Why the James Webb Space Telescope’s sunshield deployment takes so long

NASA’s James Webb Space Telescope is three days into the deployment of its massive sunshield — and it still has about three days to go.

The $10 billion Webb launched on Christmas Day (Dec. 25) to seek out heat signals from the early universe. To pick up these faint signals, the observatory’s optics and instruments must be kept extremely cold, and that’s where the sunshield comes in.