How Will We Travel on Mars Itself?

[sanman]

Okay, so the following is a slickly-packaged marketing video -- but it does appear to show footage of a vehicle actually traveling in a certain way, without a need for pre-built road infrastructure.





Under development by a company in Poland, it apparently runs on jet turbines that produce around 118–123 dB(A) at just 3m distance.

On Earth, vehicles like this would be Earth-shatteringly loud. But in the extremely thin Martian atmosphere which doesn't carry sound nearly as well, that could be quite acceptable.

But could a vehicle of this type be supported in that thin air, with the aid of the lower Martian gravity?

If not vehicles like this, then what are the best alternatives?
Shouldn't we prefer vehicles that can traverse terrain without the need for such infrastructure, in order to be able to cover as much territory as possible, for exploration as well as route flexibility?

[sanman]

More info:

[AmigaClone]

I suspect most crewed exploration. at least initially, would be done using land vehicles. These would include rovers that with an appearance similar to the Apollo rovers on the small end to  something reminiscent of several Antarctic Snow Cruisers connected with airtight flexible corridors. The later would have the facilities to serve as a mobile base.

I would expect remotely operated drones to aid in that exploration to sites where the vehicles would not be able to access.

Remember that at least initially, any vehicle on Mars would need to use electricity to move - likely produced by solar cells.

[colbourne]

Could we have some kind of aimable  rail gun on the base that fires a capsule to required destination. Capsule could land using rocket thrusters (maybe compressed gas), possibly using a parachute as well on large jumps.

To return to main base, an electric piston could be used to jump, or maybe it could be a slow wheeled journey.

This method works best when we have several bases , each with their own rail gun.

[spacenut]

A rocket powered hopper similar to the one used on the TV show "Space 1999" could be used on Mars for longer distance trips to check out certain areas.  A dedicated Starship could do this with enough fuel to make a long hop and back to base for refueling.  It would have the built in habitat, space suits, and some cargo for establishing a more remote base, until a road, rail, or hyperloop system could be installed to get people to the new base. 

I like the idea of a larger dedicated rover that could pull a trailer or trailers that a connected for a mobile base, habitat, etc.  This could be made from a Tesla tractor-trailer truck since it is designed to pull loads anyway. 

[Stan-1967]

But could a vehicle of this type be supported in that thin air, with the aid of the lower Martian gravity?

Short answer,  no.

I would expect localized exploration to be driven by orbital surveys directing surface based telerobotic assets.  Humans won’t be going on joy rides anywhere.  Mars surface is fundamentally more similar to a vacuum chamber than an earth desert or ice sheet.  Human travel on the mars surface will be for high value ISRU considerations, and then maybe scientific targets.  Every surface excursion will be like an ISS spacewalk.  Highly planned and executed with key objectives.

If mars is visited only as a scientific target,  a rover like what JAXA is planning would be great.  If it is for travel between settlement A to B ,  i think something like a railway or tram/gondola would be ideal.

I personally think trams or gondolas have been overlooked and would have better metrics for using local materials,  as well as kg/km of needed imported materials.  I also think it would require less effort to build vs the need for rail track to be overlayed on highly prepared surfaces. 

In a mars effort centered on settlement, travel needs will be driven by considerations like moving water from  A to B,  steel from B to C, concrete from A to C.  So a network of connected tramways or railways naturally develops.  An explorer could pick any point along those paths to start a localized excursion.

I don't see wheeled vehicles having great utility for very long distances.  Too much wear & tear on a very valuable asset. 


Surface travel in the hundreds or thousands of km will be very rare.  Suborbital hoppers seem most effective for that expensive task. 

[Robotbeat]

I think you’d just use pipes.

[Stan-1967]

I think you’d just use pipes.

for...?

[Robotbeat]

I think you’d just use pipes.

for...?

moving water.

[Nomadd]

 Already handled.

[Stan-1967]

I think you’d just use pipes.

for...?

moving water.

Good luck to your plan.   

How will you support the needed work crews?  How deep will you excavate & bury it & what is the thermal gradient of the martian regolith that would enable its transport without freezing?  Alternately you could heat the pipeline above ground, so add a several hundred MW power plant to your needed infrastucture. 

I suppose it is all a matter of time if colonization is the driver.  At some point a pipeline may in fact be the best solution.  But alot has to happen first.  A whole lot.

[stormhelm]

My hunch is until more advanced propulsion,, Radiation shielding,, life support beside psychological hurdles solved it will be a LONG time before crewed missions beside other problems undertaken despite Musk`s Blah blah..
I won't say more..

[Robotbeat]

Refueling with aerocapture or direct entry is advanced propulsion. Faster transits than electric propulsion or nuclear thermal.

The other stuff is solved by mass.

Artemis HLS is nearly a proper superset of a Mars mission.

[Robotbeat]

I think you’d just use pipes.

for...?

moving water.

Good luck to your plan.   

How will you support the needed work crews?  How deep will you excavate & bury it & what is the thermal gradient of the martian regolith that would enable its transport without freezing?  Alternately you could heat the pipeline above ground, so add a several hundred MW power plant to your needed infrastucture. 

I suppose it is all a matter of time if colonization is the driver.  At some point a pipeline may in fact be the best solution.  But alot has to happen first.  A whole lot.

Vacuum insulation works fine, to the point that the internal friction is enough to keep the water plenty warm. And you don’t think powering a bunch of vehicles to transport thousands of tons of water (per month? Week? Day?) won’t require a similar amount of power? A vacuum insulated pipe is easier than building a road.

[Stan-1967]

 And you don’t think powering a bunch of vehicles to transport thousands of tons of water (per month? Week? Day?) won’t require a similar amount of power? A vacuum insulated pipe is easier than building a road.

Yes, I do think think that.  Also you need to build a road to transport the people & equipment needed to make the pipeline.  So this shortcircuits the decision on how we will travel on Mars.  If we just build roads, we don't need trams/gondolas, rail, pipelines, airships, suborbital hoppers, etc.  Existing roads would be the winner always.

Transport of water, depending on the distance, is a debatable decision for pipeline/no pipeline.  It comes down to how "rich" Mars is, and what distance does it need to move?

Depending on what you want to transport, it may be that the the optimum solution for a material like water, is very non-optimal for people, concrete, steel, food, etc.  So now Martians need to be able to afford multiple transportation solutions. Modes of transport that are flexible and agnostic to the mass properties will win if Mars is "poor".

Back to pipelines, as I think it is a debatable decision that depends on many factors.

Pipelines on Mars would have substantial thermal demands to keep the water from freezing.  The energy in joules to keep it from freezing will be far in excess of the joules of mechanical work needed to move it on a tramway or railway.   Having said that if Mars builds nuke power plants, that would enable some localized vacuum pipelines.   Pipelines also work better the bigger they are, as heat transfer scales linear to the pipe diameter, when volume scales to the square, pressure being equal, and assuming the same flow velocity.

A point of reference for my thoughts on this is how a country like Iceland has geothermal plants for electricity generation, and these same plants use the excess thermal energy for supplying nearby cities with hot water as well.  You find these plants ( i.e Svartsengi, 150MW thermal) with excess spare megawatts ( 75 MW) of thermal energy are needed to supply hot water to Reykjavik only 40km away.  The temperature drop is from around 90C at the plant, and by the time it gets to users, it is around 45C.  Ambient ground temps are probably 5-10C.  How bad will this be when ambient ground temps are -60C? 

Iceland can do this because of the vast excess thermal power they have.   Where does this come from on Mars?  Ambient is -60C from freezing, so to move water over a 40 km distance ( similar  Svartsengi to Reykjavik), you need to first mine the ice, then raise the temperature of the ice to 0C, then melt the ice, and then raise it to a temperature that it wont freeze before getting to the destination.  The energy needed to just melt the ice would be more than enough to transport it via rail, tram, or any wheeled vehicle.   

I also look at many municipalities I've stayed in Northern Europe that provide hot water (potable & for heating)  as a utility service, and a single co-generation facility burning hundreds of metric tons of wood chips daily can use the thermal excess for maybe 15-20 thousand citizens within a 4km radius.  This seems feasible for localized use, and within a Mars settlement, you would want to dissipate the heat within habitable structures.  So localized makes sense.  Dissipating Megawatts of power into the ambient martian environment over long distances is simply too costly. 

[Coastal Ron]

Roads. Surface transportation that is electric driven is the cheapest form of transportation for an undeveloped area of Mars - which will be everything humans do for many years during colonization.

The carrying capacity of both roads and large vehicles will be enough for Mars colonists for many years, and will likely be permanent (with periodic upgrades of course) even as other transportation options are built.

It doesn't make sense to invest in permanent infrastructure until you know what the demand will be. Is it water? Is it mineral? Is it pre-packed supplies coming from a spaceport? Is it humans? Define the need first before defining the solution.

And roads will be perfect for autonomous driving systems, since the routes will be fairly traffic free, and any traffic there is can all be autonomous, so AI negotiation can happen when necessary if there is traffic (this won't be high speed driving).

Vehicles on Mars, because of the much lower gravity and lack of atmosphere, will be able to be much more outsized there than what we can use here on Earth. So if you need to transport large amounts of water or minerals, think of a multi-unit articulated road train being the solution. These are very popular in Australia, both for improved roads and unimproved roads.

[Robotbeat]

…

Pipelines on Mars would have substantial thermal demands to keep the water from freezing.  The energy in joules to keep it from freezing will be far in excess of the joules of mechanical work needed to move it on a tramway or railway.   …

This isn’t true, and I know because I calculated it instead of just going off of vibes, as you’re doing here. Vacuum insulation (which is particularly easy on Mars) is really good stuff.

[Stan-1967]

It doesn't make sense to invest in permanent infrastructure until you know what the demand will be. Is it water? Is it mineral? Is it pre-packed supplies coming from a spaceport? Is it humans? Define the need first before defining the solution.

......

Vehicles on Mars, because of the much lower gravity and lack of atmosphere, will be able to be much more outsized there than what we can use here on Earth. So if you need to transport large amounts of water or minerals, think of a multi-unit articulated road train being the solution. These are very popular in Australia, both for improved roads and unimproved roads.

My skepticism of roads and analog Martian/Earth vehicles like the Road Train, or the like is based on multiple considerations. 

1.Good roads take engineered road base, compaction, leveling, and paving.  That is alot of work.  A average dirt road is an order of magnitude harder on the vehicle chassis ( says various 4X4 Bronco's & Trucks I've owned and driven) and free range 4X4 is an order of magnitude worse than a gravel road.

2. Rolling friction in the wheel bearings & stator bearings (EV's)  at -60C to -110 C at night is going to hate hate hate bumpy roads.
3. Tires at said very cold temperatures will also hate this environment.

If the Road Train is crossing Meridiani Planum, I see no major problems.  Other interesting places with water, minerals, or such, may not be as ideal.

When you linked to Australian vehicles, I had hoped some "Fury Road" trucks were going to pop up.  :-)  I could also see SMPT type vehicles being needed early on to move pieces of equipment from landing sites to positions of permanent residence.  Still for short distance within a settlement only.

The low gravity would significantly improve the physics of a tram/gondola system.  Cable sag will be less for a given load, and bearing wear in the rollers has more potential to be managed with low heating requirements.  Tower stations can also be spaced further apart.  The steel cable will be just fine in the cold environment. 

Rail solutions have some of the same skepticisms as for roads.  The ground needs to be surveyed and an engineered base of material needs to be made for the track.  If that is feasible, for needs such as water or minerals, it would be a step up in carrying capacity over tram/gondolas.

I completely agree that all specifics of each need should be defined first. 

Humans will likely travel by whatever method creates the need & is best for any given solution.  The possible exception being pipelines.  :-) 

[Stan-1967]

…

Pipelines on Mars would have substantial thermal demands to keep the water from freezing.  The energy in joules to keep it from freezing will be far in excess of the joules of mechanical work needed to move it on a tramway or railway.   …

This isn’t true, and I know because I calculated it instead of just going off of vibes, as you’re doing here. Vacuum insulation (which is particularly easy on Mars) is really good stuff.

OK, show me your calcs for heat loss per km for pipe size temperature.  Was it the size of the Alaska Pipeline, or a more modest 150-200mm municipal hot water line?  You can pick a pipe size to get you the answer you want.

I do agree there could be some breakeven point if your heat loss per kilometer is less than the rolling friction energy loss of a Tram/Train, then at some point all the energy needed to melt the ice will eventually be equalized.

What values did you use for rolling friction & what cargo capacity? 

Note on earth a 6000 HP ( 4.5MW) diesel locomotive can haul 6 million kg's of cargo.  As a sense of scale, note that the G.G of a Merlin 1-D is around 10,000HP, and its thermal efficiency is probably 30-35%, so how long would it take for the waste heat of the G.G to melt a 5-6 million pound block of ice?  ( that is like the entire prop mass of a Starship sized block of ice.)

Search Labs AI says a 6000HP diesel engine uses around 250 gallons per hour of diesel.   I can fit 250 gallons of diesel in the back of a Ford F-150.  This BOEL calc feels like postulating boiling the ocean with a match.

That is the head start that a train, tram, or road based vehicle has on the pipeline.  To be precise, the pipeline yields a head start of 333.55kJ per kg of ice ( heat of fusion) to the modes of transport that don't have to melt it. 

Another perspective.  Say a tram or train car can carry 10 tons of ice.   To get that up to say 50 kph ( 13.9 m/s)(slow) would require 1MJ, and from that point on, assuming constant speed, it is just rolling friction losses all the way to the destination. 

It takes 3.3355 GJ of energy just to melt the 10 tons of ice to 0C.  That train/Tram/Vehicle can go for a long long time before the pipeline breaks even. 

[Robotbeat]

You really expect to transport dirty ice mixed with regolith? K. You have to melt it to realistically extract it, to purify it, or to use it eventually. Not sure why you think transport in solid state is an advantage as it makes nearly every step more complicated. Realistically, it ain’t gonna happen. To extract it will involve melting or even vaporizing it, so you might as well keep it liquid (with the heat of friction you’re generating anyway) so it can be used immediately.

Pipelines on Earth are FAR more efficient for transporting liquids than truck.