"None of the technical problems you'd have to solve would advance real spaceflight." That's just not true. Spaceflight is hard. There are many, many technica

"None of the technical problems you'd have to solve would advance real spaceflight." That's just not true. Spaceflight is hard. There are many, many technical problems to solve. Just because you're not going to orbit, doesn't mean that you're not advancing the state of the art. I'm a former XCOR investor. I supported them not for their suborbital program, but for their orbital vision [see e.g. https://spacenews.com/34930xcor-aerospace-makes-plans-for-reusable-orbital-vehicle/ https://spacenews.com/34930xcor-aerospace-makes-plans-for-re...]. The Lynx was a stepping-stone, a way of both funding their larger ambition and testing small parts of the larger system. The idea was to build to space as incrementally as possible, so as to be able to avoid the huge "and then we need $100M, and then it works or it doesn't" step that most space business plans have. Remember that the founding team had just come out of the crater of Rotary Rocket, which had one of those plans. Jeff Greason once said that if he could find a way to fly half a customer to space, he'd do it. Unfortunately, there were still some lumps in the capital needs, the jump from engines to the Lynx was larger than expected, the Lynx took longer than expected, and the funding wasn't there. If they'd had another $20M, it could have been amazing, but that's a common refrain. XCOR's plan was basically the opposite of SpaceX: rather than going orbital and then building in reusability, they started with total reusability and then wanted to bootstrap to orbit. Their goal was full airplane-style reuse, where you land, inspect, fuel, and go, and fly the same craft again in a matter or hours or minutes. They'd already demonstrated that kind of turnaround with their rocket-powered airplanes; I believe I saw a video of a sub-15-minute turnaround on the EZ Rocket. They'd also made engines that could withstand hundreds if not thousands of firings, and pumps that lacked the catastrophic failure modes and tiny tolerances of turbopumps. Yes, I lost all the money. But it was worth a shot.