The Hubble Space Telescope was nearly blind for its first three years because its primary mirror was ground too flat by 2.2 micrometers, and NASA’s reputation depended on a 1993 repair mission built around corrective optics the size of a refrigerator
https://atlas.whatip.xyz/post.php?slug=the-hubble-space-telescope-was-nearly-blind-for-its-first-three-years-because-its-primary-mirror-was-ground-too-flat-by-22-micrometers-and-nasas-reputation-depended-on-a-1993-repair-mission-built-around-corrective-optics-the-size-of-a-refrigerator
<p>Hubble launched in 1990 with a primary mirror polished 2.2 micrometers too flat
#micrometers #primary #hubble #nearly

TechSpot: Etching the world’s smallest QR code in ceramic pushes data storage to the nanoscale. “A team of researchers at TU Wien recently announced that they have ‘etched’ the smallest QR code ever on a ceramic film. Covering an area of just 1.98 square micrometers, the code is smaller than many bacteria and features pixels only 49 nanometers in size.”

https://rbfirehose.com/2026/02/21/techspot-etching-the-worlds-smallest-qr-code-in-ceramic-pushes-data-storage-to-the-nanoscale/