APOD: JWST on the Road to L2 (2021 Dec 31)

[Chris Peterson]

I was wondering about something: if either or both of the two "wings" of the main mirror failed to unfold into position, could the telescope still do some imaging and provide useful data? After all, there would still be at least 12 of the 18 total hexagonal mirror segments in place. I would think there would only be a loss of resolution and light gathering power.

At the very least, I imagine it would require substantial software changes, as the mirror segments are actively driven by motors to achieve the final optical performance. Without feedback from all of the mirrors, I expect the system in its current state might not perform properly.

[neufer]

I was wondering about something: if either or both of the two "wings" of the main mirror failed to unfold into position, could the telescope still do some imaging and provide useful data? After all, there would still be at least 12 of the 18 total hexagonal mirror segments in place. I would think there would only be a loss of resolution and light gathering power.

At the very least, I imagine it would require substantial software changes, as the mirror segments are actively driven by motors to achieve the final optical performance. Without feedback from all of the mirrors, I expect the system in its current state might not perform properly.

The Port Primary Mirror Wing is fully deployed and latched.
Nominal Event Time: Launch + 13 days (Friday 1/7/22)

The left/port (+V2) wing of the primary mirror is fully deployed and latched.
Each wing holds three of the 18 mirror segments. This is a motor-driven deployment.

[johnnydeep]

I was wondering about something: if either or both of the two "wings" of the main mirror failed to unfold into position, could the telescope still do some imaging and provide useful data? After all, there would still be at least 12 of the 18 total hexagonal mirror segments in place. I would think there would only be a loss of resolution and light gathering power.

At the very least, I imagine it would require substantial software changes, as the mirror segments are actively driven by motors to achieve the final optical performance. Without feedback from all of the mirrors, I expect the system in its current state might not perform properly.

The Port Primary Mirror Wing is fully deployed and latched.
Nominal Event Time: Launch + 13 days (Friday 1/7/22)

The left/port (+V2) wing of the primary mirror is fully deployed and latched.
Each wing holds three of the 18 mirror segments. This is a motor-driven deployment.

And the starboard wing folds out tomorrow, with individual mirror segment fine positioning starting a day after that, followed by coasting to the L2 insertion burn.