Space Transportation System 
Standard Technical Specifications 
Synchronous Transport Signal 
sequence tagged site 
Shuttle Transportation System 
Satellite Tracking Station 
Shared Tenant Services 
special tactics squadron 
Sales Technical Support 
Science Technology And Society 
Service Technicians Society 
Shared Tenant Service 
Shuttle Test Station 
Simple Template System 
so to speak 
Soft Tissue Swelling 
Specialty Training Standard 
Status 
STODDARD SILENCER 
Synchronous Transport Signals 
Satellite Transportation System 
Science and Technology Studies 
Secure Telephone System 
Security Token Service 
Sentinel Training System 
sequence tagged sites 
serologic test for syphilis 
serological test for syphilis 
Seville Touring Sedan 
Slater Transition State