230°C
More like 300°C
I'm guessing you're talking about a PWR. That also needs a 200atm pressure vessel to hold it.

That's only because of "no boiling" requirement.
BWR go only a tad below 300°C (say 290°C) and they operate at ~70atm.
That will still need a substantial pressure vessel, which will either be very heavy or need some serious construction work on site to mfg it.

The upside of Mars is the low average temperature increases the efficiency of the reactor several %.

BTW a small LWR, like the one on the German ship Otto Hahn weighed about 38 tonnes in a 35 m^3 volume and generated 38MW (not sure if that's thermal or electrical).

SNAP10a generated about 30Kw(t) weighing 500Kg, but using very highly enriched Uranium.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline guckyfan

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It was thermal 38MW. Little electric because the steam was directly used to drive the turbines for 7.355MW power engines.

Offline john smith 19

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It was thermal 38MW. Little electric because the steam was directly used to drive the turbines for 7.355MW power engines.
Noted. So for civilian tech small reactors that's about 1tonne/MW(t). Currently about 38x the largest package that's been landed on Mars.

I'll keep in mind that like with IVF that's not "waste" heat. It has a number of possible uses, starting with melting ice or slush to release water.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline philw1776

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FULL SEND!!!!

Offline the_other_Doug

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SpaceX will follow the water

http://www.jpl.nasa.gov/spaceimages/details.php?id=pia20756

Right now, the Planetary Protection Protocols (PPP) would forbid landing at, or even approaching, any site where a liquid briny aquifer might be discharging to the surface.  SpaceX will have to arrive at some kind of understanding as to how they are going to be respectful of the PPP and yet be able to find needful resources.

I'm guessing they will be looking for large emplacements of ice for their water supply, not briny liquid aquifers that the PPP people want to protect from our terrestrial bugs, so they can look for Martian bugs there... ;)
-Doug  (With my shield, not yet upon it)

Offline Unobscured Vision

Hi folks, new to the thread but not the subject matter. In fact, I'm quite well-versed in it. Care to let the "newbie" chime in?
Yep ... just ... yep.

Offline the_other_Doug

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Hi folks, new to the thread but not the subject matter. In fact, I'm quite well-versed in it. Care to let the "newbie" chime in?

Of course not!  You have to have at least a thousand posts here before we'll let you post here... :D :D :D

Seriously, don't ever let newbie status stop you.  If you feel you have something to offer, please feel free to jump in with both feet.  Especially if you have any actual training or education in a given subject, since that will likely make your posts a thousand per cent more informative than those the rest of us toss in... ;)

Besides, if you're a paranoid schizophrenic whose contributions to the topic have to do with detailed instructions you've received from the gray aliens about how we must treat Mars and where we can and cannot land, don't worry -- your posts won't be visible for long anyway, so you won't have to worry about it!  ;)  :)  :D

And by the way, if I hadn't said it before, welcome to the forum.  Looking forward to hearing what you have to say.
-Doug  (With my shield, not yet upon it)

Offline The Amazing Catstronaut

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Hi folks, new to the thread but not the subject matter. In fact, I'm quite well-versed in it. Care to let the "newbie" chime in?

I think I'm approaching a thousand posts and still determinedly a noob. Don't worry, fire away! The worst that can happen is a professional corrects you, and we all learn something. There is no objective right answer to this particular question, anyway, just good advice.
Resident feline spaceflight expert. Knows nothing of value about human spaceflight.

Offline llanitedave

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Hi folks, new to the thread but not the subject matter. In fact, I'm quite well-versed in it. Care to let the "newbie" chime in?

Watney?  Is that you?

Seriously, knowledge and posting history are not synonymous.  I know this first hand.  If you have something to contribute, don't hold back!
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Offline Dalhousie

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The "best" place depends as always on your goals.

For NASA that may be more to do with "interesting" science locations. Bottoms of cliffs, deep ("high" atmospheric pressure) canyons, possible ice etc.

For SX their end game is human settlement. ISRU is viewed as essential for their Methane based propellant system so water is also essential. Access to deposits of some other raw materials would be good (not sure which).

ISRU is top priority for NASA landing sites as well
Apologies in advance for any lack of civility - it's unintended

Offline Dalhousie

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Of course, it's possible in many situations to extract water from hydrated minerals, as well, but it's energy-intensive, and nowhere near as easy as finding permafrost, or even relatively pure ice deposits.  For an ample water supply, you're looking for ice, not just hydrated minerals.  At least at first, anyway.  And, of course, if it's possible to tap into a still-liquid system of briny aquifers that may yet exist on Mars, so much the better -- just dig some wells, and then treat the resulting water to remove the salts.

Hydrated minerals, specifically sulphates, are common on the surface of Mars, and easily detected from orbit and on the ground.  So they have proved easier to find.  The power required appears less than doing so from ice directly, and there are less planetary protection issues.
Apologies in advance for any lack of civility - it's unintended

Offline Dalhousie

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Along these find & follow the water ideas, SX needs to make orbital deep radar water ice surveying followed by ground truth validation high proirity

There is already near global MARSIS and SHARAD coverage.  A higher frequency radar would give better mapping of near surface ice distribution, but it would only be an incremental improvement.
Apologies in advance for any lack of civility - it's unintended

Offline Dalhousie

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SpaceX will follow the water

http://www.jpl.nasa.gov/spaceimages/details.php?id=pia20756

Right now, the Planetary Protection Protocols (PPP) would forbid landing at, or even approaching, any site where a liquid briny aquifer might be discharging to the surface.  SpaceX will have to arrive at some kind of understanding as to how they are going to be respectful of the PPP and yet be able to find needful resources.


Planetary protection requires that these special areas areas  are not interacted with by unsterilised equipment. This can be the whole spacecraft (e.g. Viking) or part of it (e.g Phoenix).
Apologies in advance for any lack of civility - it's unintended

Offline guckyfan

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From the NASA landing site workshop I gathered that they would send small highly sterilized robotic rovers to fetch samples that would then be analyzed in the hab.

I understand that once it would be established there is no indigenous life there it could be approached and used as mineral resource? Though I do hope for scientific and philosophical reasons we find life.

Offline alamo

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All good points. 

The reason I used Olympic Mons as an example is it pretty much illustrates an extreme.

Olympus Mons?
Water is a problem
HABIT can be answer
https://en.wikipedia.org/wiki/HABIT_(HabitAbility:_Brine,_Irradiation_and_Temperature)
The HABIT instrument will use salts to absorb 5 millilitres of water from the atmosphere each day, and can hold 25 ml in total. If the process works as expected, the technology could be scaled up to provide water for future crewed missions.

Thereafter

"Olympus Mons (upper left) and volcanos on the Tharsis bulge. The white features are clouds.
Warm air (containing water vapor) rises up the volcano slopes and cools at higher altitude.
The water vapor freezes to form clouds of ice crystals."

mine water from clouds?
.................................
 ::)
Ancient Bohemian Legends
https://en.wikipedia.org/wiki/Ancient_Bohemian_Legends
"Forefather Čech climbed Říp Mountain and looked around the land. Then he allegedly said: "Oh, comrades, you've endured hardships along with me, when we wandered in impassable woods; finally we arrived at our homeland. This is the best country, predestined for you. Here you won't miss anything, but you'll take pleasure in permanent safety. Now that this sweet and beautiful land is in your hands, think up a suitable name."
https://en.wikipedia.org/wiki/%C5%98%C3%ADp_Mountain





Offline the_other_Doug

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All good points. 

The reason I used Olympic Mons as an example is it pretty much illustrates an extreme.

Olympus Mons?
Water is a problem
HABIT can be answer
https://en.wikipedia.org/wiki/HABIT_(HabitAbility:_Brine,_Irradiation_and_Temperature)
The HABIT instrument will use salts to absorb 5 millilitres of water from the atmosphere each day, and can hold 25 ml in total. If the process works as expected, the technology could be scaled up to provide water for future crewed missions.

Again, the caldera of Olympus Mons is a bad idea on a whole lot of levels.  A spacecraft approaching Mars has to shed something like 13 km/sec, IIRC from some of the discussions, and propulsive slowing can only take out about 1 km/sec of that.  For the rest, you have to let atmospheric friction slow you down.

As I understand it, the air is so thin at the top of Olympus Mons that you cannot use aerodynamic braking, that doesn't dip deeper into the atmosphere for much of the braking regime, to slow down enough to kill the speed that you cannot kill with your rockets.  You would almost have to slow down to near-landing speed at "datum" altitude (what passes for sea level on Mars) and then use your rockets to climb back up to the level of the Olympus Mons caldera.

Not ever gonna happen.

There's a lot of discussion out on the internet about the really difficult problem of landing large masses on Mars.  Do a Google search on the Mars Mach 5 problem, you'll see what I mean.  This is a long-discussed problem where masses of more than about 5 tons can't be slowed via aerodynamic braking plus parachutes to where it doesn't impact the surface before it reaches a sufficiently slow speed to where landing rockets can be employed.  IIRC, by the time you slow to Mach 5 with masses much above 5 tons you're too low, even approaching areas lower than datum, for there to be time for your retropropulsion to take out the remaining energy.

That has all been based on the idea that you can't effectively use retropropulsion at speeds greater than Mach 5.  SpaceX seems to be solving the problem with earlier initiation of retropropulsion (no parachute phase), based on the experience they are developing with hypersonic retropropulsion, preceded by a long, shallow entry that travels thousands of km along the ground track as it sheds that pesky 12 km/sec the rockets can't take out.  But it's still a close-run thing; even with initiating retropropulsion at hypersonic speeds, there's not likely to be a huge amount of margin.

Guys, I truly understand the desire to land in places with great vistas and incredible views.  But there really are good, hard, physics-based reasons why some of these schemes don't work.  Really.
-Doug  (With my shield, not yet upon it)

Offline Robotbeat

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Land somewhere with dense atmosphere. Drive to some place like Olympus Mons if you must.
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Offline Lobo

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I expect we will land folk at Olympus Mons, or they will trek there, but not for a while.

The trafficability of the Olympus slopes is an interesting thought. Little or no erosion on the shield portion, with gradually reducing dust deposits, and a slope measured in single figures of degrees. Cotton wool filled with a fractal razor blade surface? Walking might be challenging, but driving vehicles with *BIG* wheels might be practical. Remember, though, that the view will be far from spectacular en-route, though the caldera will be a hit, as will be the cliffs at the base of the mountain.

As I understand, Olympus Mons is so large and gentle sloped, that if you were at it's base it'd look just like an uphill slope filling the horizon, rather than like a volcano or mountain.  That you have to be quite a ways away and elevated to see it all and appreciate it.  It'd seem like you were just going up a gentle hill for a really, really long time until you came to the caldera.

But, you know as soon as you put people on Mars, there will be people who'll want to climb it....because it's there.  And it's the biggest mountain in the Solar System.  (Although, you'd walk up it rather than "climb" as it's so gentle sloped)
Good luck climbing it without O2 though.  ;-)

Offline Lobo

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I used to be a Hellas Basin guy, but now I've converted to Valles Marineris, particularly Melas Chasma. Very deep, -5km. Has water in a couple different forms, both hydrated sulfates and nearby reoccuring linea. It has tall hills sticking up off the plane but still low craters and also a lot of flat area to land and build on. And it's not too far from high altitudes (+3km? +5km?) since it's near the cliff walls of Valles Marineris, so if you want thinner air for some reason, you're close to it. It's geologically interesting and has access to plenty of resources.

And the view is incredible.

Yea, I'd think for building a colony, your list of priorities for a potential site would be the following in order:
a)  Easy of landing and taking off (having flat, rocky areas where MCT could land without excavating too much soil and creating debris and crater issues).  You have to land and take off again as easily and safely and reliably as possible before you can do anything else.

2)  Water deposits in large accessible quantities.

3)  Flat. hard to build on slopes on Mars just as it is on Earth.  Nice and flat makes for easy to hooking modules together on the surface and easier to travel across.

4)  As thick of atmosphere as possible for various reasons like air mining and maximizing radiation protection...so the lower the better.

5)  Geologically interesting...other possible mining resources there for future mining and utilization.

6)  Scientifically interesting.  I put that all the way at the bottom because NASA scientists going to the colony to do science would have the ability to travel fairly far away from the colony to investigate interesting areas.  So they don't really have to be at the colony, as long as they are within reasonable range.  NASA will probably have some requirements to be close enough to scientifically interesting sites fully lend their support to SpaceX and partner with them.

7)  Visually interesting.  Hey, colonists want a view too.  But I think it's the lowest criteria on the list.

Offline Robotbeat

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Near equator helps solar energy production and to equalize temperatures. Also helps EDL and launching.
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Offline ThereIWas3

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I always liked the looks of Elysium Planitia, 5° N, 150° E.   Ash covered water ice?  If you take a B+W photo of some of that area and reverse the values, what you get looks exactly like icebergs on Earth.   Land between a couple of the "bergs" and tunnel into the side.

Notice how the "bergs" break up as they flow around the craters in this picture:


Offline AC in NC

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I always liked the looks of Elysium Planitia, 5° N, 150° E.   Ash covered water ice?  If you take a B+W photo of some of that area and reverse the values, what you get looks exactly like icebergs on Earth.   Land between a couple of the "bergs" and tunnel into the side.

Notice how the "bergs" break up as they flow around the craters in this picture:




You can explore this location at http://mars.nasa.gov/maps/explore-mars-map/fullscreen/

The nearer of the two craters is at 5.63 N and 150.25 E.  The image above seems to have been taken looking due South.


Resolution is not the greatest compared to the pic but at least you can check out the neighborhood and the schools.
« Last Edit: 07/14/2016 12:04 am by AC in NC »

Offline the_other_Doug

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I always liked the looks of Elysium Planitia, 5° N, 150° E.   Ash covered water ice?  If you take a B+W photo of some of that area and reverse the values, what you get looks exactly like icebergs on Earth.   Land between a couple of the "bergs" and tunnel into the side.

Notice how the "bergs" break up as they flow around the craters in this picture:




You can explore this location at http://mars.nasa.gov/maps/explore-mars-map/fullscreen/

The nearer of the two craters is at 5.63 N and 150.25 E.  The image above seems to have been taken looking due South.


Resolution is not the greatest compared to the pic but at least you can check out the neighborhood and the schools.

I've heard they have great schools, but the area itself gotten so popular and so crowded, no one ever goes there anymore... ;)

Seriously, it's this kind of region I have thought would make a good landing site.  It sure as heck looks like broken pack ice that froze up a long time ago and then got covered over with layers of volcanic ash.  Heck, the overburden might not be all that thick.
-Doug  (With my shield, not yet upon it)

Offline philw1776

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Along these find & follow the water ideas, SX needs to make orbital deep radar water ice surveying followed by ground truth validation high proirity

There is already near global MARSIS and SHARAD coverage.  A higher frequency radar would give better mapping of near surface ice distribution, but it would only be an incremental improvement.

Point being that to select potential sites for a sustainable base the more detailed survey I mention is a necessity.  There is much still in question about the cited surveys and an actual landing site base requires the far better mapping and validation of critical water resources.
« Last Edit: 07/14/2016 03:35 pm by philw1776 »
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Offline philw1776

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I've posted the latest proposed manned landing sites map previously but here's a better new version PLUS an index of Large Context Camera CTX mosaics of each site


http://astrogeology.usgs.gov/search/map/Mars/MarsReconnaissanceOrbiter/CTX/HumanExplorationZones/CTX_Human_EZ_sites_Oct2015
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Offline ThereIWas3

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Is there a link somewhere to the final report and the criteria they used?  The capabilities and goals of NASA's Mars assumptions in 2015 may be different from those of SpaceX in 2024.

Offline philw1776

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Is there a link somewhere to the final report and the criteria they used?  The capabilities and goals of NASA's Mars assumptions in 2015 may be different from those of SpaceX in 2024.

There is no final report nor is there one scheduled.  Just a list with advocates reasons.  At some time NASA may establish more specific criteria to cut the list down.  No hurry as their goal is (as has been forever) about 2 decades from now.

Yes, many have stated here repeatedly that SX will have different capabilities, goals and selection criteria.
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Offline Danderman

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How about deep in the Mariner Valley? The air pressure should be thicker there.

Offline Phil Stooke

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Yes, but also more frequent fog and dust storms.  A location with known reserves of water or other resources is more useful. 

Offline Robotbeat

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Yes, but also more frequent fog and dust storms.  A location with known reserves of water or other resources is more useful.
Fog sounds pretty useful.
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Offline ThereIWas3

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Thicker air is a help to parachute-aided landings, which have been NASA's only experience and probably what they were assuming for this sort of mission.  But SpaceX has demonstrated hypersonic retropropulsion and bullseye landings quite convincingly and that opens up quite a lot more of Mars to consideration.  Looking at those maps, most of the designated spots seem to be in the lowlands.  Elysium Planita is in the equatorial highlands, where the water came from volcanic events.  Estimates back in 2005 when that picture was taken were that the volume of water could be about the same as the North Sea on Earth.  I pick water as the deciding factor for SpaceX's interests, followed by radiation shielding by cliffs, etc.

Offline philw1776

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Yes, but also more frequent fog and dust storms.  A location with known reserves of water or other resources is more useful.

There are many RSLs seeping water indications in the valley.  Plenty of resources & high atmospheric pressure.
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Offline philw1776

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Thicker air is a help to parachute-aided landings, which have been NASA's only experience and probably what they were assuming for this sort of mission.  But SpaceX has demonstrated hypersonic retropropulsion and bullseye landings quite convincingly and that opens up quite a lot more of Mars to consideration.  Looking at those maps, most of the designated spots seem to be in the lowlands.  Elysium Planita is in the equatorial highlands, where the water came from volcanic events.  Estimates back in 2005 when that picture was taken were that the volume of water could be about the same as the North Sea on Earth.  I pick water as the deciding factor for SpaceX's interests, followed by radiation shielding by cliffs, etc.

The Robotic poster has calculated that the cliffs are not as useful for rad shielding as you and I would have thought at first glance.
Yes drilling right into a steep cliff might be helpful but cliffs up to a ten or tens of degrees from the mid valley floor not as much rad shielding as you'd think.
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Offline ThereIWas3

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I am reminded of Hiroko's under-ice settlement in the Red Mars trilogy.
  If those are ice slabs and thick enough, that could be enough shielding
 AND a source of water.

Offline Robotbeat

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Thicker air is a help to parachute-aided landings, which have been NASA's only experience and probably what they were assuming for this sort of mission.  But SpaceX has demonstrated hypersonic retropropulsion and bullseye landings quite convincingly and that opens up quite a lot more of Mars to consideration. ...
SpaceX is still definitely relying heavily on the atmosphere to slow down. So the idea that low altitude helps a lot is unchanged.
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Offline Robotbeat

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Yes, but also more frequent fog and dust storms.  A location with known reserves of water or other resources is more useful.

There are many RSLs seeping water indications in the valley.  Plenty of resources & high atmospheric pressure.
Correct. Multiple different types of water sources in Valles Marineris (some very near each other).

Ultimately, we're going to Mars mainly because it has an atmosphere. So I think it makes sense to maximize that.

Fog is a good thing, by the way, as it means there's good atmospheric water concentration. Also, beautiful. I don't think it lasts long enough in the day to be a real concern about solar power production (and it could be you want to use a lot of fission, anyway).
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Offline the_other_Doug

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Thicker air is a help to parachute-aided landings, which have been NASA's only experience and probably what they were assuming for this sort of mission.  But SpaceX has demonstrated hypersonic retropropulsion and bullseye landings quite convincingly and that opens up quite a lot more of Mars to consideration.

SpaceX has demonstrated getting a stage up to, what, somewhere between one and two km/sec?  And then bringing it back down.

Neither they nor anyone else has demonstrated bleeding off between 5 and 12 km/sec (depending on the speed of approach to Mars) purely aerodynamically, to get down to the quoted 1 km/sec the BFS will be able to handle propulsively, and then being within the needed navigation state to get to their target.

Air density will definitely matter.
-Doug  (With my shield, not yet upon it)

Offline Robotbeat

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SpaceX has demonstrated bleeding off 7km/s aerodynamically with Dragon. They intend to add propulsion to Dragon, too.
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Offline the_other_Doug

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SpaceX has demonstrated bleeding off 7km/s aerodynamically with Dragon. They intend to add propulsion to Dragon, too.

Oh, I hear you, and I basically agree.  I'm just pointing out that SpaceX has performed some but not all of these pieces, in far different environments from those contemplated at Mars, and never yet all put all of them together.

I'm not saying they're not going to.  Just that they haven't done it to the extremes they plan to, under the same circumstances, and all together in one mission profile.  I fully expect them to be able to do so, I'm just the kind of guy who hates to count my eggs before they're hatched... ;)
-Doug  (With my shield, not yet upon it)

Offline Tyber1

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If it was up to me, I'd put the colony near the top of the cliffs of Valles Marineris. It's near the equator so there is plentiful potential for solar energy and there is at least 5-6% water in the soil which isn't a ton but it's not nothing. But for me, the biggest draw of this location is that it's perfect for Mars terraforming. It would be located right near the edge of a sea where there would be plentiful water but there would be no chance of the city winding up underwater as sea levels rose. And the view would be fantastic, which can only be a good thing.

Offline Torbjorn Larsson, OM

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Thicker air is a help to parachute-aided landings, which have been NASA's only experience and probably what they were assuming for this sort of mission.  But SpaceX has demonstrated hypersonic retropropulsion and bullseye landings quite convincingly and that opens up quite a lot more of Mars to consideration.

SpaceX has demonstrated getting a stage up to, what, somewhere between one and two km/sec?  And then bringing it back down.

Neither they nor anyone else has demonstrated bleeding off between 5 and 12 km/sec (depending on the speed of approach to Mars) purely aerodynamically, to get down to the quoted 1 km/sec the BFS will be able to handle propulsively, and then being within the needed navigation state to get to their target.

Air density will definitely matter.

Yes, and if so, head room. The original Red Dragon had a projected trajectory of ~ 1000 km hugging the ground before slowing down to Mach 2-3 (~ 1 km/s on Mars) and engaging retrorockets. The best (only?) spot would be the martian lowland on the north, which has ~ 3500 km diameter. Incidentally that could place it near water ice.

But it seems the current Red Dragon may have a relaxed brake trajectory. The (my) bets are off, except that the first RD may attempt the easy out as per above anyway. But I suspect the OP was too optimistic. "Land anywhere on Mars" isn't on the martian horizon.

ADDED: I forgot, the original RD brake trajectory is emulating Apollo atmospheric conditions, including a final skip start before inverting the lift vector. [I'm not sure that is the technical name. I'm no rocket scientist.]

So I'm not sure the idea of not bleeding off the interplanetary approach speed in the atmosphere targeting some landing zone being demonstrated before is viable? Is it the "bulls eye" factor that would get us astray?
« Last Edit: 08/18/2016 08:46 am by Torbjorn Larsson, OM »

Offline Jcc

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I don't know what the solution space is for RD either, but I would think that you can also bleed off velocity in thinner atmosphere, it just takes longer (time and distance) and would be more difficult than in thicker atmosphere, with a risk of being ejected back into space. Agree that the first RD landing will go for an easier location until proved.

Offline AncientU

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Thicker air is a help to parachute-aided landings, which have been NASA's only experience and probably what they were assuming for this sort of mission.  But SpaceX has demonstrated hypersonic retropropulsion and bullseye landings quite convincingly and that opens up quite a lot more of Mars to consideration.

SpaceX has demonstrated getting a stage up to, what, somewhere between one and two km/sec?  And then bringing it back down.

Neither they nor anyone else has demonstrated bleeding off between 5 and 12 km/sec (depending on the speed of approach to Mars) purely aerodynamically, to get down to the quoted 1 km/sec the BFS will be able to handle propulsively, and then being within the needed navigation state to get to their target.

Air density will definitely matter.

JCSAT-16 was 2.25km/sec. at MECO;  EM has stated up to 2.75 (10,000km/h) is possible. 
With adequate propellant on board, the first stage could land from LMO or LLO if adequate navigation was available.  LMO is 3.6km/s; LLO is1.6km/s. 

That's the beauty of propulsive landings -- from orbit, you can land anywhere you choose.
"If we shared everything [we are working on] people would think we are insane!"
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Offline Robotbeat

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Dragon is kind of more analogous to what BFS will be doing. Orbital entry. And yeah, Dragon HAS demonstrated that. Hopefully it'll soon demonstrate propulsive landing after hypersonic reentry, too.
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Offline guckyfan

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Dragon is kind of more analogous to what BFS will be doing. Orbital entry. And yeah, Dragon HAS demonstrated that. Hopefully it'll soon demonstrate propulsive landing after hypersonic reentry, too.

I don't see an absolute need to do both in one mission. Propulsive landing after an air drop would be good enough. We do know they can do earth reentry. If anything they would want to demonstrate supersonic retropropulsion in the high atmosphere even if not needed for landing on earth.

Online ZachF

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I also vote for the Mariner Valley. Thicker atmosphere, near equator, also being geographically striking should be helpful for colony morale. Watching the fog roll over massive canyon walls on a martian sunset would be more interesting than desert as far as the eye can see in every direction.
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Offline sanman

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Valles Marineris runs pretty deep - but so does Hellas Basin - both are interesting places to look for water.

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I'm guessing you're talking about a PWR. That also needs a 200atm pressure vessel to hold it.

Most space nuclear reactor designs run considerably hotter and use a liquid metal heat pipe system for heat transfer.

Such designs are much more compact and lighter (but then they don't generate the 100s of MW that PWRs generate.

Realistically anything whose outlet temperature after power generation had been done is over 0c can be used to melt ice.

A gaseous CO2 reactor might work well on Mars.  It would produce relatively low temperature gas to run a turbine, and if you ever needed to add more working fluid, that is easily achieved by the atmosphere surrounding the plant.

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