Space travel is tricky. Hell, getting TO space is tricky; once you’re there you’ve got to deal with cosmic dust, space junk, and high-energy, ionizing cosmic rays. People at NASA are still amazed that they managed to send people to the moon over 40 years ago. One of the areas that causes much frustration is the having to engineer everything for more than one environment; rocket components have to be safe and effective in this atmosphere, in the dark abyss that is space, and during the bumpy ride there. For space ultra-light materials are ideal, but for launch components need to be sturdy AND light. For engineers the battle of tradeoffs ensues because how they want something made doesn’t always jive with what’s possible through conventional fabrication methods. It’s difficult to optimize for either weight or structural integrity when welding is involved as mass is added and strength is not uniform, so engineers must err on the side of caution and design things to be bulkier and heavier than is ideal because that’s better than risking structural failure. “But NASA already has plans to use 3D printing in orbit, so why don’t they print rocket stuff too?” I hear you saying, and perhaps NASA also heard you because they now have plans to do just that.
In my home state of Alabama is the ironically located Marshall Space Flight Center — ironic because Alabama isn’t known for esteemed literacy with regards to science. Or words. Maybe they don’t drink the water in Huntsville, Alabama, I don’t know, but somehow they manage to understand rockets there and that’s where the new Space Launch System (SLS) is being developed. The SLS is intended to be a heavy-lift rocket that will transport people and cargo beyond low orbit to asteroids and perhaps Mars, and the project will be enhanced by using selective laser melting (SLM) to print many of the parts. As you and the NASA engineers rightly figure, printing parts allows them to be lighter because there’s no welding, stronger because there’s no welding, and more quickly produced and intricate because that’s just the nature of 3D printing. If less parts can be used without sacrificing functionality, then more efficiency gains can be achieved through specifically engineering for that reality. This amounts to substantial cost savings and increased safety for anyone that will ride in the J-2X powered people missile.
NASA is employing the powerful Concept Laser M2 Cusing printer which creates metal parts by melting powdered metals with a laser, so the results will be top notch, which by space travel standards means “adequate.” I’m still at a loss as to why these technologies haven’t been used in aerospace before now, but at least some of the world’s top engineers are getting around to working with the world’s most efficient means of fabrication.