Explainer
Open data from space agencies
A large share of the archive is public. Knowing which archive, and which processing level, is the actual skill.
NASA, ESA, and several other agencies publish a great deal of mission data for anyone to download. Earth images, telescope archives, and many planetary products are free. The catch is that “free” and “ready for a caption” are not the same step.
Data is released in levels. A raw packet from the spacecraft is honest and nearly useless to a newcomer. A calibrated image, with the instrument’s quirks taken out, is what most people want. A map someone else derived from that image is one more step removed, and it already contains another person’s choices. If you are checking a claim, try to land on the calibrated product and read the processing note, not only the social-media crop.
Good front doors, as of this desk’s Phase 0 list: NASA’s Earthdata and the agency’s mission pages, ESA’s science and Copernicus data portals, and the Hubble and Webb archives. Each one asks you to learn a search box. That is still faster than emailing a scientist and hoping.
Open does not mean unlicensed in every case, and it does not mean the agency wrote your headline. Read the credit line. Say which mission and which date. And if a picture has been colourised so that invisible wavelengths become red and blue, say that too. The colour is a translation, and translations can be fair without being photographs.