Pressurized Rover Designs - How far away are we?

Nirgal82 · 2002-08-12 09:36:43

Well, I've recently started a discussion in another topic regarding filling the "potholes" in Zubrin's Mars Direct plan, with the hopes of modifiying it to present to world space agencies...
One of the things that needs consideration is, of course, a long range pressurized rover that can act as a small movable hab for long sorties during the proposed 500 day stay...
How far is anyone in regard to actually building a working prototype using the fuels produced in-situ on Mars?
Anyone ever seen the DVD version of Aliens? (the second alien movie) In it there is a scene that I believe was deleted from the original movie of a small family, Mom Dad Son and Daughter, traveling in a Rover that looked like it could handle most terrains.
I can draw a bitmap of what it basically looks like and send it to you guys via e-mail (no website of my own to post it on) upon your request.
Perhaps something that looks remotely like it can be a good starting point, that is if all designs to this point are simply in the design phase...
As for the fuel used, how efficient is it? And, just blue skying here, could it eventually be used as an alternative fuel here on Earth or would it's wate products be just as toxic if not more than what current fuels produce here today?

Your friendly neighborhood Martian...
-Matt

Bill White · 2002-08-12 12:22:10

Matt

I have envisioned a rover powered by hydrogen fuel cells.

Wired Magazine had an article a month or two ago about recent advances in design where the chassis of a vehicle is built from the fuel cells themselves rather than adding fuel cells to an existing framework. In other words, build a giant skateboard using fuel cell plates as the material forming the board. Place crew quarters on top of the skateboard - which may be multiple boards and articulated.

As for the article - it appears GM is looking into selling fuel cell cars in China and India, in about 10-15 years, using the skateboard idea. Manufacturing costs will be 1/4 or 1/3 what they are for an American style auto. But this car will be mostly fiberglass and designed for survive collisions with little more than bicycles.

Anyway, as for Mars, I say add 4 or 6 or 8 wheels to a giant skateboard. Attach a pressurized habitat on top of the board. Power the wheels by electric motors with each wheel having independent suspension and an independent motor. No axles traverse the width of the rover. Being able to run with 7, 6 or 5 wheels instead of 8 would seem a critical safety measure.

Using microchips and widely variable suspensions for each wheel, computerized traction algorithms can be written to allow each wheel to grip in an optimal manner.

Fuel cells exhaust pure, drinkable H2O - this all gets captured and recycled. If you added a photocatalytic processor to the roof of the rover, sunlight could be used to crack the H2O back into H2 for an emergency fuel source as well as carrying significant supplies of stored materials able to furnish H2 to the cells.

Fuel cells use H2 to operate and Sabatier reactors use H2 to make rocket fuel. If a rover uses a fuel cell, there will be no need to carry a Sabatier for in situ fuel production, unless you also plan on carrying a nuclear reactor around with your rover.

Phobos · 2002-08-12 20:48:41

A long time ago I wrote a message about using fuel cells on Mars and Shaun and Byron brought up the point that you'll need a good power source for splitting the water into its constituents in order to get power out of a fuel cell. I'm no expert on fuel cells and probably misunderstood something, but how will you generate the energy for splitting the water? Would solar panels be up to the job? Maybe you could burn the methane fuel in an electric generator or charge the fuel cells with the nuclear reactor that powers the hab.

Bill White · 2002-08-12 20:58:56

Photocatalysts. Here is a blurb cut from from Nature, December 2001:

Water power - A new material helps to make clean fuel from water.
6 December 2001
PHILIP BALL
Hydrogen power could have a bright future.
? DOE/NREL
Scientists in Japan have found a more efficient way to extract hydrogen, the ultimate 'green' fuel, from water. They have developed a material that uses sunlight to break water molecules into their constituent elements of hydrogen and oxygen.
The material is not yet efficient enough to be commercially viable, but its inventors believe that it can be improved. If they are right, hydrogen may soon be on tap just like natural gas.
Hydrogen burns in air without producing the sooty pollution and greenhouse gases associated with fossil fuels. The element can also power fuel cells to generate electricity. Such fuel cells can power emission-free electric vehicles.
Unfortunately, water is reluctant to give up its hydrogen. Electricity can split water, but electricity is mainly generated using polluting and nonrenewable technology.
Several 'photocatalysts' will split water quite efficiently using ultraviolet light. But this squanders most of the Sun's energy, which lies in the visible range. Visible-light photocatalysts, on the other hand, have tended to be either unstable, decomposing with prolonged use, or bad at splitting water.
Zhigang Zou of the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan, and co-workers have developed a photocatalyst that seems to be very stable, showing no evidence of degradation after extended use. It is not terribly efficient - over 99% of the light energy is wasted rather than used to split water - but this is respectable when compared with the competition.
The material, like the majority of visible-light photocatalysts, is a metal oxide, which generates hydrogen and oxygen when immersed in water in sunlight. The oxide contains indium, nickel and tantalum; the efficiency depends on the amount of nickel in the material.
Zou and colleagues believe that they can improve the efficiency by increasing the surface area of the photocatalyst - making it porous, for example, or grinding it into a fine powder - and by further tinkering with the chemical composition.

Mix H20 with photocatalysts and set out in the sunlight.

Google "photocatalysts" and you will find more. . .

In any event, Phobos, you need free H2 to run the Sabatier so either way you need hydrogen.

turbo · 2002-08-13 08:47:51

You know Matt, I seem to remember that rover scene from Aliens. I wonder if something like it could be built out of plastics? So far, a mighty 486 processor chip has made it to space while the Pentiums stayed on Earth. That 486 was specially made to handle the stresses of launch though.

Last issue of NASA's TechBriefs I saw talked about fuel cells and how less power was needed to make hydrogen from methanol, but I'd hate to have to send the stuff to Mars. Any way to make small rovers that use methane fuel? How long to get corn grown for food and ethyl-alcohol fuel?

The first rovers may have to be small, simple, and have great shock absorbers. Maybe the Soviet idea of large solar panels to charge batteries will get things started.

"Okay Barney, it's your turn to go out there and wind the rover back up."

t

RobS · 2002-08-25 20:58:51

Fuel cells using methane have been developed and are rapidly improving. I think I found the information typing "fuel cell" and "methane" into Google. The cells still operate at rather high temperatures, but they are improving in efficiency.

Many hydrogen fuel cells come with devices that crack gasoline or natural gas (methane) into hydrogen and byproducts. The latter are expelled; the former used in the fuel cell. So one can fill a rover up with methane and run it through fuel cells, either directly or indirectly.

-- RobS

P.S.: By the way, I have found the multiple use of "rover" confusing; they can be little things like sojourner, unpressurized golf-cart sized things, or pressurized van-like things. For the latter, in a novel about exploring Mars that I once wrote, I coined the term "Mobilab," from mobile + lab. It seems to capture what the vehicle was.

Phobos · 2002-08-26 22:00:22

Many hydrogen fuel cells come with devices that crack gasoline or natural gas (methane) into hydrogen and byproducts. The latter are expelled; the former used in the fuel cell. So one can fill a rover up with methane and run it through fuel cells, either directly or indirectly.
-- RobS

I never thought about the possibilities of gasoline powered fuel cells. This might make a good environmental step in powering our cars since the infrastructure is there, but maybe not if we can't find a way to dump off the byproducts in an environmentally safe manner. Or maybe the byproducts could be used in some other way?

soph · 2002-12-16 19:16:45

from an article i read, you really dont need infrastructure for hydrogen fuel cell cars. in a prototype (which just needs to be scaled up-its been tested), a pure hydrogen oxygen fuel cell gets 800 miles to a tank, and hydrogen tanks are sold with the car. each tank lasts for about a month (assuming about two fills a month), and costs $20. my family spends about $100 a month driving, at a high guess, 500 miles.

best of all, the filling could be done at home.

Ares · 2003-01-16 07:35:08

Now if we could just get rid of Hydrogen's nasty tendancy to explode. I'd hate to store those extra H2 cylinders in my garage! :;):

soph · 2003-01-16 07:48:01

I dont think H2 explodes by itself. I remember hearing that the hindenberg accident, while exasperated by hydrogen fuel, was not caused by it.

Im sure these companies have also taken any risks into account, and have designed countermeasures.

Adrian · 2003-01-16 08:08:27

Soph: Yup, I heard that it was something to do with the Hindenberg's outer lining being coated with some flammable substance (not hydrogen).

Besides, throw a match into a tank of gasoline and it'll blow up just as well as a tank of hydrogen

Bill White · 2003-01-16 14:11:32

As for rovers, why re-invent the wheel?

I believe at least some of the R&D which went into designing the new US Marine AAAV would be quite valuable in designing a rugged Mars rover.

Supposedly this new vehicle will have a substantial and robust local area network as well as sensors for detecting bio-chem warfare agents, internal air supplies, and external cameras including infra-red and night vision. The communications suite can integrate with other vehicles to create a larger data sharing network composed of several vehicles.

Obviously we lose the armor and weapons, convert to all electric drive and probably switch from tracks to oversized wheels with independent drive and suspension for each wheel but thats just engineering, right?

Dave · 2003-01-17 00:15:10

Current thoery on the Hindenburg disaster centers around the substance used to "dope" the skin of the craft. The doping solution consisted of a mixture of Iron oxide, cellulose acetate and Aluminum powder. A kind of rocket propellant (a highly energetic substance).
Electrostatic activity between the cotton skin and the airframe was poorly managed in the airships design. Eventually it built up to massive amounts and ignited the skin...the rocket propellent did the rest.

In the news reals, notice how the flames burn quickly down and around the skin of the airship, in a sparkling fireworks type flame. Hydrogen gas alone would burn upwards and has a colorless flame.

Experts therefore believe that the Hydrogen fuel was not the cause of the disaster.

MarsGuy2012 · 2003-01-27 09:55:41

My main focus is on funding a Mars expedition. I don't know too much about the engineering side of things but what I do know is:
1. Hydrogen tends to be harder to store than methane or ethelyne. It's cryogenic storage temperature is the coldest.
2. Fuel cells and batteries are less efficient than internal combustion engines. For a given energy output the mass of a fuel cell is much higher than the mass of a combustion engine.

For these reasons I would stick with an internal combustion engine powered by methane or better yet ethelyne. On Mars this would be a perfectly environmentally friendly car since the exhaust is CO2.

Number04 · 2003-01-27 11:19:13

Internal combustion? You would need to store gas and O2. And for every littre of fuel, a car uses 1000 littres of air.

Why not just use rechargable batteries? They would have a limited range, but how far do you need to go?

soph · 2003-01-27 11:29:20

ive got an idea for a fuel cell that i might try to put together. if it actually can work, you wouldnt need much fuel at all.

colonist · 2003-02-16 23:53:10

Fuel cells need O2 just like any other combustion based system. One option that I have not see discussed here is a STEAM-based Hybred Electric system. A small MONOTUBE boiler is fed with methane and O2 to produce steam. This steam is fed to a DUAL_CYCLE STEAM ENGINE. The waste heat from the steam is extracted in a heat exhanger and used to heat the rover. The condensed water is fed back into the boiler for reuse. The boiler will have CATALYTIC COMPOUNDS plated directly onto the water tubes for more efficient combustion and the exaust outlet will be fitted with a SPRING LOADED COVER that will maintain an elevated pressure in the combustion chamber to facilitate heat transfer. The electric power from the generator would be stored in batteries to allow the boiler to be run intermitantly and, as a backup, the roof of the rover would have a solar cell array.

What do you guys think?

srmeaney · 2005-03-19 23:40:01

With a network of automated refueling stations about the Mars surface, a Mobile habitat comes into it's own.

Dook · 2005-03-20 17:48:16

That's like saying "If we already had the chicken then making an egg would be easy!"

srmeaney · 2005-03-24 02:04:09

No. I'm saying that "With a network of automated refueling stations about the Mars surface, a Mobile habitat comes into it's own."

We wouldn't need to drag an atmospheric processing plant around with us. We could stop off every hundred Kilometres and refuel. That cuts the mass of the mobile hab by half.
That in turn greatly reduces the energy used to move your mobile habitat. The less energy used, the more we can do between stops.

SpaceNut · 2005-03-24 08:26:41

Such a refuelling station has been previously mentioned for compressed Co2 or mars air. But one that makes other types of fuel might not be so practical unit it is a manned fill up station.

srmeaney · 2005-03-25 09:35:41

Youre just affraid to whip out the credit card at a BP station on mars to re-fuel. Especially so with the prospect of having all the numbers tell you it's fifty dollars a litre.

srmeaney · 2005-03-25 09:38:23

Humans went to Mars just to wind up living out of mobile homes.

Tom Kalbfus · 2006-08-22 12:19:48

A long time ago I wrote a message about using fuel cells on Mars and Shaun and Byron brought up the point that you'll need a good power source for splitting the water into its constituents in order to get power out of a fuel cell. I'm no expert on fuel cells and probably misunderstood something, but how will you generate the energy for splitting the water? Would solar panels be up to the job? Maybe you could burn the methane fuel in an electric generator or charge the fuel cells with the nuclear reactor that powers the hab.

Is there any reason why you can't have a Mars rover that is powered directly by a nuclear power plant? Why do you need to go through the intermediate step of having the nuclear power plant generate fuel? Nuclear fuel is much more compact and long lasting. Why not make a hab that is a Pressurized Mars Rover instead of having a seperate stationary hab? You could just leave the Earth Return Vehicle behind ready to be used.

Grypd · 2006-08-25 15:10:48

Tom it comes down to weight and sheer grunt. A fuel burning engine ways a lot less and promotes a lot more torque than that of a nuclear electric.

New Mars Forums

Announcement

#1 2002-08-12 09:36:43

Re: Pressurized Rover Designs - How far away are we?

#2 2002-08-12 12:22:10

Re: Pressurized Rover Designs - How far away are we?

#3 2002-08-12 20:48:41

Re: Pressurized Rover Designs - How far away are we?

#4 2002-08-12 20:58:56

Re: Pressurized Rover Designs - How far away are we?

#5 2002-08-13 08:47:51

Re: Pressurized Rover Designs - How far away are we?

#6 2002-08-25 20:58:51

Re: Pressurized Rover Designs - How far away are we?

#7 2002-08-26 22:00:22

Re: Pressurized Rover Designs - How far away are we?

#8 2002-12-16 19:16:45

Re: Pressurized Rover Designs - How far away are we?

#9 2003-01-16 07:35:08

Re: Pressurized Rover Designs - How far away are we?

#10 2003-01-16 07:48:01

Re: Pressurized Rover Designs - How far away are we?

#11 2003-01-16 08:08:27

Re: Pressurized Rover Designs - How far away are we?

#12 2003-01-16 14:11:32

Re: Pressurized Rover Designs - How far away are we?

#13 2003-01-17 00:15:10

Re: Pressurized Rover Designs - How far away are we?

#14 2003-01-27 09:55:41

Re: Pressurized Rover Designs - How far away are we?

#15 2003-01-27 11:19:13

Re: Pressurized Rover Designs - How far away are we?

#16 2003-01-27 11:29:20

Re: Pressurized Rover Designs - How far away are we?

#17 2003-02-16 23:53:10

Re: Pressurized Rover Designs - How far away are we?

#18 2005-03-19 23:40:01

Re: Pressurized Rover Designs - How far away are we?

#19 2005-03-20 17:48:16

Re: Pressurized Rover Designs - How far away are we?

#20 2005-03-24 02:04:09

Re: Pressurized Rover Designs - How far away are we?

#21 2005-03-24 08:26:41

Re: Pressurized Rover Designs - How far away are we?

#22 2005-03-25 09:35:41

Re: Pressurized Rover Designs - How far away are we?

#23 2005-03-25 09:38:23

Re: Pressurized Rover Designs - How far away are we?

#24 2006-08-22 12:19:48

Re: Pressurized Rover Designs - How far away are we?

#25 2006-08-25 15:10:48

Re: Pressurized Rover Designs - How far away are we?

Board footer