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HappyMartian
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« Reply #330 on: 08/20/2012 04:19 AM » |
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I sure that a 2 wheeled truck can be designed but the real world is putting major constraints on the vehicle.
The payloads can come with different shapes, sizes, masses, densities and different parts of the same load can have different densities. The centre of gravity has to be kept between the wheels even when going over ruff ground, up and down hill, with the wheels at different heights and turning. Four wheels may be both simpler and more stable.
Well A_M_Swallow, for loading the dump truck with certain types of heavy equipment and various other massive loads it can sometimes be safer and very advantageous to have the floor of the dump box as close to the ground as is possible. And from previous discussions on this thread, a very low center of gravity seems to be a good idea for Lunar vehicles. For building and maintaining Lunar Haulage Roads a grader blade mounted on the bottom of the dump truck's frame in the middle or front of the truck could be very useful. A trailer hitch at the back of the truck would be useful for a variety of options. A winch at the front of the truck would be useful in an emergency. And another winch mounted in the front of the bed of the truck would be needed for pulling a load onto the flatbed. To carry all types of loads, you probably would want a low flatbed dump truck that you could quickly modify or adjust depending on what you need to move. And a dumping flatbed truck with four, six, eight, or ten wheels seems needed for general utility and stability. It seems there could be some real benefits to a design that keeps the floor of the long flatbed as close to the ground as possible with the axles for each large wheel independently mounted above the level of the flatbed. With such a truck, or a lowboy trailer pulled by such a truck, you should be able to readily load and move loads with vastly "different shapes, sizes, masses," and other unique characteristics. A_M_Swallow, I've helped move some pretty heavy loads with various lowboy trailers, and I've seen other folks carefully move even much heavier loads with such trailers. Similarly, a well designed low center of gravity Lunar flatbed dump truck could work out to be pretty safe and efficient in moving many types of loads. Cheers!
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HappyMartian
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« Reply #331 on: 09/09/2012 07:18 AM » |
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There might eventually be a need to dig tunnels while building lunar haulage roads. Tunnels could also be used as truck maintenance-repair garages and provide a safe living environment for the Lunar Base's astronauts. Tunnels would be good locations for productive gardens to grow wheat, corn, vegetables, and herbs to enhance the Lunar cuisine. Tunnels could also be used for research labs and as sports and exercise areas. PROPOSAL FOR A LUNAR TUNNEL-BORING MACHINE By Christopher S. Allen, David W. Cooper, David Dada Jr., Christopher S. Mahendra, and Michael A. Tagaras May 5,1988 At: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19890008382_1989008382.pdf"Abstract A need exists for obtaining a safe and habitable Lunar Base that is free from the hazards of radiation, temperature gradient, and micrometeorites. A device for excavating lunar material and simultaneously generating living space in the subselenian environment has been researched and developed at the conceptual level. Preliminary investigations indicate that a device using a mechanical head to shear its way through the lunar material while creating a rigid ceramic-like lining meets design constraints using existing technology. The Lunar Tunneler is totally automated and guided by a laser communication system. There exists the potential for the excavated lunar material to be used in conjunction with a surface mining process for the purpose of the extraction of oxygen and other elements. Experiments into lunar material excavation and further research into the concept of a mechanical Lunar Tunneler are suggested." Cheers!
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HappyMartian
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« Reply #333 on: 12/08/2012 10:42 PM » |
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Lunar Haulage Roads may need to have a dual function that is similar to highways on Earth. In an emergency, highways get used as landing runways for airplanes and helicopters. Similarly, on the Moon Lunar Haulage Roads may serve as important backup landing 'pads' or runways. If Lunar Landers are going to have wheels for surface mobility, then perhaps using brakes, or built in skid pads, in an emergency to reduce a portion of the horizontal velocity vector might make sense. Emergency crash nets that could be quickly and automatically deployed across the various Lunar Haulage Roads could also be useful. This is related to information I previously posted: "Introduction: It is unsafe or too risky to land human-class landers (>40 MT) on Martian soil without first constructing a mechanically competent surface, a landing pad." And, "The need for landing pads is the consensus of the plume/soil research community after a decade of concentrated research, including experiments, physics-bases simulations, and mission analysis. This finding has not yet been communicated widely outside the community of researchers because the consensus has been achieved only recently, so both space architects and mission planners may be unaware of the seriousness of the problem." And, "Prior missons to the Moon and Mars all successfully avoided the worst cratering regimes owing to their smaller size landers and/or environmental conditions where they were landing." And, "By building several pads in the landing elipse, the cross-range needed to get to any pad can be reduced, lessening the demands on the EDL system and improving the chances of safe landing if a problem occurs during entry and descent." From: PRECURSOR ACTIVITIES TO SOLVE PLUME CRATERING PROBLEMS FOR HUMAN-CLASS MARS LANDERS. By P. Metzger, P. Hintze, and R. Mueller At: http://www.lpi.usra.edu/meetings/marsconcepts2012/pdf/4359.pdf
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A_M_Swallow
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« Reply #334 on: 12/09/2012 02:44 AM » |
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Lunar Haulage Roads may need to have a dual function that is similar to highways on Earth. In an emergency, highways get used as landing runways for airplanes and helicopters.
Similarly, on the Moon Lunar Haulage Roads may serve as important backup landing 'pads' or runways.
{snip} The Moon does not have air so its landers will not use wings. Without wings runways have little use. However vertical landers can land in car parks.
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HappyMartian
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« Reply #335 on: 12/09/2012 06:53 AM » |
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Lunar Haulage Roads may need to have a dual function that is similar to highways on Earth. In an emergency, highways get used as landing runways for airplanes and helicopters.
Similarly, on the Moon Lunar Haulage Roads may serve as important backup landing 'pads' or runways.
{snip}
The Moon does not have air so its landers will not use wings. Without wings runways have little use. However vertical landers can land in car parks.
In an emergency landing situation you may have minimal downward velocity and considerable horizontal velocity of your horizontal Lunar Lander. If I suddenly had to make a quick choice about how to use my horizontal Lander's suddenly limited rocket thrust, or limited propellant, and had the choice of 'sliding in' or 'dropping in' to reduce my velocity, I would choose 'sliding in' and try to minimize my downward velocity prior to landing. I've been in some car accidents. If the velocity isn't too high, and proper precautionary design and preparations were made in advance, you may limp away from a bad crash. Some folks have even survived airplane crashes. There is some related car, airplane, and Orion spacecraft crash discussion in: Validation of Finite Element Crash Test Dummy Models for Predicting Orion Crew Member Injuries During a Simulated Vehicle Landing By Al Tabiei, Charles Lawrence, and Edwin L. Fasanella At: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090018048_2009016705.pdfHopefully, crash considerations will also be a part of the Lunar Lander design. Anytime you are flying close to the ground and an emergency occurs, some kind of a back-up plan is a bit better than no back-up plan. In any case, as was noted previously, "By building several pads in the landing elipse, the cross-range needed to get to any pad can be reduced, lessening the demands on the EDL system and improving the chances of safe landing if a problem occurs during entry and descent." From: PRECURSOR ACTIVITIES TO SOLVE PLUME CRATERING PROBLEMS FOR HUMAN-CLASS MARS LANDERS. By P. Metzger, P. Hintze, and R. Mueller At: http://www.lpi.usra.edu/meetings/marsconcepts2012/pdf/4359.pdf Lunar Haulage Roads could be used as emergency landing strips or pads and that consideration may influence their design, construction, and locations.
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Warren Platts
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« Reply #336 on: 12/09/2012 02:03 PM » |
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Lunar Haulage Roads could be used as emergency landing strips or pads and that consideration may influence their design, construction, and locations. Not really. Lunar haulage roads would be minimally improved, graded dirt roads. They are designed to be driven at about 10 km/hour speed limit. The problem is that it is hard to stop in 1/6 g. Anything careening in at 2 km/ sec would be demolished instantly. Now I suppose you could have a big, many kilometer long, maglev mass driver that could be used in reverse, but that would require unheard of precision flying and probably not useful in crash situation.
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HappyMartian
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« Reply #337 on: 12/11/2012 10:59 AM » |
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Lunar Haulage Roads could be used as emergency landing strips or pads and that consideration may influence their design, construction, and locations.
Not really. Lunar haulage roads would be minimally improved, graded dirt roads. They are designed to be driven at about 10 km/hour speed limit. The problem is that it is hard to stop in 1/6 g. Anything careening in at 2 km/sec would be demolished instantly.
Now I suppose you could have a big, many kilometer long, maglev mass driver that could be used in reverse, but that would require unheard of precision flying and probably not useful in crash situation.
Not "careening in at 2 km/sec“, but perhaps 'sliding in' with next to zero vertical velocity and a horizontal velocity of less than 100 meters per second, after having a problem during the final stage of landing, might be survivable if the road was straight and level. That would assume of course that the normal Lander landing flight path was directly above and aligned with the road. A large number of suitable landing areas on haulage roads could be useful emergency landing pads for large Landers as was already noted. "Introduction: It is unsafe or too risky to land human-class landers (>40 MT) on Martian soil without first constructing a mechanically competent surface, a landing pad." And, "Prior missons to the Moon and Mars all successfully avoided the worst cratering regimes owing to their smaller size landers and/or environmental conditions where they were landing." "By building several pads in the landing elipse, the cross-range needed to get to any pad can be reduced, lessening the demands on the EDL system and improving the chances of safe landing if a problem occurs during entry and descent." From: PRECURSOR ACTIVITIES TO SOLVE PLUME CRATERING PROBLEMS FOR HUMAN-CLASS MARS LANDERS. By P. Metzger, P. Hintze, and R. Mueller At: http://www.lpi.usra.edu/meetings/marsconcepts2012/pdf/4359.pdf This possibility of "improving the chances of safe landing if a problem occurs during entry and descent" also suggests that at least some parts of the Lunar Haulage Roads could possibly be more than "minimally improved, graded dirt roads" and could serve as safe emergency landing pads. Edited.
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Andrew_W
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« Reply #338 on: 12/11/2012 06:10 PM » |
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The likelihood of being able to line up on a road, reduce your horizontal velocity to a survivable speed, and have next to zero vertical velocity is about nil.
Unlike an aircraft, a spacecraft is essentially fixed in it's direction of flight, no aerodynamics to change direction.
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Solman
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« Reply #340 on: 12/11/2012 10:11 PM » |
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Now I suppose you could have a big, many kilometer long, maglev mass driver that could be used in reverse, but that would require unheard of precision flying and probably not useful in crash situation.
I've wondered about the maglev in reverse idea and agree the precision required is a huge problem. I can't help but try to imagine a solution. What if as a vehicle came in for a landing: a device or vehicle on the maglev would accelerate to match the landing spacecraft's speed and send out a small rugged rocket propelled vehicle on a tether that could effect latchment with a similar vehicle sent from the landing spacecraft. the spacecraft would then be decelerated by the maglev vehicle via the now connected tethers, while the spacecraft uses rocket thrust to maintain and gradually loose altitude for a runway landing at airliner speed or a vertical landing on rocket thrust. One advantage may be that the maglev vehicle could generate electricity while braking itself and the spacecraft.
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HappyMartian
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« Reply #341 on: 12/12/2012 10:28 AM » |
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The likelihood of being able to line up on a road, reduce your horizontal velocity to a survivable speed, and have next to zero vertical velocity is about nil.
Unlike an aircraft, a spacecraft is essentially fixed in it's direction of flight, no aerodynamics to change direction.
The lining up on one of the Lunar Haulage Roads occurs long before launch from Earth, or leaving leaving LEO, and is assured by proper mission planning and launching within the planned launch window, or LEO departure window. Contingency planning and preparation are sometimes useful for those situations when things go wrong. And things will someday go wrong because landing on the Moon is not exactly the safest activity one can do. Backup options for 'last minute landing issues' would also be somewhat reassuring for both astronauts and tourists. We do want tourists on the Moon, don't we?
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Moe Grills
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« Reply #342 on: 12/28/2012 07:40 PM » |
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OK!
The concept of a versatile lunar vehicle, serving in as variety of roles,
has been well established on this thread.
You can call such a lunar-vehicle, the SWISS-ARMY KNIFE of vehicles.
1) It can carry passengers.
2) It can be driven directly by a driver behind the wheel; or remotely by
radio-command or computer instruction..
3) It can operate by day (using solar panels); by night (using radioactive
isotopes).
4) It can serve as home away from home, with its own toilet, hideaway beds, water-heating container, food pantry.
5) It can be temporarily fitted with a type of bulldozer blade to push away rocks, or fill in craters, or simply move regolith to create a road on mountain or valley slopes.
6) It can be temporarily rigged with a grader blade to plow a smooth road
and level it where needed.
7) It can be temporarily rigged with a bobcat-type bucket to scoop up
loads of regolith to dump into specialized equipment to melt the regolith
and extract metals, silicon and oxygen. Or it can use that bucket to pile up
berms of regolithic material to protect above ground dwellings and their
inhabitants from solar flares.
Did I miss anything?
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A_M_Swallow
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« Reply #343 on: 12/28/2012 08:20 PM » |
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OK!
The concept of a versatile lunar vehicle, serving in as variety of roles,
has been well established on this thread.
You can call such a lunar-vehicle, the SWISS-ARMY KNIFE of vehicles.
1) It can carry passengers.
2) It can be driven directly by a driver behind the wheel; or remotely by
radio-command or computer instruction..
3) It can operate by day (using solar panels); by night (using radioactive
isotopes).
4) It can serve as home away from home, with its own toilet, hideaway beds, water-heating container, food pantry.
5) It can be temporarily fitted with a type of bulldozer blade to push away rocks, or fill in craters, or simply move regolith to create a road on mountain or valley slopes.
6) It can be temporarily rigged with a grader blade to plow a smooth road
and level it where needed.
7) It can be temporarily rigged with a bobcat-type bucket to scoop up
loads of regolith to dump into specialized equipment to melt the regolith
and extract metals, silicon and oxygen. Or it can use that bucket to pile up
berms of regolithic material to protect above ground dwellings and their
inhabitants from solar flares.
Did I miss anything?
It can be fitted with a crane to unload cargo landers.
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Andrew_W
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« Reply #344 on: 12/28/2012 11:43 PM » |
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OK!
The concept of a versatile lunar vehicle, serving in as variety of roles,
has been well established on this thread.
You can call such a lunar-vehicle, the SWISS-ARMY KNIFE of vehicles.
1) It can carry passengers.
2) It can be driven directly by a driver behind the wheel; or remotely by
radio-command or computer instruction..
3) It can operate by day (using solar panels); by night (using radioactive
isotopes).
4) It can serve as home away from home, with its own toilet, hideaway beds, water-heating container, food pantry.
5) It can be temporarily fitted with a type of bulldozer blade to push away rocks, or fill in craters, or simply move regolith to create a road on mountain or valley slopes.
6) It can be temporarily rigged with a grader blade to plow a smooth road
and level it where needed.
7) It can be temporarily rigged with a bobcat-type bucket to scoop up
loads of regolith to dump into specialized equipment to melt the regolith
and extract metals, silicon and oxygen. Or it can use that bucket to pile up
berms of regolithic material to protect above ground dwellings and their
inhabitants from solar flares.
Did I miss anything?
sounds like a farm tractor: Can be used to tow any type of trailer you can imagine; from tip trailers to accommodation. Can be fitted with front end loader Can be fitted with scraper blade Can be fitted with cement mixer Can be fitted with hoists Can be fitted with back hoe Can be fitted with pile driver Can be fitted with trencher Can be taken to the South Pole: http://www.nzhistory.net.nz/media/photo/dash-pole-tractorsCan even be fitted with a wide range of agricultural implements unlikely to be required on the Moon.
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