NASA Investigates Laser-Beam Welding in a Vacuum for In-Space Manufacturing

Perhaps a more direct link <a href="https:&#x2F;&#x2F;www.nasa.gov&#x2F;centers-and-facilities&#x2F;marshall&#x2F;nasa-to-transform-in-space-manufacturing-with-laser-beam-welding-collaboration&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.nasa.gov&#x2F;centers-and-facilities&#x2F;marshall&#x2F;nasa-to...</a>

Electron beam welding requires a vacuum.[1] So that&#x27;s a promising technique for space welding.<p>Until recently, the whole object had to be in vacuum. A recent breakthrough is a welding head which creates a local vacuum around the welding area, rather than putting the whole object into a vacuum chamber. This allows automated welding of big, thick objects, all the way up to nuclear reactor pressure vessels.<p>[1] <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=GMSD5izdUyY" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=GMSD5izdUyY</a>

This is a good example of a space-based research initiative that might find significant applications on Earth.<p>I think the key reason that space-based research tends to be so technologically fruitful is that it imposes a discipline on the science done, through the constraints that space imposes on meeting ambitious mission objectives.<p>Space initiatives also provide a justification for doing the kind of blue skies research that might otherwise find difficulty finding funding.

Vacuum Laser welding is very much a thing already. Years back the old president wanted my team to build one from an old Wentgate e-beam chamber. Shipper destroyed the chamber in transit and my boss got into a silly fight with the vendor and shipper which killed the project. We then got a quote from EVO Beam who builds electron beam welders and other e-beam machines who does dual process, laser and EB in the same machine. Wound up buying another EB machine instead.<p>The challenge of welding in a vacuum is the molten weld pool emits metal weld vapor which impinges on surfaces in a linear trajectory from the pool. Think PVD, physical vapor deposition. So your beam delivery optics get a nice coating of whatever you are welding. I had some fun ideas for mitigating this in our design but never put it to test.

Heat rejection and work holding seem like two hard problems in space. On the lunar surface at least you have some gravity to help with the former, but your heat affected zone is bound to be much larger because the only way heat leaves the part is radiation. Also, laser welders (at least terrestrial ones) have a copper tip that you drag across the part which keeps the laser a consistent distance away from the weld. This will also heat up in a vacuum, and naively seems like it probably won&#x27;t work.<p>When welding thin material on Earth we use copper backing plates to suck heat out of the weld area, that could work in space. In zero g it would be easy to lose them (and your clamps).<p>All these things are surmountable I&#x27;m sure, would love to know more about how they plan to do it.

Wait, if you are in a vacuum and thus there is no oxidation layer, can&#x27;t you just press two (identical) metals together and they will be joined because the electrons don&#x27;t know which of the two objects they&#x27;re in?

Welding aluminum in Earth&#x27;s atmosphere is difficult because aluminum oxide forms on the surface and it has a higher melting point than the aluminum inside. So to weld aluminum you need to keep oxygen away from the weld, usually by flooding the weld with argon or some other inert gas.<p>In a vacuum this problem wouldn&#x27;t exist and aluminum should be no more difficult to weld than steel.

Laser welding has been around for a long time and is getting more common as of recent.<p>Example: <a href="https:&#x2F;&#x2F;youtu.be&#x2F;YTCnv1RV-Ns" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;YTCnv1RV-Ns</a>

What&#x27;s wrong with using an electric current to weld? Why use such an inefficient source of heat?<p>I feel lasers might have more safety problems too.

I wonder if space vacuum would work similarly to welding techniques that require inert gas

I take it they plan on chartering more Boeing launches then.

was welding ever tried on station?