[1] Pattern Recognition Society/System (->"IEEE Standard Dictionary")

[2] Process Radiation Sampler (->"IEEE Standard Dictionary")

[3] Personal Response System

[4] Personal Rescue System (->"NASA Acronym List")

[5] Precision Ranging System (->"NASA Acronym List")

[6] Primary Recovery/Rescue Site (->"NASA Acronym List")

[7] Power Reactant (Sub-)System (->"NASA Acronym List")

[8] Provisioning Requrements Statement (->"NASA Acronym List")