What are High Altitude Platforms (HAPs)?

High Altitude Platforms (HAPs) are airships or planes, operating in the stratosphere, at altitudes of typically 17 - 22km (around 75,000 ft). At this altitude (which is well above commercial aircraft height), they can maintain a quasi-stationary position, and support payloads to deliver a range of services: principally Communications, and Remote Sensing.

Communications services include broadband, 3G, and emergency communications, as well as broadcast services. A HAP can provide the best features of both terrestrial masts (which are then not required) and satellite services (which would be highly expensive). In particular, HAPs permit rapid deployment, and highly efficient use of the radio spectrum (largely through intensive frequency re-use).

The relatively close range of HAPs compared to satellites means that imaging and remote sensing is highly effective, offering low cost and high resolution. A variety of hybrid applications may also be envisaged, such as traffic management, navigation, security management etc.

There are two fundamental types of platform technology capable of stratospheric flight: unmanned aircraft and unmanned airships. However, manned aircraft (flying in circles) could also represent a HAP. Other platform technologies, such as manned aircraft and tethered aerostats, and lower altitude UAVs (Unmanned Aerial Vehicles) may also have a developmental role towards HAPs and their applications.

For further reading, see the Technical Publications page, although this has not been updated since 2010.