What locations on Mars would be good for a human landing?

[Red_dragon]

Once humans start making trips to mars, what are some places they should land?


Well, for a base we would want to be at one of the poles for access to water, but since the first landings will likely not be staying long, and before we have confidence preforming mars missions we would want to go to somewhere near the equator so it is easier getting to orbit. Because of this, the first few missions would probably want to land closer to the equator.

[tbellman]

Once humans start making trips to mars, what are some places they should land?

There is an older thread about basically this: How will SpaceX select their 2020s landing site & where could it be?

It's been some time since people posted in it, but I suggest you start by reading that thread.  While it is specific to SpaceX's Mars plans, many of the considerations would be the same regardless of who does it.

Well, for a base we would want to be at one of the poles for access to water, but since the first landings will likely not be staying long, and before we have confidence preforming mars missions we would want to go to somewhere near the equator so it is easier getting to orbit. Because of this, the first few missions would probably want to land closer to the equator.

The poles are bad for power.  Too high cosine losses for solar panels.

The extra boost for reaching orbit you get by being located on the Martian equator is just 240 m/s compared to when launching from the poles.  Not enough to matter much.  And if you compare to mid-latitudes, the difference is even smaller; just 70 m/s more than if you are at 45°N or 45°S.

Sunlight and water are much more important.  A low elevation, preferably 2-3 km below the Mars datum, is also more important, as that gives you a denser atmosphere, which gives you a lower terminal velocity for landing.

And yes, water is very important, as any reasonable mission will want to use that for manufacturing the return propellant.  And any reasonable mission will stay on Mars for about 1.5 Earth years; opposition class missions (with about 1-1.5 months of time at Mars) are silly.

[Yiosie]

This post from the aforementioned thread shows the specific sites and surface conditions under consideration by SpaceX in 2021:

SPACEX STARSHIP LANDING SITES ON MARS.

4 prime sites and 3 secondary sites have been selected.

Notably, selected sites in Phlegra Montes appear to be glacial: 

"...hundreds of meters thick local ice deposits expressed as lobate debris aprons (LDAs) adjacent to Montes exhibit viscous flow morphologies and have radar reflectors with dielectric constants similar to nearly pure ice."

That's ice thick enough and pure enough for melt-out glacier habs, spaceports, and ISRU propellant storage chambers.

Not that SpaceX has ever said such a thing.

Still, SpaceX just happened to include extremely thick and pure ice in the downselection list.

[Phil Stooke]

Also, don't forget the poles are the most boring place on Mars.  Sure - you can study the polar ice and climate, and drill down for a climate history core.  But then what?  No - you want the base to be in the mid-latitudes where you have known ice deposits, other mineral resources, interesting geology, abundant sunlight and milder temperatures.  Then you fly a sortie mission to a pole once the base is established.

[Dalhousie]

Sites proposed in 2015 workshop

https://planetary.s3.amazonaws.com/web/assets/pictures/20151027_humans-mars-exploration-zone-map.jpg

Exploration zone definitions

https://www.nasa.gov/wp-content/uploads/2015/06/first-landing-site-announcement.pdf

[Timber Micka]

Also, don't forget the poles are the most boring place on Mars.

Said no scientist ever. If anything, the ice caps are the most attractive among several unexplored geological features on Mars, the others being volcanoes and the Valles Marineris system.
It is full of resources, including water ice, dry ice, deuterium and methane clathrate.

A decade ago, NASA really wanted to send a lander to explore the South Pole and hop around to investigate the ice cap and its abundant geysers, which are still not well understood. The mission was canned because it needed a really expansive Advanced RTG to power the spacecraft (solar arrays are structurally too weak for hops and could be quickly covered by the projections of the geysers).

Ice core sampling of the Poles would provide deep insight into the recent evolution of the Martian climate.

It's the ideal location for a Mars outpost imo.

[LMT]

This post from the aforementioned thread shows the specific sites and surface conditions under consideration by SpaceX in 2021:

A further consideration is the eventual deployment of bulk-cargo systems, to grow a base into a city-scale settlement.

If bulk cargo is delivered by a mass-produced crash-lander, low-density soil gives the easiest and best region for landing, cutting lander mass and cost. 

Posts 1 2 present downselected sites and nearby broad regions of low-density (icy) surface.  Can posters find traversable routes?

[LMT]

Also, don't forget the poles are the most boring place on Mars.

Said no scientist ever. If anything, the ice caps are the most attractive among several unexplored geological features on Mars, the others being volcanoes and the Valles Marineris system.
It is full of resources, including water ice, dry ice, deuterium and methane clathrate.

A decade ago, NASA really wanted to send a lander to explore the South Pole and hop around to investigate the ice cap and its abundant geysers, which are still not well understood. The mission was canned because it needed a really expansive Advanced RTG to power the spacecraft (solar arrays are structurally too weak for hops and could be quickly covered by the projections of the geysers).

Ice core sampling of the Poles would provide deep insight into the recent evolution of the Martian climate.

It's the ideal location for a Mars outpost imo.

A sunny Phlegra Montes base might do similar science, but at the lower cost and lower difficulty of point-to-point hops across some tens to hundreds of kilometers.  Some glacier expeditions might even be road trips.

[Phlegra Montes] Highlights

-  Identification of >16,000 km2 of viscous flow features (VFF) interpreted to be glaciers.

-  Widespread existence of landforms indicative of warm-based glacial erosion.

-  Liquid water was produced from glacier melt in a past phase of warm-based glaciation.

-  Glacier melt was more significant than previously thought.

...evidence supports a scenario in which ice has been present and stable in substantial quantities (~10^5–10^6 km3) at tropical latitudes during extended periods of the Middle to Late Amazonian history of Mars. This implies that during this time, Mars sustained periods of spin-axis obliquity in the vicinity of 45°, during which time polar ice deposits were substantially reduced in volume or perhaps even absent.

Refs.

Gallagher, C., Butcher, F.E., Balme, M., Smith, I. and Arnold, N., 2021. Landforms indicative of regional warm based glaciation, Phlegra Montes, Mars. Icarus, 355, p.114173.

Kadish, S.J., Head, J.W., Fastook, J.L. and Marchant, D.R., 2014. Middle to Late Amazonian tropical mountain glaciers on Mars: The ages of the Tharsis Montes fan-shaped deposits. Planetary and Space Science, 91, pp.52-59.

[LMT]

Another advantage of Phlegra Montes is its protection during storms, with double the sunlight for PV, relative to other candidate sites at the same latitude.  See the region at 30-34 N, 160-165 E (arrow, box).  Downselected SpaceX site PM-1 is near the edge of that region.

Related:  notes on a Phlegra Montes glacier in the protected region, esp. Zone 2 East.

[Twark_Main]

We should probably credit the original journalist who first dug up this info and posted it on their blog.

https://behindtheblack.com/behind-the-black/essays-and-commentaries/spacex-begins-hunt-for-starship-landing-sites-on-mars/

https://behindtheblack.com/behind-the-black/essays-and-commentaries/spacex-completes-1st-round-of-starships-mars-landing-site-images/

Yes, one of the 2019 candidate sites was Phlegra Montes, so at least we now have an explanation of where this all started.

[LMT]

Yes, one of the 2019 candidate sites was Phlegra Montes, so at least we now have an explanation of where this all started.

That old map doesn't show the local ice, and you marked it incorrectly.  Find sites PM-1 and PM-7, and their local ice.  Mark up the newer map.

[Red_dragon]

Actually, with the new information about the high ice deposits underground Near the equator, A base could harvest the ice. This means a near-equator base is feasible.

[LMT]

Actually, with the new information about the high ice deposits underground Near the equator, A base could harvest the ice. This means a near-equator base is feasible.

If you mean the Medusae Fossae ice, it's typically "topped by a crust of hardened ash and dry dust hundreds of meters thick".  SpaceX et al. are considering sites with ice much closer to the surface, maybe underneath < 10 meters of cover, readily harvested.  I think you'd want to spot such sites.

ESA press release:  "Buried water ice at Mars's equator?"

Might Medusae Fossae have some exposures of near-surface ice, e.g., along a rift, or in a fresh crater, perhaps?  Is there any suggestive imagery?

[JulesVerneATV]

Thorium film could replace crystals in atomic clocks of the near future
https://www.sciencedaily.com/releases/2024/12/241218131255.htm

areas of 'high' Thorium concentration on Mars
https://www.jpl.nasa.gov/images/pia04257-map-of-martian-thorium-at-mid-latitudes/
The region of highest thorium content, shown in red, is found in the northern part of Acidalia Planitia

[Dalhousie]

Thorium film could replace crystals in atomic clocks of the near future
https://www.sciencedaily.com/releases/2024/12/241218131255.htm

areas of 'high' Thorium concentration on Mars
https://www.jpl.nasa.gov/images/pia04257-map-of-martian-thorium-at-mid-latitudes/
The region of highest thorium content, shown in red, is found in the northern part of Acidalia Planitia

No numbers so it only means "high" in a relative sense.  If you plug in numbers you can see that even the most thorium at that resolution is <1 ppm.  It just Th-poor rock.  On Earth the crustal average is 12 ppm and even for mafic rocks it is 3 ppm.

[Twark_Main]

Thorium film could replace crystals in atomic clocks of the near future
https://www.sciencedaily.com/releases/2024/12/241218131255.htm

areas of 'high' Thorium concentration on Mars
https://www.jpl.nasa.gov/images/pia04257-map-of-martian-thorium-at-mid-latitudes/
The region of highest thorium content, shown in red, is found in the northern part of Acidalia Planitia

Also, atomic clocks are unlikely to be the logistical bottleneck. You can just send a few hundred Chip-Scale Atomic Clocks if it really is such a concern.