New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: We've recently made changes to our user database and have removed inactive and spam users. If you can not login, please re-register.

#1 2017-04-19 16:53:50

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,479

Trail roads on Mars

Once we have established our first base on Mars, I think clearing roads for rovers is a major objective if we are to make full use of the planet's resources.

1. Initial exploratory survey work will be undertaken by rugged Rovers with full off road suspension working in teams of maybe 3. They will need to haul fuel or PV panelling with them as they go.

2. Once routes are designated, the trail roads can be cleared by especially adapted Rovers with (smallish) bulldozer blades.  These Road Rovers will move pebbles, stones, rocks and small boulders to either side of the designated trail.  Areas where sand accumulates will be avoided, as will of course any areas where the surface is not solid and stable.

3. Robot haulage rovers (carrying water ice, basalt, iron or other ores) will be able to travel these roads using onboard self-drive computers that keep them on the smooth surface avoiding the rocky sides and which monitor orientation to the sun. Where there are very flat landscapes,  rocks may need to be placed either side of the trail to mark it.  Automatic transponders placed every couple of kms will provide an added safeguarded that the Rover stays on the designated route.  Any rover failing to "check in" with these transponders will automatically come to a halt and await human intervention. 

4.  As the trail roads become longer, stopping stations will need to be put in place serving both robot rovers and their human-passenger equivalents.  The stopping stations will provide: electric power from PV powered batteries; fresh fuel (e.g. methane), food and water. Some may evolve into proper rest stops humans - pressurised habs where they can stop and stretch their legs.

5.  For a base in Chryse Planitia we would want to develop roads to the south, to Valles Marineris and west to Mount Olympus.  South East to the Hellas Basin and North East to  Deuteronilus Mensae (at about 42 degrees north and about 25 degrees east) where large water glaciers have been identified.


Any thoughts?  Particularly about navigation on Mars.

Last edited by louis (2017-04-19 16:59:43)


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

Offline

#2 2017-04-19 17:48:49

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

Re: Trail roads on Mars

louis wrote:

Once we have established our first base on Mars, I think clearing roads for rovers is a major objective if we are to make full use of the planet's resources.

1. Initial exploratory survey work will be undertaken by rugged Rovers with full off road suspension working in teams of maybe 3. They will need to haul fuel or PV panelling with them as they go.

2. Once routes are designated, the trail roads can be cleared by especially adapted Rovers with (smallish) bulldozer blades.  These Road Rovers will move pebbles, stones, rocks and small boulders to either side of the designated trail.  Areas where sand accumulates will be avoided, as will of course any areas where the surface is not solid and stable.

3. Robot haulage rovers (carrying water ice, basalt, iron or other ores) will be able to travel these roads using onboard self-drive computers that keep them on the smooth surface avoiding the rocky sides and which monitor orientation to the sun. Where there are very flat landscapes,  rocks may need to be placed either side of the trail to mark it.  Automatic transponders placed every couple of kms will provide an added safeguarded that the Rover stays on the designated route.  Any rover failing to "check in" with these transponders will automatically come to a halt and await human intervention. 

4.  As the trail roads become longer, stopping stations will need to be put in place serving both robot rovers and their human-passenger equivalents.  The stopping stations will provide: electric power from PV powered batteries; fresh fuel (e.g. methane), food and water. Some may evolve into proper rest stops humans - pressurised habs where they can stop and stretch their legs.

5.  For a base in Chryse Planitia we would want to develop roads to the south, to Valles Marineris and west to Mount Olympus.  South East to the Hellas Basin and North East to  Deuteronilus Mensae (at about 42 degrees north and about 25 degrees east) where large water glaciers have been identified.


Any thoughts?  Particularly about navigation on Mars.

Your rovers would be battery powered and recharged by connecting them into solar arrays or the base power supply. 

If the rovers were large enough, about 13 feet long, they could have their own thin solar array on top of them and operate for maybe one hour a day then recharge the rest of the day.

I like the idea of having two six foot long ATV dozers that would be operated by the crew, essentially ATV's with a blade on the front for pushing sand.  The ATV's would each have three large batteries and have to be plugged in to base power for recharging.  But they can't go far from the base.   

Having a large self driving rover is fine to go from one point to another over a well prepared road.  Having that autonomous rover do something complicated once it gets to the other place is a different story.   

Automatic transponders would need to have their batteries changed, I don't know how often.  Maybe they could be solar powered, I don't now. 

The self driving rover will be able to go for about an hour a day but if it did not have a crew it could potentially drive around the planet as long as there was no dust storm. 

Having recharge stations is fine but recharging batteries takes time.  Why have methane at the recharging station when it would have to be delivered there in the first place? 

Because you want to send things to the Earth that requires massive amounts of water so then you need futuristic technology and infrastructure devoted just to get that all the water.  If you just get rid of the idea of sending rockets to the Earth, suddenly, you don't need any water harvesting. 

How would I navigate on Mars?  NASA would generate a 3D map based upon the topographical information that we have of Mars.  So, all I would have to do is look at my laptop 3D map and compare it with what I see out the window of my rover.  If my laptop shows a recognizable hill in front of me and I look out the window and see that hill but it's to my left, then I know where I am.  It's not GPS precision but it doesn't have to be.

Last edited by Dook (2017-04-19 17:49:29)

Offline

#3 2017-04-19 18:07:03

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,479

Re: Trail roads on Mars

I am thinking a methane-oxygen system would probably be best for long haul rovers. So the methane-oxygen would be produced at the base and delivered to the stopping/fuel stations along the route by methane tankers, which would fill up the roadside tanks. Rovers would have automated attachments for refuelling.  I'm thinking that you'd probably want these tanks sited every 50-100kms en route.

The roadside chemical batteries would be used to recharge onboard batteries running lights and electronics.

Yes, I think cruise missiles fly by topography don't they? So that should be possible even in robot rovers.

There are modern recharging systems which can charge batteries very quickly.

Water will be required for a range of uses, not just making rocket fuel. Although 1000 km roads won't be a priority for the first few years, they will become important as we expand the population on Mars.




Dook wrote:

Your rovers would be battery powered and recharged by connecting them into solar arrays or the base power supply. 

If the rovers were large enough, about 13 feet long, they could have their own thin solar array on top of them and operate for maybe one hour a day then recharge the rest of the day.

I like the idea of having two six foot long ATV dozers that would be operated by the crew, essentially ATV's with a blade on the front for pushing sand.  The ATV's would each have three large batteries and have to be plugged in to base power for recharging.  But they can't go far from the base.   

Having a large self driving rover is fine to go from one point to another over a well prepared road.  Having that autonomous rover do something complicated once it gets to the other place is a different story.   

Automatic transponders would need to have their batteries changed, I don't know how often.  Maybe they could be solar powered, I don't now. 

The self driving rover will be able to go for about an hour a day but if it did not have a crew it could potentially drive around the planet as long as there was no dust storm. 

Having recharge stations is fine but recharging batteries takes time.  Why have methane at the recharging station when it would have to be delivered there in the first place? 

Because you want to send things to the Earth that requires massive amounts of water so then you need futuristic technology and infrastructure devoted just to get that all the water.  If you just get rid of the idea of sending rockets to the Earth, suddenly, you don't need any water harvesting. 

How would I navigate on Mars?  NASA would generate a 3D map based upon the topographical information that we have of Mars.  So, all I would have to do is look at my laptop 3D map and compare it with what I see out the window of my rover.  If my laptop shows a recognizable hill in front of me and I look out the window and see that hill but it's to my left, then I know where I am.  It's not GPS precision but it doesn't have to be.


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

Offline

#4 2017-04-19 18:45:03

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

Re: Trail roads on Mars

louis wrote:

louis

You prefer methane-oxygen powered rovers to solar power?  So, the solar powered rover needs nothing sent from the Earth and can operate forever on solar but you prefer methane-oxygen because, why?

Roadside batteries would recharge rover batteries?  Electric recharging takes a long time whether it's from another battery or from a solar panel or other power supply.

Cruise missiles most likely use GPS now.  In the past they probably used the same method that WW2 aircraft used for navigation, direct heading, go this direction at this speed for this long then turn this much and go this direction and speed for this long.  Using direct heading on Mars only sort of works.  It's fine for a very slow moving rover, not so good for anything going faster because rocks and small sand hills will move you off course.  If the .5 mph tiny rover gets off course for an hour it's not that big of a deal, a big rover going 10 mph ends up off a cliff.

Offline

#5 2017-04-20 02:11:57

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,479

Re: Trail roads on Mars

As I understand it, methane/oxygen has better energy density than a battery. These are going to be large Rovers maybe a tonne or more of structure. I've nothing against using electric power - just looking for the most practical solution for long haulage.

For onboard batteries, I would have thought we are talking no more than 15-30 mins...Ouput would probably only need to be around 5 kws (so maybe something like 50Kw Hours)...not the 40Kws of an electric vehicle of size.

(I expect cruise missiles still use topogrpahy because that's less vulnerable to disruption.)

I was thinking of running the rovers at about 15 MPH on the cleared roads.  I would have thought that if you had a "bump" sensor on board (I know such things exist, because that's how they check which parts of roads need mending around the UK) then as soon as the vehicle starts to experience bumps (ie has gone of road) it would automatically come to a halt and then perform a slow correction manouevre (e.g. slow reversing) until the bumps stopped and it could continue its journey.

With transponders every few kms, the rover could check it was travelling in the right direction. Not sure they would be necessary though.

Columbus used dead reckoning for his voyage didn't he?

Here's a nice link to (truly) driverless vehicles operating in Mars like conditions.

https://www.youtube.com/watch?v=7a6GrKqOxeU

Dook wrote:

You prefer methane-oxygen powered rovers to solar power?  So, the solar powered rover needs nothing sent from the Earth and can operate forever on solar but you prefer methane-oxygen because, why?

Roadside batteries would recharge rover batteries?  Electric recharging takes a long time whether it's from another battery or from a solar panel or other power supply.

Cruise missiles most likely use GPS now.  In the past they probably used the same method that WW2 aircraft used for navigation, direct heading, go this direction at this speed for this long then turn this much and go this direction and speed for this long.  Using direct heading on Mars only sort of works.  It's fine for a very slow moving rover, not so good for anything going faster because rocks and small sand hills will move you off course.  If the .5 mph tiny rover gets off course for an hour it's not that big of a deal, a big rover going 10 mph ends up off a cliff.

Last edited by louis (2017-04-20 03:24:33)


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

Offline

#6 2017-04-20 20:53:35

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

Re: Trail roads on Mars

louis wrote:

As I understand it, methane/oxygen has better energy density than a battery. These are going to be large Rovers maybe a tonne or more of structure. I've nothing against using electric power - just looking for the most practical solution for long haulage.

For onboard batteries, I would have thought we are talking no more than 15-30 mins...Ouput would probably only need to be around 5 kws (so maybe something like 50Kw Hours)...not the 40Kws of an electric vehicle of size.

(I expect cruise missiles still use topogrpahy because that's less vulnerable to disruption.)

I was thinking of running the rovers at about 15 MPH on the cleared roads.  I would have thought that if you had a "bump" sensor on board (I know such things exist, because that's how they check which parts of roads need mending around the UK) then as soon as the vehicle starts to experience bumps (ie has gone of road) it would automatically come to a halt and then perform a slow correction manouevre (e.g. slow reversing) until the bumps stopped and it could continue its journey.

With transponders every few kms, the rover could check it was travelling in the right direction. Not sure they would be necessary though.

Columbus used dead reckoning for his voyage didn't he?

Here's a nice link to (truly) driverless vehicles operating in Mars like conditions.

https://www.youtube.com/watch?v=7a6GrKqOxeU

Dook wrote:

You prefer methane-oxygen powered rovers to solar power?  So, the solar powered rover needs nothing sent from the Earth and can operate forever on solar but you prefer methane-oxygen because, why?

Roadside batteries would recharge rover batteries?  Electric recharging takes a long time whether it's from another battery or from a solar panel or other power supply.

Cruise missiles most likely use GPS now.  In the past they probably used the same method that WW2 aircraft used for navigation, direct heading, go this direction at this speed for this long then turn this much and go this direction and speed for this long.  Using direct heading on Mars only sort of works.  It's fine for a very slow moving rover, not so good for anything going faster because rocks and small sand hills will move you off course.  If the .5 mph tiny rover gets off course for an hour it's not that big of a deal, a big rover going 10 mph ends up off a cliff.

Just because methane/oxygen has more energy density than a battery doesn't mean it's a good fuel for a first settlement on Mars because you have to break apart water to get the hydrogen then combine the hydrogen with CO2.  On Mars, water is important as water. 

I know you think they are going to be getting large amounts of water from Mars, they're not because it's not going to be easy.  There is no good source of water unless you find pure ice near your base, that's it.  If you have to go far to get it that increases the risk.  Machines will break and we don't have machines that can go out and fix other machines.     

Electricity is free on Mars, solar arrays can be very thin and lightweight.  Solar power will work, even for a big sized rover, as long as you're not in too much of a hurry. 

As for using jamming to disrupt cruise missiles navigation, other than the US only a few countries of the world have any ability to jam anything and even then it's rather pitiful.

Transponders every few kms would guide a rover?  How are you going to replace the batteries in the transponders when they go dead once a week?

Columbus used dead reckoning for his voyage?  Dead reckoning was pretty much used until WW2.  You want people to depend on that for their lives now?  If a vehicle has a driver they can pick a point and drive towards it.  A robot using dead reckoning won't know which way to correct the wheel if a bump pushes them slightly off course.

Offline

#7 2017-04-21 04:46:26

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,479

Re: Trail roads on Mars

We are going to have to disagree about water Dook.  I think, based on the published evidence, it's a slam dunk either through soil extraction, atmospheric extraction or glacier mining.

I've nothing against PV Powered Rovers, except they would be v. small unless you had roadside charging, which would mean your roadside PV facilities had to be pretty large and your rovers would have to make frequent quite lengthy stops (because you would be charging up a big EV battery). I just think it's easier to manufacture the methane at base using PV power.

The transponders would be solar powered with a battery. 


Dook wrote:
louis wrote:

As I understand it, methane/oxygen has better energy density than a battery. These are going to be large Rovers maybe a tonne or more of structure. I've nothing against using electric power - just looking for the most practical solution for long haulage.

For onboard batteries, I would have thought we are talking no more than 15-30 mins...Ouput would probably only need to be around 5 kws (so maybe something like 50Kw Hours)...not the 40Kws of an electric vehicle of size.

(I expect cruise missiles still use topogrpahy because that's less vulnerable to disruption.)

I was thinking of running the rovers at about 15 MPH on the cleared roads.  I would have thought that if you had a "bump" sensor on board (I know such things exist, because that's how they check which parts of roads need mending around the UK) then as soon as the vehicle starts to experience bumps (ie has gone of road) it would automatically come to a halt and then perform a slow correction manouevre (e.g. slow reversing) until the bumps stopped and it could continue its journey.

With transponders every few kms, the rover could check it was travelling in the right direction. Not sure they would be necessary though.

Columbus used dead reckoning for his voyage didn't he?

Here's a nice link to (truly) driverless vehicles operating in Mars like conditions.

https://www.youtube.com/watch?v=7a6GrKqOxeU

Dook wrote:

You prefer methane-oxygen powered rovers to solar power?  So, the solar powered rover needs nothing sent from the Earth and can operate forever on solar but you prefer methane-oxygen because, why?

Roadside batteries would recharge rover batteries?  Electric recharging takes a long time whether it's from another battery or from a solar panel or other power supply.

Cruise missiles most likely use GPS now.  In the past they probably used the same method that WW2 aircraft used for navigation, direct heading, go this direction at this speed for this long then turn this much and go this direction and speed for this long.  Using direct heading on Mars only sort of works.  It's fine for a very slow moving rover, not so good for anything going faster because rocks and small sand hills will move you off course.  If the .5 mph tiny rover gets off course for an hour it's not that big of a deal, a big rover going 10 mph ends up off a cliff.

Just because methane/oxygen has more energy density than a battery doesn't mean it's a good fuel for a first settlement on Mars because you have to break apart water to get the hydrogen then combine the hydrogen with CO2.  On Mars, water is important as water. 

I know you think they are going to be getting large amounts of water from Mars, they're not because it's not going to be easy.  There is no good source of water unless you find pure ice near your base, that's it.  If you have to go far to get it that increases the risk.  Machines will break and we don't have machines that can go out and fix other machines.     

Electricity is free on Mars, solar arrays can be very thin and lightweight.  Solar power will work, even for a big sized rover, as long as you're not in too much of a hurry. 

As for using jamming to disrupt cruise missiles navigation, other than the US only a few countries of the world have any ability to jam anything and even then it's rather pitiful.

Transponders every few kms would guide a rover?  How are you going to replace the batteries in the transponders when they go dead once a week?

Columbus used dead reckoning for his voyage?  Dead reckoning was pretty much used until WW2.  You want people to depend on that for their lives now?  If a vehicle has a driver they can pick a point and drive towards it.  A robot using dead reckoning won't know which way to correct the wheel if a bump pushes them slightly off course.


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

Offline

#8 2017-04-21 07:57:12

Antius
Member
From: UK
Registered: 2007-05-22
Posts: 901

Re: Trail roads on Mars

Dook wrote:
louis wrote:

As I understand it, methane/oxygen has better energy density than a battery. These are going to be large Rovers maybe a tonne or more of structure. I've nothing against using electric power - just looking for the most practical solution for long haulage.

For onboard batteries, I would have thought we are talking no more than 15-30 mins...Ouput would probably only need to be around 5 kws (so maybe something like 50Kw Hours)...not the 40Kws of an electric vehicle of size.

(I expect cruise missiles still use topogrpahy because that's less vulnerable to disruption.)

I was thinking of running the rovers at about 15 MPH on the cleared roads.  I would have thought that if you had a "bump" sensor on board (I know such things exist, because that's how they check which parts of roads need mending around the UK) then as soon as the vehicle starts to experience bumps (ie has gone of road) it would automatically come to a halt and then perform a slow correction manouevre (e.g. slow reversing) until the bumps stopped and it could continue its journey.

With transponders every few kms, the rover could check it was travelling in the right direction. Not sure they would be necessary though.

Columbus used dead reckoning for his voyage didn't he?

Here's a nice link to (truly) driverless vehicles operating in Mars like conditions.

https://www.youtube.com/watch?v=7a6GrKqOxeU

Dook wrote:

You prefer methane-oxygen powered rovers to solar power?  So, the solar powered rover needs nothing sent from the Earth and can operate forever on solar but you prefer methane-oxygen because, why?

Roadside batteries would recharge rover batteries?  Electric recharging takes a long time whether it's from another battery or from a solar panel or other power supply.

Cruise missiles most likely use GPS now.  In the past they probably used the same method that WW2 aircraft used for navigation, direct heading, go this direction at this speed for this long then turn this much and go this direction and speed for this long.  Using direct heading on Mars only sort of works.  It's fine for a very slow moving rover, not so good for anything going faster because rocks and small sand hills will move you off course.  If the .5 mph tiny rover gets off course for an hour it's not that big of a deal, a big rover going 10 mph ends up off a cliff.

Just because methane/oxygen has more energy density than a battery doesn't mean it's a good fuel for a first settlement on Mars because you have to break apart water to get the hydrogen then combine the hydrogen with CO2.  On Mars, water is important as water. 

I know you think they are going to be getting large amounts of water from Mars, they're not because it's not going to be easy.  There is no good source of water unless you find pure ice near your base, that's it.  If you have to go far to get it that increases the risk.  Machines will break and we don't have machines that can go out and fix other machines.     

Electricity is free on Mars, solar arrays can be very thin and lightweight.  Solar power will work, even for a big sized rover, as long as you're not in too much of a hurry. 

As for using jamming to disrupt cruise missiles navigation, other than the US only a few countries of the world have any ability to jam anything and even then it's rather pitiful.

Transponders every few kms would guide a rover?  How are you going to replace the batteries in the transponders when they go dead once a week?

Columbus used dead reckoning for his voyage?  Dead reckoning was pretty much used until WW2.  You want people to depend on that for their lives now?  If a vehicle has a driver they can pick a point and drive towards it.  A robot using dead reckoning won't know which way to correct the wheel if a bump pushes them slightly off course.

I suspect the optimum system depends upon a lot of factors, not least how far you wish to transport things and how long you are prepared to wait.  On Mars, there isn't much traffic around.  You could unroll a PV sheet made from smaller rigid cells attached to a tough polymer backing, charge the rover and then roll it up again.

You would need 450kg of water to make 1000kg of bipropellant.  Much of that water may be recoverable for re-use from the vehicle exhaust.  For propellant manufacture we would also require Sabatier reactors and the power source required to power them would be substantially larger than that required to provide the equivalent required power for batteries - at least twice as large.  That may turn out to be a bigger issue than water.  I suspect that if a Mars base is so limited in water that it cannot make the propellants necessary for resource exploitation, then you built it in the wrong place.  Without abundant water, the capabilities of the base will be very limited and will not grow much with time.

Last edited by Antius (2017-04-21 08:18:19)

Offline

#9 2017-04-21 08:16:02

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,479

Re: Trail roads on Mars

The fallback position on water would be an atmospheric extractor. I posted about that recently. It was 885 Kg Mass, using 15 Kws (average constant power) for 45 Kgs of water per sol (at least in the northern hemisphere and in the summer).  So, 10 sols to get your quoted 450kgs of water. 

I'd certainly have one of those on Mission One.

One suggestion I have put forward before is to have your solar powered rover have a huge PV panel trailer behind it and a huge PV canopy above, to the side and infront (clear vision is not an issue with an robot rover) - maybe 1000 sq. metres in total. The articulated trailer (maybe a V shape would be best) would bounce along on supportive inflatable balls like plastic footballs. This could probably generate something like 40 KwEs at peak times.  Something like that might actually be more useful for initial exploration, since you wouldn't need to refuel it. 

Antius wrote:
Dook wrote:
louis wrote:

As I understand it, methane/oxygen has better energy density than a battery. These are going to be large Rovers maybe a tonne or more of structure. I've nothing against using electric power - just looking for the most practical solution for long haulage.

For onboard batteries, I would have thought we are talking no more than 15-30 mins...Ouput would probably only need to be around 5 kws (so maybe something like 50Kw Hours)...not the 40Kws of an electric vehicle of size.

(I expect cruise missiles still use topogrpahy because that's less vulnerable to disruption.)

I was thinking of running the rovers at about 15 MPH on the cleared roads.  I would have thought that if you had a "bump" sensor on board (I know such things exist, because that's how they check which parts of roads need mending around the UK) then as soon as the vehicle starts to experience bumps (ie has gone of road) it would automatically come to a halt and then perform a slow correction manouevre (e.g. slow reversing) until the bumps stopped and it could continue its journey.

With transponders every few kms, the rover could check it was travelling in the right direction. Not sure they would be necessary though.

Columbus used dead reckoning for his voyage didn't he?

Here's a nice link to (truly) driverless vehicles operating in Mars like conditions.

https://www.youtube.com/watch?v=7a6GrKqOxeU

Just because methane/oxygen has more energy density than a battery doesn't mean it's a good fuel for a first settlement on Mars because you have to break apart water to get the hydrogen then combine the hydrogen with CO2.  On Mars, water is important as water. 

I know you think they are going to be getting large amounts of water from Mars, they're not because it's not going to be easy.  There is no good source of water unless you find pure ice near your base, that's it.  If you have to go far to get it that increases the risk.  Machines will break and we don't have machines that can go out and fix other machines.     

Electricity is free on Mars, solar arrays can be very thin and lightweight.  Solar power will work, even for a big sized rover, as long as you're not in too much of a hurry. 

As for using jamming to disrupt cruise missiles navigation, other than the US only a few countries of the world have any ability to jam anything and even then it's rather pitiful.

Transponders every few kms would guide a rover?  How are you going to replace the batteries in the transponders when they go dead once a week?

Columbus used dead reckoning for his voyage?  Dead reckoning was pretty much used until WW2.  You want people to depend on that for their lives now?  If a vehicle has a driver they can pick a point and drive towards it.  A robot using dead reckoning won't know which way to correct the wheel if a bump pushes them slightly off course.

I suspect the optimum system depends upon a lot of factors, not least how far you wish to transport things and how long you are prepared to wait.  On Mars, there isn't much traffic around.  You could unroll a PV sheet made from smaller rigid cells attached to a tough polymer backing, charge the rover and then roll it up again.

You would need 450kg of water to make 1000kg of bipropellant.  Much of that water may be recoverable.  For propellant manufacture we would also require Sabatier reactors and the power source required to power them would be substantially larger than that required to provide the equivalent required power for batteries - at least twice as large.  That may turn out to be a bigger issue than water.  I suspect that if a Mars base is so limited in water that it cannot make the propellants necessary for resource exploitation, then you built it in the wrong place.  Without abundant water, the capabilities of the base will be very limited and will not grow much with time.


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

Offline

#10 2017-04-21 09:42:09

Oldfart1939
Member
Registered: 2016-11-26
Posts: 894

Re: Trail roads on Mars

Just for grins, you should be looking at some of the excellent 6 WD military vehicles, or even 8 WD vehicles. Pulling a trailer should be small task for these. It really began back in the mid 1950s with the British Saracen 6 WD armored personnel carrier chassis, and also the Saladin armored car design. They shared the identical chassis build by the British firm Alvis. These would be able to handle almost ANY terrain encountered outside of steep gullies and ravines. I choose to power these with methylox fuel, too. Reliance on PV in this application is simply too power intensive. Read your Zubrin!

Offline

#11 2017-04-21 09:49:03

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

Re: Trail roads on Mars

louis wrote:

louis

I'm all for atmospheric extraction of water because it's simple and you do it at the base, no methane powered robotic rovers needed. 

A PV powered rover would be small?  Who told you that?  I designed a long range rover that is 13 feet long and would carry a crew of two for Mars exploration.  Solar is the way to go because it's plentiful. 

Having recharging stations for batteries doesn't make sense because the rover would have it's own solar array on it, so it doesn't need recharging stations.  You're trying to make a settlement on Mars way more difficult and complicated than it already is. 

It's easier to manufacture methane at the base using PV power?  So, to you, it's easier to take your base water, use electricity to break it down with an electrolysis machine, separate the hydrogen and oxygen, combine the hydrogen and outside CO2 into methane, pump the methane into another tank, then fill the methane and oxygen tanks on a rover that has an internal combustion engine. 

That's easier than using a solar array and electric motors on each wheel?  The solar powered rover is only limited in range by the food and onboard oxygen carried.

How far can your methane/oxygen powered rover go before it has to be refueled?

The transponders would be solar powered with a battery?  Mars night time temperatures get down to -111 C, how are you going to prevent the transponder batteries from freezing?

Offline

#12 2017-04-21 10:42:00

Oldfart1939
Member
Registered: 2016-11-26
Posts: 894

Re: Trail roads on Mars

As with most complex and difficult problems, there is no single, simple solution. I happen to like Dook's proposal for atmospheric water extraction, and a parallel course during, but especially before, ground water/ice melting proposals. In the long run, it's only prudent to have several options, and a fall-back position should one of the proposals not pan out.

To address the question of "how far can a methane/LOX rover travel?" Read your Zubrin. He discusses that in exquisite detail in "Entering Space."

...how are you going to prevent the transponder batteries from freezing? Small RTUs. These are routinely utilized on all NASA deep space probes for this purpose.

Offline

#13 2017-04-21 10:46:24

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,479

Re: Trail roads on Mars

I agree about pursuing different options. The more options and back up the better, at least when it comes to the fundamentals like water, food, oxygen and even habitat.


Oldfart1939 wrote:

As with most complex and difficult problems, there is no single, simple solution. I happen to like Dook's proposal for atmospheric water extraction, and a parallel course during, but especially before, ground water/ice melting proposals. In the long run, it's only prudent to have several options, and a fall-back position should one of the proposals not pan out.

To address the question of "how far can a methane/LOX rover travel?" Read your Zubrin. He discusses that in exquisite detail in "Entering Space."

...how are you going to prevent the transponder batteries from freezing? Small RTUs. These are routinely utilized on all NASA deep space probes for this purpose.


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

Offline

#14 2017-04-22 06:03:47

elderflower
Member
Registered: 2016-06-19
Posts: 476

Re: Trail roads on Mars

Tyres have been a problem on the rovers. I posted somewhere an idea of compounding rubber tyres with longish half life alpha emitters to provide a little heat for them and thereby keep them flexible, or maybe to provide a separate heating component using the same kind of materials, in an annular ring inside regular cold weather tyres. Filling them with liquid radioactive material is not a good option as there would be a spill if a tyre burst.

Offline

#15 2017-04-22 10:26:55

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

Re: Trail roads on Mars

elderflower wrote:

Tyres have been a problem on the rovers. I posted somewhere an idea of compounding rubber tyres with longish half life alpha emitters to provide a little heat for them and thereby keep them flexible, or maybe to provide a separate heating component using the same kind of materials, in an annular ring inside regular cold weather tyres. Filling them with liquid radioactive material is not a good option as there would be a spill if a tyre burst.

Don't use rubber tires.  Use aluminum or carbon composite wheels shaped like the keyboard bracket symbol, [ , with rubber grip pads fixed to the outside bottom.

Offline

#16 2017-04-22 11:14:27

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 2,636
Website

Re: Trail roads on Mars

When you drag metal through rocks, eventually the rocks win.  The sharper the rocks,  the sooner they win.  No pure metal has decent mechanical properties,  they all have to be alloys. 

Those aluminum tires on Curiosity were a serious design mistake.  Aluminum does not have the toughness needed to keep the rocks from winning quickly.  Neither does titanium:  it has no ductility,  which means it's going to crack and shatter pretty quickly. 

The body of the wheel (or spokes) can be different,  but I think you need a steel rim as the tire.  Not one of the hard-but-brittle alloys,  something with a lot of strain capability for toughness.  Maybe a 300-series stainless steel.  It's quite good cold.

If you do rubber tires,  the sharp rocks are going to cut them,  even if you keep them warm to avoid embrittlement.  That's probably not what we want.   

I don't think I'd use an organic composite for the wheel body or spokes.  In the cold,  they'll get very brittle and fragile.  It's well below all known glass transition temperatures for polymers. 

I'd recommend stainless steel rim tires,  with tank tread lugs on them,  and curved spring steel spokes made like leaf springs.  That gets the suspension springiness needed for handling built into the wheels,  simplifyng the suspension design on the chassis.  This will work at low speeds (like 30 mph and slower),  but do NOT drive it faster:  you'll have an accident from inadequate handling.  If you break a lug,  you can easily weld another one on. 

GW

Last edited by GW Johnson (2017-04-22 11:22:08)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

Offline

#17 2017-04-23 05:15:09

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,479

Re: Trail roads on Mars

What about robust hydraulic "legs" fixed to a rotating disc-wheel.  Each leg would look a bit like a long hammer with the "foot" where the hammer head would be. The "feet" would be slightly curved, to meet the terrain nicely.  The hydraulic legs have natural suspension of course thanks to the hydraulics. At night the legs could be retracted into the disc and kept warm by internal heating. 6 legs to a wheel?

GW Johnson wrote:

When you drag metal through rocks, eventually the rocks win.  The sharper the rocks,  the sooner they win.  No pure metal has decent mechanical properties,  they all have to be alloys. 

Those aluminum tires on Curiosity were a serious design mistake.  Aluminum does not have the toughness needed to keep the rocks from winning quickly.  Neither does titanium:  it has no ductility,  which means it's going to crack and shatter pretty quickly. 

The body of the wheel (or spokes) can be different,  but I think you need a steel rim as the tire.  Not one of the hard-but-brittle alloys,  something with a lot of strain capability for toughness.  Maybe a 300-series stainless steel.  It's quite good cold.

If you do rubber tires,  the sharp rocks are going to cut them,  even if you keep them warm to avoid embrittlement.  That's probably not what we want.   

I don't think I'd use an organic composite for the wheel body or spokes.  In the cold,  they'll get very brittle and fragile.  It's well below all known glass transition temperatures for polymers. 

I'd recommend stainless steel rim tires,  with tank tread lugs on them,  and curved spring steel spokes made like leaf springs.  That gets the suspension springiness needed for handling built into the wheels,  simplifyng the suspension design on the chassis.  This will work at low speeds (like 30 mph and slower),  but do NOT drive it faster:  you'll have an accident from inadequate handling.  If you break a lug,  you can easily weld another one on. 

GW


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

Offline

#18 2017-04-23 10:17:07

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 2,636
Website

Re: Trail roads on Mars

I dunno about legged walkers,  regardless of what moves the legs.  Such a thing could go where wheeled vehicles cannot,  yes,  but the technology is still very immature. 

Wheeled rovers seem to have been working fairly well on Mars,  at least until some idiot put aluminum tires on a vehicle meant to traverse sharp rocks.  Wheeled rovers also seemed to work well on the moon for the astronauts,  and those wheels were very similar to what I described above. 

I think we ought to "dance with who brung us",  and just use what worked before.  Min development work that way.  Cheaper,  and ready-to-go sooner. 

GW

Last edited by GW Johnson (2017-04-23 10:17:37)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

Offline

#19 2017-04-23 10:44:58

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,479

Re: Trail roads on Mars

I was suggested legs on wheels (or discs if you prefer) so the wheel is rotated which turn brings the six legs on each wheel into contact with the ground successively, rather than Big Dog type legs (although Big Dog is v. impressive!). With 4 wheels there would be 26 in play and between 4 and 8 in contact with the terrain  at any one time depending on how rocky and uneven it was. The advantage I was suggesting is that they would have some direct give through the hydraulic system but would be very robust in terms of contact with the ground.

GW Johnson wrote:

I dunno about legged walkers,  regardless of what moves the legs.  Such a thing could go where wheeled vehicles cannot,  yes,  but the technology is still very immature. 

Wheeled rovers seem to have been working fairly well on Mars,  at least until some idiot put aluminum tires on a vehicle meant to traverse sharp rocks.  Wheeled rovers also seemed to work well on the moon for the astronauts,  and those wheels were very similar to what I described above. 

I think we ought to "dance with who brung us",  and just use what worked before.  Min development work that way.  Cheaper,  and ready-to-go sooner. 

GW


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

Offline

#20 2017-08-22 19:35:58

IanM
Member
From: Chicago
Registered: 2015-12-14
Posts: 149

Re: Trail roads on Mars

Regarding roads, paving costs vary based on one Google search I did. A 2000 study courtesy of the Ohio DOT gives, adjusted for inflation, $754,000/mile ($469,000/km) for a four-lane road including ramps, while another source claims that a mere two-lane undivided rural road can cost up to $2-3 million a mile ($1.25-1.875 million/km) to build anew. The Carroll County Department of Public Works gives a figure of $797,000/mile ($500,000/km) for the overall 25-year life cycle of a paved road, though most of this is in mid-life rehab rather than construction. This is of course assuming we want a conventional concrete-paved road (which we probably don't, at least initially, given the costs below).

Using Louis's example of Chryse Planitia as the origin, and Olympus Mons as the destination, eyeballing the map (admittedly rather cursorily) gives roughly 3,300 miles of road (5,300 km), which is roughly the distance to drive from Halifax to San Diego. Using Carroll County's figures gives $2,630,100,000 to pave and maintain the road over 25 Earth years. Assuming the population stays at 100 this means $1,052,040/person per Earth year. I don't know how much it would cost to get some rovers to clear some rocks, but it will most probably be a lot cheaper than this.

On another note, I think we should be like the Autobahn and not have any formal speed limits (outside of urban areas), but rather an advisory one of around 80 mph (130 km/h), although given the unpaved nature of these roads the limit would probably be lower. Even going 80 mph on my hypothetical Chryse-Olympian Highway would take 41 hours and 15 minutes of continuous driving to make it all the way through. Especially given that people need sleep, I think rest areas and hotels will be a necessity on this.


The Earth is the cradle of the mind, but one cannot live in a cradle forever. -Paraphrased from Tsiolkovsky

Offline

#21 2017-08-23 16:18:47

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 10,375

Re: Trail roads on Mars

Mars roads will initially be just less rubbled filled and smoothened out for quicker transport from place to place but being equivelant to a dirt road here on earth at its best. There will be no designing them with crushed stone and gravel beds for asphalt to be laid on top of....thats centuries away for sure.

Offline

#22 2017-08-24 04:03:59

louis
Member
From: UK
Registered: 2008-03-24
Posts: 2,479

Re: Trail roads on Mars

I agree SpaceNut - they will be like a combination of dirt road you find in deserts such as Sudan, SW USA and Australia and the ice roads of Canada and Alaska.  Laying proper "metalled" roads would be hugely costly in terms of resources and labour.

Curiosity clearly does often leave a "footprint". It may well be the case that some routes are not advisable because of accumulations of sand, or periodic flooding, or unstable ground. But I am confident routes can be found that will be able to take vehicles massing tonnes.

For one thing, speed is not really going to be an issue.  If humans need to travel several thousand miles, they will probably do it by rocket hopper. All vehicles apart from exploratory ones will be self-driving robot vehicles in my view.

One option might be to create real ice roads. Once we have located plentiful supplies of water, it might make sense to simply ice over the routes, so creating a smooth, durable surface for vehicles to travel on. This could be done robotically.  Robot constructors could lay down blocks of ice as foundation and then spray on layers of water on top. Regolith could be heaped up and compacted either side to provide added stability.

I think on the ice roads of North America very big trucks travel at about 40 mph. Maybe that would be the best solution. 


SpaceNut wrote:

Mars roads will initially be just less rubbled filled and smoothened out for quicker transport from place to place but being equivelant to a dirt road here on earth at its best. There will be no designing them with crushed stone and gravel beds for asphalt to be laid on top of....thats centuries away for sure.


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

Offline

Board footer

Powered by FluxBB