ok, yes, spaceshipone did have a heat shield because it heats up as it falls back down into the atmosphere BUT it is not the same as the shuttle for example which is in orbit and must re - enter the atmosphere at a very precise angle (because of it great orbital speed).
spaceshipone went straight up and came straight down.
there was no orbit.
ok, a 100 km above the earth is where you can put something in orbit in order to avoid atmospheric drag. that doesn't mean you are in orbit if you reach that hight, silly :-)