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#1 2016-09-28 12:40:00

Dook
Banned
From: USA
Registered: 2004-01-09
Posts: 1,409

Long Range Rover

This is the Manned Mars Rover idea that I posted years ago but it is simplified, improved.  It's very close to the Mars Direct rover weight requirements and it would be more dependable.  Also, I added pictures and changed the name. 

Long Range Rover

The Long Range Rover is as simple as possible since that was the basic idea put forward in the Mars Direct plan. Simplicity of function is the main focus taking into account weight while providing an acceptable level of redundancy for mission essential and crew life support systems.   

The vehicle is designed to carry a crew of two and operate primarily during the day.  The vehicle operates entirely on DC power.  The vehicle would primarily operate on one wheel drive but two, three, and four wheel drive can be used if absolutely necessary but that uses a lot of battery power and greatly limits range.  Keeping within it's solar cell recharge capability I think the vehicle can travel about 20 miles a day.  Using all of it's battery power the vehicle could definitely go farther but afterwards it would have to sit and recharge for about two months, less if it is recharged by another solar panel array. 

The main limitation on the vehicles operation is the crews oxygen supply, water, and food.  The only true limitation the vehicle alone has is battery life and equipment failure.  With a crew of two the vehicle has a 45 day supply of oxygen on board so at 20 miles a day the vehicle could go out about 400 miles, 450 miles absolute max, before it has to return to base.  Using the weight figure from "The Case for Mars" the pressurized rover has a weight allowance of 2,800 lbs. Currently this design is estimated to be 2,816 lbs.  On Mars it would have a two person crew and be loaded with food and water but with Mars lower gravity it should weigh less. 

Vehicle Structure
The body of the vehicle is a carbon composite tube with a rounded carbon composite nose and three forward windows.  Overall the vehicle is 9' wide, 9' tall, and 13' long, not including the rear step and front tow point. Carbon composite construction provides an excellent strength to weight ratio and reduces the amount of heat loss compared to metal construction. 

The vehicle also has a vertical aft pressure bulkhead with a wide access door and an internal bulkhead that provides a 3.5' foot long rear depressurization area that keeps the cabin pressurized while exiting the rover.  The depressurization area has wall storage for the two space suits, it has the four rear batteries under the floor, a seat on the left side with storage underneath for food and water, and a plastic toilet on the right side for storing packaged waste.   

There are three forward aircraft grade windows. When the vehicle is not in motion insulated covers can be affixed by velcro over the inside of the windows to reduce internal heat loss or left off to help cool the cabin. The cabin floor is made of fiberglass honeycomb panels supported by fiberglass honeycomb ribs. The floor panels can be opened to gain access to the two under floor oxygen bottles and 26 batteries if necessary.

The vehicle has two steel tow fittings, one on the front and one on the rear.  The fittings attach to steel plates that are supported by steel tubes that attach to the suspension mounts. 
On the rear bulkhead there is a pressure relief valve that, when manually opened, will release oxygen from the depressurization area so you can open the rear door. 

The driving station at the front inside cabin is very simple.  It has two swiveling captain's chairs, a drivers accelerator pedal, a brake pedal, a steering wheel, one HF radio (1 spare radio in back), switches that send power to each individual drive motor, and the switches for the two forward LED lights.
weight @ 600 lbs?

Suspension
Two separate steel suspension frames bolt to the composite body, one for the forward wheels and one for the rear wheels.  Each wheels suspension frame has an upper steel "A" arm, a lower steel "A" arm, a bracket in between the "A" arms to mount the electric motor, and a coil over shock absorber between the body and lower "A" arm.  The electric motors connect to a steel shaft that goes to a swiveling U joint that connects to another steel shaft that goes to the wheels.  The wheels are five foot tall with a 1' wide footprint and are made of 1/4" thick aluminum alloy with multiple rubber grips. The wheels provide about 2.5' of ground clearance. 

Steering is through a steel shaft that goes to a small 90 degree gearbox and then to another steel shaft that goes through the floor and under the vehicle to steer the front wheels. A rubber boot over the steering shaft prevents loss of pressurization.  The front wheels also have two solenoid operated caliper style brakes on the front wheel rotors that activate when the brake pedal is pressed, normally the vehicle would coast to a stop.
weight @ 400 lbs?

Solar Cells
Small solar cells cover the top half and sides of the vehicle.  Estimated that they produce a total of about 1kw an hour average.  During daylight, some cells will always get direct sunlight and some cells will always get some indirect sunlight.  The vehicle does not have to face a certain direction to recharge although it would make the most power when one of it's sides is facing the sun. All eight batteries are recharged by the solar cells.   
Weight 200 lbs?

Batteries
Eight AGM 12 volt deep cycle car batteries with 14,700 watts each battery.  The forward batteries are mounted in pairs on the inside of the vehicle on the floor near each motor.  The two forward pairs of batteries power one or both front motors.  The forward, right pair of batteries are mounted under the right bed, the forward left pair of batteries are mounted under the left bed.  The two rear pairs of batteries power one or both of the rear motors.  All four rear batteries are mounted in an insulated compartment on the centerline under the floor in the depressurization area.         
weight, 98 lbs ea, so 784 lbs for batteries, another 20 lbs for cables, total 804  lbs

Propulsion Motors
Four 48 volt DC, 11.4 hp each, electric golf cart motors, one motor per wheel, provide power.  Each motor fits into a recessed area of the body and is mounted on a steel plate that is welded to  the suspension brackets. There are four on/off switches on the forward console that send electricity to the motors.  Normally, only one motor, one wheel, is used at a time to save electricity.  Two, three, and four wheel drive is only used when absolutely necessary because it uses too much power. 
Weight 30 lbs each, so 120 lbs total

Oxygen Cylinders
The vehicle carries four compressed oxygen cylinders with 435 cu ft internal storage each.  The bottles are 55" long and 9" wide, they weigh 148 lbs each and they are mounted under the floor.  The oxygen bottles supply oxygen to the oxygenation/pressurization system that supplies oxygen to the interior of the vehicle and keeps the interior pressurized to 5 psi. The four bottles provide enough oxygen for 45 days for a two person crew, 90 days for an emergency crew of one.  The space suit oxygen cylinders would be refilled simply by connecting a line to a recharge point and manually opening a valve.   
weight 148 lbs each, total of 592 lbs

Carbon Dioxide Removal
Three small, quiet (26 dba), fans (1.25 watt/55 cfm) operate continuously, night and day, to pull cabin air into a tube that directs the air over the two carbon dioxide scrubbers that remove carbon dioxide down to <10ppm. Mounted on the right side, middle, aft. Primarily powered by the DC One bus, backup powered by the DC Two bus, uses minimal power, 3.75 watts an hour.

Miscellaneous Equipment: 100 lbs?

There is an external electrical connection for connecting the Long Range Rover to the habitat's main battery pack so that when the rover is not being used it's solar cells can supply power to the habitat. 

There is an oxygen/CO2 level sensor, an inside temperature gauge, and an internal pressure gauge.

The two bed frames are 6' long, 2.5' wide, and raised 2' from the floor and each has a thin mattress.  Under each bed is the forward batteries and storage for food and water. 

There is a single AM antenna on the back of the vehicle.   

Two LED driving lights recessed into the front of the vehicle.

Spare lithium hydroxide canisters for carbon dioxide removal.

Emergency portable spare air containers.

Last edited by Dook (2016-09-28 13:01:04)

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#2 2016-09-28 12:43:32

Dook
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From: USA
Registered: 2004-01-09
Posts: 1,409

Re: Long Range Rover

Long%20Range%20Rover%20Top%20and%20Side%20Views.jpg

Last edited by Dook (2016-09-28 12:49:05)

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#3 2016-09-28 13:20:18

elderflower
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Posts: 1,096

Re: Long Range Rover

You need to carry dilution gas (Argon/Nitrogen mixture would be a by product of the fuel manufacturing process if it uses atmospheric CO2). Pure oxygen comes with most severe fire risks.

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#4 2016-09-28 13:45:05

louis
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From: UK
Registered: 2008-03-24
Posts: 4,725

Re: Long Range Rover

Looks like a well thought proposal. 

In terms of range, I have often wondered about a staging post system - so you place  resource dumps at 20 mile intervals e.g. PV Panel arrays, water, artificial air, even food. It would take a while to build up the staging post system but would then allow for further exploration.

Another thought I had was - could a rover tow a massive lightweight PV array behind it? This might mean the batteries could be lighter.  A 200 sq. metre array might be mounted on a lightweight skin under which were attached rubberised balls to allow it to bounce off the rocks as the Rover progressed.

Other possibilities including using methane to power the vehicles.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#5 2016-09-28 14:02:43

Dook
Banned
From: USA
Registered: 2004-01-09
Posts: 1,409

Re: Long Range Rover

elderflower wrote:

You need to carry dilution gas (Argon/Nitrogen mixture would be a by product of the fuel manufacturing process if it uses atmospheric CO2). Pure oxygen comes with most severe fire risks.

If you add nitrogen to the atmosphere you have to follow certain procedures when you exit and enter the vehicle or you will get the "bends". 

Zubrin pointed out in "The Case for Mars" that Apollo astronauts operated for weeks in a pure oxygen atmosphere and he recommended using the same for the rover.  Having a low pressure rover means you can have a low pressure space suit for outside excursions. 
Pure oxygen does pose a serious fire hazard, especially in a confined space with batteries that give off hydrogen.

I don't have a perfect answer, it's a risk.

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#6 2016-09-28 14:23:54

Dook
Banned
From: USA
Registered: 2004-01-09
Posts: 1,409

Re: Long Range Rover

louis wrote:

Looks like a well thought proposal. 

In terms of range, I have often wondered about a staging post system - so you place  resource dumps at 20 mile intervals e.g. PV Panel arrays, water, artificial air, even food. It would take a while to build up the staging post system but would then allow for further exploration.

Another thought I had was - could a rover tow a massive lightweight PV array behind it? This might mean the batteries could be lighter.  A 200 sq. metre array might be mounted on a lightweight skin under which were attached rubberised balls to allow it to bounce off the rocks as the Rover progressed.

Other possibilities including using methane to power the vehicles.

I really like your staging idea.  As is this rover can already operate purely on it's solar cells but that means you have to go rather slow.  You could set up solar panel recharge areas and use the LRR to sprint to one of these staging areas, spend the whole next day recharging your batteries, then sprint again the next day to the next staging area.  The solar recharge area would have to have a pretty big array. 
My original idea of this rover design used a large flat panel solar array mounted on a frame above the rover that could be tilted to face the sun.  The idea was that all of your solar cells would get more direct sunlight and thus, make more power, but you would always have to worry about which way the panels were tilted and where the sun was while you were driving around hills and rock fields.  The main reason I got rid of the flat panel array on top of the vehicle was that I didn't think the mount/frame would survive the flight and landing without being seriously bent.   

This rover has a tow fitting on the rear for towing a cart that would be needed to move solar panels, food, water, and habitat building materials. 

The rocket that delivers you to the surface is not going to be the one that takes you home so you will need a way to drive over to the next rocket which would be 50-100 miles away.  This rover would be perfect for long range runs to pick up the latest supplies.

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#7 2016-09-30 18:22:41

Dook
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From: USA
Registered: 2004-01-09
Posts: 1,409

Re: Long Range Rover

Mars Cart

A four wheeled fiberglass cart that is 10' long and 5' wide with a flat bed that is 1" thick.  The bed of the Mars Cart is 3' above the ground.  The wheels are 2.75' tall, made of 1/4" thick aluminum alloy with solid rubber pads.  There are no axles for the wheels, each wheel mounts directly to the sides of the Mars Cart.  If you were looking at the fiberglass Mars Cart from the front without wheels it would look like an upside down "U".

The top of the bed of the Mars Cart is covered with solar cells that are beneath a 1/4" thick plastic panel that protects the solar cells from being damaged when the cart is being used to haul supplies.  When pulling the cart empty the solar panel wire can be plugged in to the Long Range Rover external charging point to help power the rover.  The carts 50 sq ft of solar panel should produce about 350 watts an hour on Mars. 

The wheels on the Mars Cart rotate freely, they can't be locked or steered.  There is no wheel brake and the wheels don't turn sideways.  The tow bar pivots to the left or right as the pulling vehicle turns, the cart follows. 

The Mars Cart tow bar is 4' long and made of thin, 1/8", tube of steel and it has a typical female hitch fitting on the front and another female hitch fitting on the back that fit onto hitch ball's mounted to the front of the Mars Cart and the hitch ball on the rear of the Long Range Rover and ATV's. 

The front hitch on the Mars Cart is thin steel plate, 1/8" thick, 1' wide and 10' long, that runs the length of the bed.  This plate has many small bolts that go completely through the fiberglass bed so the hitch can't rip off the front of the fiberglass cart. 

The Mars Cart should be able to move all Mars Habitat building components: solar panels, plants, food, pre-assembled wall sections, floor sections, and ceiling sections.  Water and plants could be moved during the daytime but they would have to be moved inside the Long Range Rover at night so they don't freeze on the exposed Mars Cart. 

I don't know if the cart would be able to carry the biggest RTG reactors.  They weigh about 1,000 lbs but that is earth weight, on Mars they would be half that.  The cart should be able to carry all the smaller RTG's and it should be able to move a full sized MOXIE unit as well depending on how heavy it ends up being.   

The cart also has a compartment built in to the underside of the bed that stows a cargo net and cargo straps.   



Mars%20Cart.jpg

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#8 2016-10-02 20:42:03

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 15,866

Re: Long Range Rover

Having the batteries inside the living space will require hydrogen gas monitoring when the batteries are in a charging condition for some of the battery types that might be used..

We have also talked about why if we are going RV'ing around mars that we would want all the crew to go in the same directon to allow for rescue by the others is a unit did have a problem.

Hopefully the trail will have experiments and beacons placed along the way to mark followup interests as we want more than just exploration to occur.

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#9 2016-10-02 22:05:59

Dook
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From: USA
Registered: 2004-01-09
Posts: 1,409

Re: Long Range Rover

SpaceNut wrote:

Having the batteries inside the living space will require hydrogen gas monitoring when the batteries are in a charging condition for some of the battery types that might be used..

We have also talked about why if we are going RV'ing around mars that we would want all the crew to go in the same directon to allow for rescue by the others is a unit did have a problem.

Hopefully the trail will have experiments and beacons placed along the way to mark followup interests as we want more than just exploration to occur.

I believe there are small hand held hydrogen detectors you can use.  The problem is how to vent the hydrogen from the rover without having to open the pressure doors and lose all of your oxygen.

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#10 2016-10-05 23:50:27

kbd512
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Posts: 2,902

Re: Long Range Rover

Dook wrote:

I believe there are small hand held hydrogen detectors you can use.  The problem is how to vent the hydrogen from the rover without having to open the pressure doors and lose all of your oxygen.

Why would you mount heavy, low energy density batteries in a pressurized compartment with a 100% oxygen atmosphere where electrical equipment is co-located?

Is there some reason for not using substantially lighter LFP batteries and mounting them somewhere outside of the pressure vessel?

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#11 2016-10-06 12:44:20

Dook
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From: USA
Registered: 2004-01-09
Posts: 1,409

Re: Long Range Rover

kbd512 wrote:
Dook wrote:

I believe there are small hand held hydrogen detectors you can use.  The problem is how to vent the hydrogen from the rover without having to open the pressure doors and lose all of your oxygen.

Why would you mount heavy, low energy density batteries in a pressurized compartment with a 100% oxygen atmosphere where electrical equipment is co-located?

Is there some reason for not using substantially lighter LFP batteries and mounting them somewhere outside of the pressure vessel?

That's a good point.  The main reason for keeping them inside is to prevent them from freezing but they don't have to actually be in the main compartment.  They could be under the floor and have the floor panels sealed and the under floor could be vented to release the hydrogen. 

As for why didn't I use the lithium batteries?  Because the lithium batteries have a tendency to set themselves on fire. 

As for the batteries being heavy, this Long Range Rover meets the weight requirements set by Zubrin in Mars Direct, well, it's 18 lbs over but that should be acceptable.

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#12 2016-10-06 14:48:14

kbd512
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Posts: 2,902

Re: Long Range Rover

Dook wrote:

That's a good point.  The main reason for keeping them inside is to prevent them from freezing but they don't have to actually be in the main compartment.  They could be under the floor and have the floor panels sealed and the under floor could be vented to release the hydrogen.

In actual NASA rovers that have been sent to Mars, small radioactive heat sources are used to keep electronics and batteries warm.  You insulate the "warm box" and place the heat source inside the warm box with the electronics and/or batteries.  It's worked pretty well for Spirit and Opportunity.

Dook wrote:

As for why didn't I use the lithium batteries?  Because the lithium batteries have a tendency to set themselves on fire.

That can happen and it has happened.  However, anything that generates hydrogen and electricity in a pure oxygen atmosphere is asking for trouble.  Short circuiting electrical equipment and a pure oxygen atmosphere killed the first Apollo crew on the pad and that happened without any hydrogen gas involved.  An explosion in a Mars rover would almost certainly be a lethal event, even if the astronauts were wearing their suits.

Dook wrote:

As for the batteries being heavy, this Long Range Rover meets the weight requirements set by Zubrin in Mars Direct, well, it's 18 lbs over but that should be acceptable.

I was trying to suggest that you could get substantially better energy density, and thus store more power for those cold Martian nights, from a more suitable battery chemistry.  LFP's are pretty well proven technology at this point and could substantially lower the associated weight.

The new graphene polymer batteries going into commercial production for EV's late this year or earlier next year can store substantially more power than the best commercial lithium batteries.  We're talking 1kW/kg.  No memory effect, no reactive metals, and a much lower risk of "thermal events" as GM is fond of calling them.

A lighter rover can carry more of whatever you feel is lacking.  You're going to want to avoid metal parts in the vehicle, to the extent possible.  You're going to receive a moderate does from GCR's on the surface of Mars and when fast moving ions strike metals they typically produce a shower of secondary radioactive particles that can be more damaging to humans than simply being struck by the ion.

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#13 2016-10-06 19:07:34

Dook
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Registered: 2004-01-09
Posts: 1,409

Re: Long Range Rover

kbd512 wrote:
Dook wrote:

That's a good point.  The main reason for keeping them inside is to prevent them from freezing but they don't have to actually be in the main compartment.  They could be under the floor and have the floor panels sealed and the under floor could be vented to release the hydrogen.

In actual NASA rovers that have been sent to Mars, small radioactive heat sources are used to keep electronics and batteries warm.  You insulate the "warm box" and place the heat source inside the warm box with the electronics and/or batteries.  It's worked pretty well for Spirit and Opportunity.

Dook wrote:

As for why didn't I use the lithium batteries?  Because the lithium batteries have a tendency to set themselves on fire.

That can happen and it has happened.  However, anything that generates hydrogen and electricity in a pure oxygen atmosphere is asking for trouble.  Short circuiting electrical equipment and a pure oxygen atmosphere killed the first Apollo crew on the pad and that happened without any hydrogen gas involved.  An explosion in a Mars rover would almost certainly be a lethal event, even if the astronauts were wearing their suits.

Dook wrote:

As for the batteries being heavy, this Long Range Rover meets the weight requirements set by Zubrin in Mars Direct, well, it's 18 lbs over but that should be acceptable.

I was trying to suggest that you could get substantially better energy density, and thus store more power for those cold Martian nights, from a more suitable battery chemistry.  LFP's are pretty well proven technology at this point and could substantially lower the associated weight.

The new graphene polymer batteries going into commercial production for EV's late this year or earlier next year can store substantially more power than the best commercial lithium batteries.  We're talking 1kW/kg.  No memory effect, no reactive metals, and a much lower risk of "thermal events" as GM is fond of calling them.

A lighter rover can carry more of whatever you feel is lacking.  You're going to want to avoid metal parts in the vehicle, to the extent possible.  You're going to receive a moderate does from GCR's on the surface of Mars and when fast moving ions strike metals they typically produce a shower of secondary radioactive particles that can be more damaging to humans than simply being struck by the ion.

When better batteries become available then I'm all for using them. 

As for the weight, the vehicle might actually be getting too light.  It's launch weight is going to be 2,816 lbs on the Earth but on Mars it will weigh half that.  Spread out between four wheels that's 352 Mars lbs per wheel. 

The main reason for not using metal construction was to save weight and prevent heat loss.  As it is the vehicle may get too warm in the day time, the motors are outside of the cabin so they don't heat the inside but still.

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#14 2016-10-31 14:05:58

Dook
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Re: Long Range Rover

The lowest wattage battery pad warmer I found was 60 watts, that's 1,440 watts a day.  That will drain a battery in ten days.  So, for the trip to Mars the Long Range Rover's battery warmers would have to get power from the Mars Hab to keep them from freezing in space. 

On Mars there's no way you could power a rover with solar if you have to have battery warmers on constantly.  Maybe if there were two warmer pads under each battery, a 60 watt warmer pad for space and then a small 5 watt one, just enough to keep some heat in them on Mars?

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#15 2016-12-26 19:47:25

Lake Matthew Team - Cole
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Registered: 2016-12-21
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Re: Long Range Rover

Plastic Panels

kbd512 wrote:

You're going to want to avoid metal parts in the vehicle, to the extent possible.  You're going to receive a moderate does from GCR's on the surface of Mars and when fast moving ions strike metals they typically produce a shower of secondary radioactive particles that can be more damaging to humans than simply being struck by the ion.

Good point.  Thinking along those lines, cryogenic plastic could be an important shielding material, and in situ manufacture could be an important industry.  If, say, rover body and supplemental shielding (2m+) could be fashioned from ISRU plastic, the cargo mass required for rover delivery would be significantly reduced. 

DuPont Vespel is an interesting example plastic, with many good cryogenic properties.  However the manufacturing process might be too energy-intensive or too complex to implement, especially if all Vespel precursor molecules (dianhydride, diamine, etc.) must be manufactured from very simple in situ feedstock.  I'm wondering if other cryogenic plastics would be easier to manufacture. 

Option:  If sand and/or fines are abundant near the manufacturing site, then less plastic is required for rover shielding.  Rationale:  If plastic is used not as thick shielding, but only as encasement for the sand, then a modular sand-and-plastic shielding system could be devised.  This would require only a thin layer of ISRU plastic to form each modular block, via injection mold.

Last edited by Lake Matthew Team - Cole (2016-12-26 20:09:36)

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#16 2017-01-11 12:23:19

elderflower
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Registered: 2016-06-19
Posts: 1,096

Re: Long Range Rover

Here's a thought:
The rover metallic tyres are subject to rapid damage. If we could use "rubber" tyres, a bit like earth rough terrain vehicles, they would be less subject to damage. It is my understanding that these cannot be used as the temperatures on Mars get well below the allowable temperature for any candidate tyre material.
Tyres could be heated but the bit in contact with the very cold ground would not get warm enough using radiant heat or perhaps inductive heating of the wheels. But tyres could be self heating by compounding the rubber for them with a radioisotope. I would suggest a long half life alpha emitter.

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#17 2017-01-11 12:53:43

Oldfart1939
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Registered: 2016-11-26
Posts: 1,652

Re: Long Range Rover

A possible material for a Mars rover construction is ABS. The properties can be varied through the amount of the butadiene rubber included in the formulation, but this is a "plastic" I've suggested this for a lot of Mars construction, also for an in situ manufacturing project.

I'd also suggest as does Robert Zubrin, thinking about using an internal combustion engine running on methane and oxygen. That would alleviate the battery hydrogen issue entirely.

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#18 2017-01-12 04:33:06

elderflower
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Registered: 2016-06-19
Posts: 1,096

Re: Long Range Rover

Compounding and injection moulding require very large machines consuming a lot of power and operating at very high pressures. These are used for large batches of products employing expensive moulds with powerful hydraulic clamps, ejector pins, cooling channels etc. Not suitable for Mars.
We need reinforceable resins that will set without high pressure. These can be used for casting and moulding by hand, and moulds can be light as they won't get used many times. To join moulded parts we need also some kind of elastic material such as silicones or polyurethanes.
Because of the short shelf life of these materials, shipping them from earth is not likely to be practical so ISRU will be necessary to prepare them.

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#19 2017-01-12 09:56:34

Oldfart1939
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Registered: 2016-11-26
Posts: 1,652

Re: Long Range Rover

I suspect that the first rovers will be shipped complete from Earth, that way they can be made from  appropriate materials. I also would venture to say they'll be pretty small and have limited seating capacity, on the order of a Polaris Ranger; maybe 2 or maximally 4 seats. All of the enclosure could be of carbon fiber reinforced polymer (type to be determined) but all the running gear (engine or electric motor, transmission, axles, etc.) will be metal. The ISS is mostly constructed from metals, so the scattered radiation from GCR is not really a big issue. On Mars, we'll be able to somewhat attenuate the exposure due to the atmosphere, but never eliminate entirely.

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#20 2017-01-13 08:18:40

elderflower
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Re: Long Range Rover

We could probably use Mars dust mixed with a little resin applied over the roof as an effective shield.

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#21 2017-01-13 23:24:52

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 15,866

Re: Long Range Rover

It looks like we could use some help from an unusual source as The Surprisingly Modern Tech inside an Amish Horse-Drawn Buggy
They have learned to not count of high tech but on how to impliment its use...

Amish aren’t against technology. Communities adopt new gadgets such as fax machines and business-use cellphones all the time—as long as the local church approves each one ahead of time, determining that it won’t drastically change their way of life.

Which means they still carry with them that hard working ethic and frontiers aditude.

I think all will enjoy as we are really starting mars at a simular place as we can not dump a world of resources onto Mars just to make it easy.....

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#22 2017-01-31 23:43:50

Dook
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Registered: 2004-01-09
Posts: 1,409

Re: Long Range Rover

Replies to the above:

The wheels are aluminum alloy with solid rubber treads, not metallic tires. 

The vehicle will normally be operated during the day, when it's warmer on Mars, up to 70 degrees F, not at night except in an emergency.  The aluminum alloy wheels with solid rubber treads will be fine. 

Could you use ABS plastic for a rover construction?  Sure, why would you?  A carbon composite tube is just as light weight and much, much stronger than ABS.  This would allow the Long Range Rover to be carried underneath the Mars lander, in between the landing legs, instead of having a Mars lander with a built in hanger.

An internal combustion combustion engine that uses methane/oxygen could be used instead of batteries?  On the Earth it could, on Mars it can't.  A very small internal combustion engine, lets say a 30 cu in (17 hp) lawn mower motor, uses 30 cu in of oxygen each cycle, each round.  At 3,000 rounds per minute (RPM) that is 90,000 cu in of oxygen used per minute.  Whatever oxygen tank you tried to carry with you would run out in a few minutes.   
     
Someone suggested using Mars dust mixed with resin to put on the roof of a rover as a shield.  Where are the solar cells going to go then?

The first rovers shipped from the Earth will be small?  I doubt it.  It depends on how close NASA thinks it can get the Mars Lander to the ISRU Earth Ascent Vehicle.  In Mars Direct the estimates for each successive landing were 400-800 kilometers from each other.  With SpaceX manuevering rocket lander the distance could be reduced but still there are many variables with high speed aerobreaking that it's still going to be over the horizon and perhaps 100's of miles away.

Last edited by Dook (2017-01-31 23:45:11)

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#23 2017-02-01 00:09:08

Oldfart1939
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Registered: 2016-11-26
Posts: 1,652

Re: Long Range Rover

My suggestion, re: power source for the rover did not depend on gaseous oxygen, but a tank of LOX. An engine powered by the tanks of LOX and LCH4 could go a long way. Those fuels are already postulated for production to facilitate the Earth Return.

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#24 2017-02-01 07:02:05

elderflower
Member
Registered: 2016-06-19
Posts: 1,096

Re: Long Range Rover

Dook, Only about 70% of the nominal  displacement of a normal reciprocating engine is ingested. This is due to failure to totally clear the exhaust gases and to pressure losses in the inlet and exhaust systems. Of this 70% only about 23% is actually O2. The balance is N2 and a bit of Ar.
To replace the Nitrogen/Argon buffer gas an engine on Mars would probably use atmospheric CO2. You definitely need some buffer gas as the combustion temperature using LOX and CH4 is far too high for this type of engine.
Torpedoes have been driven by peroxide and fuel for many years. Most have given up on this mixture due to unscheduled disassembly events with disastrous consequences, but it might be possible to develop a safer system. This would allow use of a storable oxidiser which could be prepared on Mars.
Peroxide can be a monopropellant or can be used with fuel eg methanol, which can be made from synthesis gas quite easily and is also storable.
Peroxide needs stabiliser addition and that would have to be shipped from earth. Some tin compounds are generally used.

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#25 2017-02-01 08:11:16

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Long Range Rover

SpaceNut wrote:

It looks like we could use some help from an unusual source as The Surprisingly Modern Tech inside an Amish Horse-Drawn Buggy
They have learned to not count of high tech but on how to impliment its use...

Amish aren’t against technology. Communities adopt new gadgets such as fax machines and business-use cellphones all the time—as long as the local church approves each one ahead of time, determining that it won’t drastically change their way of life.

Which means they still carry with them that hard working ethic and frontiers aditude.

I think all will enjoy as we are really starting mars at a simular place as we can not dump a world of resources onto Mars just to make it easy.....

They would have to develop a spacesuit for the horse. Can you imagine how difficult it would be to get a horse in a space suit, then the space suit would have to be cleaned after the horse poops and pees in it! And just how do you transport a horse to Mars anyway? The spacesuit designed to keep the horse alive on Mars so it can pull a cart, is very modern tech indeed! In fact its so modern than it hasn't been invented yet! NASA hasn't done any work on horse spacesuits, there aren't even any prototypes!

Last edited by Tom Kalbfus (2017-02-01 08:11:49)

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