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I know the Aerospace industry has been at the forefront of exotic alloys and new matrix and carbon based construction.
Sometimes a fresh idea is a good one.
Simply put. Are the materials currently used for space travel the lightest availble at a given cost, and to translate that, if you save 5 lbs on a given payload/satellite, will it net you a savings in cost?
Also, by taking advantage of current chip technology, storage technology, and memory technology, that would lend to reduce space taken up, and possibility for more redundant equipment.
Does anyone else think that this could help, or have other ideas along these lines?
We are only limited by our Will and our Imagination.
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speaking of weight reduction. . .there is an unique oppoturnity in the field of weight reduction in space! things weigh nothing in space! (sorry if I'm too startisic, make fun of my spelling if you like)
If what you really mean is mass reduction, then realize this. . .there is no gravity in space. on earth gravity produces straitificoin of all things (oil and water, heavy goes to bottem and light goes to top) and the major problem with alloys is that when the mixing time comes they do exactly that. a perfect mix (or as near to a perfect mix) can be achived in zero g. further more, the casting of steel also falls into this same realm, (steel is a very dirty product to make) and is about 300-900x stronger without this stritification. of course the natural questoins are
1.Where do we get it?
2.What are the benefits?
The asteroids are a prime canditate to gather the ores to make the metals. Go to www.parksweb.com/nateweb to read more about how I think the actual process will be done.
The benefits are pretty oboius. (spelling, sorry!) first off, with metal 300-900x stronger a lot less of it will be needed to make any ships. all the ore is ready to be processed in near earth orbit is not exceedingly difficult (NASA sent the shoemaker probe to land on a near earth asteroid) and is said to be easier to reach a asteroid than to go to the moon. Am I advocating ships to be built in orbit? maybe, after a time peroid after the resquite techology is in place. But the unfished metal could be returned to earth by casting crude saucers (lord help me . . .flying saucers) and loading the semi-finished metals to be shot to earth and processed. ballons could be attached to the saucers to deploy once they hit the ocean to float them, and ocean going ships could retrive them.
"I am the spritual son of Abraham, I fear no man and no man controls my destiny"
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I don't think anyone's talking about alloys being that much stronger, but your point is well taken. There are probably materials that can be made in weightlessness that cannot be made on Earth; at least not yet. The problem is (1) no one has yet determined for sure that something can be made in weightlessness that can be sold for a profit, and (2) if something comes along that seems promising, there is a lot of pressure to figure out a way to make that same thing on Earth, simply because it's cheaper. So, so far, no one has developed something that can only be made in space and that Earth really needs.
But eventually that will probably happen. No one traveling over the Atlantic in the early 1500s could have anticipated the plant resources unique to the Americas either, such as tobacco, chocolate, vanilla, potatoes, tomatoes, corn (maize), etc.
-- RobS
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for more historical precedent look to the atlantic packet building industry. The white pine forests of new england contained superior wood for masts and the oak forests in the american interoir were far easier to acess then the dimished forests of england. . . .perhaps history will repeat itself in using asteroid materials to create spaceships.
It has been proven that steel will be 300-900x stronger when cast in zero gravity.
"I am the spritual son of Abraham, I fear no man and no man controls my destiny"
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It has been proven that steel will be 300-900x stronger when cast in zero gravity.
Can you cite a source on that? I've read that carbon nanotubes have a theoretical possibility of attaining a tensile strength 200x that of steel, but I've never heard of any materials that could be 900x stronger than steel, at least tensile wise.
My people don't call themselves Sioux or Dakota. We call ourselves Ikce Wicasa, the natural humans, the free, wild, common people. I am pleased to call myself that. -Lame Deer
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I believe I read it in "Investing in Space" although I'm not sure if that is were it came from. It is a very new book, look it up at the library. The author is a former CNN newsman (so i'm covered if he was wrong. . .j/k)
"I am the spritual son of Abraham, I fear no man and no man controls my destiny"
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Well, just in the different types of steel and ways of forming it, you get some incredible strength differences. I also imagine you are talking about forged instead of Cast. Forged steel is much stronger. It should be possible to get unique steel alloys in space. but I would say there is atleast a 20-40 fold difference in strength between the different blends and alloys of steel.
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The question is what is the exact strength for different alloys. Iron or low-carbon steel (0 to 0.3% carbon) has an ultimate tensile strength (strength before it breaks by pulling) of 25,000 psi, and an elongation strength (strength before it stretches) of 18,000 psi. This is designated in the steel industry as F-0000.
Iron-Nickel has a few alloys depending on the blend. FN-0408 is composed of 4Ni;0.6C;1.6Cu;0.55Mo. Notice this includes not only nickel and carbon, but also copper and molybdenum. It has an ultimate tensile strength of 100,000 psi, and an elongation strength of 65,000 psi.
Stainless steel has more types than you can shake a stick at. SS-410 is composed of 13Cr;0.8Si;0.8Mn; that is chromium, silicon and manganese. Its ultimate tensile strength is 66,700 psi and elongation strength 56,900 psi. This form of stainless steel does not elongate much before it becomes brittle, it's pretty hard.
There are literally dozens of alloys, each with different characteristics regarding density, tensile strength, elongation strength, elongation %, transverse rupture strength, hardness, resistance to chemical corrosion, and how it reacts to heat. The result, though, shows about a 4 times increase in strength between pure iron and steel alloys. Titanium is much stronger, and titanium alloys are stronger yet.
Manufacturing technique can also affect strength of the steel component. On manufacturer of bolts claims their bolts with forged heads, rolled threads, and heat treated (tempered) have 4 times the tensile strength as bolts with cut threads.
Actually, I doubt that zero gravity alloying will be able to produce results that cannot be met or exceeded by alternate techniques here on Earth. Zero gravity is useful for growing protein crystals for X-ray crystallography. That permits analyzing a protein to get its molecular structure. This is very important in pharmaceutical research. It has been attempted on the space shuttle, but they tried to return to Earth with the crystals for analysis on the surface. The forces of re-entry destroyed the crystals, so the analysis must be done on the space station. So zero gravity is useful for research, but a zero gravity manufactured super alloy? I don't think so.
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Getting back to the starting message of this thread, advanced materials are a fundamental part of the space industry. Use of space inflatables reduces weight a lot. Mars Direct already incorporates aerobraking and aerocapture to eliminate use of propellant to enter Mars orbit. In-situ propellant production greatly reduces the propellant required for a round trip. Mars Direct also includes use of Weldalite for the habitat, which is an aluminum-lithium alloy. The habitat could be further reduced in weight by using an inflatable. NASA has proposed using an inflatable habitat for Mars based on TransHAB, but the micrometeoroid shield is really not necessary on the surface of Mars. Mars has an atmosphere so micrometeorites do not reach the surface.
The computers on Shuttle were 4 redundant computers each the size of a kitchen refrigerator, and a 5th backup computer almost as large. Today a single laptop computer has more computing power than all of Shuttle's computers combined. In fact, a single high-end palm-top computer has enough computing power to navigate the spacecraft. You would probably want to add some redundancy, and definitely require a radiation shield, but the final end result would be about the size and weight of a single laptop computer. You could add file servers to store digital movies, music, or technical journals in electronic form, field reports, and letters from home. Even with radiation hardening and shock hardening for the landing, such a file server would be the size of a single laptop computer. For redundancy you could use a dual processor motherboard with a RAID-5 hard drive controller. You could add a second server as a backup. The fancy redundant circuits that NASA uses for flight control computers, redundancy that permits any single component to be bypassed if it burns out, would not be required for the file server. If you really want to go overboard with file server reliability, you could use a high reliability operating system such as QNX or VxWorks. These are both versions of Unix that have already been proven in space. VxWorks was used on Mars Pathfinder, Mars Odyssey, and now on the two new Mars rovers that were just launched. QNX is used on CanadArm2, the Space Station Remote Manipulator System.
Other means to reduce weight: composite propellant tanks. Graphite fibre and epoxy was used for the hydrogen tank on Delta Clipper (DC-X). It worked fine, the only problem with a composite tank for X-33 was when they attempted to replace the solid wall tank with a hollow wall honeycomb structure. The hollow wall proved to create micro-cracks that let liquid propellant in. When the tank warmed the cracks sealed shut, then the cryogenic liquid propellant boiled to gas and blew out the tiny cells. Ok, so we have learned: you have to use a solid wall design when using composite materials with cryogenic propellants. Furthermore, Carbon Overwrapped Pressure Vessels (COPV) use a thin metal tank reinforced with carbon fibres wrapped around it. That isn't as light as graphite epoxy, but it has already been used on satellites. With oxygen tanks you have to worry about carbon fibre burning with the liquid oxygen. You have to line the tank with something that will not spontaneously combust with liquid oxygen. COPV provides a metal liner. For those interested in details, aluminum reacts with oxygen but it produces aluminum oxide also known as corundum or colourless sapphire. The oxide is stronger and harder than pure aluminum and provides a barrier between oxygen and the remaining aluminum. You can see this with an aluminum pot at home. If you scrub it with steel wool it will appear bright and shinny for while, but after several minutes will become dull. That dullness is caused by a film as thin as a soap bubble of sapphire.
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Thanks Robert, Do you have any good links for some of that info or any sources?
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Thanks Robert, Do you have any good links for some of that info or any sources?
Steel: The Wakefield Corporation
Bolt manufacturer: Al Rashed Fasteners
VxWorks: Wind River
QNX: QNX Software Systems Ltd,
X-33 tank failure: Cornell University
DC-XA composite (graphite-epoxy) liquid hydrogen tank: NASA Commercial Technology Network
Composite Overwrapped Pressure Vessels: NASA Scientific & Technical Information
Radiation hardened single board computer: Maxwell Technologies This is only a Pentium @ 120MHz (not a Pentium 4 or a Pentium 2, just a Pentium) and it has only one processor, but it is commercial-off-the-shelf now, as well as radiation and shock hardened.
Space shuttle computers: Redundancy Management Technique for Space Shuttle Computers This shows the 5th computer is actually the same as the other 4.
Space shuttle computers (with pictures): by Phill Parker
TransHAB: ILC Dover
Mars Direct (from the Mars Society web site): Habitation Mass Definition Sheet and Mars Direct Transfer and Surface Habitation Layout
Any other sources you would like?
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Thanks Robert,
could you tell us in your opinion what we could do in zero gravity aboard the ISS that couldn't be done otherwise ?
We cannot do materials, we cannot do crystals, or if we can do it, an umanned satellite can do it better and cheaper, that's how I see the big picture.
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Thanks Robert,
could you tell us in your opinion what we could do in zero gravity aboard the ISS that couldn't be done otherwise ?
We cannot do materials, we cannot do crystals, or if we can do it, an umanned satellite can do it better and cheaper, that's how I see the big picture.
Ah, the space station debate. In his book "The Case for Mars", Robert Zubrin argued against a space station. I argue that any manned activity in space is good. A space station is not necessary for a manned mission to Mars (as Robert Zubrin so eloquently argued), but there are other uses for it. Some scientific experiments are best done by humans who can observe and make changes to the experiment based on observed results. Some experiments are relatively easy for a human, but difficult to automate. Protein crystallography is one which may be difficult to automate. How do you move the crystal from the growth chamber to the X-ray analyzer and orient the crystal for analysis? Crystals grown often are fluffy like snowflakes, not a solid octahedron or what have you.
The response of the human body to microgravity has been studied extensively by Mercury, Gemini, Apollo, Skylab, and Mir. We know pretty well what will happen to the human body and how to mediate the risks. However, medical researchers are always trying to find out more about osteoporosis, and how to better deal with zero gravity conditions.
I see the ISS as an excellent test bed for long duration life support equipment. We will need that for a trip to Mars. Rather than fight against a space station that is already in orbit, let's rally for improving the technology. A trip to Mars cannot afford the inefficient use of water that is currently on ISS. We need to augment the electrolysis based life support system with a Sabatier reactor. That will combine all of the hydrogen from the electrolysis tank with half of the carbon dioxide from the sorbent system to form methane and water. The methane can be dumped into space instead of hydrogen and carbon dioxide, and the water recycled. This will recycle all the oxygen and prevent water loss. We also need to deploy the water recycling system developed by NASA to recover water from all sources, including solid human waste and wash water.
I wish the satellite repair module was not cancelled. Canada was going to contribute that, but it was cancelled when Space Station Freedom was cancelled. When the ISS was reborn, Canada did not restore its commitment to contributing a whole module. Satellite repair is very practical. Most commercial satellites are in geosynchronous orbit, though, so an on-orbit tug would have been required. Such a tug is within NASA's expertise, not the CSA.
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Ah, the space station debate. In his book "The Case for Mars", Robert Zubrin argued against a space station. I argue that any manned activity in space is good. A space station is not necessary for a manned mission to Mars (as Robert Zubrin so eloquently argued), but there are other uses for it. Some scientific experiments are best done by humans who can observe and make changes to the experiment based on observed results. Some experiments are relatively easy for a human, but difficult to automate.
I am afraid that in all these experiments, there is no really need for such mamouthesque space station. I am not at all against science in space, or man in low earth orbit, but I wanted to pointed of the disproportion of what scientist needs to make microgravity experiments and what they have. It's all a matter of proportion. If you have a limited budget to make experiments, and you set up an experiment for 100 000 dollars, do you need a 60billion $ space station to do it ? What about a smaller, mir-size or skylab-size semi automatic module, dedicaced for science ? it would be easyer than the ISS to maintain, and you might be able to make more scientific experiments with the money saved.
The ISS is a huge project, but if it is to grow the same crystals and hatch the same salamanders than in the old skylab, what's the point ?
However, I am confident that in the long term, the ISS might find more usages. So, I hope that engineers have designed the ISS to sustain long duration in space, a hundred of years at least.
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I don't think anyone is arguing the current ISS design is the best. I would have liked to see something with a smaller number of larger modules. Shuttle C or Ares could have launched a Skylab size module in a single throw. I know, Shuttle C is smaller than Ares, but Skylab is smaller than the throw capacity of a Shuttle C with 3 main engines. Again I'm calculating that throw capacity as the sum of the cargo capacity of the current Shuttle plus the mass of the orbiter itself, then subtract the mass of the engines. In the 1970's NASA had intended to replace Skylab with a second one, then the third Skylab would be the core of an international space station. The launch cost alone would have greatly reduced the cost of ISS. But none of this has happened. We have what we have, so let's make the best of it.
The ISS life support system is fine for a few months, but not enough for a 2 year trip to Mars. You need the enhancements I mentioned to make it suitable. NASA does want to make those enhancements, but the question is whether ISS will retain sufficient funding to do it. I'm afraid that political backlash against the ISS will only result in reduced funding to all manned space activity. We have to demonstrate to congress that a manned mission to Mars can be affordable. Developing the technology on ISS means very little new technology will be needed for Mars. Let the space advocacy community pull together.
United we stand, divided we fall.
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United we stand, divided we fall.
I'm afraid that political backlash against the ISS will only result in reduced funding to all manned space activity. We have to demonstrate to congress that a manned mission to Mars can be affordable
It's unconceivable that after so much money spend, the ISS could lost her financial support, even if the US remains the only partner of this international project. Regarding "demonstrate the congress", politicians are oportunists, if they see an advantage for a Mars mission, they'll do it, even if the design is 10 times more expensive than Mars direct.
After all, they already funded ISS, why not a Mars mission? and politicians can change: some democrats were supporting the war in Iraq and now they criticize it like crazy. Obviously, politic is what matters for politicians, not the design of the Mars mission. I am sure many are already convinced that an Apollo-like project is necessary at that point.
Developing the technology on ISS means very little new technology will be needed for Mars.
Of course, but I thought the technology was already there. Maybe some details are missing for a MArs mission, details that matters, but I thought that the mission was feasible even now. You mention a 2 years life survival capability is requested, do you really think it's necessary for MArs ?
Things have changed, the "case for MArs" need some updates now, like abundant water on MArs (no need to bring H2), new ionic or nuclear propulsion that NASA is studying and that could shorten the trip to 3 months.
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It's unconceivable that after so much money spend, the ISS could lost her financial support, even if the US remains the only partner of this international project.
You're right, ISS will not be scrapped. However, further modules could be cancelled, at least US modules. Most importantly, congress will not see political gain if space advocates criticise the space accomplishments that have been made. What political gain could they expect by sending a manned mission to Mars if there is such strong criticism of the current space activity?
As for cost, remember congress was originally promised that the space station would cost $8 billion. Now the cost including operation is close to $100 billion. So why should they trust the cost estimate of $20 billion for Mars Direct? Or even the $55 billion of NASA's design reference mission. They remember that NASA had asked for $450 billion. If they spend that much on space, they won't have money for other political projects and would have major backlash from tax reduction advocates.
I thought the technology was already there.
Technology is there, conceptually, but I would like it proven before committing the lives of astronauts to a 2 year mission. ISS is the perfect place to prove it; if something goes wrong they can come back to Earth quickly.
You mention a 2 years life survival capability is requested, do you really think it's necessary for MArs ?
Mars Direct calls for spending 10% more propellant to reduce the trip to Mars to 6 months. Then astronauts will require 14 on the surface waiting for the planets to line up for their return. Then another 6 months back to Earth. Nuclear propulsion could reduce trip time further, but it would require dramatic increase in Isp while retaining high thrust to significantly reduce it to less than 6 months. Ion propulsion could reduce the total mass to space, reducing cost. Reducing transit time to 3 months would require both high thrust and high Isp. According to Robert Zubrin's book, a transit time of 130 days or less would make Mars aeroentry impossible. You would have to slow the spacecraft with propulsion at Mars. To get there in 3 months requires a specific impulse around 8 times current chemical rockets. Nerva only has 2 times the Isp of chemical rockets. The NSTAR ion engine is 6.8 times chemical rockets, but the new ion engines are hoped to be 18 times; however ion engines are so gradual in their change of velocity that a spacecraft would have passed Mars and headed into deep space before slowing down. VASIMR is supposed to have 20 times, but I don't know if it can produce the thrust required. The first working prototype will have to be built first.
In any case, you would have to wait for the planets to line up for a return to Earth. Whether the round trip is 26 months or 22 months makes little difference; you still need about 2 years of life support. Depending on extracting water from Mars is tricky. What if alkali dissolved in the water or fines prevent the water filters from working properly? Depending on Mars for life support is something you can consider for the second trip. We know what the atmosphere of Mars is, but we don't know the exact composition of permafrost. Engineers could design a system to extract water from permafrost after getting a sample to examine. That sample can be obtained either with a Mars Direct style manned mission that brings hydrogen to Mars for ISPP, or a robotic sample return mission.
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What political gain could they expect by sending a manned mission to Mars if there is such strong criticism of the current space activity?
Well, maybe it was time to criticize a little bit. If you don't criticize, nothing improves. The political gain of a manned Mars mission is like for Apollo : international prestige in many domains, reputation of efficiency, success, commitment etc.
the space station would cost $8 billion. Now the cost including operation is close to $100 billion. So why should they trust the cost estimate of $20 billion for Mars Direct? Or even the $55 billion of NASA's design reference mission. They remember that NASA had asked for $450 billion.
They will certainly be more careful. But there is a limit of cost for a single manned mission, could it really be above $450 billions ? If all you need is the shuttleC for a "demo" mission of feasibility, maybe that first demo mission can be set up for much less. Time will say how much costs a mission to Mars. I hope that the war will end soon that the people of the world can focuse on something else. Mars is perfect for that.
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if such experiments are performed or if crystals are grown it is better to have people on standby to actually witness it. Machines are still extremly limited in the scope of activities. To make a machine that can do these experiments we need one with AI, and that is not availble. It has to be availble, and no matter how close scientests are, it doesn't matter unless it IS availble. Besides, robots make poor mechanics anyways. I have never seen one fix my lawnmower (very, very simple machine-I did fix one myself this morning) and have the ablity to make reasonable decisions in an moderate amount of time. Sure, robots and machines are able to build cars, but only in an very, very controlled enviroment without any extra varibles to upset the assembly line. There is no subsitute for humans.
"I am the spritual son of Abraham, I fear no man and no man controls my destiny"
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oh yeah by the way, it was Lou Dobbs who wrote about the strength of metal being 300-900x stronger. sorry it took so long!
"I am the spritual son of Abraham, I fear no man and no man controls my destiny"
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The quote for being able to produce alloys that are 300 - 900x stronger than their earth based counterparts is wrong. Also the effect of gravity on the alloying elements of materiasl is a commonly held misconception. Temperature and compositional gradients drive the formation of alloys also affected by size factors, electrochemical factors and valency factors ala Hume Rothery.
The truth of the matter is that whilst gravity can have an affect, mostly through convection currents, its affects are easily dealt with either during casting or via processing - as everyone jas done for the last few thousand years before we had access to space.
At the end of the day, materials science is still quite a basic process when it comes to making new discoveries - engineers and scientists commonly produce thousands upon thousands of different compositions and test them all for their properties, and when they do a find a new or unexpected property they attempt to explain it, and then work on it further - but there is no way to predict totally new materials. It is nearly impossible to go through a thought process and expect to be able to predict exactly what you will produce when dealing with new compositions and processes.
I have no idea what materials will come out of a space programme and i have no doubt that they will be both innovative and better than their previous counterparts for what they are designed for - but these materials have not yet been discovered nor are they likely to be until there is a lot more infrastructure up there.
In terms of current materials that could be applied to the space programme, as robertdyck alluded to, there are often alot more factors that need to be taken into account than weight alone. safety is always of primary importance - and alot of materials werent developed to be used in, nor have they been tested in the extreme conditions we would wish to use them in.
Btw, carbon is the future and not just in terms of nanotube composites. Also a friend of mine is coming to end of some great pice of work which should do for titanium what the Hall-Heroult method did for aluminium. Exciting stuff. (God im a geek! ??? )
nick
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Btw, carbon is the future and not just in terms of nanotube composites. Also a friend of mine is coming to end of some great pice of work which should do for titanium what the Hall-Heroult method did for aluminium. Exciting stuff.
I agree with his statement very much. As with many fields, technology is developed by one industry and borrowed/perfected by another. I have seen Amazing things done with mountain bikes. I had one bike that had a 3AL/2.5V titanium frame that weigher a scant 3.2 lbs, magnesium alloy in the suspension fork legs, 7000 series Aluminum, 6000-series Alumium, 6al/4v Titanium, Manganese on the Seat rails. ETC ETC. Thats what led me to think of this topic. I have worked with Regular Mil Spec Equipment, then seen Minature versions, and been, OMG!, but the use of Exotic lightweight materials EVERYWHERE. Also, I know Transmitters are converting back to Solid State, but I am unaware of Thermal issues or Power Issues. I also don't know what the Noise Floor in Space is Compared to Earth, Completely different subject though.
We are only limited by our Will and our Imagination.
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What about concreate?
"I am the spritual son of Abraham, I fear no man and no man controls my destiny"
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What about it? ???
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Wouldn't that be stronger? I know it does stratify and that only a certain amount of it is ever poured at one time.
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