PARIS (ESA PR) — With help from a cryocooler, Webb’s Mid-Infrared Instrument has dropped down to just a few degrees above the lowest temperature matter can reach and is ready for calibration.

The James Webb Space Telescope will see the first galaxies to form after the Big Bang, but to do that its instruments first need to get cold – really cold. On 7 April, Webb’s Mid-Infrared Instrument (MIRI) – a joint development by ESA and NASA – reached its final operating temperature below 7 kelvins (minus 266 degrees Celsius).