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#1 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2003-01-25 15:37:18
Hi.
Something you may want to think about in your rover adventure. Electrolysis for separating H2O is a energy demanding and slow process. It will however be one of the primary ways to leach hydrogen and oxygen out of the water ice on Mars for future Martians. For a balloon to support a scout mission for rover I would think it would be more economical to bring your own ready made fuel. You also must inflate it in a timely manner. Water ice if you dont know where it is on Mars you would have to transported to there anyway.
The gas that I would use is one of the following: Zubrins Methanol, Hydrogen, Helium or ammonia. A small amount of helium or hydrogen would be used to start the process I like the combination of two of them. Hydrogen to inflate a small amount of the balloon then the tank separates and falls to the surface and ammonia to finish it up. We have designed the shape of the balloon envelope to do this. The balloon envelope will have to be very thin to work on Mars. Pioneer Aeronautics R. Zubrin and JPL have done a good job testing methanol out at high altitudes. The balloon was made out of very thin black polyethylene. So we know it will work. The next trick is trying it with a much larger Balloon.
As I said before we have no doubt that the Windsurfer would work on Venus and Titan. We can make it out of more heavy-duty material for Venus and Titan. We will have to try harder to make it work on Mars. But we think that we can do it. Here is a sneak preview of another method we are looking into. 
#2 Re: Planetary transportation » Air Transportation on Mars - Gravity's affect on Air travel on Mars » 2003-01-05 20:53:38
Solar concentrators can concentrate light to a solar cell. The last I have read on them is they have limitation of 4 suns. The solar cell has a problem overheating if you go above that. Now if you are concentrating 4 times the light onto a solar cell but only using a small amount of the electromagnetic spectrum then the maximum up to this date you can count on is 30 percent efficiency. This is the amount of sunlight hitting a solar cell from a solar concentrator. Maybe this is what Dr Zubrin is alluding to. Most of the other light is wasted and scattered back out into space or transferred into heat energy. According to this new discovery they can increase the efficiency to 50 percent to even the maximum of 76 percent. If this proves to be affordable it will help transform the way we live on this planet and the way we travel and live within our inner solar system.
#3 Re: Planetary transportation » Air Transportation on Mars - Gravity's affect on Air travel on Mars » 2003-01-05 20:02:07
One problem in using solar cells on Mars Verses Earth is you have 1/2 the solar radiation hitting the solar cells on Mars then you do on Earth. Don?t forget the amount of dust in the Martian atmosphere will effect the amount of light falling on the planet. Your best solar cells can get only 30 percent efficiency. So you would have to scale it up to 2 times the surface area of what you would use in low Earth orbit. If you can increase the efficiency to 50 or 76 percent, the maximum allowed theoretically, by using the full electromagnetic spectrum of light hitting the solar cells, then you would have a powerful tool that you could use on solar powered flight on Mars. This also can be used to drive VASMIR, Ion engines etc. A research group at Berkley has just claimed to do that.
"A team led by Wladek Walukiewicz, working with researchers at Cornell University, and Ritsumeikan University, Japan, has discovered that, contrary to earlier reports, the band gaps of the In1-xGaxN ternary alloy system extend over a very wide energy range (0.7 eV to 3.4 eV) and thus provide a near-perfect match to the solar energy spectrum. This creates the opportunity to design and fabricate new multijunction solar cells that will have greatly improved efficiencies, possibly reaching the theoretically predicted ultimate efficiencies."
Here is the link.
solar cell discovery
#4 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2003-01-01 02:30:56
I bet that idea of using a sail might work great at a place like Titan. If Titan actually has oceans of liquid and strong winds it might be the first place we send an extraterrestrial sailboat
Thanks. Actually Titan and Venus was our first choice to use a probe like this. It could be modified to move in a liquid or on a solid surface. There isn't much sunlight on Titan so solar cells are out of the question. It could generate its own energy from the wind with the rover wheels moving on the surface. This is much like a bicycle wheel does with a generator.
We later thought about using this on Mars when we found out about a study at Ames to build wind turbines their. Wind sails use less wind speeds then wind turbines do. The balloon would have to be scaled up anyway because of the thin atmosphere. A balloon envelope of at least 30 to 40 M diameter would be required to explore Mars. A balloon of that size has a lot of surface area that can be pushed by the wind. The drag chute could easily be scaled up to accommodate the need for extra power to get it over the obstacles. The balloon and the drag chute would be tethered above the wind-sheltered areas on the surface. On Titan you could use a balloon with a diameter under 10 meters.
#5 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2003-01-01 02:27:32
Is the martian soil electrostatically charged ? If this is the case, what about using a pure electrostatic "levitation" over the charged soil.
I have also wondered about that. There were electrostatic levitation observations of the lunar dust by the Apollo astronauts on the moon.
#6 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2003-01-01 02:24:08
If that ice is extracted and melted, how would it react with the dust ? Can we expect some strong exothermic reaction ?
Then, the dust and the ice could be the base for a basic thermic martian engine...just speculations here.
I'm not sure how that would work. Maybe the Beagle and these new rovers will tell us more about the chemical makeup of Mars. It is an alien world so expect the unexpected.
#7 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2002-12-31 07:35:40
Below are some pictures I installed into a photo gallery.
The first picture shows the rover scaling a rocky hill full of rocks being pulled up from the force of the wind on the drag chute . The second and third on top was from using a (Jibe) windsail to move a rover in a 5-mph and a 7-mph wind. The bottom pictures are CAD 3-D rendered pictures of what it might look like on Mars, or Titan.
I tried posting it before in the first post and it didnt work. I'll try it again the same way you suggested. Thanks.
#8 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2002-12-29 21:48:31
The Windrover works on earth, right, but can you be certain that it would work on Mars with the reduced energy behiend the winds?
By the way, I reckon that windsurfing idea is quite cool. <!--emo&:D
neutrino
We have done some preliminary calculations on what it will take to make it work on Mars. We are confidence in our calculations however we are supplying them for peer review to verify our numbers. We are more than confidant this would work on Titan and Venus. Again thanks for your input.
I would like to post some pictures on here but what Im doing isnt working. Any ideas?
#9 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2002-12-26 20:22:25
I'm not knocking Zubrins idea. It?s a good one. To make methane using the CO2 in the atmosphere they would need hydrogen. To get the hydrogen they would have to extract it from the water ice on the surface of Mars. They can also ship it from Earth to Mars. To extract it from the water ice from the Martian surface will take energy. To rocket it there from Earth will take more energy. Everything has to be in place to make this all happen. When humans start exploring Mars this will probably be there first choice. But according to NASA humans aren't going to get there before 2022. What are we going to do in the meantime? The wind is constantly blowing on Mars. So why not sail across the Martian landscape as our ancestors did across the seas when they found the New World. They didn?t have nuclear or chemical rockets. The wind is there and it's free.
#10 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2002-12-26 19:32:26
soph
couldnt a rocketplane using a nuclear engine, or methane fuel (which could be made whenever it lands) provide more flexibility and speed?
Neutrino
How many nuclear rocket planes have they sent up into space? I do agree with building nuclear spaceplanes. It?s a very hard sell to even get one off the ground. They have been on the drawing board for over 40 years. Using Methane as combustable fuel for a chemical rocket will take a lot of resources to make it happen, the wind is free.
Auqakah
I have to point out that the 'dust' on Mars is in all likelihood far different to the dust on Earth. Firstly, its smaller. More like fines than dust. ("Its /fines/, not dust, how can you call it dust? Thats like calling a pebble a boulder!") Bet you all know where that quote is from
neutrino
Webster dictionary: Dust - Matter in the form of fine, dry particles.
neutrino
I am aware the dust particles are considered smaller on mars. Our humid atmosphere has a way of keeping the smaller dust particles out of our atmosphere. Does 2 or more atoms make a molecule, or 2 or more molecules make a fine, or two or more fines make dust-matter. If this is true then as little as 8 atoms could make dust-matter. That would make it weigh less than most fines. They haven't broken down the dust-matter on Mars to be sure what it is yet. So aren't we rushing things a bit by calling it a fine? When they start calling it a Martian fine storm then I will change my vocabulary.
Viking site was approximately 6.5 to 9.2 millabars. At the bottom of Hellas is extrapolated out to be 13 millabars. Earth's at sea level is 1013 millabars.
Where are those robotic planes going to get their lift? One of the proposed 4 scout missions that are still being considered by NASA uses a flying probe with wings. Mars winds varies from 10mph to 60 mph. Remember CO2 has 1 1/2 times the kinetic energy then O2 or N2 when traveling the same speed when it strikes an object. Why do they have to consider the wind velocity for landing a probe? What do you think they used to slow down the pathfinder with before it landed? A parachute. If as you have said that the atmosphere is to thin to have much pressure, then why did they ever consider using a parachute to slow down the pathfinder? Flying around in the upper atmosphere of Mars is great but where are you going to get most of your good data? That?s from roaming the surface of the planet. The Windsurfer will be able to do both.
Thanks soph / Auqakah for contributing to this discussion
#11 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2002-12-24 11:31:48
soph
but i really dont see it as being a replacement for conventional proposals. sorry if i seem to be harsh, im just offering my opinion
neutrino
No problem. That?s what a message board is all about. I've had much, much worse rejections. We are confident in what we are doing and have done many tests and were amazed at what we found out. This thing really works. The Windsurfer is a new devise that makes land sailing possible over all sorts of terrain. The pioneers that first set foot in the New World used the power of the wind to get them here and back. The wind is free and doesn?t need any elaborate set up or expensive equipment to make the Windsurfer operational. Like our founding fathers in the New World using the wind will help get us there. We can start exploring Mars more aggressively now. We made QuickTime movies that are available at our web site to show people how it works. We showed how easily climbed up a rocky cliff.
Echus_Chasma
Could'nt you use hydrogen for the balloons on Mars?, because there is only like 0.13% oxygen, I think, in Martian atmosphere, would'nt hydrogen react on Mars much less than as it does on Earth?
neutrino
There are several different ways to inflate a balloon with gas on Mars. There are some drawbacks to each method. Hydrogen is the lighter of the gases and the one that will give the most lift per volume. Helium is the second lightest and is the preferred lifting gas of today on earth because of the Hindenberg disaster. Although it has been proven that explosive hydrogen gas it used didn?t cause the raging fire. On Mars you wouldn?t have to worry about an explosive fire because there isn't enough oxygen in the atmosphere to cause it to combust. Dr Zubrin and Pioneer Astronautics demonstrated another method to inflate a Martian balloon. It uses solid Methanol when exposed to the sun caused it to vaporize and inflate the balloon. Methanol is easy to store because it is kept in a solid state before vaporizing. Helium and Hydrogen requires a pressurized tank. Pressurized tanks means more mass on the payload traveling to Mars, therefore more cost to get it there.
Another big advantage of having the Windsurfer is it could use a Zero pressure balloon and doesn?t need a superpressure balloon to be operational. It doesn?t need ballast because it is tethered to a rover therefore the balloon doesn?t need to be open to the atmosphere. It doesn?t ascend and descend during the daytime or nighttime. It will be pulling on the rover more during the daytime because of the solar heating of the gas inside reducing the weight on the rover by over 25 percent. At night there will be still enough lifting force in it to keep it and its drag chute, Windsurfing sail and some light instruments aloft. So there will be no need to vent the gas to the atmosphere to maintain altitude. In other words the rover will be its ballast. As a result the balloon could stay aloft for over a month. When the balloon finally falls to the surface the rover will have enough power to continue its research on the ground.
#12 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2002-12-22 21:11:46
Echus_Chasma
Thanks for responding.
Just one small thing, dunno how relevant it is too your post, but because the amount atmosphere on Mars is quite small does'nt that mean there is less power behiend the Martian winds, even though they are quite fast.
neutrino
The thin atmosphere on Mars is a concern however everything is relative and will be to scale. The balloon on Mars will have to be big because of the thin atmosphere. This depends on where you drop it. The bigger the balloon the more surface area it has that will be pushed by the wind. The drag chute can easily be scaled up or down depending on what is in-store for it.
We are in the process of modeling the Martian atmosphere and how it will effect the pressure on the balloon and the drag chute. The drag chute will be made out of lightweight heavy-duty material. Carbon fiber mesh is being considered for the drag chute. The drag chute in the picture at the arrow-space-innovations.com web site was made out of 50 in diameter umbrella stock that weighed 1.6 oz.. The balloon had 5 oz of lifting force left. The helium used was not pure so the 14 cu ft of gas for the 36 in balloon should lift about 14 oz. The rover weighed more than four times the force of balloons 5 oz lifting gas on it yet with the right sail configuration was pushed by a 5-mph wind.
We even plowed one of these into a bridge. The drag chute and balloon were above the bridge, the wind was strong enough on the drag chute to pull the rover up and over it and land it gently down on the other side.
How far are these new rovers they are sending to Mars going to go once they land? The landing zone will be most likely flat like the Viking and the Pathfinders were. They could miss their planned trajectory landing location by as much as over 50 miles when they land. If they can go only 200 yards what are they going to do?
The atmosphere is about 110 to 170 times less dense than Earth's is at sea level, at the Viking and pathfinders locations. Depends on when you take the atmospheric pressure readings.
Hellas crater basin that is 1500 miles in diameter has strong winds and overcast most of the time. This is the hardest place on Mars to get good pictures. At the bottom of Hellas if you use NASA s numbers, which was, extrapolated out to be about 13 millibars. This is the pressure you would encounter on Earth at approximately 85,000 /95,000 ft. We have sent balloons up to 140,000 ft that could lift over 3 tons. On Mars the same balloon could lift 7.5 tons. These were huge balloons but we wouldn?t have to lift a 7.5-ton rover. Therefore we wouldn't need as big a balloon. The balloon would have to lift only a fraction of the weight of the rover. The drag chute and the windsurfing sail and tether and small instruments would add some of the weight back that isn't used to lift the rover by the balloons lifting gas.
At Hellas you could use a balloon that has about 1/2 the volume of lifting gas than one that is at the Viking sites. 1/2 the volume of gas doesn?t mean that the balloon would be 1/2 the diameter. It will reduce the size of the balloon enough to lower the cost and help insure a successful insertion into the Martian atmosphere. Hellas, the northern plains area or deep down in Valles Marinais, is the best place on Mars to use a probe with a balloon like the Windsurfer. All three are good candidates for finding life on Mars, if life existed there.
Echus_Chasma
Sort-of like getting hit by a train at 50km compared to being in the rain with winds of 50km.
Neutrino
We tested these in wind speed above 60km per hour. How fast is the solar wind hitting a solar sail? Or how fast is light traveling when it hits a light sail?
Dont underestimate the power of the Martian wind. Mars has global dust storms that are carried by the wind. In a wind at the same speed and density CO2 gas has 1 1/2 times more kenetic energy then O2 or N2 gas does.
#13 Re: Planetary transportation » Revolutionary way to explore other worlds - A wind riding rover » 2002-12-20 01:03:27
Press release on 12-18-02
The Windsurfer
First initial test has been completed on a new wind-riding rover that will revolutionize the way we explore other atmospheric rich worlds
The Windsurfer is one of those new innovations that will enable humans to perform robotic missions on other worlds that have an atmosphere. The Windsurfer can land on the surface of these worlds after descent through the atmosphere with only the payload and instruments that it brings along. After landing it can be used to guide a rover to a location previously chosen with only the help of the wind. It can move over most terrain it may encounter which includes climbing up rocky mountains or down to the bottom of canyons or craters with the help of its balloon and drag chute. Once at the preferred location the rover can be commanded to detach from the Windsurfer and conduct its experiments.
There may be a need for the rover to stay attached to the Windsurfer. The wind surfing sail can be programmed to tack into the wind, this will keep the drag chute from opening and the rover would remain stationary. Then it would continue on its journey mapping the planet at birds eye view with cameras attached to the balloon and to the rover on the surface. When the rover gets to a canyon ridge and falls down into the canyon below, the drag chute will be activated to help bring it to a soft landing. When the rover is at the bottom of a canyon the drag chute will be activated by the wind in the unsheltered area far above it to help pull the rover out of the canyon. The rover tethered to the Windsurfer below will act like a ruder on a ship and help steer it into the direction chosen to explore.
It will generate its own power by the movements of the wheels over the terrain like a bicycle generator does. Its lights will be turned on at night and will run off the wheel-generator from the rover. At an average speed of 10 mph the Windsurfer can cover 240 miles per day. It has the potential to cover thousands of miles while operational. The Windsurfer will carry a solar cell backup generator. The balloon material may be made out of new supperpressure balloon technology that NASA is developing that can stay airborne for up to 300 days. If the supperpressure balloon material isn't available then there are several different types of other balloon material that can be used.
The balloon will be designed to naturally rotate in high winds. This will improve lift while reducing the stress on the balloon and the tethered rover. The drag chute will activate when the angle of the tether changes from vertical. If the rover is stopped by an obstruction then the balloon will be pushed by the wind and the angle of the tether will change enough to activate the drag chute. This would give it more force to get the rover over obstacles. In some cases with changing wind speeds the rover would jump from one place to another.
There will be several different missions that can use this new technology. The mission may be one of commercial importance to some movies and theme parks such as Universal Studios, Dream Works and Walt Disney. Part of the mission could be planned to extract movies of the planet by a rover or balloon moving over its surface. These movies can later be shown at theme parks around the world or be an actual part of footage of the planet in a motion picture. Another goal is to bring some of the shots of the rover in real time to a worldwide audience over the Internet. The advertisers will broadcast it at their web locations for public viewing. All the information gathered will be available to the world's scientific community.
The team to insure the success of this adventure will be from some of the top aerospace engineers around the world. NASA, ESA and other nations Space programs will be contracted for the use of some of their facilities.
Quicktime movies of some of our first tests are at our website at arrow-space-innovations.com
If you go to the web page click on the Windsurfer Home page and it will direct you to where you may want to go.
Here is a photo gallery of some of the first test we did. The first picture is a rover climbing a rocky cliff with the help of the wind blowing on the drag chute. It did it many times that day.
Arrow Space Innovations
Web Page arrow-space-innovations.com
http://arrow-space-innovations.com]Arrow Space Innovations
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