Scientific, economic and political knowledge about climate relies on satellite data. Images, maps, measurements and graphs generated with satellites are now part of the structure of the social order, often taken for granted, surrounded by an aura of truth, self-evidence, neutrality, objectivity and accuracy, understood to be given and unquestionable, rarely subject to scientific probing or political dispute.

Yet, satellite data are not objects that are out there waiting to be collected. CLIMASAT understands satellite data as relational entities that include more than sensing technologies and data handling systems: they also imply a set of individual actors, institutions and forms of organization that intervene in their development, maintenance, dissemination and use, the sociotechnical arrangements from which they emerge, and the power relations that go with them.

Sensors inside satellites collect light reflected and radiated from the Earth’s surface and atmosphere, converting it to digital intensities before transmitting them to the ground station -or the cloud. These data are then dated, located, calibrated, reduced, filtered, stabilized, corrected and converted into other data about the atmosphere, the oceans or the land surfaces. These data can, in turn, be further analysed and reprocessed for more detailed knowledge through retrieving, inverting, classifying, mapping, coloring, plotting, comparing and a myriad f other processes.

These data journeys involve a complex array of individual actors and organizations, including industry, universities and research centers, governmental organizations (civilian and military; national and international), media, and NGOs, encoding power relations, inequalities, values, routines and norms.

Data management is central to climate knowledge, also because the long-term scale requires data to be continuously revisited, corrected, reentered, reassessed and reanalyzed. Issues are not only to accumulate as much data as possible into databases but also to extract uses for all this data, including ensuring data dissemination, be it free of cost, in exchange for other data, or upon purchase.

In today’s data economy, satellite data are processed, classified, curated, archived and stored in specializing datacenters. Datacenters enact, materialize and infer forms of material, institutional, political, economic and cultural power as qualities of the data they curate.

Beyond being the epicenter of climate science, satellite data are also a matter of public policy and economic planning.

Connecting data back to the historical context in which they were produced, circulated and used allows us to emphasize how satellite data were defined, who controlled them, and why they matter today.