"Very much" is out of place here. X-33 had 5 risky technologies to prove, and any failure with them could ground the project. Formally they failed when the comp

"Very much" is out of place here. X-33 had 5 risky technologies to prove, and any failure with them could ground the project. Formally they failed when the composite tank structure broke (the liquid gas evaporated and composite layers detached), but even with the proposed fix (a more conservative and less performant aluminum tank) they still had to clear the other problems. So, Venture Star probably was just "possible technology". Still risky at the time, at the beginning of the millennium.