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i`d say a direct drive system like the old kid`s big wheel.
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From:
http://www.newmars.com/forums/viewtopic … ...;st=150
Mountain Biking On Olympus Mon
Poised ontop of ancient fire,
Wrapped in elastics tighter then I desire.
I lift my bike with my hand,
I Prepare to descend down extraterrestrial land,
Down I go with barley any grade,
No wind but no oil on my chain.
Thou sand and gravel bellow my feet
My bike is light and barley sinks,
My legs are strong, the gears are high,
When I hit a lip a really fly,
Riding faster I begin to see the,
a cloud of red ahead of me.
Blazing dust burns my face,
Well, boulders appear in front
Of me with little trace.
Fearless I continue my decent
In the face of wind that wont relent,
The dust begins to thicken and my
Bike begins to slow, I don’t know
How much further I can really go.
My speed begins to drop as the wind
Begins to push, my legs begin to
Burn from my calf up to my touch.
I check me gear and it says I can take
A right if I need a warm place to
Stay the night. Not much further,
And I can rest Althogh it is not the
Bottom I know that this is best,
Off my bike I step into the hab
I good nights sleep, will really
Make me glad.
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On earth, by creating dual front and rear wheels, riders in th Iditabike can ride through snow, which presents similar problems to sand.
That sounds like a fun bike. How does the chain attach to the front weels. Is it difficult to turn? Does anyone have any pictures?
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excellent, john. im`m wondering would it be better for legs to be encased or exposed?
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excellent, john. im`m wondering would it be better for legs to be encased or exposed?
That obviously depends on what kind of suite you have. If you a pneumatic power suite I discribe in the thread:
http://www.newmars.com/forums/viewtopic … ...23;t=52
Then let them be exposed. Of course in that case why use a bike in the first place. I think on the moon the bikes should work really well because they would be so light. If you were strapped to the seat imagine what kind of gear ratio you could use. You would literally fly.
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i mean not completely exposed to the martian atmosphere obviously, but let`s say a suited marscrew riding trike or the whole thing encapsulated. it would seem that a pedaling marscrew wearing a suit while inside an eclosed trike would get somewhat redundant. so it would seem one or other would be better.
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I think it will be difficult to transfer the torque from an airtight compartment to the wheel. Any mechanical method would be prone to extra where and tear or friction. Any electromechanically method would add extra weight. Transportation on mars is interesting. Transportation on the moon is real interesting since it is so efficient. I once herd the lunar rover could be powered by a nine volt battery. Of course I don't know how big a nine volt battery. It would probably need one bigger then a walkie talkie. Anyway, I can't wait for radio isotope batteries.
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Hmmm, one mechanical suit for a preasured bike would be for a chain to derive an external set of legs which then drives an external bike. It would look kind of funny.
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72.74 mph is the current world land speed for human powered vehicle.
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72.74 mph is the current world land speed for human powered vehicle.
Maybe on flat ground. Ever watch Warren Miller Television. On one show he showed some footage of speed skiing. People also went down the same runs on snowboards and mountain bikes. They are going so fast that when they fall they burn a whole through there suite. They have special aerodynamic suits that allow them to go a fare amount faster then terminal velocity. At least the skiers go faster. I am not sure about the mountain bikers and snowboarders. A skier has a much better aerodynamic shape.
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72.74 mph is the current world land speed for human powered vehicle.
Well I suspect that recored will be broken on the moon.
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ya i`ve seen it, been a long time tho. at the moment i only get, tbs, tnt, usa, wgn, in addition to "regular" tv. i remember the skiiers have a deal where their chests rest on their knees, holding them rigidly that way in a hardshelled pod.
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i think the problem of going from the suit to the wheels isn`t really a problem. marscrew could breathe the air in the wheels. i remember seeing a device like this once. i believe it was a hose reel, or a windable extension cord.
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On earth, by creating dual front and rear wheels, riders in th Iditabike can ride through snow, which presents similar problems to sand.
That sounds like a fun bike. How does the chain attach to the front wheels. Is it difficult to turn? Does anyone have any pictures?
I have found only this page:
http://www.spicercycles.com/index.cgi?c … ...20Bikes
Here some different sort of AWD : http://www.christini.com/]http://www.christini.com/
IMHO the Bike in the first page uses hydraulics for the front wheel.
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The big problem pedalling a bike on Mars or the moon would be the stiffness of the pressure suit. I bet it would take more energy to bend the suit than move the bike! So it might be easier to have a small enclosed compartment and pedal without a suit inside the compartment, convert the pedaling into electricity, and power the bike electrically. Wow, that would be complicated. . .
-- RobS
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& there`s the problem of air & sweat. the air would possibly used up quicker than Marscrew relatively relaxed in a rover. & sweating causes problems too. so, a balance of simplicity, comfort, & utliity are needed.
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convert the pedaling into electricity, and power the bike electrically. Wow, that would be complicated. . .
Not really, all you need is one three phase motor and one three phase generator. Such electromechanically torque transfer may already be used in ships where it is difficult to transfer the torque mechanically. It only gets complicated if you want to start storing a fraction of the electricity for future use. Or if you want to regain some energy in breaking operations. Other alternatives include purely magnetic transfer. I think the best way to do mechanical transfer is to have two linear actuators While on actuator is increasing the volume of the pressurized area the other is decreasing the area. This linear motion is then transferred into rotational motion similar to how a crank shaft works on your car.
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Problems I see with the idea.
#1. As the farscaper mentioned, stiffness of the suits would be a major obsticle. As an avid bike rider knows, riding a bike on rough terrain requires a good amount of physical agility over the whole body. The rider would probably spend more energy working against the suit, then he would peddling, in this is the case, walking might be a better method.
#2. High speed accidents. Falling off a bike is bad enough on Earth, but it could be disaterous on Mars where a suit rip could spell doom. While Mars has lower gravity than Earth, a heavy body in motion still has intertia, which could cause a lot of damage if the rider was to lose control, which could definetly be a problem on rocky martian soil (heck, I do it sometimes on flat concreat, so go figure).
#3. Purpouse. What exactly would these bikes be used for? On an early mission the crew should probably not be going to far away from base-camp or a rover for safety reasons. With limited destinations none to far apart, a bike becomes less usefull. Also since lopping/skipping is a faster and more efficent stride on mars, and requires little physical agility, it may be more attractive for medium range transport.
#4. Loss of toqure. On earth a rider can generate alot of toqure by using his bodys weight to push down on the pedal. This is most usefull in off-rode/rough rode riding where toqure is most necessary. On mars where such conditions are universal, the loss in gravity hurts this affect. Sandy soil also agrivates this problem.
#5. Safety. Safety must be a primary concurn on any martian mission. I mentioned these concurns earlier, but they are worth repeating. Operating a bike could be very dangerous for an its riders. It is inherintly more accident prone then walking, and produces accidents of greater severity than walking could. Because of this, biking expidtions should not be alowed to transpire long distances away from a pressurised safe area. This should apply to foot travel as well, astronaughts should not be allowed to travel solo long distances away from the help the might need if there was an accident.
Solutions for some of these problems.
#1. This is the toughest, by sitting the rider down and adding more wheels the requirments for physical agility are lessened, but not eliminated. This arangement also makes the rider lose the toqure he could gain from his weight.
#2. The solution to this problem is the same as number one. Add more wheels, and it has the same additional problems. But lowering the center of gravity and adding more stabilisation points are the only solution to loss of balance.
#3. While I do not see a use for bikes to engage in long range solo adventures, that is not all they might be used for. One idea that springs to my mind is the transportation of moderatly heavy equipment. A "bike" could tow a trailer of some sort which could contain addition equipment. Two such riders (perhaps in a tandem vehicle), carring additional life-support and science equipment might even be allowed to conduct recon short distances from the base (like say maybe 30k or so). This might be useful for taking multiple soil samples around the base (while the rover is out on a expedition), or montoring/repairing seismic/weather stations (although this could probably be done mostly via radio). Anything that lets the crew get more excersise is usefull as well though.
The problem with this, is that there may not necessarily exist a need to transport moderatly heavy equipment from one location to another, at least not on such a regular basis to justify a bike. And, adding mass (such as a trailor) increase the amount of toqure the riders must generate to accelerate and manuver on rough terrain.
#4. I actualy have a solution to the toqure problem though. Modern electric assitance motors already exists for bikes. They are fairly compact, pretty reliable, and can generate additional toqure for the rider. They are totaly self-contained, recharged by the riders peddling. A device such as this could be easily attached to any bike. Big/multiple tires can also help to a degree, but do big and to many, and you start to increase the amount of forces necessary to move the bike.
#5. I belive my solutions to the safety problem can be addressed by simple mission planning. No riding at high speed of dangerous terrain. Stopping is going to take longer on mars due to lack of toqure, which should be taken into consideration. No solo expiditions great distances from a base and help.
He who refuses to do arithmetic is doomed to talk nonsense.
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3wheeled recumbent configuration, pulling a 1wheeled trailer. & this would be left outside all the time, although it would be nifty to use the drive as a stationary power source, use it for trimming algae, washing clothes, operating a small centrifuge, generating elctricity, etc.. indeed this could well a focal point of a whole base considering the stationary aspect. small amounts of power would be needed all the time.
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The amount of solar energy needed to recharge batteries or to even supply power would be minimal for a motor assisted bike at low speed operation. Making the enclosure for the astronaut to be seated in, out of solar cells. Picture one of the small electric cars for size.
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i`m even thinkin we oughta configure an unmanned probe this way, munus seat, pedals, enclosure,etc.
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i`m even thinkin we oughta configure an unmanned probe this way, munus seat, pedals, enclosure,etc.
I'm dubious about this. A recumbent tricycle still relies in large part upon it's rider for active balance, espeicaly upon rough terrian. A rover has no easy way to simulate this (I mean you could use gryscopes or what not, but that would be heavy). Without active balance, a low center of gravity and more points of stability are even more important, and most small rovers have more than enough power a 4 wheeled transport, I mean they are rolling around up there right now. Why mess with what works?
He who refuses to do arithmetic is doomed to talk nonsense.
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i`m simply thinking of unmanned probe which could be sent now which is purposely built to be useful for future manned missions. surely some way to do this without compromising integrity of current design. i guess maybe this falls into another thread.
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The big problem pedalling a bike on Mars or the moon would be the stiffness of the pressure suit. I bet it would take more energy to bend the suit than move the bike!...
Exhaustion is the biggest danger. Biking in a pressure suit has to be a highly demanding activity. EVA's are like diving--physical exhaustion can cost you your life. And it's very easy to get exhausted in a pressure suit.
I don't think it'd work very well as a backup plan, for that very reason. It'd put you in even more danger, because if you really were in a bad situation (e.g., running out of air, or broken rover far from base), you surely would get exhausted riding that bike, so having it along would give you a dangerous false sense of secuity.
It's something the first or second expedition teams should try out though, maybe biking loops around the base to see how viable it is.
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i agree. this wouldn`t be used on the first. for one, the terrain would hafta be mapped quite well. for another, first would be too busy for such. one would as much as possible wanna build this from indigenous materials. indigenous by the way, doesn`t necessarily mean Mars or The Moon, just Off-Earth. one must remember that pedal powered vehicles have been 300+yrs in the designing & have still more innovations on the way.
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