The secondary mirror—visible in the top right corner of the image—is among the most important pieces of equipment on the NASA/ESA/CSA James Webb Space Telescope (JWST) and is essential to the success of the mission.
![](https://scx1.b-cdn.net/csz/news/tmb/2019/deploymentte.jpg)
Source:
https://phys.org/news/2019-08-deployment-webb-secondary-mirror.html