Nose Lines Matter

As in the visible lines on the nose of something that will go at hypersonic speeds.  OK, so it's a slow news day in the Space Business, I'm trying...

With the desired number of Starships that SpaceX talks about building, you've got to believe that the design of these ships is going to be heavily researched with the emphasis on what industry calls Design For Manufacturability or DFM.  If the plan is to build ten or twenty, saving a few dollars on each vehicle or an hour here and there isn't a big deal.  On the other hand, if the quantity goes up, those few dollars start to matter.  They matter even more if there's time saved with the cost savings.  

The story over on Teslarati is on how the noses of Starships have changed over the design process.  It gets more important when you know that the manufacturing processes used for the noses are essentially the same as those used to produce the fuel and oxygen tank domes.  

Though improvements and changes have almost certainly been made in the last ~18 months, the early unflown prototypes and the noses of Starships SN8, SN9, SN10, SN11, SN15, SN16, S20, and S22 have all been constructed in roughly the same way. SpaceX would first produce a series of thin, stamped sheets (gores) of steel. Once aligned on custom-built jigs, each of those gores would be welded together to form a slightly conical ring. Five total ‘rings’ would be assembled, each narrower and more conical than the last. The five sections would then be stacked one by one and welded together along their circumferences.

Altogether, something like 120 complex vertical welds would be needed just to assemble the most basic structure of a nose, followed by four or five no less complex circumferential welds to turn those sections into one cone. SpaceX’s upgraded design seeks to simplify that process mainly by increasing the size of the gores. Aside from modestly reducing the number of longitudinal sections needed to form the cone, SpaceX has also reduced the number of stacked sections from five to two, slashing the total number of gores needed by at least a factor of two or three. While not quite as substantial, the same simplification also reduces the length of vertical and circumferential welds needed to assemble a nosecone.

In this photo (BocaChicaGal at NASASpaceflight.com), with an early nose cone on the left and an early 2022 nose on the right.  The one on the left is obviously not as smooth as the newer one on the right, and there are more obvious horizontal weld lines.  The nose lines look better on the right.  I know the number of gores has been reduced, but don't have a number showing the change from the earliest to the most recent noses. 

It appears that the first of the new noses to be used will be on Starship SN24, which is currently being built.  

The same manufacturing engineering team is working both the noses and tank domes, so the concept has moved to those designs, too.  SpaceX appears to have also decided to increase the size of dome gores and reduce the number of stacked sections required for assembly, from three to two.  The number of pieces for a tank dome has been reduced from 43 to 18, so the number of welds has gone down massively.

Conceptual rendering of the new domes (left) vs. the original domes as they work in the Starship from Brendan Lewis on Twitter.  The bottom dome is unaffected since it has the plumbing to attach the six Raptor engines, three sea level and three vacuum. 

No matter what sort of thing you're assembling, from computer to smartphone to a Starship, it's always a priority to investigate reducing both the component count and the number of assembly operations.  Those two usually go together.  Elon Musk has already said that manufacturing is the hard part and that when you're producing things, all the money spent on the "glamor" work in design ends up as a small, marginal cost compared to all the costs you incur by manufacturing improperly. 

When you're expecting to need to build tens of thousands of Starships, an hour saved on each one gets pretty darned important.