First off, thanks to KapteinB for linking to the twits at spinlaunch. I enjoyed taking it apart even if I can't really believe in it. That led me to do some exploration of my own which is about where I discovered the batshit insanity of the Sprint program.

Sprint accelerated at 100 g, reaching a speed of Mach 10 in 5 seconds. Such a high velocity at relatively low altitudes created skin temperatures up to 6,200 °F (3,430 °C), requiring an ablative shield to dissipate the heat.[1][2] The high temperature caused a plasma to form around the missile, requiring extremely powerful radio signals to reach it for guidance. The missile glowed bright white as it flew.

I found my buddy Scott Lowther above, who I used to give $10 a month to for several years, because not surprisingly "zirconium staples" is a statistically-significant search term.

The early SPRINT motor that was described to me was a nitrocellulose/nitroglycerine motor with a difference. Rather than mixing the components and then pouring into the motor, the nitrocellulose powder was sifted into the motor a thin layer at a time. (The motor, conical in shape, was upside down, forming a “cup,” with a metal mandrel in the core. The powder would thus form a layer that would bond to the conical motor walls, and when the mandrel was withdrawn, leave a large void volume in the center.) Then an early industrial robot would reach down into the motor case and carefully place zirconium “staples” onto the powder. These staples were described as looking like regular office staples, except one of the “arms” was bent up 90 degrees so that the staple covered all three X-Y-Z axes. Once the staples were in place, more powder would be added, then more staples, then more powders, etc. When the motor was properly filled with powder and staples, nitroglycerine would be carefully poured in; it would infiltrate the powder and turn it all to gel while leaving the staples in place. The gel would set up solid and the mandrel would be removed from the motor.

I dunno. It ain't a great day for democracy. but I'm reminded that we survived the '60s and '70s, despite our best efforts.