Roads on Mars

SpaceNut · 2022-05-08 20:02:16

The Incredible Story of the US Army’s Earth-Shaking, Off-Road Land Trains

You need to get 500 tons of supplies from Fairbanks, Alaska to the Arctic Ocean—a journey of about 400 miles through pure wilderness. There are no roads, very few airstrips, and endless ice. You're going to have to withstand minus 68 degree temperatures.

tahanson43206 · 2022-05-08 20:16:00

For SpaceNut re this topic and Post #26

The topic's been languishing. You sure brought it back in style! A land train like that would sure work nicely on Mars.

The fuel consumption of a vehicle like that on Earth would be significant. Some of the suggestions of Calliban for small nuclear plants might be a good fit for the Mars version.

(th)

Mars_B4_Moon · 2022-09-13 03:13:05

If kiwis go to Mars then Mars will have 'Metal Roads'? Roads have existed whenever there was human civilization from Egypt, to China to Rome to the Middle East to South America, Street paving has been found from the first human settlements around 4000 BC in cities of the Indus Valley civilization on the Indian subcontinent. Growing Timbers and Bamboo? gravel road is a type of unpaved road surfaced with gravel that has been brought to the site from a quarry or stream bed. They are common in less-developed nations, and also in the rural areas of developed nations such as Canada and the United States. In New Zealand, and other Commonwealth countries, they may be known as metal roads. Logging timber roads are constructed to provide access to forest for logs and other forest management operations. Calcium chloride chemical provides dust suppression through its hygroscopic properties, allowing moisture to be drawn in and retained by the compound. Calcium chloride can be applied in either dry pellet or flake or wet dissolved pre-prepared solution form. Successful applications can be effective for up to three years, depending on the weather and traffic conditions for the roadway.Log roads are commonly narrow, winding, and unpaved, but main haul roads can be widened, straightened or paved if traffic volume warrants it. The old ancient corduroy road or log road is a type of road or timber trackway in placing logs, perpendicular to the direction of the road over a low or swampy area.
Dirt and Gravel
https://www.dirtandgravel.psu.edu/sites … es/General
PDF
https://www.maine.gov/dep/land/watershe … manual.pdf
maintaining
https://purl.fdlp.gov/GPO/gpo55219

Military improvised Corduroy road
http://www.history.army.mil/books/wwii/ … v/ch05.htm

If Trees or Shrub or bush and Bamboo are grown on Mars then how strong will this wood be? Maybe you can build puncheon or plank road uses hewn boards instead of logs, resulting in a smoother and safer surface, boardwalk or boarded path, or promenade an elevated footpath, walkway, for unstable, swampy or helping cross fragile lands, footbridge or pedestrian overpasscould be designed solely for bikes pedestrians, a simple road type bridge for transport of small goods and links two points on a cliff face.

It is possible some AI machine or Flying Drone or Mars Robot dog might help in construct of these bridges and roads.

How To Build a Footbridge
http://www.redwoodbridges.com/build_footbridge.html

"Pedestrian Overpasses/Underpasses".
https://web.archive.org/web/20130604031 … passes.cfm

How to compact sand, dirt and crusher dust in preparation for pavers
https://masterhire.com.au/articles/how- … compactor/

Materials to Make a Driveway Over Sand
https://homeguides.sfgate.com/materials … 03312.html

A Beautiful Look At Antarctica’s Harrowing Ice Runways
https://www.atlasobscura.com/articles/a … ce-runways

Aside from the weather and relative isolation, there is one other major consideration for living in McMurdo: how to get there.
One option is the slower, old-fashioned way, by ship. The other, faster option is flight, which is made possible through the three ice runways that service McMurdo. There’s the Pegasus White Ice Runway, which sits on glacial ice with a surface of “white ice”—3-4 inches of compacted snow—making it suitable for wheeled aircraft. There’s also the main Ice Runway, for all types of aircraft, and Williams Field, a skiway for ski-equipped aircraft.

Once a bridge or road is in frequent use it might be domed off to protect against radiation or save on air and heating, it could eventually become part of the larger colony structure.

Last edited by Mars_B4_Moon (2022-09-13 03:26:00)

Calliban · 2023-10-23 13:11:31

Given the abundance of sulphur in the Martian regolith, sulphur could replace asphalt for road surfaces.
https://en.m.wikipedia.org/wiki/Sulfur_concrete

On Earth, asphalt-gravel mix is laid on a bed of stones, which are sorted to be about 1" in diameter. The asphalt-gravel mix is laid to a depth of 1-2". In the UK, motorway lanes are typically 12' wide. But this is driven by legacy roads, which carried carts. These were wide enough to be pulled by two horses side by side. On Mars, we can start fresh and will probably opt for wider roads, say 20' (6m) lane width. Regolith provides most or all of the materials we need. The road would consist of a foundation of large stones, stacked in layers to a depth of 2' on ground that has been cleared of large stones. Next would be a layer of fines, about 6" thick. On top of the fines layer, would be a layer of coarse stones 0.5 - 2" in diameter, to a depth of about 1'. The uppermost layer would be a mixture of sulphur and fine grit, from 1/16th to 1/2" grade, laid to a depth of 2".

If sulphur is about 20% of total volume, then we would need some 60 litres per lane-m, or 96.5m3 per lane-mile. The density of sulphur is about 2kg/litre, so a mile of two-lane road would need about 400 tonnes of sulphur. As sulphur is abundant in regolith at about 3% by weight, we could extract it by heating regolith to 150°C. A solar furnace could do this. Each cubic metre of bulk regolith has a mass of 2000kg, so should contain some 60kg (30 litres) of sulphur. So, about four cubic metres of regolith must be processed to produce each metre of 2-lane road. The fines will contain the bulk of the sulphur, so sieving the regolith into different grades allows the volume of material heated to be minimised. The larger rocks provide the road bed, the fines provide the intermediate layer, folliwed by coarser stones and then the fine grit sulphur mix. Regolith size distribution will vary from place to place.

To build roads we need a number of different machines. We need loaders that can scoop regolith and load into a second machine that can sieve it into different grades. We need an oven that can bake sulphur out of the fines. We need a mixer that produces a hot paste of sulphur and gravel and lays it as a thin layer. We need a machine that can lay interlocking layers of large stones. We need another machine that lays the fines and coarse stones and a roller to compact the layers together. We may need crushers in places where rocks are too coarse.

Roman roads were famous for their straightness. This has advantages for vehicle roads as well, as turning places a lot of shear stress on road surface. Bumps and depressions also lead to locally high shearing and compressive forces that can crack the road surface. Building roads with solid foundations that spread load and avoid sinkage, is important for minimising maintenance requirements. It is also beneficial in reducing fuel consumption, which is something that must be manufactured on Mars. So we should aim to build robust roads that are as straight as possible, with flat or gently sloping surfaces.

Last edited by Calliban (2023-10-23 13:44:23)

Calliban · 2023-10-23 16:05:10

I ran a few calculations on the energy consumption of a Martian truck driving on paved and unpaved topography. One of the things I had not previously appreciated is the energy cost of gradients on roads. Truck tires on well maintained asphalt road surface have a rolling resistance of 0.006-0.01.
https://www.engineeringtoolbox.com/roll … _1303.html

A 100 tonne load driven on flat road for 1km, would require 3.73MJ work energy under Martian gravity. But if the truck must ascend a gradient of just 5° on the same road, the energy consumption increases to 36.35MJ/km, almost a 10-fold increase. If a road is traversing hilly terrain, the truck can recover some energy on the descent phase. The engine will idle during this phase, but will still waste energy due to pumping losses. Given that Mars will be largely empty, it makes a great deal of sense planning road routes to minimise the need for ascent.

Power requirement for a 100 tonne vehicle over different terrain, driving at 30kph:

Flat, paved road: 31.06kW
Paved road 5% incline: 302.92kW
Flat gravel road, Crr = 0.02: 62.12kW
Gravel road, 5% incline: 334kW
Unimproved regolith, flat, Crr = 0.04: 124.24kW

In terms of reducing overall fuel consumption, eliminating gradients is just as important as paving the road. This suggests that road construction should be aided by detailed topographical surveys and should cut through hills and other obstructions, rather than attempt to go over them.

On Mars, vehicle fuel and oxidiser is something that must be manufactured from electricity with heavy round trip energy losses. The need to carry oxidiser also greatly reduces the effective energy density of fuel. Both factors combine strongly to suggest that it would be economically beneficial to build roads early on Mars andvto put a great deal of effort into ensuringbthat roads are flat and straight. Compacted gravel roads should halve the energy requirements of moving freight compared to non-compacted regolith. Paved roads, will halve energy consumption again. Given that roads can be produced from regolith that is sieved, sorted into grades and compacted together, the energy cost of roads will be modest. So a Martian settlement should build roads early.

A future Mars with an extensive paved road network, could use compressed liquid CO2 to power vehicles.
https://en.m.wikipedia.org/wiki/Compres … gy_storage

A single tonne of liquid CO2 expanded at room temperature, will release some 50kWh of mechanical energy.
https://en.m.wikipedia.org/wiki/Compres … gy_storage

This is enough to propel our 100 tonne truck some 50km on a flat, paved road. If a 100 tonne truck carries some 10 tonnes of L-CO2, this should allow a range of 500km (300 miles).

Last edited by Calliban (2023-10-23 16:31:05)

GW Johnson · 2023-10-24 11:30:22

The coefficient of rolling friction for a tire on hard pavement is in the neighborhood of 1-2%. On hard dirt it is closer to 20%, but only if a large tire and not overinflated. On soft dry, non-compactible sand (as in sand dunes), it can easily exceed 100%.

You have to balance the cost of emplacing infrastructure (like paving a road) against the rolling friction costs of big tires on a graded, packed dirt road. It won't cost a lot to grade and pack a dirt road. It costs a lot more to actually pave it with a proper road bed. (It costs a whopping lot more than that, to lay track for rail transport.)

Those are infrastructure costs as judged here on Earth. Why would you ever believe they will be that low on Mars? With interplanetary transportation costs? For everything you must bring?

That minimal infrastructure-to-emplace is why I like the "truck train" idea on a graded, packed dirt road. Unlike here, you can leave the grading spoils as berms along each side of the road. There is no rainfall runoff problem to address on Mars.

GW

Calliban · 2023-10-27 07:23:45

We could simply dig up the first 12' of regolith, remove the rocks and leave a bed of compacted fines, with larger rocks dumped in heaps along the verge. Maybe we could build a single vehicle that could do this non-stop. Something that looks a bit like a combine harvester at the front and a steam roller at the back. If it could work constantly at 0.3m/s or 1'/s, it could make 9500km (5900 miles) of road per year. That is enough to go halfway round the planet. As cities and other infrastructure grow, we couid pave the dirt track roads as finances allow.

I remember an old episode of Thunderbirds which featured a machine that would clear terrain and lay road in its wake. On Mars, we need something not disimilar. Maybe it can be nuclear powered? If so, it couid actually dump waste heat into the spoils that it scoops up.
https://thunderbirds.fandom.com/wiki/Gr … on_Vehicle

Kris DeDecker wrote an article about electric road trains used in Germany between the late 19th century and 1920s.
https://solar.lowtechmagazine.com/2009/ … ad-trains/

It occured to me recently that something like this could work at low speeds on Mars using a single segmented DC cable, without need for an earthing or neutral return phase. If the road train is long enough, cable sections between the poles could be alternately phased -ve and +ve. Trolley arms would connect to the cable at the front and rear of the train. By passing the current through a rectifier, the motors would receive constant phase DC electric power, even as the phases change between the trolley arms. We would position solar panels along the track, providing direct DC power to the cable. The current would be a function of local sunlight intensity and so woukd the speed of the train. The pole would be made from cast basalt. The cable sections would be carbon steel fibre.

The road train would look a lot like those referenced by SpaceNut in post 26. As the train may be a mile or more long, each car in the train needs independant steering to follow the contours of the road, though would not need independant propulsion. Power cars would be distributed throughout the train. From above, it would resemble a snake trailing across the landscape. I think speed would be low, averaging perhaps 2mph, with a peak of 6mph at high noon and obviously zero at night. A 1000 mile trip would take 3 weeks. A circumnavigation of the planet would take at least 9 months in a straight line. A year more realistically.

Last edited by Calliban (2023-10-27 08:28:14)

New Mars Forums

Announcement

#26 2022-05-08 20:02:16

Re: Roads on Mars

#27 2022-05-08 20:16:00

Re: Roads on Mars

#28 2022-09-13 03:13:05

Re: Roads on Mars

#29 2023-10-23 13:11:31

Re: Roads on Mars

#30 2023-10-23 16:05:10

Re: Roads on Mars

#31 2023-10-24 11:30:22

Re: Roads on Mars

#32 2023-10-27 07:23:45

Re: Roads on Mars

Board footer