Office of Primary Responsibility 
Office of Professional Responsibility 
Operations Planning Review 
Orbiter/Payload Recorder 
operate 
operator 
Officer Performance Report 
Officer Performance Reports 
Offices of Primary Responsibility 
operative 
Optical Page Reading 
Over Pressure Relief 
Office of Planning and Research 
Office of Prime Responsibility 
Offsite procurement request 
operating 
Optical Pattern Recognition 
Oregon Pacifc Railroad 
Other People's Resources 
Oxygen Pressure Regulator 
Objective Progress Report 
Office of Personnel Relations 
Office of Population Research 
Office of Public Responsibility 
Officer of Primary Responsibility 
Official Pattern Release 
Oil Production Rate 
Once Per Revolution 
oparational 
opener