After trying to build an SSTO today, I noticed that the rapier engine is completely missing. I can't find it in the SPH, nor the VAB, not even if I look at the tech tree. The engine icon under available part of the node "Aerospace Tech" is completely empty.
Any idea what could have gone wrong/How I can fix it?
Edit: I' using mechjeb, kerbal alarm clock and Kerbal engineer.
Edit2: I solved the problem: Along time ago I tried to mess around with the thrust values of the rapier (but didn't trust myself to edit anything in the end) and apparently didn't change the .txt file back to .cfg but to .cfc