ARC Engines were one of the companies graduating at the recent TechStars demo day in Adelaide. As another commenter pointed out it seems much of the innovation

ARC Engines were one of the companies graduating at the recent TechStars demo day in Adelaide. As another commenter pointed out it seems much of the innovation is the improvements you can make to the internal chamber design through 3D printing. I also gather they’re onto (at least) their second generation of working rocket http://arc-engines.com http://arc-engines.com