Russian Space Agency 
Range Standardization and Automation 
Rehabilitation Services Administration 
Rivest-Shamir-Adleman 
Rural Service Area 
Rational Software Architect 
Reference Satellite A 
Registry System Administrators 
Republic of South Africa 
ROOSA-MASTER 
Royal Society of Arts 
runway safety area 
Russian Solar Array 
rabbit serum albumin 
Radio Set Adapter 
Railway Study Association 
random sequential adsorption 
rat serum albumin 
recurrent spontaneous abortion 
Rehabilitative Services Administration 
Reliable Service Area 
Remote Storage Area 
Remote Supervisor Adapter 
Repair Service Answering 
Repair Service Attendant 
Research Society on Alcoholism 
respiratory sinus arrhythmia 
retrograde storage area 
Revised Shapley Ames 
Right Shift Algorithm