fatal: Could not parse object '75b6966cc51aa89b6daf1efce5b18d11a3c48c5f'.
From https://github.com/NASA-Tensegrity-Robotics-Toolkit/NTRTsim
 * branch            master     -> FETCH_HEAD
HEAD is now at 75b6966 Delete tgBlockField.cpp
75b6966cc51aa89b6daf1efce5b18d11a3c48c5f