MOP-4 is the fully engineered flight spare of the Meteosat 7 weather satellite. The Meteosat series of geostationary satellites has provided images of Earth and data for weather forecasts since 1977. This satellite was launched in 1997 and is in geostationary orbit 36,000km above the equator at 0 longitude. With a value of £3 million, the flight spare is the most valuable item in the collection.

Google Earth is a virtual globe, map and geographic information program that was originally called Earth Viewer. It maps the Earth by the superimposition of images obtained from satellite imagery, aerial photography and GIS 3D globe.