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well, i'm thinking of having a pre-colonization gear-up with the first few missions. If you were to use a fuel tank from the space shuttle as your craft to get to mars, you'd have to add your hab module and your crew return vehicle with associated heat shields, but I'm not sure how you'd get the tank to the surface. If you could work out a tether that would work in martian gravity, you could do that much sooner than one for earth gravity. Then your astronauts could just climb the thing if it comes down to it, and though they may spend weeks and weeks climbing, they'd still be able to get to their ship. That would add complexity to an initial mission, but there's no reason that once we get enough equipment to do good science there, we couldn't send one of the follow on missions to GMO and drop a carbon tether. Heck, kevlar might work since the loads would be less, and you could simply have an electric lift mechanism big enough to carry three crew members and about a hundred pounds of rocks. In the mean time, a small, rather chintzy unpressurized, no-life-support systems rocket could carry one astronaut and some rocks that needed to be run through a zero-g mass spectrometer or something. AND, you could leave all your systems on orbit without the risk of landing damage. You'd really be saving weight if you didn't supply the crew return module with a heat shield, since you could always dock with the space station to get back home on a shuttle flight, instead of bringing the CRV all the way down through the atmosphere. The small rockets i'm speaking of could be made to weigh very little, and you could use biologicals to produce the components to many fuels, as long as you have some sort of distilling facility for alcohol, and ISPP could be used to produce oxygen.
Anyhow, take it easy y'all
Rion
well, as far as the ice thing is concerned, we're more worried about weight savings and cryogenic/pressure concerns than we are with how long the balloon takes to pressurize, however I think we will incorporate a small pressure tank, so that the water gets electrolyzed, and the hydrogen collects in a small pressure vessel before being released into the balloon. It really would suck if the balloon got ripped to shreds on a rock while it was half inflated. I think methanol is a bit risky though, because it will be ice cold on the voyage out, and unless you maintain enough pressure it won't have enough of a change from storage to inflation pressure to keep it from being a solid chunk. Sure it'll sublimate, but so will ice in a near vacuum condition. I think for our purposes, with our level of experience with the medium, a chunk of ice with some electrodes is the best bet, though I hadn't thought of inflation time.
And that, my friends, is why folks like me post on this type of board, so that potential problems can get addressed before launch, and before final build even gets thought up, so we don't wind up throwing three hundred pounds of useless junk at Mars.
Thanks, and keep the ideas rolling,
Rion
I think i could rig up a windmill filled with hydrogen, maybe made of a vynil compound similar to those big beer bottles you find inflated in quickie marts and bars, that would provide a decent amount of power, but more importantly, would be self supporting with a tether. Also, it would only weigh as much as its skin, as opposed to a "real" windmill which would utilize a rigid structure and a support pylon. Really the windmill would be supplemental, and used only when you needed lighting.
I think crops could be grown using martian light, but if you're carrying all your food with you it shouldn't be an issue. If you grow stuff there, then plan on using lots of windows, or a low-pressure transparent bubble that is inflated, and bermed with martian soil. I'm thinking you'd have one of these little power loader things that you can get at taylor rental, although quite beefed up so you could use it at really cold temps, but it would be a front-end loader, without a cab, you just walk behind it and use handles. You'd excavate a four foot deep trench, a little longer than your hab and "greenhouse" combined, and then pile the hundred or so cubic yards of martian regolith back on top. The hab and greenhouse would heat it enough to melt and resolidify the material, and provide quite a considerable amount of structural rigidity, so the only supported portion of the roof would be an eight or ten foot wide swath that wasn't covered in soil. Lights could supplement the growing cycle, but so could a pair of reflectors, one on either side of the open swath, that could fold up near sunrise and sunset to reflect light into the greenhouse. This would have two sacrificial layers on top, maybe polyethelene, so during dust storms it could get shredded and not lose pressure. The plants inside could sustain the life support system with additonal oxygen, although potentially not enough to breathe for more than a few hours, but it would lighten the load, as long as the door was open.
I think i'm wandering a bit... the windmill would just be used when you needed something other than ambient light for walking around (like in high winds/dust storm) and maybe at night if there are winds. Solar panels could be used otherwise, but I can't imagine that you'd be doing things like washing clothes, cooking, and welding on a rover at the same time. You could schedule things like that so that the computers had enough power, and the mass spectrometers, centrifuges, etc. could run. I would also assume that you could have a max. current draw for the computer and science instruments, so that you couldn't turn something new on until something else got turned off, if you were over the limit. A nuclear reactor may not be necesary, as long as you can keep the solar panels clean, and as long as there's a smooth surface on top of them, the wind should blow dust off as effectively as it blows it on. So you'd need a small solar farm, and about ten hydrogen filled windmill balloon devices, and you could probbably have more solar panels (kilowatts) than you could have reactor(s) for the weight. I imagine a three ton reactor wouldn't output what three tons of thin solar panels could, if you minimized structure by simply berming soil up at an angle and laying them down with a simple carbon fiber/lexan housing and a 3 sun power reflector.
Let me know if I'm off base, but I just remember seeing an inflatable aircraft a while back, and if you can build an inflatable wing, you should be able to put it on a hub and make it go in a circle in the wind. Later all,
Rion
I was sort of envisioining something akin to a modified lunar plan, where your crew return vehicle (command module) orbits, and you can transfer crews from the orbital station to the surface and back, and the orbital crew can manage incoming supplies and new crew members, since you may not want to bring your folks back if things are going well and they're cool about staying for another six months. Otherwise, when the new crew module gets there, you simply use the old crew module to take everyone home, and the orbital lab module would be left behind to link up with the new lab module, so you can send mars rocks up and check 'em out before a return mission. I would assume lifting a few pounds at a time from the surface wouldn't be anything huge, and with the thin martian atmosphere an empty lift rocket would be able to use a very thin/light reusable heat shield to go up and down four or five times?
why couldn't you use an NTR with hydrogen AND oxygen? In that case, i'm sure the nuclear thermal engine would heat both enough to enable combustion, so you would be adding heat to the exhaust stream, increasing the temperature by roughly 3000 degrees farenheit. In any case, I don't see why you couldn't use the oxygen for life support systems, or with other fuels as an oxidizer???
I was thinking about how to repair a cracked frame member or something in the field, and I had a fairly decent idea:
MIG WELDING ON MARS!!! hey, i just had a brain fart. Mig welding requires a CO2 buffer gas! Just make everything out of steel or whatever, and you can have a wire feed welder that's pretty easy to use. No modification necesary. You just don't have an internal gas tank to weld with, since the whole environment is the same buffer gas you'd use anyhow. On earth it keeps you from getting hydrogen and oxygen into the weld, causing embrittlement and premature oxidation.
Maybe we can handle welding with off the shelf stuff, we'd just have to have a couple hundred watts handy.
The other option is what they use to repair ship propellers in the field. You'd have a piece of tape with iron oxide powder in it, and another piece with aluminum powder, then you run a short pulse of electricity, fusing the tapes, and you have a weld. You put one piece of tape on one part, and one on the other. You can fix brass, bronze, iron/steel, and I believe aluminum. There are other thermite reactions involving zinc and copper oxide, and several others which may be more compatible with different metals. Anyone care to look into it more? I'm going to try some stuff with vynil tape and some metal powders and maybe use my friend's stick welder to provide the AC pulses for a few seconds, and see how it works on bar stock. OH yeah, the other thing is this works underwater, without oxygen, and in extreme cold, that's why they use it on ship propellers inthe field, since you can't really lift a fully loaded cargo ship into drydock.
Take it easy y'all
Rion
yeah, that's the idea.
I was just thinking if you could use ISPP effectively, say without having to process anything but the fuel, and use packed martian regolith for oxidizer (just for fun, get a chlorine tablet for pool water conditioning, drill a hole in the middle- you can use an xacto knife- and put it in a coffee can away from flammables, then arrange for a dixie cup to fall down on it, filled with brake fluid- so it tips over and spills the fluid into the hole- you'll get a hypergolic reaction similar to what i'm thinking of) you could just pack regolith into a chamber with a hole down the middle, pop out whatever form you need, and then use methanol or whatever you create from your hydrogen and CO2 with the ISPP rig. Then you're back home. You'd have to get from the surface to mars orbit no matter what methods you use, unless you build a really really big vehicle on the surface and launch direct.
anyhow, my idea was to simply load your vehicle with enough engine and propellant to get back to earth on a free-return type trajectory, just barely getting out of mars orbit, but to try and make enough propellant on the surface to get you back at whatever rate you wanted to be able to design to. I'm not sure that the mass advantage would be significant if you're using nuclear ion propulsion, but i'm thinking what i could buy off the shelf yesterday, not what might be proven in ten years... so chemical/solar ion would be it, and i don't think there's quite enough raw power to get the thrust numbers you'd need. with chemical you could brake quickly and powerfully, so you could go faster for longer, and cut your transit time by quite a bit, but if that would really be a benefit, say cutting a week or two off transit, or would it just be an unneccesary improvement, say taking a day or two off transit time, who's to know?
I'd have to do too much math for a hohmann transfer, but i can fire up my old copy of STK and probbably figure it out in a week or two, when i have some time.
Till later y'all,
Rion
oh yeah, blah, the other idea was to just make a fuel that could react with your regolith, instead of extracting fuel and oxidizer... i read from the viking missions that the soil is supposed to contain alot of peroxides or something that are quite reactive, which is why viking put up so much fuss for signs of microbial life on mars... somthing about the way UV reacts with iron oxide to make highly energetic reactants, so when you mix it with water it goes fizz.... who knows. We need some more data, so maybe i'll add that to moltov's sensor package....
anyone else have some data on what I'm talking about with the soil? I think it was in Malin's mars book.
Later,
Rion
Hey, that's a link for Brian walker's website. He's using a hydrogen peroxide rocket to get up to 50 miles. I was thinking something like what he's got could be used on mars to get back to on orbit components.
Let's say the mission goes like this: you have a surface nuclear reactor, separately stored fuel rods or pebbles for a pebble bed design (my personal preference), and various "luxury" items that you would ONLY need on the surface, packed in a frame and on one end of a tether. In addition to this equipment, the crew habitat, crew return vehicle, and life support systems would be on the other end. This would be equipped with a propulsion module and tankage for the return trip.
Once you got to the surface, assuming you got there safely, you would set up a rocket much like the one depicted in the site linked above. ISPP would be easily used to get the vehicle up to about 90 or 100 miles altitude over mars, and a tether catch system could be used to capture with the orbiter. three or four of these would be available, and very lightweight since they'd be shipped empty. In any case, you'd hop in, fire up, and a computer would guide you to the on orbit crew return vehicle, which would have just enough fuel to get on a long slow free return path back to earth. You'd link up, and transfer your extra propellant, and then one or two of the other rockets would be carrying extra fuel and your fellow crew member(s), and one would carry nothing but a few hundred extra pounds of fuel, so you could have enough fuel to get all the way back to earth.
If someone works out JLN lab's lifter, or our electrokinetic thruster, then the propellant required to get back to earth could be significantly reduced, so you'd just get out of mars orbit, and accelerate over a few weeks back to earth, but barring that, you'd use a fusion type propulsion system, or Ion propulsion.
What do you think? Do you think we should take the CRV all the way to the surface, only to have to heft all that weight back up, or should we use an unpressurized capsule like walker's design with our intrepid explorers in pressure suits? I think it's risky to take your way back home all the way down and up, in case something screws up, you don't lose your way back home completely. Something like this system would potentially preclude sending an advance CRV and hab, like in mars direct. Anyhow, let me know what you think, this might just be another brain fart...
Rion
I tend to think that if a plane could fly on mars, a helicopter could fly as well. The whole dirigible idea is probbably the best, since you could have a big clear envelope lined on the bottom with flexible solar cells, and hover/lift doesn't require any power, and neither does propulsion if you use one of those drag chutes that someone mentinoed as far as the rover propulsion goes. I'm not sure how it would work exactly, but if you can tack a sailboat, i'm sure you can tack a dirigible against the wind. As far as affixing a sail, that may be the hardest part, so parachutes might suffice. anyhow, hang in there guys, and keep the ideas flying...
Rion
Talk about great, I'm taking a class now on CNC, fun stuff. Anyhow, one other point is a pressure fed design may actually wind up heavier than a turbopum fed design, so you may wish to go hybrid, using some form of piston pump with a pressure system to keep feed rates up.
Keep 'em coming,
Rion
as a matter of fact, you do keep talking about your mission/projects. I don't really see how anyone can contribute to the forum without making at least a passing reference to their own perogative. In my case, the way I learn about things is by doing, not by simply reading or going to class. My last post was in reference to the inflatable tank idea several posts earlier, using ice as a propellant storage concept, so I related it to the mission which I have been designing for the past two years, since it is what I know, and I did not wish to extrapolate on topics with which I was not familiar. Adrian has corrected the error of my ways insofar as posting off-topic, but this most recent post in this forum would seem to me to be quite on topic with prior posts by other members.
As far as the accusation of duplicating your mission, I hardly see how your mission is unique, since you yourself admit using Zubrin's idea of inflating balloons with methanol and the like. I hardly think mine is terribly original either, but I certainly did not take your idea. Often in history several researchers have come to the same conclusions, or at least remotley similar ones, on the same topics. Whittle and Ohain both came up with the jet engine around the same time, but lack of mutual knowledge is questionable, but other developments have resulted in quite similar technologies hitting the market at nearly the same time. Sometimes there is only one way to do something easily.
I'll go on and stop here, since any bickering between us is counter productive to the purposes of this forum. Just to let you know I sent you a personal message through the board's messenger function several days ago regarding my areas of research and with several questions about yours, but since I have not taken the time to download the entire site and read it offline yet, I had no prior knowledge of your mission plans. If you would like to discuss it in more detail, please email me at chi2orionis@hotmail.com, or simply reply to my message on the board's messenger, assuming it was delivered/sent correctly.
As for the other members of the forum I apologise for any incursion into your otherwise harmonious enjoyment of the information presented here. I am new to the forum, and am not exactly a part of your community yet, though I hope to fully integrate myself within the framework which has been laid out thus far. The invitation to inquiry via email extends to all.
Thank you, and good night,
Rion Motley
any way to just move it?
Hey, i just read the first post and part of the second, so if some of what I say is duplicitous, just let me know...
The reason we use pure oxygen is the same reason submarines use an oxygen/helium mix (research subs where you need to get in and out all the time) because of the "bends". The bends are caused when nitrogen literally fizzes out of your blood like carbon dioxide in your soda. This results from a rapid pressure change, so instead of the nitrogen simply dissolving out of the blood and diffusing through the lungs, it forms bubbles which can go to the brain and other vital organs and cause a gas embolus and you literally drop dead for no apparent reason. Just so you know, an embolus is anything that causes a blockage in a blood vessel, such as a blood clot, air bubble, misguided catheter, etc. My mother had/has pulmonary emboli, and this is a condition where someone creates blood clots which go to the lung (hence pulmonary) and cut off the blood supply to varioius parts of the lung. In her case, three out of five lobes were completely collapsed, and two of the clots were large enough that they should have collapsed both lungs, and she would have experienced instantaneous cardiopulmonary failure.
This is why we use pure oxygen. In the event of explosive decompression, assuming our folks are in suits, the pressure change would be survivable, but only if there is no nitrogen in the atmosphere. Running your habs at the currently used pressures of roughly 10 psi, which is about 2/3 of our sea level 14 psi, the pressure drop felt in the suits would still be 4-5psi. This is way too much pressure change to experience without getting the bends. The suits would have to repressurize very rapidly to prevent medical problems. On russian vehicles, if a spacewalk is to be attempted, decompression has to occur before the walker can go out into space, since the pressure would drop from the sea level pressure, and since it's bottled air, he's breathing 70% nitrogen. American space walkers don't have to worry about that, but they do have to worry about not smoking, not letting plastics get too hot and outgas, and potentially spontaneously combusting, and you can't leave oily rags lying around. Of course you don't really encounter oily rags in a space environment, but on mars you might, if you had to work on the rovers...
So to answer your questions, we use 10psi air supply on the shuttle/ISS, 14 psi on the ground, and we use pure oxygen because we don't want to get bent.
I would suggest using an 80/20 mix of oxygen/helium like what divers use when going really deep. This would limit the risk of fire, while making us sound really funny. I would also reccomend that if a rover is taken to mars, since we'll need to use it for a year or thereabouts instead of 2 weeks like in apollo, we need a garage. MOLTOV will be testing out a few things to see how feasible it will be to dig a 6 foot deep trench in which to inflate a garage type structure. I got the idea from this indoor tennis court that you simply inflate over an outdoor court, and you have an instant climate controlled dome that kinda looks like those things in the X-files movie (you know, the bees in the middle of the corn fields...?) Anyhow, on earth you can afford leakage, so you just have a big blower kick on when it starts dropping pressure, but on mars you might be able to afford leakage, since gravity is only 1/3 as powerful, and there's less air pressure pushing the thing in... if you simply pumped it full of ambient martian air at a few extra PSI, then all you'd have to worry about sealing would be the inside surface which could be completely separate and replaceable. kinda like putting two ziplocs inside one another, then inflating the outer one. Anyhow, this way you could simply depressurize the interior, drive the rover in, zip the door shut, repressurize, and work on your rover if you needed to. There would have to be a reservoir though, if you didn't want to lose alot of helium gas. The unfortunate thing is you can't use CO2 for a buffer gas since it's toxic above about 1%, and there's apparently plenty of CO on mars, and that's toxic at much lower concentrations. Let's keep brainstorming though.
Happy thinking,
Rion Motley
OH MY GOD. Nuclear ramjets are great, and I'll admit that they're not that radioactive, but i'll also tell you this: put 3 or 4,000 in the air, every day, each with hundreds of pounds of fissioning material, with hundreds of pounds of air flowing through them every second, and you've got .000015% of 3,000 x 450 lb/s = way more air than I want to think about that's radioactive. The other problem is you've got radioactive fuel that you've got to dispose of. We have a hard enough time doing that with the limited amount of fuel we use in terrestrial reactors. I'd like to see something like propellantless propulsion come out, and then we'll be just fine.
Do a search on www.google.com for Thomas Townsend Brown, or Jean Louis Naudin. The former is an old-timer from the fifties that worked with flying saucers running on high voltage. The latter is a rather quirky french guy who found the old research documents and decided, "hey, i can do this". Nasa has a patent on an orbital maneuvering thruster that requires no propellant. What a concept! It runs on electricity, roughly 100 kilovolts, at minimal currents. The way you power something like this is with a nuclear reactor using sodium or some other low melting point metal, perhaps indium alloys or something, but the point is, you have a liquid metal flowing through a hot reactor, then a magnetic field, and back again, resulting in a thermal Hall effect electric generator.
The key to using nuclear power is to isolate it from not only the crew and passengers on a vehicle, but to isolate it from the outside environment. The next step is to figure out how to deal with nuclear waste. I'd love to turn uranium into some beta emitters at 100% conversion efficiency, or at least something near it, but what happens is you run out of absorption cross section. Your fuel rods get pigeon-holed/swiss cheesed enough that a neutron released by one fission reaction isn't ever absorbed, so you wind up with neutrons absorbed more by moderators than other fuel. That's ok if you don't mind reprocessing the fuel, and still having radioactive byproducts. Nuclear power isn't clean, guys. At all.
no
the way you control speed is just like a regular motor with an armature rotating on a shaft and magnets on the housing, but in this case instead of spinning, the armature is superconducting and on the bottom of the train, moving in a straght line. still, it's wire cutting across magnetic field lines. the motor could be set up for current dependent speed, but you don;t want that. Heavier loads require more current to suspend the train an equal height above the rail bed. if you need to slow down and stop every once in a while, you'll have to turn off your voltage, and that sucks when you don't want to have wheels and all to actually land on a rail bed when you're setting in a station. permanent magnets let you use any technology you want for propulsion, but you don't burn energy while sitting still, except a set of small electromagnets that help keep you still, OR a simple set of clamps that you can lower to act as a stabliizer when you're sitting still and being loaded unevenly. kinda like those thi8ngs that drop down on fire trucks and front end loaders when they're on uneven terrain.
anyhow, if you go superconductor, you want the whole thing to act like an AC motor, where voltage doesn't vary the speed, it's the frequency of the pulses that governs the speed of the train. voltage in that case would be freed to allow a varying altitude above the rail bed. who knows, maybe we can find lots of niobium on mars, but i think iron would be easier to get, melt, and turn into permanent magnets.
Uncle sam commissioned some research and development back in the sixties for a small MOL, which would look like the upper stage of a rocket, but once you got into orbit and launched your satellite or whatever, the MOl would be in orbit with cameras and the like, and would be a manned spy satellite until a small capsule returned to earth with the crew and film... then another apollo capsule (might have been gemeni) would resupply the "lab" and bring up the next crew. I'm not sure if the first crew would return via the new capsule or if the capsule would be left for the new crew to return... in any case, it was a neat idea.
I think we could do something like that for mars, leaving folks in mars orbit for extended periods, with small landing and return vehicles shuttling back and forth every few months. The orbital vehicle could be made of shuttle fuel tanks just shipped to mars with a strap on electric thruster system, and maybe ten or twelve pounds of nitrogen gas for an RCS/guidance system. Who cares how long it takes an empty hull to get to mars? with a launch every few months, they could send three or four of the tanks out, then send a teeny little command module with five or six astronauts, and a ten by ten by eight foot cylindrical compartment behind them so they could run around and not go totally crazy in the head.
> I'm thinking they'd take playstation or something of that sort along so they could have some fun and break the tension instead of being utterly reclusive during the whole trip. (of course you'd have a fair compliment of exercise bikes and all that for zero G health maintenance, and maybe a tether to the burnt out upper stage, or another SS Fuel tank for artificial graity?) I'm thinking it would be neat to develop a time-delay web surfing device, where you could send an ISP request, then get the site a few minutes later, then put in your search to google or whatever, and then have it sent to you. Might be able to do it with a simple radio modem and just deal with the lag, who knows... anyhow, back to my main point,
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once the tanks are there, they'd enter mars orbit. You'd dock with one, and put on a self-welding collar to the end. They do this now with ship propellers. Aluminum powder is impregnated into a plastic strip, and iron oxide into another, then you literally tape the part in place with the strips, then run a current between the strips, triggering a thermite reaction that produces a perfect weld every time. It would be great in the vacuum of space, besides, a small plasma welder could be used once everything was linked up, to weld in gussets and the like for reinforcement. Once you're hooked up to one of the tanks you can load all your freeze dried food in to the tank for storage. The next tank could be filled to the brim with material, since you now have an empty tank to put the stuff in so you can have room to move around while you're unpacking. these tanks would be best suited to projects like sorting geological samples for testing on-orbit and potential return to earth for further study. I'm sure samples will be really interesting, but after the first hundred pounds or so, we'll start getting gads of samples that are exactly like something we've already got, so we'll want to screen them post-extraction, so we don't waste an equally large amount of fuel getting low-value samples back to earth. Besides, if you can ID the rocks and all on orbit, and return them to the surface, you know where you put them back, and can go back and collect the same samples again from their native environment without exposing them to all sorts of space radiation. I think I got sidetracked again, but the point is you'd have a nice big space on-orbit that would be cheap to acquire, since it's space junk to nasa, and relatively cheap to get to mars, since you can use the small amount of residual hydrogen in the tank for an ion propulsion system to utilize. Other advantages abound, but the cheif disadvantage is that I don't know what the internal structure of the tanks actually looks like. I know what it has to withstand, so it's perfect from a sheer strenght standpoint for a spacecraft or space laboratory, but whether there are room-sized spaces inside or not, i don't know. The whole tank could be baffled so densely that you couldn't wlak around in it, or it could be as open as a gas station underground storage tank, which you could easily play a regulation game of badminton in. Either way it might be useful at least for storage of pressure and temperature sensitive items for long periods. if a person couldn't fit between the baffles, you could cut a small passage, and at least stack your boxes of freeze dried broccoli in the thing, so you free up space for your mass spectrometers and all. If nothing else, we'll need a place to put all this ISPP fuel, so why not re-use the space shuttle's tank, and throw a big carbon fiber/ kevlar/ceramic aeroshield on the thing, toss a parachute pack on it, and throw it at the base station before you get started so you don't wind up turning your inflatable hab into the first manned whoopee cushion on mars. Then you just do your welding and fuel line routing when you get down to the surface and are able to roll the tank into place and pack some regolith around her to keep the whole shebang in place.
I've gone on a bit longer than I expected, but I have a bunch of ideas. I really do need some folks to send me a message either through email or through the board's personal messenger service, so I can add some folks to our research group. We are at the point where we can start designing components and program requirements so people can have long-range contributions. I would like to get to a point where when we need a fifty dollar battery, someone in the group says "hey, i just sold my old mountain bike on E bay, why don't I buy it for the group", or "hey, you guys need someone to program that little chip to guide the solar panels? I work for a company that uses the same chip in toasters... I think i can help you out". anyhow, the only way that happens is if we get the word out to enough people. I figure if fifty thousand people hear about us, and twenty pecent decide to send us a check for ten dollars, we'll be funded through the rest of our budget. We only need about sixty thousand dollars to get to mars with MOLTOV, and our new microprobe precursor mission would only cost a few hundred to a thousand dollars to launch. Every step will bring us closer to a private, nonprofit, public-access mars mission, and eventually to an affordable, regularly scheduled flight to mars with private individuals and scientists aboard.
Thanks for your time,
Rion Motley
this is exactly what we're talking about with our balloon mission. Our landers will require oxygen to stay warm, or at least can use it instead of sheer electrical power, and won't have enough of a mass budget to handle the high pressure tankage for pure hydrogen. What happens with water is the hydrogen and oxygen are bonded together, which requires a small amount of energy to break them apart, but they literally hold themselves together for the voyage. The vapor pressure for water at orbital and interplanetary temperatures, and at mars surface temperatures, is thousands of times lower than that for liquid oxygen or hydrogen. The difference between the vapor pressure for ice at orbital and mars surface temperatures is very small, however for cryogenic fuels of any sort, a small temperature change can drastically increase the amount of boil off experienced. This results in a net loss of propellant. I can store our ice in a lightweight polyethylene container similar to an RC aircraft or car fuel tank normally used for methanol or gasoline, run some electrodes in wrapped around a dual channel tube to collect the two gases, and either use solar concentrators to melt the ice, or use a small nichrome heater wire. in any case, the energy required for the electrolysis is actually only about twice that required for a solenoid valve, which will be eliminated (potentially) in a design using electrolysis to inflate the balloons, so one more potential frozen component is eliminated. We just have to come up with a way to eliminate steam from the system, so I think we'll just have a convoluted perforated tube, or some sort of foam filling the tank so that any steam would refreeze, then be melted and electrolyzed before it left the tank, otherwise, the balloon could be filled with vapor, lift off, then have the steam freeze on the inside of the balloon, and it would no longer provide lift, and that difference could cause the balloon to crash. Its something we'll need to test this winter or next winter outdoors or in a large freezer before we go much farther with the design, because one entire lander's payload depends on the success of the balloon system.
So yes, as long as you can separate steam from oxygen and hydrogen in a zero gravity environment (where a fractioning column wouldn't work) you can use ice instead of separate high pressure cryogenic tanks for your fuel, and eliminate boil off to 0%.(you'd have to get the ice up pretty hot before it boiled off to any degree that your tank couldn't handle).
Take it easy y'all,
Rion
why does maglev have to go fast? If you keep speeds down, you don't have to build as accurately, and you don't even need superconducting magnets. Permanent magnets would work just as well, and probbably weigh less in the long run, since you don't have all the cooling requirements (I'm assuming that daily temperature swings are too great to simply use a martian room temp. superconductor (aren't there some superconductors that work at least near dry ice temps?) In any case, you just line the track with magnets at a slight angle, one row on each side of the track, and then the train has magnets on the bottom, also at an angle. You lose a little lift capacity for the sake of stability. Take care, and keep the ideas flowing.
Rion
hey, anyone ever think of using a bicycle on mars? What about pegasus, some guy pedaled accross the english channel in a pedal powered plane. seeing as how there's less gravity, one wouldn't have to pedal quite so hard to get up, and drag would be reduced with the lower density, even with a larger wing. In any case, you could use a bicycle to charge up some batteries, and supplement the solar panels on an aircraft.
someone made mention of high speed transport on mars. This would NOT be less efficient. Higher speeds don't require more energy, they just require the same energy levels for more time, assuming you have some sort of transmission. I can get 40 miles per gallon in my '95 tracker, but I have a five speed. I can go upwards of 100 miles per hour. My friend has an RSX, with roughly the same power to weight ratio, but he can only max out at 25 mpg, and can go 120 miles per hour or better. with regenerative braking, big wheels, and an efficient engine, you should be able to gear it up to go as fast as you want, given terrain conditions and the abilities of the suspension system.
I think that's it for now, except with a helicopter, you don't need a bigger rotor. Not really, anyhow. Since the atmosphere is so much thinner, the local speed of sound is vastly higher. You can thereby spin an airfoil up much faster than on earth. Higher tip speeds equal higher lift, with a properly designed airfoil. Therefore you can pack a standard helicopter with the proper gearing (again with gearing...) to attain a higher tip speed. This would enable roughly equal lifting capability, with perhaps a 10 or 20 percent loss in total lift, but since you have a 60 percent loss in effective vehicle weight, you more than offset the loss. sure you might want a bigger rotor, but i don't see the problem with folding it up? Anyhow, take care, and keep the ideas rolling in.
Rion Motley
AH! i forgot the other point I wanted to bring up!!!! I read some of the other replies about inflating the balloon... we're using ICE!. it's solid, dense, and we have plenty of hydrogen in there. The problem comes with what to do with all the oxygen we'll produce... Dumping it seems a bit of a waste, but i'm sure we'll come up with a use for it eventually. Perhaps another experiment will need it, or maybe we'll need to generate heat for the rover, so we could use it to burn some form of hydrocarbon fuel in a puff combustor... who knows, but the idea is you embed a tiny little heater wire in the ice, then run two electrolysis wires through the ice somewhere near the heater wire. You could even use the heater wire as one of the electrodes, reducing the number of wires needed. These wires would be coiled around a small ceramic form to keep them from hitting one another as the ice melted and potentially pushed them together, but the ceramic form would also provide an escape route for the electrolysed gas. Hydrogen would be produced at one electrode, and oxygen at the other, and as long as they were connected by a tiny strip of liquid water, we'd be set. Also the ice would aid in maintaining pressure, so as we heated and liquefied a bit of water at a time to generate gas, the pressure would be contained by the structural integrity of the ice itself, reducing tank weight. Anyhow, we think ice is cool. No pun intended.
Rion
Good Idea. Our MOLTOV mission outline calls for one of the landers to carry six ballons which would be released to free-fly over the surface, with a seventh communications ballon carrying a low-gain antenna to improve LOS communications, and potentially enable the landers to talk to one another or act as relay stations, sending important data from lander to lander until one of them had a LOS to the orbiter.
The other use for balloons will be on Landers 2 and 3, each with a communications balloon, but also with a small sojourner type rover. The main difference, however, will be that the rover will carry a balloon nearly identical to the communications balloon, so after it scouts the immediate area of the lander, it would unfurl and inflate the balloon, then descend to a predetermined location. Of course, we would be praying that the wind would carry us to within a mile or two of our intended destination, but that's the interesting thing about the whole enterprise: you never know what new data you might wind up with.
Projected landing sites are Cydonia (wonder if we'll take a look at the face from above?) where it's relatively flat, but with considerable large geological formations worth investigating. Also on the board are Olympus mons, Utopia Planitae, and several sites near the poles. We need to get some input on desired sensors and will more than likely take a poll as far as where the most interest lies, so we can pick our landing site to give the most useful and in-demand data which will not be provided by other upcoming missions. In any case, the rover would be able to cover several tens of miles in a very short time period, but navigation would be a problem, since the balloon would be simply carried by the wind. We had thought about using a semirigid balloon system and going blimp with the whole thing, but that presents some space constraints (weight isn't really a problem, since we're still 50 pounds under budget) as far as folding a rigid structure into a small box that the rover could carry. Also reusability is an issue. We would like to be able to land and take off up to three or four times, so that if we miss our target, and winds improve, we can investigate a new site, OR if another balloon finds something really neat, we could hop over to the new site. Any input would be appreciated, but good idea with the wind surfer.
One question about the surfer idea: what happens when you hit a rock? Really big inflatable wheels?
take care,
Rion
the reason I posted twice is the reason for the mission is to scout for a future manned mission... Anyhow, we're planning some small experiments to see exactly how little we can take with us and still provide thermal control and the like for a manned habitat. I think we could easily send a much lighter habitat than what is currently planned. I'm thinking of inflatable structures, buildings using regolith cut from the ground like homesteader-style sod houses, and any number of things that we can use on-site instead of carrying a major load of structure with us. I don't mind bringing batteries and electrical equipment, solar panels, test equipment and communications hardware, weight that does something, in other words, but structure is just that. Once you get it to where you're going, it just sits there.
Anyhow, That's why I duplicated the post, since the project would draw interest from both areas. It got your attention, didn't it? ;-)
anyhow, take care,
Rion Motley
Hey, i'm working on an unmanned scout mission... check my post in unmanned missions. Take care all,
Rion
I don't know that it's all that impractical, but possibly unneccesary. CNC machining has brought an amazing amount of cost savings and simplification to the manufacturing process. Literally, I've designed a component on a computer, dragged it onto a floppy, walked down the hall, put the floppy in a CNC mill, and had a component made. Regenerative cooling isn't all that hard to deal with as long as the engine is large enough to permit you to machine the channels in the nozzle for coolant flow.
As far as the practicality of using ablation to adjust for altitude, it may simply be lighter to go with another stage, instead of adding all that ablative material which will actually reduce your exhaust velocity. That's another consideration that I didn't think of until just a few minutes ago. As the ablative material burns, it will increase your mass flow rate, but also reduce the temperature of the exhaust flow. You'd be better off to simply go with an extendable nozzle on an upper stage of a two or three stage rocket, and make the whole thing out of one of these new metal ceramic composites or other refractory material.
but still, get that book, and take a look. Fail or succeed you can always learn something by trying out your ideas. Get a blow torch and some durham water putty... have fun!
Rion