“final, bone-chilling temperature,”
I used to work at an observatory.
3.6 Kelvins was what one instrument needed.
I think Webb is at 13.6 Kelvins.
I’m pretty sure freezing water is 273.15 Kelvins.
You are not talking bone chilling.
Most people don’t think of temperature as energy.
If it gets too cold it’ll just disintegrate................
Bones don’t chill at 13.6K?
Most of Webb’s sensors are stabilized at 32-39 Kelvins.
The MIRI instrument is chilled to 6 Kelvin, which is it’s desired temperature.
https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html