Painting the Earth in 3D, without a single moving mirror: NASA's CASALS sweeps away the blind spots

From orbit, laser instruments that map Earth's forests and terrain have always worked one thin line at a time — leaving millions of unmeasured acres in the gaps between lines. At NASA's Goddard Space Flight Center, John Yorks and his team built CASALS to sweep instead: it steers laser light using colour itself, cycling through 256 wavelengths so each pulse lands in a different spot, painting a continuous 3D swath with no heavy moving mirrors to fail in space. Flying on a King Air aircraft, the prototype picked out individual tree branches from about five kilometres up — and caught 80% of the light that bounced back, so even dark ground and dense forest give up their shape. A space version could give scientists the first complete, three-dimensional picture of a changing planet.

SDG 9 · Industry, innovation and infrastructure — Mechanism: tech innovation