It is not possible to go into orbit from a single speed boost at the surface, even without an atmosphere, because the "orbit" would still contain the starting p

It is not possible to go into orbit from a single speed boost at the surface, even without an atmosphere, because the "orbit" would still contain the starting point. In other words, the orbit would intersect with the surface of Earth. (Well, unless you go all the way to escape velocity.) To fix this, an additional "apogee kick" is needed. The Spinlaunch concept is to get a small rocket + payload to 60 km altitude. Then the rocket would fire and actually put the payload in orbit. The catapult would only provide up to 2 km/s out of the ~ 10 km/s or so required to get to orbit. Saving those 2 km/s of rocket delta-v could be significant, because rocket size goes up exponentially with delta-v.