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. 2016 Dec 22;7:13844. doi: 10.1038/ncomms13844

Figure 2. Optical and SAR satellite timeline for major Earth Observing satellites with systematic and global coverage.

Figure 2

The history of satellite platforms in orbit from launch to instrument failure/de-orbit are shown for (a) the major optical satellites and (b) Synthetic Aperture Radars that have acquired images on a global basis, as of late 2016, coloured by operator. Also shown are anticipated upcoming launches, which are approximate and subject to change. Many other satellite systems exist for imaging the Earth13, but are limited in coverage, availability and suitability of the data for use in studies of earthquake deformation, and so have been omitted for brevity. Earth observing satellites before 1985 have also been omitted for clarity. SAR satellites are grouped by radar wavelength (L-band 15–30 cm, C-band 3.75–7.5 cm and X-band 2.4–3.75 cm12) and the optical satellites by the image spatial resolution. Note that the ERS-2 mission is shown as ending when gyroscope failure in February 2001 made interferometry almost impossible, but the satellite mission continued until September 2011. ALOS-1, as well as carrying a SAR, had a 2.5 m resolution panchromatic optical system with forward, backward and nadir looking cameras (PRISM), and a 10 m visible and near-infrared imager (AVNIR). Planned SAR missions with multiple satellites in a constellation are shown with split arrow tails. The acronyms for space agency operators or commercial owners are given in the legends. ASI, Agenzia Spaziale Italiana (Italian Space Agency); CNES, centre national d'etudes spatiales (France - National Centre for Space Studies); CONAE, Comisión Nacional de Actividades Espaciales (Argentina - National Space Activities Commission); CSA, Canadian Space Agency; DLR, Deutsches Zentrum fur Luft- und Raumfahrt (German Aerospace Centre); ESA, European Space Agency; INTA, Instituto Nacional de Técnica Aeroespacial (Spain - National Institute of Aerospace Technology); KARI, Korean Aerospace Research Institute; JAXA, Japan Aerospace Exploration Agency; NASA, National Aeronautics & Space Administration (USA).