| C&T | Communications & Tracking | - | Atmospheric Research Center |
| CADH | Communications And Data Handling | - | Atmospheric Research Center |
| CARA | Center For Astrophysical Research In Antarctica | - | Atmospheric Research Center |
| CASCA | Canadian Astronomical Society | - | Atmospheric Research Center |
| CASSINI | Saturn Orbiter And Titan Probe | - | Atmospheric Research Center |
| CATS | Cheap Access To Space | - | Atmospheric Research Center |
| CBR | Cosmic Background Radiation | - | Atmospheric Research Center |
| CCAFS | Cape Canaveral Air Force Station | - | Atmospheric Research Center |
| CCD | Charge-Coupled Device | - | Atmospheric Research Center |
| CCDS | Centers For The Commercial Development Of Space | - | Atmospheric Research Center |
| CCRS | Canada Centre For Remote Sensing | - | Atmospheric Research Center |
| CCSDS | Consultative Committee For Space Data Systems | - | Atmospheric Research Center |
| CD-ROM | Compact Disk Read-Only Memory | - | Atmospheric Research Center |
| CDA | Command And Data Acquisition | - | Atmospheric Research Center |
| CDDT | Countdown Demonstration Test | - | Atmospheric Research Center |
| CDM | Cold Dark Matter | - | Atmospheric Research Center |
| CDS | Command And Data Subsystem | - | Atmospheric Research Center |
| CEA | Center For EUV Astrophysics | - | Atmospheric Research Center |
| CELSS | Controlled Ecological Life Support System | - | Atmospheric Research Center |
| CERES | Clouds And Earth's Radiant Energy System | - | Atmospheric Research Center |
| CETA | Crew And Equipment Translation Aid | - | Atmospheric Research Center |
| CFA | Harvard-Smithsonian Center For Astrophysics | - | Atmospheric Research Center |
| CFC | ChloroFluoroCarbon | - | Atmospheric Research Center |
| CFF | Columbus Free Flyer | - | Atmospheric Research Center |
| CFHT | Canada-France-Hawaii Telescope | - | Atmospheric Research Center |
| CFPA | Center For Particle Astrophysics (Berkeley) | - | Atmospheric Research Center |
| CFRP | Carbon Fibre Reinforced Plastic | - | Atmospheric Research Center |
| CG | Center Of Gravity | - | Atmospheric Research Center |
| CGF | Crystal Growth Furnace | - | Atmospheric Research Center |
| CGRO | Compton Gamma Ray Observatory | - | Atmospheric Research Center |
| CHARA | Center For High Angular Resolution Astronomy | - | Atmospheric Research Center |
| CIRRIS | Cryogenic InfraRed Radiance Instrument For Shuttle | - | Atmospheric Research Center |
| CIS | Commonwealth Of Independent States | - | Atmospheric Research Center |
| CIT | Circumstellar Imaging Telescope | - | Atmospheric Research Center |
| CITA | Canadian Institute For Theoretical Astrophysics | - | Atmospheric Research Center |
| CITE | Cargo Integration Test Equipment | - | Atmospheric Research Center |
| CLAES | Cryogenic Limb Array Etalon Spectrometer | - | Atmospheric Research Center |
| CM | Command Module | - | Atmospheric Research Center |
| CM | Center Of Mass | - | Atmospheric Research Center |
| CM | Central Meridian | - | Atmospheric Research Center |
| CMB | Cosmic Microwave Background | - | Atmospheric Research Center |
| CMBR | Cosmic Microwave Background Radiation | - | Atmospheric Research Center |
| CMCC | Central Mission Control Centre | - | Atmospheric Research Center |
| CNES | Centre National D'Etude Spatiales | - | Atmospheric Research Center |
| CNO | Carbon-Nitrogen-Oxygen | - | Atmospheric Research Center |
| CNSR | Comet Nucleus Sample Return | - | Atmospheric Research Center |
| COBE | COsmic Background Explorer | - | Atmospheric Research Center |
| COMPTEL | COMPton TELescope | - | Atmospheric Research Center |
| COMSAT | Communications Satellite (Corporation) | - | Atmospheric Research Center |
| COSTAR | Corrective Optics Space Telescope Axial Replacement | - | Atmospheric Research Center |
| CPCG | Commercial Protein Crystal Growth | - | Atmospheric Research Center |
| CR | Correlation Radiometer | - | Atmospheric Research Center |
| CRAF | Comet Rendezvous/Asteroid Flyby | - | Atmospheric Research Center |
| CREAM | Cosmic Radiation Effects And Activatiom Monitor | - | Atmospheric Research Center |
| CRIM | Commercial Refrigerator Incubator Module | - | Atmospheric Research Center |
| CRISTA | Cryogenic Infrared Spectrometer Telescope For Atmosphere | - | Atmospheric Research Center |
| CRL | Communication Research Lab | - | Atmospheric Research Center |
| CRRES | Combined Release/Radiation Effects Satellite | - | Atmospheric Research Center |
| CSA | Canadian Space Agency | - | Atmospheric Research Center |
| CSIRO | Commonwealth Scientific And Industrial Research Organization | - | Atmospheric Research Center |
| CSM | Command And Service Module | - | Atmospheric Research Center |
| CSTC | Consolidated Satellite Test Center | - | Atmospheric Research Center |
| CTIO | Cerro Tololo Interamerican Observatory | - | Atmospheric Research Center |
| CV | Cataclysmic Variable | - | Atmospheric Research Center |
| CXBR | Cosmic X-ray Background Radiation | - | Atmospheric Research Center |
| CYSB | Cape York Space Base | - | Atmospheric Research Center |
| CYSF | Cape York Space Facility | - | Atmospheric Research Center |
| CYSP | Cape York Space Port | - | Atmospheric Research Center |
| CZCS | Coastal Zone Color Scanner | - | Atmospheric Research Center |
