Preferred Landing Sites

[sanman]

Large deposit of water ice the size of Lake Superior found just under the martian surface at Utopia Planitia:

http://phys.org/news/2016-11-mars-ice-deposit-lake-superior.html






Why not simply go where the water is? If that's what's most useful to you, and what you'll need the most of, as a potential propellant source, then why not just find the spot with the greatest amount of accessible water, and target all your operations at that site? At least Utopia Planitia isn't at the poles, so you'll get a little bit of help achieving escape velocity.

Otherwise, what other possible criteria would be important for selection of landing site and location of settlements?


And the place has got one other plus - since Musk is a notorious sci-fi nerd, I'm sure he knows (as the rest of us do) that Utopia Planitia is the location of the shipyard where the USS Enterprise is built in the 24th century, in the Star Trek story universe.

https://en.wikipedia.org/wiki/Utopia_Planitia#In_popular_culture

I'm sure he wouldn't pass up mentioning that, if this place met all his other criteria for a suitable spot. 

[guckyfan]

They won't need that much water. Even 10km³ will go a long way. Since that much water is in many locations they can look for other criteria.

[Hotblack Desiato]

Well, they don't need that much for their initial plans. But simply having this amount of resources available  clearly helps in the long run (and I'm thinking in centuries).

Nice discovery

[sanman]

They won't need that much water. Even 10km³ will go a long way. Since that much water is in many locations they can look for other criteria.

But we're talking about the vision of building a city, and of sending a million colonists to live and work there. Even if the colony recycles water efficiently, there's still going to be a lot of spaceships departing for Earth (since their recyclability is key to the whole plan), and those will be needing a lot of water collectively.

The Mars settlement will be a spaceport in its own right - at least over the long run - and thus you'll want to have abundantly ample resources available for scaling over the long term.

[philw1776]

Posted it here before but since this is another thread on manned landing sites...

NASA survey of potential landing sites...

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

N.B. Nili Fossae is the closest to this Lake Superior glacial ice in Utopia Plantina

And here's a writeup for each site under consideration...

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

Note that this is NASA with their considerations for landing sites. SX's preferences with colonization as the goal could be quite different, such as no emphasis on search for life, or untangling the geohistory (sic) of Mars.  Maybe.

The problem with the site cited (Heh) here is its northerly location.  For robust colonization you don't just need the water you also need metric oodles of energy to extract the ice, disassociate the water and brew rocket fuel.  If its solar power, close to the equator is substantially better.  If nukes, which I'm certain the anti-nukes and solar acolytes will oppose, then the northern plains with subsurface water are the best spots as long as they're not too far north (extra delta V to land and launch) or high (want as much atmosphere to slow down on landing as possible).

I'm intrigued by the differing tradeoffs.  It's safe to say that SX will likely do more in orbit water, etc. surveys  and ground truth verification before landing ITSs there.

[guckyfan]

They won't need that much water. Even 10km³ will go a long way. Since that much water is in many locations they can look for other criteria.

But we're talking about the vision of building a city, and of sending a million colonists to live and work there. Even if the colony recycles water efficiently, there's still going to be a lot of spaceships departing for Earth (since their recyclability is key to the whole plan), and those will be needing a lot of water collectively.

The Mars settlement will be a spaceport in its own right - at least over the long run - and thus you'll want to have abundantly ample resources available for scaling over the long term.

Fuelling the spaceships for sending 1 million people and the cargo ships will not consume 1km³ of water, leaving 9 for the settlement. That's 9.000t of water for each of the 1 million settlers.

Long term they will spread out to where different kinds of resources are.

I admit to making that remark somewhat tongue in cheek. It is still true.

[redliox]

Large deposit of water ice the size of Lake Superior found just under the martian surface at Utopia Planitia:


Why not simply go where the water is?

Well the main disadvantage of Utopia Planitia is it is very, very, very boring.  Viking 2 landed in the closest thing to what was Utopia's more interesting terrain, with the crater Mie to the east and Hrad Vallis to the south.  I glanced at a map of the coordinates - there are a few ruples features and a spattering of small, unnamed craters...but literally nothing on the scale of tens, if not hundreds, if kilometers.  Aside from a bland landscape, the science may be minimal outside of deep drills.

I think a big reason why Utopia Planitia is such a boring place is, in the ancient wet days of Mars, it was Mars' equivalent of Earth's abyssal plains under the ocean.  These regions technically dominate huge chunks of the Earth's surface, and by dominate I'm talking on the scale of continents since they are legitimately a full HALF of Earth's true surface (certainly if you talk to any oceanographers).  Utopia is basically a fossilized version of these massive mud flats.

Otherwise, what other possible criteria would be important for selection of landing site and location of settlements?


And the place has got one other plus - since Musk is a notorious sci-fi nerd, I'm sure he knows (as the rest of us do) that Utopia Planitia is the location of the shipyard where the USS Enterprise is built in the 24th century, in the Star Trek story universe.
I'm sure he wouldn't pass up mentioning that, if this place met all his other criteria for a suitable spot. 

Science and safety are the essential criteria.  I'd personally rank a flat spot adjacent to Valles Marineris the best.  However, I would put Utopia as my second choice now since it is generally safe and ice rich.  My only additional requirement would be some form of long-range transport for a Utopia base to expedite exploration.

I don't know what Musk's perference would be on where to setup a Mars base for ITS.  Utopia might be fitting, but given his choice of "Heart of Gold" he may favor more British-themed locales bear-in-mind. 

[matthewkantar]

I would imagine that the newly landed Martians would be looking for H2O buried deep enough to be liquid. Makes getting to it a little harder, but getting it out much easier. It might even be pressurized, so no pumps would be necessary to get it to the surface. I have read that the core temp of Mars is estimated to be 5-7000 degrees F. I have not found even a guess as to how deep a well would need to go to find 32 degrees F.

Matthew

[wes_wilson]

Musks presentations always show the red mars turning blue.  Perhaps elevation should also be considered a significant factor in selecting the first landing site.  Somewhere above global sea level if the planet were terraformed and somewhere not likely to become a lake or other inland body of water but perhaps next to a future place like this.

[meekGee]

Large deposit of water ice the size of Lake Superior found just under the martian surface at Utopia Planitia:


Why not simply go where the water is?

Well the main disadvantage of Utopia Planitia is it is very, very, very boring.  Viking 2 landed in the closest thing to what was Utopia's more interesting terrain, with the crater Mie to the east and Hrad Vallis to the south.  I glanced at a map of the coordinates - there are a few ruples features and a spattering of small, unnamed craters...but literally nothing on the scale of tens, if not hundreds, if kilometers.  Aside from a bland landscape, the science may be minimal outside of deep drills.

I think a big reason why Utopia Planitia is such a boring place is, in the ancient wet days of Mars, it was Mars' equivalent of Earth's abyssal plains under the ocean.  These regions technically dominate huge chunks of the Earth's surface, and by dominate I'm talking on the scale of continents since they are legitimately a full HALF of Earth's true surface (certainly if you talk to any oceanographers).  Utopia is basically a fossilized version of these massive mud flats.

Otherwise, what other possible criteria would be important for selection of landing site and location of settlements?


And the place has got one other plus - since Musk is a notorious sci-fi nerd, I'm sure he knows (as the rest of us do) that Utopia Planitia is the location of the shipyard where the USS Enterprise is built in the 24th century, in the Star Trek story universe.
I'm sure he wouldn't pass up mentioning that, if this place met all his other criteria for a suitable spot. 

Science and safety are the essential criteria.  I'd personally rank a flat spot adjacent to Valles Marineris the best.  However, I would put Utopia as my second choice now since it is generally safe and ice rich.  My only additional requirement would be some form of long-range transport for a Utopia base to expedite exploration.

I don't know what Musk's perference would be on where to setup a Mars base for ITS.  Utopia might be fitting, but given his choice of "Heart of Gold" he may favor more British-themed locales bear-in-mind. 

I don't think immediate science value would play a big role in the selection.

This is not a one-time mission, it is about colonization. Once you're established on Mars, the benefit to science on Mars are so much greater than you'd get by optimizing the landing site for science.

It's like arguing which telescope to build, whereas in the long view, the best thing you can do for astronomy is to invest in cheap and more powerful launch technology.

[Jcc]

Musks presentations always show the red mars turning blue.  Perhaps elevation should also be considered a significant factor in selecting the first landing site.  Somewhere above global sea level if the planet were terraformed and somewhere not likely to become a lake or other inland body of water but perhaps next to a future place like this.

The time scale between establishing a first colony and eventual filling of lakes or oceans via terraforming (if ever) will make it a non-issue. If the best place for initial colonies happens to be an area that gets flooded 1000 years from now so be it, they can build on higher ground later.
Or do you think they can produce standing water in a lake 50 years from now? I don't think so.

[MickQ]

Utopia Planitia may be boring BUT it has a basically unlimited water supply.  IMO, the ideal place to set up the solar and ISRU plants needed.  Plenty of area to build an initial base to establish a foothold.  Plenty of room to locate landing zones far enough away from other structures.  So what if you have to drive 10klm from the ITS to the base.  It's not hard with the right vehicles.

Land, get set up safe and comfortable and then worry about science and exploration.

[philw1776]

a little far north for best solar

[redliox]

Posted it here before but since this is another thread on manned landing sites...

NASA survey of potential landing sites...

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

N.B. Nili Fossae is the closest to this Lake Superior glacial ice in Utopia Plantina

Excellent point, and that site is indeed somewhat close to the Utopia ice field.

The other Utopia site is at Hebrus Valles, at 20 N and 126 E.  Some indications of potential permafrost and possibly subsurface caverns, the later because of ancient melting.  Considering Utopia's past as an ancient ocean floor, the hydrogen abundance Odyssey's detected over most of the planet, and the ice discovery it isn't a stretch to think this site will include either some ice or chemically-bound water.

Further reason to support Hebrus Valles, especially for those thinking long-term (taken from the section on HV here https://www.nasa.gov/sites/default/files/atoms/files/mars-c-abstracts_in_order_of_presentation10242015_0.pdf ):

The predicted typical
mean annual surface temperature for the EZ investigated
latitudes is -60ºC [5]. At these temperatures,
permafrost could have a mechanical
strength close to that of limestone [6, 7], which
could have stabilized evacuated caverns. Chemical
precipitation from circulating brines in terrestrial
cold springs can produce cements along the
periphery of feeder conduits, thereby enhancing
their overall structural stability [8]. Cements developed
in association with cold water circulation
include calcite, aragonite, Fe-Mn oxides, sulfides
and sulfates [9,10]. On Earth, caverns are known
to occur in ice-welded sediments such as in association
with networks of ice wedges in permafrost
[11] and ice-welded moraine deposits [12]. Some
glacier caverns are known to have remained stable
over decades [13]. Subsurface caverns and
steep walls in Hebrus Valles might represent natural
terrain features that can be adapted for construction
purposes (minimum ROI requirement).,
Hence, infrastructure can be emplaced or constructed
the LS (minimum ROI requirement).

Taken together, the site landscape could be incorporated into construction and the soil is chemically useful, possibly still has water in some form in it, and a potential fossil bed all at once.  I'd call this a potentially good site; not my personal first choice but still should be kept high on the list.

[redliox]

a little far north for best solar

Correct in regards to Utopia overall.  The Hebrus Valles site I mentioned is more southerly but likewise farther from direct ice deposits.  Also, given we're talking about SpaceX's plans, in the end they may not choose a site NASA scientists advocate simply because they might favor engineering concerns more heavily than science (such as the need for solar power).

[RonM]

a little far north for best solar

Correct in regards to Utopia overall.  The Hebrus Valles site I mentioned is more southerly but likewise farther from direct ice deposits.  Also, given we're talking about SpaceX's plans, in the end they may not choose a site NASA scientists advocate simply because they might favor engineering concerns more heavily than science (such as the need for solar power).

For colonization, engineering concerns are more important than scientific research. Once the initial base for the colony is established, explorers can drive rovers to more interesting sites for science.

The key is to build a colony that will eventually become self-sufficient. Once the "beachhead" on Mars is established, other benefits such as science and multi-planet species will naturally follow.

Access to water is the most important ISRU factor. Utopia Plantina sounds to me like a good place to start.

[MickQ]

a little far north for best solar

Correct in regards to Utopia overall.  The Hebrus Valles site I mentioned is more southerly but likewise farther from direct ice deposits.  Also, given we're talking about SpaceX's plans, in the end they may not choose a site NASA scientists advocate simply because they might favor engineering concerns more heavily than science (such as the need for solar power).

For colonization, engineering concerns are more important than scientific research. Once the initial base for the colony is established, explorers can drive rovers to more interesting sites for science.

The key is to build a colony that will eventually become self-sufficient. Once the "beachhead" on Mars is established, other benefits such as science and multi-planet species will naturally follow.

Access to water is the most important ISRU factor. Utopia Plantina sounds to me like a good place to start.

No mountains to block sunlight and room for more than enough solar panels to meet any requirements for a first base.  The wagon trains can roll from here to all those other more interesting places.

[guckyfan]

Elon Musk wants an attractive site, a place people want to go to. An endless flat desert is not that attractive. Also probably not that variable in available resources.

[AncientU]

Utopia Plantina sounds like one site where there is great potential. NASA has others with various drawing points... initial effort should be to investigate 2-4 of these leading candidate sites and determine which has the features most favorable.  It could be that ice fields are completely riddled with features (crevaces, un-navigable surfaces, whatever) that make them dangerous... Or perfect.

Other sites near glaciers might have essentially unlimited water, but not the disadvantages...

We should examine potential sites (dare I say it... actually explore a bit) before going all-in on one that was selected from orbit.  NASA is all over this exploration concept, so get on with it.

[guckyfan]

We will see what landing sites will be selected for the 2020 Red Dragons.

[rocx]

Perhaps we could open a target bingo for Red Dragon at some point. Let the collective wisdom of this forum place their bets where the mission will be targeted. And then later a touchdown bingo, of course.

[wes_wilson]

Musks presentations always show the red mars turning blue.  Perhaps elevation should also be considered a significant factor in selecting the first landing site.  Somewhere above global sea level if the planet were terraformed and somewhere not likely to become a lake or other inland body of water but perhaps next to a future place like this.

The time scale between establishing a first colony and eventual filling of lakes or oceans via terraforming (if ever) will make it a non-issue. If the best place for initial colonies happens to be an area that gets flooded 1000 years from now so be it, they can build on higher ground later.
Or do you think they can produce standing water in a lake 50 years from now? I don't think so.

I think elevation is a decision criteria with no present cost and significant future cost.  If I were making the landing site decision it would be a criteria on my decision matrix; albeit one given less weight than landing/launching friendliness, local resources, and solar influx.

The timeline for terraforming is probably best for another thread.  However, my view is that it could be much shorter term than most people think.  On earth, we've already warmed the planet several degrees over the last 150 years as a byproduct of our society.  A focused industrial effort to produce super greenhouse gases could effect more rapid change on a shorter timescale.  Further, Mars doesn't have the same strong feedback mechanisms in place to prevent climate change.  A little warming will release a lot of CO2. 

So, I think elevation is a factor if you're planning for long term inhabitation of Mars. 

[The Amazing Catstronaut]

The timeline for terraforming is probably best for another thread.  However, my view is that it could be much shorter term than most people think.  On earth, we've already warmed the planet several degrees over the last 150 years as a byproduct of our society.  A focused industrial effort to produce super greenhouse gases could effect more rapid change on a shorter timescale.  Further, Mars doesn't have the same strong feedback mechanisms in place to prevent climate change.  A little warming will release a lot of CO2.  A breathable, stable oxygen atmosphere without unacceptable toxin levels, strong magnetic field and a biosphere is a whole different basket of eggs - but temperature and liquid water isn't.

So, I think elevation is a factor if you're planning for long term inhabitation of Mars.

Agreed. Whilst it probably doesn't matter if initial work is low level, there's no genuine reason why it needs to take a thousand years to significantly raise the temperature (a thousand years is the time between the early middle ages and the present day, think of the technology climb in that time. We will likely have a technology development rate in the near future which exceeds what we learnt in 1000 years in 100, 50, or less, and it will just keep on climbing. With present day tech it hypothetically doesn't need a thousand years, with unknowable future tech? Assume better ratios under optimistic, Muskian colonisation scenarios).

There's a lot of satisfactory mid-ground or higher ground sites that it's unlikely to be a problem anyway.

[RonM]

The timeline for terraforming is probably best for another thread.  However, my view is that it could be much shorter term than most people think.  On earth, we've already warmed the planet several degrees over the last 150 years as a byproduct of our society.  A focused industrial effort to produce super greenhouse gases could effect more rapid change on a shorter timescale.  Further, Mars doesn't have the same strong feedback mechanisms in place to prevent climate change.  A little warming will release a lot of CO2.  A breathable, stable oxygen atmosphere without unacceptable toxin levels, strong magnetic field and a biosphere is a whole different basket of eggs - but temperature and liquid water isn't.

So, I think elevation is a factor if you're planning for long term inhabitation of Mars.

Agreed. Whilst it probably doesn't matter if initial work is low level, there's no genuine reason why it needs to take a thousand years to significantly raise the temperature (a thousand years is the time between the early middle ages and the present day, think of the technology climb in that time. We will likely have a technology development rate in the near future which exceeds what we learnt in 1000 years in 100, 50, or less, and it will just keep on climbing. With present day tech it hypothetically doesn't need a thousand years, with unknowable future tech? Assume better ratios under optimistic, Muskian colonisation scenarios).

There's a lot of satisfactory mid-ground or higher ground sites that it's unlikely to be a problem anyway.

Sure our technology will improve, but that doesn't matter to thermodynamics. We're talking about an incredible amount of energy required to not just increase the temperature but to transition frozen CO2 from solid to gas. It will be a very long time before there are oceans on Mars.

Let's try to keep the unknowable future tech out of the conversation because, well, it's unknowable.

[philw1776]

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

[meekGee]

I'd add stable soil that is easy to excavate, or maybe a large salt deposit, so the underground portion of the colony can happen faster and with less equipment

[LMT]

An Ice Dart at Hew Thermopylae

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

What he said.    

I'll throw a dart at the 2-km filled crater at 33^o 35' N, 177^o  31' W.  It's a ground-ice prospect for the hypothetical "Hew Thermopylae" site in Erebus Montes.

Hew Thermopylae meets philw1776's general requirements.  Notably, it's also a low-latitude site of geologically recent glaciation.  There are several places one might prospect around there for remnant deep glacial or periglacial ice, under good PV sunlight.  Why not drop Red Dragon in the center of this filled crater, as a first prospect?

Also, if SpaceX is serious about tunneling, the site's block mesa rock likely falls between the practical limits of "too hard for Roadheader" and "too soft for room-and-pillar tunnels".  And this is a brutal constraint on tunneling, as we saw in that thread.  Most Mars rock seems out-of-range, one way or the other.  Rock strength -- uniaxial compressive strength (UCS) -- may prove the most stringent site criterion.

Assuming, again, SpaceX is serious about tunneling.

[LMT]

For colonization, engineering concerns are more important than scientific research. Once the initial base for the colony is established, explorers can drive rovers to more interesting sites for science.

The key is to build a colony that will eventually become self-sufficient. Once the "beachhead" on Mars is established, other benefits such as science and multi-planet species will naturally follow..

You may well be right about that.  Engineering challenges are so great that engineering desperation may in time drive SpaceX to put down a stake wherever the challenges are mitigated, regardless of the science or scenery.

Of course, the Lake Matthew Team has a particular view of those challenges, and mitigations.  We'd prefer to win the "landing site bingo" by painting the bingo balls with our own, as-yet unstated, site coordinates.

It's not cheating if you legally change the rules. 

[philw1776]

Here's a fun overflight of Kasei Valles, one of the potential manned landing sites under consideration by NASA
Courtesy ESA Mars Express



Interesting cliffs, valleys, mesas and erosional features
Downside, no (yet) known large water resources within easy access

[DOCinCT]

Utopia Planitia may be boring BUT it has a basically unlimited water supply.  IMO, the ideal place to set up the solar and ISRU plants needed.  Plenty of area to build an initial base to establish a foothold.  Plenty of room to locate landing zones far enough away from other structures.  So what if you have to drive 10klm from the ITS to the base.  It's not hard with the right vehicles.

Land, get set up safe and comfortable and then worry about science and exploration.

Do you want to live in New England (hills, valleys, waterfalls, lakes, forests, etc.) or in Kansas/Nebraska?

[Ionmars]

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
...
...

I am becoming sold on the idea that low elevation for landings is a higher priority than water. Water ice can be transported but elevation is hard to change.

[meekGee]

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
...
...

I am becoming sold on the idea that low elevation for landings is a higher priority than water. Water ice can be transported but elevation is hard to change.

Low elevation, and easy to excavate geology.

I think salt deposits would be awesome, because they give you stability, plus a neat way to process minerals.

I think that water, while super important, will also not be difficult to find, so will not be the deciding factor.

[Ionmars]

I have always likes Melas Chasma as a low altitude landing site, but the lowest elevation on Mars is Helles Basin. It is about 7100 m deep and the plain within the crater is about 2300 km east to west. Frequent dust storms may reduce its desirability for a colony, but here's an idea how to utilize it:
1. Draw a straight line from the SE straight across Helles Basin that ends in Melas Chasma to the NW..
2. From orbit, align your spaceship toward this line and enter the atmosphere at the SE edge of the Basin.
3. Follow the line across the basin about 1000 m above ground level for maximum deceleration. . Your GNC program must adjust for any unexpected dust storms that it may encounter.
4. At the west end of the basin abruptly swerve upward into a parabolic arc that allow you to coast toward Melas Chasma.
5. Restart engines for final descent to a pinpoint landing at the colony landing site.

[Space Ghost 1962]

Hellas Basin has primarily been rejected in the past due to a) being too south in latitude, b) being rocky as well as having dust storms.

Mind you that recently there is evidence that the "rocky" is likely ... surface ice! Which would be ideal for ISRU, as a bulldozer might effectively collect enough water for ISRU. And ... there may be enough of a crustal magnetic field. which along with the increased atmospheric density ... would have the least radiation (and perchlorate) issues for habitation.

But here are the problems - likely static effects and dust accumulation is largest too, so optical density/scattering would be the worst on Mars. Also, solar would have the lowest yield due to the inclination.

Also, the dynamic pressures (overdone to embellish risk in the movie "The Martian") would be the largest force winds and most active on Mars. Wonder if you could feasibly extract wind power 

And, of course, with the increased density ... less need for a pressure suit ...

So there are many factors that make Hellas Basin ... peculiar ... for a landing site.

[guckyfan]

Mind you that recently there is evidence that the "rocky" is likely ... surface ice! Which would be ideal for ISRU, as a bulldozer might effectively collect enough water for ISRU. And ... there may be enough of a crustal magnetic field. which along with the increased atmospheric density ... would have the least radiation (and perchlorate) issues for habitation.

But here are the problems - likely static effects and dust accumulation is largest too, so optical density/scattering would be the worst on Mars. Also, solar would have the lowest yield due to the inclination.

Interesting point about the local magnetic field. I had wondered before if they might help with local radiation but have not come around to ask that question.

The inclination should not have too much effect with canted solar arrays, though with initial arrays only rolled out on the ground. Canted solar arrays should help reduce dust accumulation.

I have also thought later, though not early, solar arrays could be located in the highlands, much reducing dust problems.

[Ionmars]

...
...
The inclination should not have too much effect with canted solar arrays, though with initial arrays only rolled out on the ground. Canted solar arrays should help reduce dust accumulation.

I have also thought later, though not early, solar arrays could be located in the highlands, much reducing dust problems.

With landing sites and habitats in lowlands and solar farms i the highlands I am imagining some very LONG power lines.(?)

Edit: I guess I was thinking NASA-scale rather than Elon-scale, so long lines are probably fine.

[ZachF]

A poster on Reddit made this map of solar irradiance, so If solar power is the (likely) starting energy source, you're going to be likely limited in practicality to between ~10S and ~30N.

https://docs.google.com/spreadsheets/d/e/2PACX-1vQTCtGVlkzmRRGn_NKhkMWEio6Ae0C_5EqLFjbaUNqm0o5pwkhqDThYOEm3ZuNoT4McPdOn9B5ibMQ7/pubchart?oid=1930243735&format=image

[philw1776]

Given that, those water rich high northern latitude ice fields 40+ degrees are out for colonies unless a political miracle occurs and the public goes pro-nuke.  Making propellant requires an electricity rich colony.

[guckyfan]

That spreadsheet is for horizontally arranged panels. It gets a lot better at higher latitudes when they are canted to the local latitude.

[Bob Shaw]

Utopia Planitia may be boring BUT it has a basically unlimited water supply.  IMO, the ideal place to set up the solar and ISRU plants needed.  Plenty of area to build an initial base to establish a foothold.  Plenty of room to locate landing zones far enough away from other structures.  So what if you have to drive 10klm from the ITS to the base.  It's not hard with the right vehicles.

Land, get set up safe and comfortable and then worry about science and exploration.

Do you want to live in New England (hills, valleys, waterfalls, lakes, forests, etc.) or in Kansas/Nebraska?

Do you want to live, full stop?

[Paul451]

Do you want to live in New England (hills, valleys, waterfalls, lakes, forests, etc.) or in Kansas/Nebraska?

Given that people migrated from the north-east to the mid-west...

[philw1776]

Utopia Planitia may be boring BUT it has a basically unlimited water supply.  IMO, the ideal place to set up the solar and ISRU plants needed.  Plenty of area to build an initial base to establish a foothold.  Plenty of room to locate landing zones far enough away from other structures.  So what if you have to drive 10klm from the ITS to the base.  It's not hard with the right vehicles.

Land, get set up safe and comfortable and then worry about science and exploration.

Do you want to live in New England (hills, valleys, waterfalls, lakes, forests, etc.) or in Kansas/Nebraska?

Do you want to live, full stop?

I can see showman Musk saying in a deep voice, "Come with me if you want to live"

[mikelepage]

Wanted to draw attention to this:

A possibly interesting site for large payload landing is Hadriacus Palus, which is just east of Terby crater on the very northern edge of Hellas Planitia.  It has a latitude of 27.25 South which is within the 30S cutoff for solar power considerations - it also has probable water ice deposits, nearby mineral deposits, and generally high scientific value - leading to it being ranked 16th out of all the landing sites in the 2020 workshop:

Evaluation paper here:
http://www.hou.usra.edu/meetings/explorationzone2015/pdf/1052.pdf

Rough map here


As you can see, if the entry approach was from the direction of Rabe crater, you would have nearly 1000km (in a straight line) of some of the thickest atmosphere on Mars to slow your ITS down, before using your craft as a lifting body to get back up to a landing altitude of -2.6km.

Quick BOE you would cover those 1000km in about 200 s of 3xg deceleration (to get from 8km/s to 2km/s), and I'm hoping the ITS can do the rest by itself...

[philw1776]

Much discussion in other SX Mars threads about tunneling underground and Mars habitats.  One possible class of non-surface but proximate to surface habitats is living inside Yardangs as people have on Earth for thousands of years, e.g. Cappadocia Turkey.  These natural structures may be exploitable on Mars.  This site, Appolonarus Sulci, is only 12 degrees south of the equator and best of all has a soil containing 7.5% water in the upper centimeters.

http://www.hou.usra.edu/meetings/explorationzone2015/pdf/1043.pdf

A major advantage to landing a human mission near the Medusae Fossae is the potential to use the formation itself as a source of feedstock for civil engineering projects. The Medusae Fossae represents a vast source of fine-grained, easily mineable material that could be used to build landing pads, berms, roads, habitations, emergency shelters, equipment shelters, etc  In addition, dwellings could be dug directly into the side of yardangs, providing natural protection from temperature extremes, radiation, and small meteors. Volcanic tuff deposits have served as building material for human beings for milennia. Cities such as Rome and Naples sit above extensive tuff quarries and underground tunnels, cisterns, storerooms. In the Cappadocia region of modern Turkey, early Christians built and enlarged underground cities, some of which were capable of housing more than 20,000 people and their livestock...

[Paul451]

Wanted to draw attention to this:
A possibly interesting site for large payload landing is Hadriacus Palus, which is just east of Terby crater on the very northern edge of Hellas Planitia.

The problem with Hellas Basin is that it's where the dust storms come from and most frequently occur.

If you're using solar power, you want to avoid Hellas like the plague.

[FutureSpaceTourist]

Paul Wooster, SpaceX, on Mars landing site selection: looking at sites at latitudes < 40˚, elevation as low as possible. #LPSC2017

https://twitter.com/jeff_foust/status/843229275025227777

Wooster: identified several candidate sites, but many likely too rocky. Arcadia region looks promising. #LPSC2017

https://twitter.com/jeff_foust/status/843229571642286081

Edit: from context I think he's talking about Red Dragon landing site

[Dalhousie]

Wanted to draw attention to this:

A possibly interesting site for large payload landing is Hadriacus Palus, which is just east of Terby crater on the very northern edge of Hellas Planitia.  It has a latitude of 27.25 South which is within the 30S cutoff for solar power considerations - it also has probable water ice deposits, nearby mineral deposits, and generally high scientific value - leading to it being ranked 16th out of all the landing sites in the 2020 workshop:

Evaluation paper here:
http://www.hou.usra.edu/meetings/explorationzone2015/pdf/1052.pdf

How do you know it was ranked 16th?

[Phil Stooke]

Go to this page at JPL:

https://marsnext.jpl.nasa.gov/workshops/index.cfm

The top link on that page ('letter summarizing the findings...') gives a ranked list of sites from that workshop.  That was the first 2020 workshop, and Hadriacus Palus was only ranked 21st out of 21 in the second workshop, so it's not doing too well.

[Dalhousie]

Thanks!

[Dao Angkan]

Amazonis Planitia. < 40˚ latitude, low elevation, not too rocky, and highest water ice concentrations at that latitude.

Circled;

[redliox]

Amazonis Planitia. < 40˚ latitude, low elevation, not too rocky, and highest water ice concentrations at that latitude.

That's pretty sweet to learn.  If the priority is ice not a bad choice.  It looks like a mix of both Amazonis and Arcadia technically; then again most of the northern plains may as well just be counted as one giant extension of Vastis Boreallis.  As I stated in the Red Dragon thread, other regions could just as easily suffice if this is just an engineering test but I have to admit if the priority is ice (and eventually setting up a colony) the region is a very fair choice.

That map you posted also show a surprising number of southerly sites.  What is known about them?

[Robotbeat]

But if there's lots of water in other forms, then focus should be on power. And if you're using solar, you'd really like to be close to the equator (within 10-30 degrees), as you can generate a lot more power especially in winter compared to more polar sites. What if you're only saving, say, 1MJ/kg to extract water from hydrated minerals if you pick a 45 degree latitude site with ice, but you produce half as much solar energy and most of your water needs to be electrolyzed at ~20MJ/kg? Then a more Equatorial site is far better... Especially when launch delta-V is taken into account.

[FutureSpaceTourist]

Here's Jeff Foust's write-up of Paul's Woosters comments:

http://spacenews.com/spacex-studying-landing-sites-for-mars-missions/

[sghill]

But if there's lots of water in other forms, then focus should be on power.

IMHO, site selection should focus on the the preponderance of minerals and their ease of extraction. Energy is cheap, creating a viable economy is not.

[rsdavis9]

Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.

[redliox]

Here's Jeff Foust's write-up of Paul's Woosters comments:

http://spacenews.com/spacex-studying-landing-sites-for-mars-missions/

Judging from Paul's (and the spacenews writer Foust's) commentary, we ought to keep an eye out regarding Arcadia Planitia.  An impression is given that the Red Dragon could still be sent anywhere on Mars, but obviously icy and flat seems preferred.

[Dao Angkan]

Amazonis Planitia. < 40˚ latitude, low elevation, not too rocky, and highest water ice concentrations at that latitude.

That's pretty sweet to learn.  If the priority is ice not a bad choice.  It looks like a mix of both Amazonis and Arcadia technically; then again most of the northern plains may as well just be counted as one giant extension of Vastis Boreallis.  As I stated in the Red Dragon thread, other regions could just as easily suffice if this is just an engineering test but I have to admit if the priority is ice (and eventually setting up a colony) the region is a very fair choice.

That map you posted also show a surprising number of southerly sites.  What is known about them?

Yes, it's borderline Amazonis/Arcadia. It may well be where Paul Wooster was referring to. The white squares are where presumed water ice was seen sublimating after fresh impacts, it's thought to be close to the surface. Red Dragon might expose some from landing.

The more southerly sites with high water concentrations are generally high elevation and cratered or rocky terrain, so difficult to get to. The Northern plains also look to be easier to travel about for any future human explorers.

Arabia Terra has some lower elevation craters near to the equator with higher concentrations of water ice, but difficult to get to.

[philw1776]

Not good for solar power in winter.  Not exactly exciting topography for settlers. The "fun" factor Elon oft mentions.
Perhaps SpaceX wants earliest RD missions to have easiest ice access to validate ISRU tech and then proceed to base selection forays.
Also NASA landing site priority criteria are not likely SpaceX's priorities.

[Dalhousie]

Not good for solar power in winter.  Not exactly exciting topography for settlers. The "fun" factor Elon oft mentions.
Perhaps SpaceX wants earliest RD missions to have easiest ice access to validate ISRU tech and then proceed to base selection forays.
Also NASA landing site priority criteria are not likely SpaceX's priorities.

First of all we don't know the conop for the mission. It might not be intended to survive the winter.  Or it might be powered down over winter.  Or the panels might be tilted to allow winter operations. We don't even know whether Red Dragon will run on solar power.  It might rely on batteries and have a surface mission that lasted only a few days.

[Robotbeat]

Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.

The problem is the low power in winter.

[redliox]

Not good for solar power in winter.  Not exactly exciting topography for settlers. The "fun" factor Elon oft mentions.
Perhaps SpaceX wants earliest RD missions to have easiest ice access to validate ISRU tech and then proceed to base selection forays.
Also NASA landing site priority criteria are not likely SpaceX's priorities.

First of all we don't know the conop for the mission. It might not be intended to survive the winter.  Or it might be powered down over winter.  Or the panels might be tilted to allow winter operations. We don't even know whether Red Dragon will run on solar power.  It might rely on batteries and have a surface mission that lasted only a few days.

Indeed.  The priority is seeing if a Dragon can land on Mars.  As I mentioned earlier that means it could be sent anywhere regardless of ice.

If there is to be one, extremely base and minimalistic, long-term function this lander could offer it could be to serve as a beacon.  If it can sustain a little power, this could include a Sputnik-esque radio beep or numerous reflective panels specific for laser range-finding.  Either function could give future landers something to refer to and home in on.

[Dalhousie]

More on the Space News web site.  Gives details of some other landing sites considered - Deuteronilus Mensae, Phlegra Montes and Utopia Planitia - all ruled out because they were too rocky. Interesting that Utopia, where Viking 2 landed, was considered to be unsuitable.  Indicates the surface roughness tolerance on the landing system to below Viking 2 levels.

See more at: http://spacenews.com/spacex-studying-landing-sites-for-mars-missions/

[meekGee]

Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.

You can fix the elevation angle, but can't fix the shorter days.

I'm with RB here.  If we're stuck with solar, maximizing power is the #1 consideration. 

With water, all you need is to pass a certain threshold, not maximize - and I think you can pass that threshold in many locations.

EDIT:
And yes, sites for initial RDs might be different than sites for colony.

Actually, after an initial from-orbit survey, some RDs might be used to get ground measurements in the top ranking locations

[notsorandom]

More on the Space News web site.  Gives details of some other landing sites considered - Deuteronilus Mensae, Phlegra Montes and Utopia Planitia - all ruled out because they were too rocky. Interesting that Utopia, where Viking 2 landed, was considered to be unsuitable.  Indicates the surface roughness tolerance on the landing system to below Viking 2 levels.

See more at: http://spacenews.com/spacex-studying-landing-sites-for-mars-missions/

The Viking missions were a gamble in some ways. They did not have the ability to image the surface at a high enough spatial resolution to detect all hazardous boulders. They could look at lower resolution imagery and rule out the bigger stuff but couldn't see the smaller yet still dangerous obstacles. They also bounced radar off the landing sites from Arecibo. The dispersal of the reflected signal gave them an idea how rough the surface was. In the case of Red Dragon they selected Utopia as a possible site just as the Viking people did decades before. However this time with the better imagery they dropped the site. The Viking team might very well have done the same if they had MRO and MGS imagery available too.

[Phil Stooke]

Yes, they would have dropped Utopia if they had better images.  The selection - rather desperate because all other options were looking bad - was based on an unfortunate failing of image interpretation.  The best images of the site were very low contrast and resolution compared with the Viking 1 images, but they seemed to have a pervasive texture misinterpreted as sand dunes.  The assumption was that rocks produced as crater ejecta would be covered by the wind-blown sand , leaving a smoother surface. 

To clarify another point, only Viking 1's site could use earth-based radar to estimate rock abundance, and even there interpretation was very uncertain.  As Gerry Soffen said after the second landing, he was amazed that they had two successful landings.

[notsorandom]

Right they didn't have radar for Utopia. Its been a while since I read through the site selection history. They did use radar again for Pathfinder. But shortly afterwards Global Surveyor arrived and was able to provide high enough resolution imagery for the MERs.

[Dalhousie]

Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.

You can fix the elevation angle, but can't fix the shorter days.

I'm with RB here.  If we're stuck with solar, maximizing power is the #1 consideration. 

With water, all you need is to pass a certain threshold, not maximize - and I think you can pass that threshold in many locations.

Remember the following:

1) We don''t the power requirements, or how it might be supplied.

2) Shorter daylight in winter is balanced by longer daylight in summer.  Power usage can be adjusted accordingly. Viking 2 data (similar latitude) indicates that surface irradiance varies between 0.3 and 4 kwh/m2.  Assuming 30% efficiency that is 0.1-1.3 kwh/day.  A Phoenix type array (3.1m2) would supply 0.3-6 kwh per day.

Note these are horizontal irradiance values.  Inclined panels would achieve nearly twice this.

[meekGee]

Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.

You can fix the elevation angle, but can't fix the shorter days.

I'm with RB here.  If we're stuck with solar, maximizing power is the #1 consideration. 

With water, all you need is to pass a certain threshold, not maximize - and I think you can pass that threshold in many locations.

Remember the following:

1) We don''t the power requirements, or how it might be supplied.

2) Shorter daylight in winter is balanced by longer daylight in summer.  Power usage can be adjusted accordingly. Viking 2 data (similar latitude) indicates that surface irradiance varies between 0.3 and 4 kwh/m2.  Assuming 30% efficiency that is 0.1-1.3 kwh/day

Personally, I'm hoping they'll go with nuclear, but that's a separate issue.

The total energy requirement are reasonably well known.  Tons of methane per BFS, liters of O2 per person, etc.

[Dalhousie]

Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.

You can fix the elevation angle, but can't fix the shorter days.

I'm with RB here.  If we're stuck with solar, maximizing power is the #1 consideration. 

With water, all you need is to pass a certain threshold, not maximize - and I think you can pass that threshold in many locations.

Remember the following:

1) We don''t the power requirements, or how it might be supplied.

2) Shorter daylight in winter is balanced by longer daylight in summer.  Power usage can be adjusted accordingly. Viking 2 data (similar latitude) indicates that surface irradiance varies between 0.3 and 4 kwh/m2.  Assuming 30% efficiency that is 0.1-1.3 kwh/day

Personally, I'm hoping they'll go with nuclear, but that's a separate issue.

The total energy requirement are reasonably well known.  Tons of methane per BFS, liters of O2 per person, etc.

I don't there is any chance of anything nuclear (except perhaps RHUs) flying to Mars on the 2020 Red Dragon.

[meekGee]

Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.

You can fix the elevation angle, but can't fix the shorter days.

I'm with RB here.  If we're stuck with solar, maximizing power is the #1 consideration. 

With water, all you need is to pass a certain threshold, not maximize - and I think you can pass that threshold in many locations.

Remember the following:

1) We don''t the power requirements, or how it might be supplied.

2) Shorter daylight in winter is balanced by longer daylight in summer.  Power usage can be adjusted accordingly. Viking 2 data (similar latitude) indicates that surface irradiance varies between 0.3 and 4 kwh/m2.  Assuming 30% efficiency that is 0.1-1.3 kwh/day

Personally, I'm hoping they'll go with nuclear, but that's a separate issue.

The total energy requirement are reasonably well known.  Tons of methane per BFS, liters of O2 per person, etc.

I don't there is any chance of anything nuclear (except perhaps RHUs) flying to Mars on the 2020 Red Dragon.

I agree.  I was talking in the context of colony siting.

[philw1776]

The thread comments can be confusing.  Some of us are referring to colony site landing sites while others are referring to RD landing sites.  The criteria could be quite different, e.g. lack of solar irradiance circa 40 degrees north might not be a big issue for a RD mission, but could be a big negative for an all-seasons colony, assuming no nukes.

[guckyfan]

The thread comments can be confusing.  Some of us are referring to colony site landing sites while others are referring to RD landing sites.  The criteria could be quite different, e.g. lack of solar irradiance circa 40 degrees north might not be a big issue for a RD mission, but could be a big negative for an all-seasons colony, assuming no nukes.

IMO it is a safe assumption that a RedDragon landing site would be chosen to be a likely colony site.

Maybe not for a 2018 like mission where landing was the main/only goal. But for 2020 missions. If the choice was right, then a first ITS can use a radio beacon from that landing to home in on.

[Dalhousie]

The thread comments can be confusing.  Some of us are referring to colony site landing sites while others are referring to RD landing sites.  The criteria could be quite different, e.g. lack of solar irradiance circa 40 degrees north might not be a big issue for a RD mission, but could be a big negative for an all-seasons colony, assuming no nukes.

IMO it is a safe assumption that a RedDragon landing site would be chosen to be a likely colony site.

Maybe not for a 2018 like mission where landing was the main/only goal. But for 2020 missions. If the choice was right, then a first ITS can use a radio beacon from that landing to home in on.

I don't think that is a safe assumption at all. 

[Phil Stooke]

Nor do I!  It makes sense, I guess, to put a Red Dragon with a beacon at the colony site before we start pre-landing the habitat and supplies, but allowing for a wee bit of a delay that would likely be a decade from now (minimum), so all the early dragons will be doing other things.  They are already being promoted as delivery of customer cargo, so the sites will be chosen to suit the customers for quite a while.

[Dalhousie]

Nor do I!  It makes sense, I guess, to put a Red Dragon with a beacon at the colony site before we start pre-landing the habitat and supplies, but allowing for a wee bit of a delay that would likely be a decade from now (minimum), so all the early dragons will be doing other things.  They are already being promoted as delivery of customer cargo, so the sites will be chosen to suit the customers for quite a while.

Agreed.  Red Dragon should be seen separate from any Mars settlement programs.  Beyond engineering tests and gaining of experience it is a way of generating income by flying paid payloads to Mars.    And there are many devils hiding in those details!

[philw1776]

The thread comments can be confusing.  Some of us are referring to colony site landing sites while others are referring to RD landing sites.  The criteria could be quite different, e.g. lack of solar irradiance circa 40 degrees north might not be a big issue for a RD mission, but could be a big negative for an all-seasons colony, assuming no nukes.

IMO it is a safe assumption that a RedDragon landing site would be chosen to be a likely colony site.

Maybe not for a 2018 like mission where landing was the main/only goal. But for 2020 missions. If the choice was right, then a first ITS can use a radio beacon from that landing to home in on.

Way, way too early for SpaceX to have selected a colony site.  A needless rush.  RD MAY for example pick an "ice near the surface" site simply to test ISRU methods most easily. 
With Musk's statement that multiple RDs will transit to Mars each opposition once EDL, etc. is flight proven, there are lots of opportunities to validate, compare & contrast multiple colony sites via ground truth RD landings.
Only Elon believes that ITS will start flying in the early 2020s, so there are many oppositions next decade to fly many RD missions.

Bottom Line: RD site & colony site criteria for the next oppositions may be quite different.
They will in time converge.

[Dao Angkan]

Even for a colony the landing site might be some distance from the colony site. For example the possible Red Dragon Amazonis/Arcadia landing site offers a large flat plain for travelling far further south overland.

[guckyfan]

I just argue from the timeline given. I am aware that the timeline will slip, like everybody is. But presently they are working towards it. That does not leave any room. 2020 for Red Dragon. 2022 for the unmanned ITS. That timeline means the 2020 Red Dragons are direct precursors for the first colony flights. Remember there is the need to build substantial capacity for fuel production at that first landing site. They don't do that randomly for any number of locations until they like one for settlements.

That does not mean they would not abandon the first site if it for some reason turns out to be untenable but it would be a major and costly setback.

I don't just assume Elon Musk is only talking nonsense about his plans.

[Dalhousie]

I just argue from the timeline given. I am aware that the timeline will slip, like everybody is. But presently they are working towards it. That does not leave any room. 2020 for Red Dragon. 2022 for the unmanned ITS. That timeline means the 2020 Red Dragons are direct precursors for the first colony flights. Remember there is the need to build substantial capacity for fuel production at that first landing site. They don't do that randomly for any number of locations until they like one for settlements.

That does not mean they would not abandon the first site if it for some reason turns out to be untenable but it would be a major and costly setback.

I don't just assume Elon Musk is only talking nonsense about his plans.

When it comes to timelines, he talks nothing but nonsense. 

There is also a huge difference between a Red Dragon mission which could feasibly launch in 2020 (although may well slip to 2022 based on record) and the ITS fantasies.

So let's stick to Red Dragon landing sites.

[Robotbeat]

I just argue from the timeline given. I am aware that the timeline will slip, like everybody is. But presently they are working towards it. That does not leave any room. 2020 for Red Dragon. 2022 for the unmanned ITS. That timeline means the 2020 Red Dragons are direct precursors for the first colony flights. Remember there is the need to build substantial capacity for fuel production at that first landing site. They don't do that randomly for any number of locations until they like one for settlements.

That does not mean they would not abandon the first site if it for some reason turns out to be untenable but it would be a major and costly setback.

I don't just assume Elon Musk is only talking nonsense about his plans.

When it comes to timelines, he talks nothing but nonsense. 

There is also a huge difference between a Red Dragon mission which could feasibly launch in 2020 (although may well slip to 2022 based on record) and the ITS fantasies.

So let's stick to Red Dragon landing sites.

Red Dragon is hardly less of a fantasy. SpaceX will pursue ITS until it goes bankrupt, at which point Red Dragon missions will stop, too.

Not long ago, folks would say VTVL and Red Dragon were fantasies. And ITS is the reason for these Red Dragon missions anyway.

[Dao Angkan]

So, how far is reasonable to travel from the launch site? I'm presuming that the best site for landing is unlikely to be the best site for a colony. If landing in Amazonis at a latitude of 35° N where would you head towards? It looks flat enough that you might be able to head south all the way to the equator, or maybe head south east towards Olympus Mons. I think it's roughly 300km every 5°, so how far should we expect vehicles to be able to travel? Maybe you'd have to set up battery charging stations every xxxkms.

[Dalhousie]

I just argue from the timeline given. I am aware that the timeline will slip, like everybody is. But presently they are working towards it. That does not leave any room. 2020 for Red Dragon. 2022 for the unmanned ITS. That timeline means the 2020 Red Dragons are direct precursors for the first colony flights. Remember there is the need to build substantial capacity for fuel production at that first landing site. They don't do that randomly for any number of locations until they like one for settlements.

That does not mean they would not abandon the first site if it for some reason turns out to be untenable but it would be a major and costly setback.

I don't just assume Elon Musk is only talking nonsense about his plans.

When it comes to timelines, he talks nothing but nonsense. 

There is also a huge difference between a Red Dragon mission which could feasibly launch in 2020 (although may well slip to 2022 based on record) and the ITS fantasies.

So let's stick to Red Dragon landing sites.

Red Dragon is hardly less of a fantasy. SpaceX will pursue ITS until it goes bankrupt, at which point Red Dragon missions will stop, too.

Not long ago, folks would say VTVL and Red Dragon were fantasies. And ITS is the reason for these Red Dragon missions anyway.

I think you are mistaken on several counts.  When proposed jointly by NASA and SpaceX Red Dragon was clearly feasible with technology either proven or under development and within the framework of current budgets.  The justification of Red Dragon is not  ITS with which it has almost nothing in common.  Red Dragon is a way of commercially transporting payloads to Mars.

There are plenty of ITS threads.  Let's focus on Red Dragon here.

[guckyfan]

I think you are mistaken on several counts.  When proposed jointly by NASA and SpaceX Red Dragon was clearly feasible with technology either proven or under development and within the framework of current budgets. 

Yes and it involved a number of proposed NASA missions using Red Dragon capabilities, none of which were followed up on so far.

The justification of Red Dragon is not  ITS with which it has almost nothing in common.  Red Dragon is a way of commercially transporting payloads to Mars.

There are plenty of ITS threads.  Let's focus on Red Dragon here.

This is where you go wrong IMO to an extent that is completely incomprehensible to me. The Red Dragon missions as proposed by SpaceX are an integral part of their Mars plans. Precursors to ITS missions. Just look at the slides of the IAC announcement by SpaceX. They are part of the Mars timeline.

That does not rule out the possibility that NASA could purchase Red Dragon flights for their own missions in the future. Even once ITS has landed, that covers just one location. There are no doubt many locations that could still be explored by robot missions.

[Dalhousie]

I think you are mistaken on several counts.  When proposed jointly by NASA and SpaceX Red Dragon was clearly feasible with technology either proven or under development and within the framework of current budgets. 

Yes and it involved a number of proposed NASA missions using Red Dragon capabilities, none of which were followed up on so far.

The justification of Red Dragon is not  ITS with which it has almost nothing in common.  Red Dragon is a way of commercially transporting payloads to Mars.

There are plenty of ITS threads.  Let's focus on Red Dragon here.

This is where you go wrong IMO to an extent that is completely incomprehensible to me. The Red Dragon missions as proposed by SpaceX are an integral part of their Mars plans. Precursors to ITS missions. Just look at the slides of the IAC announcement by SpaceX. They are part of the Mars timeline.

That does not rule out the possibility that NASA could purchase Red Dragon flights for their own missions in the future. Even once ITS has landed, that covers just one location. There are no doubt many locations that could still be explored by robot missions.

It plain enough.  Red Dragon has been marketed specifically as a commercial systems for flying paying payloads to Mars.

ITS could never happen, could be a complete failure, or could be delayed for a decade or more with little impact on the Red Dragon program.

[Robotbeat]

There are no "commercial" payloads to Mars except SpaceX's own ISRU payloads to prepare for ITS. That's 95% of the purpose of Red Dragon.

[Robotbeat]

I understand the skepticism that SpaceX will succeed. I do NOT understand the skepticism that SpaceX is actually serious about their stated intentions. They may be crazy, but they're sincere.

Red Dragon is about ITS and settling Mars. Full stop.

[dglow]

And, to a small extent, making good on Elon's original mission behind SpaceX. If we don't see a small terrarium on RD, I'll be surprised.

[Dalhousie]

I understand the skepticism that SpaceX will succeed. I do NOT understand the skepticism that SpaceX is actually serious about their stated intentions. They may be crazy, but they're sincere.

Red Dragon is about ITS and settling Mars. Full stop.

The evidence clearly shows otherwise.

[AncientU]

...

It plain enough.  Red Dragon has been marketed specifically as a commercial systems for flying paying payloads to Mars.

ITS could never happen, could be a complete failure, or could be delayed for a decade or more with little impact on the Red Dragon program.

You omitted the possibility that ITS could be a success.
Red Dragon is a precursor flight or flights for the follow-on ITS program -- Dragon has minimal utility in its present configuration other than the vehicles will already be paid for by crew and cargo flights.  It will fly until a dedicated design Mars spaceship replaces it.

[redliox]

...

It plain enough.  Red Dragon has been marketed specifically as a commercial systems for flying paying payloads to Mars.

ITS could never happen, could be a complete failure, or could be delayed for a decade or more with little impact on the Red Dragon program.

You omitted the possibility that ITS could be a success.
Red Dragon is a precursor flight or flights for the follow-on ITS program -- Dragon has minimal utility in its present configuration other than the vehicles will already be paid for by crew and cargo flights.  It will fly until a dedicated design Mars spaceship replaces it.

I think the point is, as far as currently known, SpaceX is specifically seeking a site for landing a Red Dragon.  That's it....for now.

Unless Elon Musk speaks loudly and specifically, we can only presume the Arcadia/Amazonis Planitia site is for the first Red Dragon.  The 2nd and onward Dragons could fly to the top of Olympus Mons, or ITS to the bottom of Hellas Planitia likewise as far as we know.  Inversely the site could be useful for a colony...but there's no confirmation, only interest for the first Red Dragon landing site.  The only other given is that the Red Dragon technically could land most places on Mars if the vendor is willing.  We can guess, not much else.

End of line.

[Robotbeat]

Red Dragon's stated purpose (besides building SpaceX's Mars EDL tech--for ITS) is to test ISRU technology, specifically some kind of water extraction. They need this ISRU for ITS, no other reason.

[AncientU]

...

It plain enough.  Red Dragon has been marketed specifically as a commercial systems for flying paying payloads to Mars.

ITS could never happen, could be a complete failure, or could be delayed for a decade or more with little impact on the Red Dragon program.

You omitted the possibility that ITS could be a success.
Red Dragon is a precursor flight or flights for the follow-on ITS program -- Dragon has minimal utility in its present configuration other than the vehicles will already be paid for by crew and cargo flights.  It will fly until a dedicated design Mars spaceship replaces it.

I think the point is, as far as currently known, SpaceX is specifically seeking a site for landing a Red Dragon.  That's it....for now.

Unless Elon Musk speaks loudly and specifically, we can only presume the Arcadia/Amazonis Planitia site is for the first Red Dragon.  The 2nd and onward Dragons could fly to the top of Olympus Mons, or ITS to the bottom of Hellas Planitia likewise as far as we know.  Inversely the site could be useful for a colony...but there's no confirmation, only interest for the first Red Dragon landing site.  The only other given is that the Red Dragon technically could land most places on Mars if the vendor is willing.  We can guess, not much else.

End of line.

Selection criteria are specifically for settlement per SpaceX. 
Please don't ignore the only data point we have been provided.

Wooster, who is involved in Mars mission planning in addition to his “day job” as manager of guidance, navigation and control systems on SpaceX’s Dragon spacecraft, said that site selection is based on several criteria. One is access to large quantities of ice near the surface that could, ultimately, support human settlements.

Another is to be close to the Equator and at a low elevation for solar power and better thermal conditions. “It’s probably hard to find that along with ice,” he acknowledged, so the focus has been on four locations at latitudes no more than about 40 degrees from the Equator.

There is interest in sending Red Dragons to other sites for paying customers, but that isn't why this site selection is being done.

Those landing sites are of particular interest, he said, for SpaceX’s long-term vision of establishing a human settlement on Mars, but he said the company wouldn’t rule our sending Red Dragon spacecraft elsewhere on the planet to serve other customers. “We’re quite open to making use of this platform to take various payloads to other locations as well,” he said. “We’re really looking to turn this into a steady cadence, where we’re sending Dragons to Mars on basically every opportunity.”

http://spacenews.com/spacex-studying-landing-sites-for-mars-missions/

[Dalhousie]

Red Dragon's stated purpose (besides building SpaceX's Mars EDL tech--for ITS) is to test ISRU technology, specifically some kind of water extraction. They need this ISRU for ITS, no other reason.

However the experiment is realsitically be supplied by NASA who have the experitise here. Which means that its has broader application than SpaceX fantasies.

[Dalhousie]

There are no "commercial" payloads to Mars except SpaceX's own ISRU payloads to prepare for ITS. That's 95% of the purpose of Red Dragon.

Actually NASA is the customer that has shown the most interest for Mars payloads.

[Dalhousie]

I understand the skepticism that SpaceX will succeed. I do NOT understand the skepticism that SpaceX is actually serious about their stated intentions. They may be crazy, but they're sincere.

Red Dragon is about ITS and settling Mars. Full stop.

So are Mars one. 

[Dalhousie]

...

It plain enough.  Red Dragon has been marketed specifically as a commercial systems for flying paying payloads to Mars.

ITS could never happen, could be a complete failure, or could be delayed for a decade or more with little impact on the Red Dragon program.

You omitted the possibility that ITS could be a success.
Red Dragon is a precursor flight or flights for the follow-on ITS program -- Dragon has minimal utility in its present configuration other than the vehicles will already be paid for by crew and cargo flights.  It will fly until a dedicated design Mars spaceship replaces it.

If it lands and returns data, it will be a success regardless of the timeline. 

Musk has also said that Red Dragon will continuing flying after ITS (if and when that happens)

[Dalhousie]

...

It plain enough.  Red Dragon has been marketed specifically as a commercial systems for flying paying payloads to Mars.

ITS could never happen, could be a complete failure, or could be delayed for a decade or more with little impact on the Red Dragon program.

You omitted the possibility that ITS could be a success.
Red Dragon is a precursor flight or flights for the follow-on ITS program -- Dragon has minimal utility in its present configuration other than the vehicles will already be paid for by crew and cargo flights.  It will fly until a dedicated design Mars spaceship replaces it.

I think the point is, as far as currently known, SpaceX is specifically seeking a site for landing a Red Dragon.  That's it....for now.

Unless Elon Musk speaks loudly and specifically, we can only presume the Arcadia/Amazonis Planitia site is for the first Red Dragon.  The 2nd and onward Dragons could fly to the top of Olympus Mons, or ITS to the bottom of Hellas Planitia likewise as far as we know.  Inversely the site could be useful for a colony...but there's no confirmation, only interest for the first Red Dragon landing site.  The only other given is that the Red Dragon technically could land most places on Mars if the vendor is willing.  We can guess, not much else.

End of line.

Selection criteria are specifically for settlement per SpaceX. 
Please don't ignore the only data point we have been provided.

It's not the only data point we have been provided. Please don't ignore the others.

Wooster, who is involved in Mars mission planning in addition to his “day job” as manager of guidance, navigation and control systems on SpaceX’s Dragon spacecraft, said that site selection is based on several criteria. One is access to large quantities of ice near the surface that could, ultimately, support human settlements.

Another is to be close to the Equator and at a low elevation for solar power and better thermal conditions. “It’s probably hard to find that along with ice,” he acknowledged, so the focus has been on four locations at latitudes no more than about 40 degrees from the Equator.

There is interest in sending Red Dragons to other sites for paying customers, but that isn't why this site selection is being done.

This mission will primarily be an engineering test to see if they can actually land.  Anything extra will be a bonus.  Incidentally, Arcadia is marginally closer to the poles than the equator.

Those landing sites are of particular interest, he said, for SpaceX’s long-term vision of establishing a human settlement on Mars, but he said the company wouldn’t rule our sending Red Dragon spacecraft elsewhere on the planet to serve other customers. “We’re quite open to making use of this platform to take various payloads to other locations as well,” he said. “We’re really looking to turn this into a steady cadence, where we’re sending Dragons to Mars on basically every opportunity.”

http://spacenews.com/spacex-studying-landing-sites-for-mars-missions/

Unless they have got customers they won't be sending Red Dragons every opportunity.

[Robotbeat]

Red Dragon's stated purpose (besides building SpaceX's Mars EDL tech--for ITS) is to test ISRU technology, specifically some kind of water extraction. They need this ISRU for ITS, no other reason.

However the experiment is realsitically be supplied by NASA who have the experitise here. Which means that its has broader application than SpaceX fantasies.

No. NASA is pursuing CO/O2 ISRU, not useful for SoaceX who needs water processing. SpaceX is primarily their own customer for initial Red Dragon flights. NASA is the 5%, SpaceX the 95%. SpaceX is developing this capability without prompting from NASA.

[Robotbeat]

A LOOOT of unsourced assertions by Dalhousie about how SpaceX doesn't mean what they say.

That is off-topic.

[Robotbeat]

I understand the skepticism that SpaceX will succeed. I do NOT understand the skepticism that SpaceX is actually serious about their stated intentions. They may be crazy, but they're sincere.

Red Dragon is about ITS and settling Mars. Full stop.

So are Mars one.

Correct. Mars One is serious (I think) about their ambitions. Doesn't mean they'll succeed.

[Dao Angkan]

This mission will primarily be an engineering test to see if they can actually land.  Anything extra will be a bonus.  Incidentally, Arcadia is marginally closer to the poles than the equator.

Unless I'm missing something, then surely <°40  is closer to the equator than the poles? Parts of Arcadia are closer to the poles, but those parts of Arcadia are clearly ruled out. I think that relatively high water ice levels extend as far south as 35°, borderline Arcadia/Amazonia. Parts of Arcadia clearly extend past <°40.

[RonM]

I understand the skepticism that SpaceX will succeed. I do NOT understand the skepticism that SpaceX is actually serious about their stated intentions. They may be crazy, but they're sincere.

Red Dragon is about ITS and settling Mars. Full stop.

So are Mars one.

Correct. Mars One is serious (I think) about their ambitions. Doesn't mean they'll succeed.

Even if Mars One was the most successful TV show in history, they would be at least an order of magnitude short of funding a Mars mission. If the Mars One team tagged along with a SpaceX flight, then they could afford to give it a go.

So, how far is reasonable to travel from the launch site? I'm presuming that the best site for landing is unlikely to be the best site for a colony. If landing in Amazonis at a latitude of 35° N where would you head towards? It looks flat enough that you might be able to head south all the way to the equator, or maybe head south east towards Olympus Mons. I think it's roughly 300km every 5°, so how far should we expect vehicles to be able to travel? Maybe you'd have to set up battery charging stations every xxxkms.

Now that's an interesting question. Would it be practical to have the colony far away from the landing site?

Probably not, but land a Red Dragon with a bulldozer-style rover and make a safe pad for ITS to land. Send two or three Red Dragons if there's a chance one might not survive landing.

[Robotbeat]

Imagine if we had a thread about Mars One landing site but didn't actually want to talk about sites Mars One wanted to land.

[RonM]

Imagine if we had a thread about Mars One landing site but didn't actually want to talk about sites Mars One wanted to land.

Sounds like most threads. Anyone have thoughts OT?

[CraigLieb]

Would an on-orbit solar power array with microwave transmission help ease the poor winter angles for ground based solar power and make Northern sites more viable?  It certainly adds a level of complexity which may be too much to overcome.

[Dao Angkan]

https://library.e.abb.com/public/564b3711c060164dc1257b0c00552e50/HVDC%20Light%20power%20cables.pdf

HVDC Light power land cables start from 1.2kg/m, or 1.2t/km. A cable from 35° N to the equator would be roughly 2,100km, so maybe 2520 tonnes of cable (although Mars conditions and a higher priority for lower weight cables would probably result in a different cable being used on Mars).

You would have to estimate if on-orbit solar power would be cheaper for the same amount of power.

[notsorandom]

Its probably better to angle the solar arrays and just use more of them than trying to do space based solar or laying thousands of miles of transmission line. There is also nuclear of course.

[guckyfan]

Long term solar arrays at high altitude and spaced 7000km east and west would solve both dust storm and night storage problems. There would always be one of 3 sites in full sun.

[AncientU]

Long term solar arrays at high altitude and spaced 7000km east and west would solve both dust storm and night storage problems. There would always be one of 3 sites in full sun.

Just call the utility company and request they string power lines...

[jpo234]

Water Might Be Easier to Find on Mars Than We Thought

https://gizmodo.com/water-might-be-easier-to-find-on-mars-than-we-thought-1821990091/amp


The original paper:
http://science.sciencemag.org/content/359/6372/199

Thick deposits cover broad regions of the Martian mid-latitudes with a smooth mantle; erosion in these regions creates scarps that expose the internal structure of the mantle. We investigated eight of these locations and found that they expose deposits of water ice that can be >100 meters thick, extending downward from depths as shallow as 1 to 2 meters below the surface. The scarps are actively retreating because of sublimation of the exposed water ice. The ice deposits likely originated as snowfall during Mars’ high-obliquity periods and have now compacted into massive, fractured, and layered ice. We expect the vertical structure of Martian ice-rich deposits to preserve a record of ice deposition and past climate.

[Rocket Science]

Let's send some robo-drill rigs and settle this once and for all...

[jpo234]

Let's send some robo-drill rigs and settle this once and for all...

Something like this: http://exploration.esa.int/mars/43611-rover-drill/

[philw1776]

Problem is that this ice is still at high latitudes ~55 degrees.  Bad for solar especially in LONG winter. Need nukes.

[jpo234]

Problem is that this ice is still at high latitudes ~55 degrees.  Bad for solar especially in LONG winter. Need nukes.

From the gizmodo.com article

this is a big deal because there’s a considerable amount of this mantling material on Mars at about 30 degrees latitude in both hemispheres

So in addition to finding the shallowest water ice deposits known on Mars, the researchers are also the first to observe active erosion of the Martian midlatitude ice scarps.

[philw1776]

Problem is that this ice is still at high latitudes ~55 degrees.  Bad for solar especially in LONG winter. Need nukes.

From the gizmodo.com article

this is a big deal because there’s a considerable amount of this mantling material on Mars at about 30 degrees latitude in both hemispheres

So in addition to finding the shallowest water ice deposits known on Mars, the researchers are also the first to observe active erosion of the Martian midlatitude ice scarps.

Not from the Science paper but another researcher's enthusiastic comment.  Layered ice there not yet observed.
Make it so.

[saliva_sweet]

Can anyone access the supplement of that Science article? When I try to download it I'm getting "Ordered macro-microporous metal-organic framework single crystals" - that's not what I want.

[KelvinZero]

Problem is that this ice is still at high latitudes ~55 degrees.  Bad for solar especially in LONG winter. Need nukes.

I was wondering.. is it really that bad if you find a nice mountainside facing the equator? Even at Louth crater ( ~70°) where white ice is visible from orbit, I think you are at least avoiding the long uninterupted night of a polar winter, and one rim of the crater would be nicely angled towards the sun.

It would be good to know what the drop of efficiency of solar panels around 55° is. I think this could be mainly dictated by the time the sun is beneath the horizon. You do not have to lie it flat on the ground. So long as the sun is above the horizon you can angle your panels to directly face it. This can reduce dust gathering as well. You have lots of free space so you could lay them out in one very long wall instead of a more sensible square; so that they will not occlude the panels behind them.

[philw1776]

Problem is that this ice is still at high latitudes ~55 degrees.  Bad for solar especially in LONG winter. Need nukes.

I was wondering.. is it really that bad if you find a nice mountainside facing the equator? Even at Louth crater ( ~70°) where white ice is visible from orbit, I think you are at least avoiding the long uninterupted night of a polar winter, and one rim of the crater would be nicely angled towards the sun.

It would be good to know what the drop of efficiency of solar panels around 55° is. I think this could be mainly dictated by the time the sun is beneath the horizon. You do not have to lie it flat on the ground. So long as the sun is above the horizon you can angle your panels to directly face it. This can reduce dust gathering as well. You have lots of free space so you could lay them out in one very long wall instead of a more sensible square; so that they will not occlude the panels behind them.

You said it in your post.  The problem at high latitudes is that for the LONG Martian winter the sun is below the horizon fo the vast majority of hours per day.  Angling panels does not help with this.  The game is Kilowatt HOURS.
 

[saliva_sweet]

You can't also ignore the low solar angle if there is any kind of attenuation going on (from dust for example).

[KelvinZero]

You said it in your post.  The problem at high latitudes is that for the LONG Martian winter the sun is below the horizon fo the vast majority of hours per day.  Angling panels does not help with this.  The game is Kilowatt HOURS.

Absolutely. I said it in my post because that is the thing I wanted to talk about, with numbers.
My guess is that the ratio of time above the horizon at 55° is not that bad during winter, not a show stopper, but does anyone know the actual fraction?

The effect of dust storms at higher latitudes is a more complex question. Maybe that is a show stopper. Lets get the basic fraction first.

---
(edit) I managed to find some numbers for earth:
http://aa.usno.navy.mil/faq/docs/longest_day.php

At 25°, the shortest day is 10h 35m
at 50°, the shortest day is 8h 04m
at 60°, the shortest day is 5h 52m

Mars has a slightly worse tilt though, 25° instead of 23.5°

Very roughly though, It looks like the factor at 55° during the shortest day is around half the time above the horizon that you would get near the equator. On the other hand during summer I assume you get more time above the horizon that even at the equator. The year round average is another interesting question, though normally the most immediate concern is the worst case.

[Zed_Noir]

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?

[Ludus]

It’s got thicker atmosphere, probable glaciers, and isn’t too bad latitude wise. Probably on the short list.

[Robotbeat]

It’s got thicker atmosphere, probable glaciers, and isn’t 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.

[redliox]

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.

[Restless]

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.

[jpo234]

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.

[Restless]

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.

[Robotbeat]

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.

[speedevil]

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.

[aero]

And pigs eat potatoes.

[Valerij]

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.

[speedevil]

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.

[Valerij]

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.

[John Alan]

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... 

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... 

[Lar]

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.

[rsdavis9]

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... 

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.

[John Alan]

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... 

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... 

[Ludus]

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 won’t 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.

[Valerij]

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.
   

[Valerij]

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.

[saliva_sweet]

If melt water penetrates ...

At any sort of reasonable latitudes of Mars, this would be such a wonderful problem to have. Water, liquid or ice, is unstable at any depth below ~ 40 degrees latitude.

[DaveH62]

With the low air pressure I think you could build a thin carbon or ceramic skeleton for turbine blades and a Mylar skin and build wind turbines very large. I’d guess optimization of the shape would be different than we see hear due to low air pressure and potential high speed wind. The math shouldn’t be too complex, similar to earth with some basic adjustments.