| H2O | Water (vapor) | - | Scuba Diving |
| HIMSS | HIgh-resolution Microwave Spectrometer Sounder | - | Scuba Diving |
| HIRDLS | HIgh-Resolution Dynamics Limb Sounder (EOS) | - | Scuba Diving |
| HIRES | HIgh RESolution | - | Scuba Diving |
| HIRIS | HIgh-Resolution Imaging Spectrometer (EOS) | - | Scuba Diving |
| HIRS | High-resolution Infrared Radiation Sounder | - | Scuba Diving |
| HIS | High-resolution Interferometer Sounder | - | Scuba Diving |
| HRIR | High Resolution Infrared Radiometer | - | Scuba Diving |
| HSB | Humidity Sounder For Brazil | - | Scuba Diving |
| HSRL | High Spectral Resolution Lidar | - | Scuba Diving |
| HST | Hubble Space Telescope | - | Scuba Diving |
| HZ | Hertz | - | Scuba Diving |
