The @NASAWebb has arrived here in Houston for its last cryogenic test before launch in 2018. Learn more: https://www.nasa.gov/feature/james-webb-space-telescope-arrives-at-nasa-s-johnson-space-center …pic.twitter.com/okU0z0jpZT
-
What's the purpose of that kind of tests?
It's an end-to-end optical test to recheck alignment of all the telescope optics. Read more here: https://jwst.nasa.gov/faq.html#mirrortests …