| Acronym | Meaning |
 | HFDS | Hydrogen Fluid Distribution System |
 | PMI | Preventive Maintenance Instruction |
 | MERL | Materials Engineering Research Laboratory |
 | LC | Integrated Circuit |
 | DPP | Data Processing And Software |
 | SEM | Seller's Engineering Memo |
 | CDMS | Command And Data Management Subsystem |
 | NESR | NNESRNatural Environment Support Room |
 | OPA | Operations Planning Analysis |
 | HIGH | PressuHigh Pressure |