| AASC | Astronomy and Astrophysics Survey Committee of the National Academy of Sciences |
| AGN | Active Galactic Nuclei |
| ALMA | Atacama Large Millimeter Array (NSF/Europe, planned) |
| ASCA | Advanced Satellite for Cosmology and Astrophysics, Japan/NASA (defunct) |
| Astro-E2 | An X-ray and gamma-ray satellite jointly developed by the US and Japan (planned) |
| BE | Beyond Einstein |
| Beppo-SAX | Satellite per Astronomia, Italy/Netherlands (operating) |
| BOOMERanG | Balloon Observations Of Millimetric Extragalactic Radiation and Geophysics (defunct & 2003) |
| CCD | Charge Coupled Device. A solid state detector of electromagnetic radiation, pioneered in the 1970s for military and astronomical use now also found in consumer digital cameras. |
| CGRO | Compton Gamma-ray Observatory (defunct) |
| Chandra | Chandra X-ray Observatory (operating) |
| CMB | Cosmic Microwave Background |
| COBE | Cosmic Background Explorer (defunct) |
| Con-X | Constellation X-ray Mission (planned) |
| CPU | Comittee on the Physics of the Universe of the NAS |
| DOE | Department of Energy |
| EGRET | Energetic Gamma Ray Experiment Telescope on CGRO. |
| ESA | European Space Agency |
| FUSE | Far Ultraviolet Spectroscopic Explorer (operating) |
| GALEX | Galaxy Evolution Explorer (2003) |
| GLAST | Gamma Ray Large Area Telescope |
| GPB | Gravity Probe B (2003) |
| GRACE | Gravity Recovery and Climate Experiment, NASA/Germany (operating) |
| GRB | Gamma-ray burst |
| Herschel | ESA/NASA far infrared mission (planned) |
| HST | Hubble Space Telescope (operating) |
| INTEGRAL | International Gamma-Ray Astrophysics Laboratory, ESA/Russia/NASA (operating) |
| JWST | James Webb Space Telescope (formerly Next Generation Space Telescope - NGST, planned) |
| LIGO | Laser Interferometer Gravitational-wave Observatory, NSF (operating) |
| LISA | Laser Interferometer Space Antenna (planned) |
| MAP | Microwave Anisotropy Probe (operating) |
| MIDEX | Medium-class Explorers. The most expensive class of NASA Explorer mission. |
| NAS | National Academy of Sciences |
| NASA | National Aeronautics and Space Administration |
| NGC | J.L.E. Dreyer’s 1887 New General Catalog (of nebulae and bright galaxies) |
| NICMOS | Near Infrared Camera and Multi-Object Spectrometer on the Hubble Space Telescope |
| NSF | National Science Foundation |
| OSS | Office of Space Science (NASA) |
| PI | Principal Investigator |
| Planck | ESA/NASA cosmic microwave background mission (planned) |
| ROSAT | Röntgen (X-ray) Satellite, Germany (defunct) |
| RXTE | Rossi X-ray Timing Experiment (operating) |
| SEU | Structure and Evolution of the Universe (OSS Theme) |
| SIRTF | Space Infra-red Telescope Facility (2003) |
| SMEX | Small Explorers. The less expensive class of NASA Explorer mission. |
| SNAP | Supernova/Acceleration Probe, DOE (planned) |
| SOFIA | Stratospheric Observatory for Infra-red Astronomy, NASA/Germany (planned) |
| SMART-2 | ESA Small Mission for Advanced Research in Technology 2: LISA Test Package (planned) |
| SPIDR | Spectrometry and Photometry of the Intergalactic mediums’ Diffuse Radiation (planned) |
| ST7 | Space Technology 7. NASA Disturbance Reduction System technology project. (planned) |
| Swift | A multi-wavelength gamma-ray observatory (2003) |
| ULDB | Ultra-Long Duration Balloons |
| VLBI | Very Long Baseline (radio) Interferometry |
| XMM | X-ray Multi-mirror Mission, ESA/NASA (operating) |
