The best ways to get around Mars

[Hyperion5]

Railways and tunnels only go between to points.
Off road vehicles go in all directions there is ground under them.
So use trucks with trailers behind them.
No maintenance of rails or tubes. Just smooth out the path and if it is damaged could just go around it till fixed later unlike a damaged rail track.

Easy to move a small colony if there is not to much infrastructure.

At some point if the population grow and there was to colonizes to go between or and space port then they might install a tunnel made if iron ( seems to be plenty of that lying around ). Large enough diameter could add power lines, water, gas, ect. Don't think it would be pressurized above surface atmospheric pressure.

Well we can all agree with using trucks in the early days, but roads, just like with rail, will also require some level of maintenance.  It may be less than here on Earth thanks to there being no rain and earthquakes, but you will eventually need to upgrade those roads for heavier loads with gravel.  Gravel in turn steadily gets crushed, meaning you have to add more of it every few years.  So while much cheaper than rail, eventually you'll get to the point where the heavy traffic and large payloads the trucks are carrying demands either a concrete or metal road.  It's at that point where railroads become very effective competitors to trucks.  Why?  It might not occur to some people, but car travel is heavily subsidized by the government, whereas there is very little subsidization of freight rail in contrast.  I'm sure this argument about public subsidies would not be lost on the martian authorities. 

For railroads to be built, you need the colony to hit a critical mass of people and prosperity.  Once it reaches that point the economics of trains being over 4X as energy-efficient as trucks is what changes the game despite their greater infrastructure & maintenance costs.  This is why American freight railroads are doing so well and able to garner a 42% share of the freight market in the continental US.  Even better from the standpoint of the martian authorities would be the fact that railroads, unlike trucks, do not require a public subsidy to work once they're properly set up.  Now sure you'll probably need to do some sort of public-private partnership to begin, but beyond that freight railroads are pretty self-sustaining. 

As for only going between two points, that's also the case for trucks, Rocketman, as they can't be in two places at once.  While trains lack the flexibility of trucks, railroads have little difficulty in building branch lines, switches and spurs to take trains in different directions.  Now sure rail can't go where there's no infrastructure, but neither could a large martian truck.  Speaking of those trucks, I'd be curious to see what a dual-propellant vehicle like that would look like.  It'd need a pressurized cab with an air lock, which would change a lot of things.  I'd guess that would force the scale up considerably, and would probably do likewise for trains.  There's also the matter of how big the propellant tanks would have to be and where you'd put them.  An electric truck would be simple, because you'd just put the massive batteries at the bottom.  But where would you put the Carbon Monoxide & Liquid Oxygen tanks on a CO-O2 truck?  I get the feeling the Carbon Monoxide tank would be the one farthest from the pressurized cabin.  Alternatively, where would you put the CH4 & O2 tanks for a methalox truck? 

[guckyfan]

I agree with Hyperion, with the small exception that I don't see a need for a pressurized cabin on those trucks. I am quite sure they will run fully robotic. Much easier under martian conditions than on earth roads and highways.

Transport for humans will need different vehicles or maybe use different trailers while the engine part remains the same.

[KelvinZero]

My unsubstantiated opinion:

Rail is better suited to Mars than Earth because towns are going to be compact nodes, not spread out like say LA. The lack of air friction will also make the lower contact friction of rail more significant. Magnetic rail will also benefit from the lower gravity. I think all these have been mentioned.

Since rail is practical on earth (and the other two large options, sea and air are rather less practical on mars) it is a no brainer that rail is a very solid contender of the options we currently know about.

It is just a question of what timescale. Of course wheels will be useful earlier and will never be completely replaced with rail.

The first use of rail may be to carry ore very short distances so it could start surprisingly early.

[Dalhousie]

Pipelines need cleared lines to be laid, also bridges, cuttings, pumping stations, and an access road.  Depending on what is being pumped and ambient conditions they may need heating or cooling as well.

Like railways, they make sense only when particular volumes and time frames justify it.  That will vary according to the situation.

If terrestrial experience is any guide, trucks are far more viable for surface transport than anything else in remote areas, except at the very largest scales.   You can build a road suitable for a road train across most reasonably flat ground with a handful of machinery and people.  You can't build pipelines or railways that easily

[gbaikie]

So let's say it's been two decades after first landfall and we've got some substantial infrastructure in place.  The martian authorities discover a big deposit of water 150 km away and decide they need to build a settlement nearby.  What's the best way of both taking materials and the power required to build it there? 

CO/O2-powered trucks?
Methalox-powered trucks?
Electric trucks? 
CO/O2-powered trains?
Methalox-powered trains?
Electric trains? 
Nuclear-powered trains? 

Now I know what you're thinking--that last one sounds crazy.  But bear in mind, you can set rails to whatever gauge you want on Mars!  A nuclear-powered locomotive or two would give you complete operating independence, allowing rapid construction of the line there, massive haul capacity, no worries about resupply, and it'd be able to power the settlement up in the early days before it's connected to the grid.  I wouldn't use it for much else, but there is something to be said for taking a massive, reliable source of power with you to the building site.  I've said my part, so I'll let everyone else conjecture as to the best way to bring a settlement into being using martian transport means. 

Pipes.

Avg temp is below zero, so water in pipes would freeze, I'd think?

Cheers, Martin

Water has high specific heat. And Mars air doesn't transfer heat well, so it mostly lose heat from radiating. Say water is somewhere around 5 to 10 C. At 5 C [278 K] a black body surface radiate 338 watts per square meter. One square meter with 1 mm of water is 1 kg of water.
1 kg of water is 4.204 kJ/kgK. Takes 4204 joules loss to cool 1 C.
And freeze 1 kg water: 334 kJ/kg. So 334,000 joules.
And the temperature air is essentially irrelevant. But temperature of ground is important as ground above 0 K inhibits radiant heat loss.

So to freeze water one has to cool all the volume of the pipe to near 0 C.
Let's see, need to know speed of flow and distance. And diameter of pipe. Let's say 10 cm [around 4"] diameter. So if had chunk of 10 cm pipe which 1 meter long, it's surface area is .32 square meters and 7850 cc- 7.85 kg of water. So 5 times 4204 times 7.85 is 165,000 joules. So 165,000 divided by 108 is 1527 seconds- 25.4 minutes.
So 25 mins 5 C cools to 0 C if surface is blackbody and surrounded with 0 K. So can't be faster than that unless there is significant conduction or convection of heat.
Each meter section has 7.85 kg of water. if 1 kg of it froze it requires heat loss of 334,000 joules. At 108 joules per second loss, it requires
3092 seconds- less than hour.
So if one meter of pipe was losing 108 watts a second of heat and it starts at 5 C, it will freeze solid in less than 8 hours [25,803 seconds: 7.16 hours.
If water is traveling at 5 m/s or 18 kph. If losing 108 watts it cools 5 C in
7.6 km and gets 1 kg of the 7.8 kg frozen in another 15.4 km.
And 7.6 + 15.4 = 23 km. So at 5 m/s a 10 cm diameter pipe if loses 108 watts per second will freeze solid at 23 km distance in 7.16 hours.

Now haven't added details. Pipe painted black has emissivity of:
Black Body Matt    1.00
Black lacquer on iron    0.875
Black Parson Optical    0.95
Black Silicone Paint    0.93
Black Epoxy Paint    0.89
Black Enamel Paint    0.80
http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html
Unpainted steel:
Steel Oxidized    0.79
Steel Polished    0.07
Stainless Steel, weathered    0.85
Stainless Steel, polished    0.075
Stainless Steel, type 301    0.54 - 0.63
Steel Galvanized Old    0.88
Steel Galvanized New    0.23.
So at .8 instead of 1, 108 watts would be 86.4 watts per second loss.
So that adds another hour or couple km.

Now a big difference would piping the water during the day. It's seems quite possible 5 C water could get warmer than 5 C going through the pipeline. One way would piping water at beginning in the morning. If
water traveling 5 m/s in 12 hours it travels 216 km.
So have reservoir  up a hill, and then allow water to fall for 200 km starting in the morning, and last of water could keep flow hours after sundown. And during most of night have pipe empty. So instead using pipe 24 hours a day, one use it say 18 hours a day.
The reservoir can more volume of water in ratio to it's surface area- and therefore not lose much heat during nite. And during day one use solar energy to heat water.
So reservoir could say 10 meters in diameter and 2 meters deep [or bigger]. So 10 meter diameter is 78.5 square meters and 157 cubic meters of water [157 tons of water]. Sunlight is about 600 watts and as we know square meter at 5 C will loss about 300 watts at night [338 watts times .8 is 270 watts]. The water will not get much warmer. And trying to make it too warm in large container on mars is problem due water boiling and creating pressure. Point only is one wants to keep average temp of water warming and bit and not having net cooling.

Sequence. Have smaller reservoir at bottom of hill which fill with water. And this small reservoir can heated with sunlight. And pump up hill which could be within 5 km. And if small reservoir water is 5 C or more, one shouldn't have problem with freezing- regardless of day or night being pumped. And starting at dawn, and assuming water temp is 5 C, you open valve in bigger reservoir into the 200 long pipe, and shut valve 16 hours later [open the 200 km pipe to atmosphere so water drains out of pipe.
So let's see how much water is in a pipe 200 km long. 10 cm diameter is
78.5 square cm. Or meter length has 7.8 kg. So 1.57 million kgs.
And had reservoir 157,000 kgs, so obviously too small. And more correct size would be 40 meters in diameter giving 2.5 million kgs of water.
So 12 hours moves 1.57 million kg. Plus 4 hours gives a 1/3 more, so 2 million kg.
Which means one must pump 2 million kgs of water up the hill. Or .087 million kg per hour each 24 hours. And the 200 km pipe with 1.57 million per 12 hours is doing .13 million kg per hour when full. So roughly large reservior is full in morning and about 1/2 full when it stops draining and at it's lowest water level.
And if want to go further than 200 km, have more pumping and reservoirs.
But should also pump only during daylight if using solar panels to collect electricity, to run the pump. So instead large reservoir on hill losing water level during day, it's gaining it, so 2 million in 12 hour- average of .16 million kg per hour pumped.

Compared to a train. Tanker is about 10,000 gallons or 38 cubic meters:
http://en.wikipedia.org/wiki/Tank_car
So 38,000 kg- 52.6 train cars. Per day. Or if going 200 km- it might take
4 hour to haul it, and 4 hours to return the empty tanks. So 3 loads in 24 hours per engine. Or 52.6 divide by 3 is 17.5 cars. Might have 50 to 60 cars, which are being loaded and unloaded so train engine doesn't need to wait.

Anyways, more of problem with water freezing than I thought, but seem it's easy to manage it, anyhow. Smaller diameter pipe would freeze quicker and larger diameter pipes would not freeze if water kept moving.
With smaller pipes you might be able to use more pressure and faster water velocity to avoid freezing

 

[KelvinZero]

I think I heard somewhere that Mars atmosphere actually does suck heat away very effectively, at least it is nothing like a linear relationship with pressure. Can anyone confirm that?

(deja vu.. Im sure this has been resolved before somewhere on this site)

[guckyfan]

I think I heard somewhere that Mars atmosphere actually does suck heat away very effectively, at least it is nothing like a linear relationship with pressure. Can anyone confirm that?

It has been discussed somewhere in this thread:

http://forum.nasaspaceflight.com/index.php?topic=29820.0

There are three mechanisms that transport heat.

One is convection and that is very much reduced due to the thin martian air.

One is conduction which surprisingly (to me) is not much reduced. But conduction of heat in air is already low on earth. Heat loss due to atmosphere on earth is much more convection so much reduced on Mars though I cannot quantify.

One is radiation and that might be the main problem for heat loss. I have already suggested to have a very thin plastic  sheet propped up by minimal air pressure. That shield can reduce radiation losses a lot with an infrared reflecting coating inside with very little mass.

[KelvinZero]

I think I heard somewhere that Mars atmosphere actually does suck heat away very effectively, at least it is nothing like a linear relationship with pressure. Can anyone confirm that?

One is convection and that is very much reduced due to the thin martian air.

One is conduction which surprisingly (to me) is not much reduced. But conduction of heat in air is already low on earth. Heat loss due to atmosphere on earth is much more convection so much reduced on Mars though I cannot quantify.

I think convection would be outperformed by a light breeze in most cases.
Oops, just reading up on convection. I think I have missunderstood what it is. (not just movement of air due to heat rising)

Here is the link to the first time I asked (and you were there too )
http://forum.nasaspaceflight.com/index.php?topic=32201.msg1066267#msg1066267

Some info here, but I didn't spot a simple comparison to earth in it:
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/22216/1/97-0683.pdf

[MP99]

@gbaikie,

Unless the flow in the pipe is turbulent, I'd think you will get a layer of ice forming on the shaded side of the pjpe.

I also think it's unlikely that you'll be able to setup the pipe to be all-downhill, which is necessary for the pipe to drain towards the end of the day. Pipes are almost always pumped, I believe.

However, I'd think the water could start out pretty hot, and be re-heated along the way - perhaps at pumping stations.

[A_M_Swallow]

The pipes could be lagged.  The air is low pressure so it can form part of the lagging.  Something like wall of pipe, air gap, inward reflecting surface, insulator and paint.

[A_M_Swallow]

For people planing on using electric vehicles on Mars, here is the state of the art on the Earth.
http://www.bbc.co.uk/news/technology-23810535

[Hyperion5]

For people planing on using electric vehicles on Mars, here is the state of the art on the Earth.
http://www.bbc.co.uk/news/technology-23810535

That's not the "state-of-the-art" that people here were talking about, Swallow.  They're talking about battery-powered electric cars like this bad boy: http://blog.roundrockoffices.com/wp-content/uploads/2013/06/tesla-model-s.jpg. 

The advantages of going with batteries are many, starting with the amount of power you can store in the car.  The car can still be solar-powered, but via a power grid hooked up to large solar panels, not solar panels on it.  Tesla's making a good case for why you'd want to have electric cars powered by batteries on Mars.  The only real issue, besides range, appears to be insulating the batteries.  Does anyone know what kind of difficulties something like a Tesla Model S (but modified for martian roads) would have on Mars?  How would the batteries hold up? 

[MickQ]

For CO/O2 engined trucks make the prime mover a mobile ISRU plant with a small reactor for power and small onboard buffer tanks for the CO & LOX.  The plant runs continuously, feeding the engine when needed or into the tanks.  All cargo can be towed on/in trailers of different types: freight, tanker, hab, lab, earthmoving/construction equipment.

As to roads, if in an area with a high enough water content in the soil, what about microwaving a strip 3 meters wide to melt the frost and allow it to re freeze in maybe a more compacted form ?  A number of runs may be needed over the same route but with constant traffic and occasional re heating it may be just as hard as concrete.

Mick

[Zed_Noir]

For people planing on using electric vehicles on Mars, here is the state of the art on the Earth.
http://www.bbc.co.uk/news/technology-23810535

That's not the "state-of-the-art" that people here were talking about, Swallow.  They're talking about battery-powered electric cars like this bad boy: http://blog.roundrockoffices.com/wp-content/uploads/2013/06/tesla-model-s.jpg. 

The advantages of going with batteries are many, starting with the amount of power you can store in the car.  The car can still be solar-powered, but via a power grid hooked up to large solar panels, not solar panels on it.  Tesla's making a good case for why you'd want to have electric cars powered by batteries on Mars.  The only real issue, besides range, appears to be insulating the batteries.  Does anyone know what kind of difficulties something like a Tesla Model S (but modified for martian roads) would have on Mars?  How would the batteries hold up? 

IIRC the batteries on the Tesla model S is liquid cooled and control by the car's computer. It is almost Martian ready, just need radiator side body panels added.

You could put 2 Tesla battery packs into 2 separate chassis modules with six hub motor driven wheels total and get something like the M561 Gama Goat articulated truck used by the US Army in the 70's and 80's.

Quite sure Tesla Motors should come up with something interesting for Martian surface transportation. Since they have the electrical motor & battery technology in house.

[gbaikie]

@gbaikie,

Unless the flow in the pipe is turbulent, I'd think you will get a layer of ice forming on the shaded side of the pipe.

Yes. The water must be flowing. And there should enough turbulence if water is moving around 5 m/s.

I also think it's unlikely that you'll be able to setup the pipe to be all-downhill, which is necessary for the pipe to drain towards the end of the day. Pipes are almost always pumped, I believe.

On earth one gets 1 atm [14.7 psi] per 33 feet. So on Earth a hill 330 feet high will give 147 psi.
Not sure what it is on Mars perhaps it's simply 1/3 of 1 atm per 33 feet, so 330 feet high hill on Mars is 49 psi.
If the hill is the highest point along the 200 km distance then you don't need to pump the water. So one would put the reservoir on the summit of the hill, and one have higher hills along the 200 km path along as one isn't running the pipe thru the summit of these higher hills. So along as shoulder and valley were not higher than your hill.

Though water won't go uphill if there no pressure behind it, so need consistent slope for water drains out of the pipe [or pressurize the pipe].

However, I'd think the water could start out pretty hot, and be re-heated along the way - perhaps at pumping stations.

"The boiling point for water on the surface of Mars is 7°C."
http://waxworksmath.com/Papers/LiquidWaterOnMars.pdf

Though doesn't require that much pressure to increase the boiling point significantly.

[Hyperion5]

For people planing on using electric vehicles on Mars, here is the state of the art on the Earth.
http://www.bbc.co.uk/news/technology-23810535

That's not the "state-of-the-art" that people here were talking about, Swallow.  They're talking about battery-powered electric cars like this bad boy: http://blog.roundrockoffices.com/wp-content/uploads/2013/06/tesla-model-s.jpg. 

The advantages of going with batteries are many, starting with the amount of power you can store in the car.  The car can still be solar-powered, but via a power grid hooked up to large solar panels, not solar panels on it.  Tesla's making a good case for why you'd want to have electric cars powered by batteries on Mars.  The only real issue, besides range, appears to be insulating the batteries.  Does anyone know what kind of difficulties something like a Tesla Model S (but modified for martian roads) would have on Mars?  How would the batteries hold up? 

IIRC the batteries on the Tesla model S is liquid cooled and control by the car's computer. It is almost Martian ready, just need radiator side body panels added.

You could put 2 Tesla battery packs into 2 separate chassis modules with six hub motor driven wheels total and get something like the M561 Gama Goat articulated truck used by the US Army in the 70's and 80's.

Quite sure Tesla Motors should come up with something interesting for Martian surface transportation. Since they have the electrical motor & battery technology in house.

Now this talk about Tesla tech on Mars is a fun topic.  So let's say Elon tasks a few engineers with creating a "martian" Tesla Model S.  What modifications would the car need to be able to handle the martian environment and terrain?  For starters I would think that they'd have to trim back to one door in order to pressurize the cabin.  Given the Model S' 47/53 weight distribution, I'd put the life support & pressurization gear up front in the "Frunk".  The interior walls of the car would be modestly heavier to handle pressurization in the cabin.  I'd jack up the car 4-6 inches (10-15 cm) to better handle the terrain.  The earth tires would have to go for something better suited to Mars, but what?  Also, would the batteries & electric motor require any modifications, or are they "Mars-proof" as they stand? 

[go4mars]

Batteries are the lower risk way for surface tech.  Wireless power transmission would seem preferable to me. 

Hyperloop type system should work on Mars without tunnels.  CO2 has higher speed of sound, and is compressible.  Add a bigger compressor and a chilled skirt, and you have a coating of dry ice allowing your nearly supersonic dusty hovercraft to slip in whatever direction you want over somewhat rough terrain. 

I still think CH4/O2/H2O plasma tunnelling will be pretty common.  The inconel tip and high temp pipe will be good for the very deep geothermal power anyway.  Need to get deep for the air pressure..

I also like the notion of electric dirtbikes, and the fact that Tesla's are all aluminum (can handle Martian temp range).  I also really think rocket powered hoppers will play a role. 

I'll return to this if I have time.  Cool thread!

[HappyMartian]

Now this talk about Tesla tech on Mars is a fun topic.  So let's say Elon tasks a few engineers with creating a "martian" Tesla Model S.  What modifications would the car need to be able to handle the martian environment and terrain?
...

Replace the rear-mounted 310 kW, 416 hp electric motor with four 15 hp electric powered motors on each of the wheel/brake units. Replace the single wheels with large dual wheels on the back wheel/brake units. Replace the front bumper with a lightweight V shaped 'rock plow'. Reinforce the hood and mount a 3 hp geared electric winch there. Put an advanced active GCR shielding unit on the roof. Add a strong trailer hitch.

Pull a small tri axle inflatable Airstream type of trailer that has an advanced active GCR shielding unit on its roof, electric motor powered wheels, extra batteries, oxygen tanks, food, water, toilet, recycling unit, and an airlock. The trailer is connected to the car with a lightweight flexible tunnel that was a leftover prop from the movie E.T. the Extra-Terrestrial. 

Behind the trailer tow a second trailer. It has an advanced radioisotope thermoelectric generator capable of putting out 12,000 watts of electricity and weighs less than 600 kilograms. Flexible hoses move waste heat, in the form of hot water, from the generator to the first trailer and the car.
 
Drive slow and enjoy the view.

See: http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator


Edited.

[malu5531]

A lot of people have put a ton of thought into getting to Mars, terraforming it, expanding living space and landing on Mars here on NSF.  However, I found there doesn't seem to be a lot of thought given to how best to move around once we get there.

Interesting thread, here's my 2 cents.

Rovers

Personally I don't believe in any type of internal combustion engine; converting electricity (solar or nuclear) into fuel (Methane + Oxygen) is a way of storing energy. Electrolysis of water to get Hydrogen is inefficient. For cars on earth we (Tesla, etc) use Li-Ion batteries to store energy, not Methane or hydrogen from water. As batteries evolve they will keep getting better.

 - Already a decent sized battery could provide hundreds of miles of range on a charge.
 - We need electricity for life support and it's convenient/flexible to have one source of energy on board.
 - Batteries can be swapped for "instant refuel" at dedicated refueling stations (like refuelling Methane + Lox)
 - Rovers can "self-recharge" when not in use
 - In a pinch it might be possible to have "limp home" mode, using solar energy, at least on auto-pilot for weeks/months.

The one downside is batteries tend to lose charge over time, so it would not be a great option for travel away from settled areas. 

Fuels such as Lox, will have the same problem. And there is no point in a "mobile fuel factory" (since it only adds ineffectiveness between the power generator and propulsion). If you have a good energy-source on board, it should be more efficient to store this energy in batteries than through complex harvest of raw material and chemical reactions. Any ICE-based system will have to rely on "refuelling stations", just like electric cars.

Nav aids

I add a point here, which I find interesting; navigation. Ever tried to drive without a map or GPS? - it can be quite a challenge. Now, try this with every hill and patch of land looking "exactly" the same for hundreds of miles..

Clearly a GPS system would be awesome, but not possible initially. I would propose a system of ground based radio beacons (solar powered with batteries for nighttime operation). It could perhaps just be NDB or VOR beacons, in use for 50+ years on earth in marine and aviation. (search youtube for demonstrations on how to use these instruments for navigation in an aircraft).

http://en.wikipedia.org/wiki/VHF_omnidirectional_range
http://en.wikipedia.org/wiki/Non-directional_beacon

VOR are a bit more complex/expensive to build but more resistant to interference, while NDB would rely on a bit more complex equipment in the rover.

Note; Must be strategically placed on hilltops or using masts to get line-of-sight.

It might also be possible to (cheaply?) design/make a modern ground based navaid system using digital radio beacons that are cheaper to deploy and more convenient to use.

Railroads

I would combine maglev trains and railroads into one; remove the complexity of magnetic levitation while keep the advantage of linear accelerators. On earth our atmosphere create a need to bring propulsion a long for long-distance rail-line, however, not so for theme-park rides; here linear accelerators are often used.

My "guesstimate" is that on Mars, thanks to the low atmospheric pressure and low wheel friction, it would be more efficient / easy to build a rail network (no mag-lev, saving costs) and let the unpowered cars be propelled forward by linear accelerators at suitable intervalls / hillsides. There would be no need to bring fuel, a nuclear reactor or distribute electric power through over head lines (or in track, like on a subway).

The low friction and pressure between wheels and rail would also allow greater speeds compared to earth. For emergency breaking it would perhaps be necessary to lower "breaking wheels" into the ground, use parachutes or breaking rockets.

Flying

Not so sure about flying per-se, but hoppers / using the Mars-SSTO ferries for ballistic transport, would be fast, efficient and "cheap" when Methane/Lox fuel is produced locally for transport of goods from LMO to the surface. I believe this could be a major mode of transport in the early-to-mid days of exploration, before other infrastructure is established.

The hoppers could initially be the same SSTO-ferries that also allow transportation to/from Phobos, Deimos and LMO space stations. (if SSTO ferries are used, which I believe they would)

Mobile network / communications infrastructure

While I'm at it, I add another infrastructure related point; communication. Rovers, people in EVA and when on/off duty in the colony; people need communication. Making phone calls or surfing the "martian internet" (youtube.mars, twitter.mars, facebook.mars, etc) .

Since a mars space program "on a budget" would like to avoid re-inventing the communications systems and mobile devices it would be easies to re-use what's already on earth; LTE networks and iPhones/Android COTS phones.

Cell radius in an LTE network can be configured between ~50m to ~10000m. I'm sure on Mars, with new RF regulations (also an interesting question for discussion), even more powerful LTE transmitters could be allowed for even larger cells. Say 100+km? However, this would perhaps require modified clients or optional repeaters / external antennas. Another option could be to equip rovers with local/mobile LTE base station (this is possible) with a smaller range (say 100 meter or so) and a directional (or more powerful omnidirectional) link to the physical network. I know the military have deployed mobile 3G cells.

So, while you're at/near the colony your mobile device communicates with the nearest LTE cell tower, and when you're in (or near) the rover, your communication might go through the local mobile LTE cell. Initially there's probably only one fixed cell tower on Mars, or two for redundancy, but later as the colony grows and capacity demand increase, there will be need for more (and smaller) cells.

This would allow all colonists access to the local internet with Gbps connectivity and Earth based companies could set up local clones of popular services used on earth (such as Twitter or Facebook) on some type of Martian "compute cloud" (Amazon / Blue Origin?) for PR, or later, profit.

As for phone calls or texts, since this is the most "green field"/"blue ocean" deployment you can do; no support for legacy voice or text systems are required and it will be unpractical to "call earth"; which means legacy phone systems can be abolished. Instead some app, like Skype or Facetime, could be used for local phone/video calls and texting over IP. Ideally EVA and Rover excursions would communicate over IP, avoiding the hassles of traditional radio communications.

What are your thoughts on "Communications infrastructure on Mars"?
(perhaps this should be a separate thread?).

[go4mars]

I was imagining the hovercraft to still be accelerated from base by swiveling linear accelerator, but if using broadcast power, could just have it accelerate itself to nearly mach 1.