NASA Investigates Laser-Beam Welding in a Vacuum for In-Space Manufacturing (nasa.gov) 41
NASA hopes to stimulate in-space manufacturing through a multi-year "laser beam welding collaboration" with Ohio State University. The project "seeks to understand the physical processes of welding on the lunar surface," according to NASA.gov, "such as investigating the effects of laser beam welding in a combined vacuum and reduced gravity environment."
The goal is to increase the capabilities of manufacturing in space to potentially assemble large structures or make repairs on the Moon, which will inform humanity's next giant leap of sending astronauts to Mars and beyond. "For a long time, we've used fasteners, rivets, or other mechanical means to keep structures that we assemble together in space," said Andrew O'Connor, a Marshall materials scientist who is helping coordinate the collaborative effort and is NASA's technical lead for the project. "But we're starting to realize that if we really want strong joints and if we want structures to stay together when assembled on the lunar surface, we may need in-space welding."
The ability to weld structures in space would also eliminate the need to transport rivets and other materials, reducing payloads for space travel. That means learning how welds will perform in space. To turn the effort into reality, researchers are gathering data on welding under simulated space conditions, such as temperature and heat transfer in a vacuum; the size and shape of the molten area under a laser beam; how the weld cross-section looks after it solidifies; and how mechanical properties change for welds performed in environmental conditions mimicking the lunar surface. "Once you leave Earth, it becomes more difficult to test how the weld performs, so we are leveraging both experiments and computer modeling to predict welding in space while we're still on the ground," said O'Connor.
In August 2024, a joint team from Ohio State's Welding Engineering and Multidisciplinary Capstone Programs and Marshall's Materials & Processes Laboratory performed high-powered fiber laser beam welding aboard a commercial aircraft that simulated reduced gravity. The aircraft performed parabolic flight maneuvers that began in level flight, pulled up to add 8,000 feet in altitude, and pushed over at the top of a parabolic arc, resulting in approximately 20 seconds of reduced gravity to the passengers and experiments. While floating in this weightless environment, team members performed laser welding experiments in a simulated environment similar to that of both low Earth orbit and lunar gravity. Analysis of data collected by a network of sensors during the tests will help researchers understand the effects of space environments on the welding process and welded material.
They performed that laser-beam welding in a vacuum chamber during the parabolic flight (on a Boeing 727), according to the article — and successfully completed 69 out of 70 welds in microgravity and lunar gravity conditions. "The last time NASA performed welding in space was during the Skylab mission in 1973...
"Practical welding and joining methods and allied processes, including additive manufacturing, will be required to develop the in-space economy."
The ability to weld structures in space would also eliminate the need to transport rivets and other materials, reducing payloads for space travel. That means learning how welds will perform in space. To turn the effort into reality, researchers are gathering data on welding under simulated space conditions, such as temperature and heat transfer in a vacuum; the size and shape of the molten area under a laser beam; how the weld cross-section looks after it solidifies; and how mechanical properties change for welds performed in environmental conditions mimicking the lunar surface. "Once you leave Earth, it becomes more difficult to test how the weld performs, so we are leveraging both experiments and computer modeling to predict welding in space while we're still on the ground," said O'Connor.
In August 2024, a joint team from Ohio State's Welding Engineering and Multidisciplinary Capstone Programs and Marshall's Materials & Processes Laboratory performed high-powered fiber laser beam welding aboard a commercial aircraft that simulated reduced gravity. The aircraft performed parabolic flight maneuvers that began in level flight, pulled up to add 8,000 feet in altitude, and pushed over at the top of a parabolic arc, resulting in approximately 20 seconds of reduced gravity to the passengers and experiments. While floating in this weightless environment, team members performed laser welding experiments in a simulated environment similar to that of both low Earth orbit and lunar gravity. Analysis of data collected by a network of sensors during the tests will help researchers understand the effects of space environments on the welding process and welded material.
They performed that laser-beam welding in a vacuum chamber during the parabolic flight (on a Boeing 727), according to the article — and successfully completed 69 out of 70 welds in microgravity and lunar gravity conditions. "The last time NASA performed welding in space was during the Skylab mission in 1973...
"Practical welding and joining methods and allied processes, including additive manufacturing, will be required to develop the in-space economy."
Zero conduction (Score:3)
Welding ought to be a bit more efficient in space, what with the almost complete lack of conductive heat loss from the objects being welded and lack of contaminants due to a lack of atmosphere for them to be billowing around in. You'd still have conductive loss along those objects, of course, and cooling things down afterwards will be more challenging. Patience and radiative cooling, I guess.
But it's space... in a lot of cases you can just (for values of 'just' that involve being in the hostile environment of space) polish contact points on two bits of metal and squeeze them together and they'll cold weld themselves.
Re: Zero conduction (Score:1)
How do you figure a vacuum affects heat conduction? You know, considering heat conduction is what happens in solids?
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Convection is powered by conduction, which is how the cooling fluid is heated.
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I think the OP means that heat, in a vacuum, can't dissipate like it can in a gaseous environment. Since it's a vacuum, there is nothing to transport the heat away from the weld and the metals. The people below who have welding experience will correct me if I'm off base (highly possible), but welding involves using a certain type of heat (in the general sense) to create the weld. If the heat between the two pieces gets too hot, the weld will be affected.
In the case of welding in a vacuum, sure, the metals
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Re: Zero conduction (Score:4, Insightful)
Re: Zero conduction (Score:4, Insightful)
The people below who have welding experience will correct me if I'm off base (highly possible), but welding involves using a certain type of heat (in the general sense) to create the weld. If the heat between the two pieces gets too hot, the weld will be affected.
Too hot or too long softens a larger area around the weld, in which case the parts may change shape to an unacceptable degree as well as messing with any special heat treatment that might have been used. You can't avoid changing the material but you do want to keep the affected area as small as possible. Go way too hot and the parts you're trying to weld together will start to drip away* leaving you to either scrap the parts and try again or fill the gap and hope it's as strong as the original metal. If you're welding thin sheets the problem is much, much worse; you can easily melt a sizeable hole in the piece if you use too much heat.
*Protip: wear the leather apron. Always. It's just as important as the visor. One day I was welding a car chassis on some axle stands while sitting cross-legged on the ground so I could better see what I was doing.
I didn't spot the little hole in my trousers until later in the day,
or the little hole in the front of my underwear,
or the little hole in the back of my underwear,
or the little hole in the seat of my pants...
IOW a little gobbet of molten metal came within an inch of where no man wants molten anything.
Wear. The. Apron.
Re: Zero conduction (Score:2)
Re:Zero conduction (Score:5, Informative)
In welding, the two (or more) separate pieces of metal need to become one. "Cold Welding" is effectively impossible, though an adhesive bond could conceivably work well enough for some purposes. Heat needs to be applied to a level that at least softens the metal and allows for a modicum of "flow" between molecules and/or atoms of the two pieces... which means either heating both pieces up and pressing them together (commonly used for welding the ends of pipes and tubes together) or clamping them together tightly and applying heat to force the pieces to merge (often seen in the sheet metal industry--automotive, for instance--as "spot welding"). Both are essentially inductive welding, but they wouldn't necessarily be sufficient for assembling an atmosphere-tight vessel meant for human occupation...
I question that even a laser would really be able to work effectively without some means of flowing new metal into the joint to be bonded, as compared to the inductive methods above.
As for the heating and cooling you describe... you really wouldn't want a rapid cooling effect if you can help it; you're more likely to shatter the weld if it cools too quickly and honestly a slower cooling period would help to relieve stress in the bond on larger pieces. The complete lack of oxygen in space would eliminate the oxidation process which is what weakens most welds.
Re:Zero conduction (Score:4, Informative)
He's referring to "vacuum welding" or "cold welding" where like metals will weld themselves together in a vacuum. From the wiki article on cold welding [wikipedia.org]
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Cold welding works fine, but it requires both pieces to be polished smooth surfaces that are shaped to allow "perfect" contact, and so clean that there are no absorbed gasses on the surfaces. I'm not totally sure how strong a weld that makes, but definitely can happen...though only in a REALLY good vacuum.
The problem is that ANY surface imperfections weakens the weld a LOT. And volatiles adsorbed onto the surfaces that are to be brought into contact counts as an imperfection.
Re: Zero conduction (Score:3)
"Cold Welding" is effectively impossible, though an adhesive bond could conceivably work well enough for some purposes.
It doesn't happen in an atmosphere precisely because there is an atmosphere but in a vacuum it's quite real and has to be designed around.
Heat needs to be applied to a level that at least softens the metal and allows for a modicum of "flow" between molecules and/or atoms of the two pieces...
Molecules? That's not how alloys work. Plastics yes, I suppose, though I wouldn't bet on there being much chemistry involved when one welds plastics. When you weld metals you have to melt the parts you want to attach together. Softening won't do it.
which means either heating both pieces up and pressing them together (commonly used for welding the ends of pipes and tubes together)
I think most pipe joins are done with MIG/TIG and a jig. You could do friction welding but that's impractical on long lengths
Re:Zero conduction (Score:4, Interesting)
I’m gonna guess that welding in space could be pretty good, as long as they choose the right alloys and tailor the parameters. This is a place where real research would be needed, and no commercial entity would fund it. A perfect use of taxpayer research money.
Re: Zero conduction (Score:2)
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I think you should expect problems with gas torch welding if there's no atmospheric pressure. The other two should work fine. But laser welding should allow welding at a distance (as gas torch welding does on Earth). And it's probably got other advantages (besides requiring fewer shipments of supplies).
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And it's probably got other advantages (besides requiring fewer shipments of supplies).
For starters, you aren't restricted to welding conductive materials. As for gas torches, you don't use those at a distance, unless you count an inch or so as significant. Whether they would work at all is an interesting question but not one I'd expect them to waste time answering.
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Arc welding, spot welding and gas torch welding
I don't think arc welding would work in a vacuum. You need a gas for the arc to pass through. An electric arc is electricity turning gas into plasma which conducts the current better than the gas in its normal state. You could try to supply a stream of gas for the arc, but it would tend to expand rapidly in all directions meaning you'd need a lot of gas and I'm not sure if you could maintain a high enough density to support an arc.
I also don't think torch welding would work. Rather than having a nice di
Laser welding in space... (Score:4, Interesting)
Having been a welder myself, there are questions that occur suggesting a re-think. Has anyone actively attempted welding in a vacuum? The low-G factor is almost irrelevant (up to a point) but the no-atmosphere welding could be a major factor that could make the welding much easier. Most welding is performed with either a gas jet or other "flux" intended to drive oxygen in particular out of the weld area in order to reduce or eliminate the risk of corrosion at the weld point (seam, etc.). These fluxes can actually create a spattering effect as metal tends to get blown out of the weld during the welding process...most obviously with electric arc welding but also with different gas welding methods. The laser will obviously minimize that spattering but is it really necessary when the arc welder simply doesn't need the flux?
Additionally, speaking on the low-G factor... how can we be sure the metal will flow INTO the joint if no gas or 'flux' is used? On the Moon or any reasonably measurable gravity a flat weld would be pretty effective in the direction of gravity, but vertical or even overhead welds could result in 'drips' and 'runs' which may or may not affect the strength of the weld. I noted the ballistic flight experiments, which were mostly successful, but has anyone, yet, attempted BOTH microgravity/zero atmosphere welding combined?
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I am a very bad welder, but I have had some of these same thoughts. What I've wondered about space welding is what wins, the surface tension of the bead, or the escaping fumes. And if that's even an issue, can you solve it with choice of alloys. I'm sure this has been postulated about and I just haven't found the right papers, though. Oxygen reduces the surface tension, so that part seems like a win...
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Why would the fumes escape in zero-G? No convection would happen. All I can think of is pressure, so anything that vaporized (under zero pressure) would tend to leave. Liquids would be held by "wetting" and surface tension. Perhaps this means that the weld area should be heated slowly across certain transition boundaries (where something changes state).
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Why would the fumes escape in zero-G?
Expansion due to change of phase.
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Just "expansion due to change of phase" wouldn't suffice. I think it would need to vaporize to leave the area. Even then, unless it's in a vacuum there's no convection. Hot gasses don't rise.
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Just "expansion due to change of phase" wouldn't suffice. I think it would need to vaporize to leave the area.
What phase do you think we're talking about it changing to which produces gases?
Even then, unless it's in a vacuum there's no convection. Hot gasses don't rise.
The subject of this discussion is NASA Investigates Laser-Beam Welding in a Vacuum for In-Space Manufacturing.
You're 0 for 2.
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What I've wondered about space welding is what wins, the surface tension of the bead, or the escaping fumes.
You're not the first. Until today I had no idea the Soviets tried to find out [wikipedia.org].
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Without some kind of gas, I doubt you can establish an arc of any kind, such as you'd need for spray transfer or TIG welding. The shielding gas provides this medium, but in a vacuum it would spread and dissipate rather quickly. The advantage of laser welding is would not require an arc to do the heating.
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Robot welder (Score:2)
That would be cool, a robot welder.
Re: Robot welder (Score:4, Funny)
Did anybody else... (Score:2)
read that as laser-beam wielding?
(space combat, Buck Rogers, Flash Gordon etc)
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Yeah.
Pew, pew, pew.
MTG cums in panties (Score:1)
nuf sed
Re: (Score:2)
You should not say such thing about MTG, she does not wear panties.
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I'm almost afraid to ask... how do you know?
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They wore stretched wild boar intestines back in her preferred era.
Welding gas (Score:2)
Inert gases are used in welding to keep the oxygen out and give a much cleaner weld.
Re: Welding gas (Score:2)
Cold welding? (Score:1)
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A good cold weld requires that both surfaces be not only clean, but also smooth, and shaped appropriately. (Flat is easiest.) Fluids will flow to adapt to imperfections in the shape, but solids don't do that.