How to achieve nanometer precision in space?

What people said

infogulch · 2022-03 · Strong recommendation

The actuator is a genius flexure design that is both mechanically simple and accurate. Breaking Taps 3d-prints a working replica and describes the design. I highly recommend: [VIDEO] The actuator breaking wasn't as concerning after seeing the design.

Read the original HN comment ↗

bigiain · 2026-01 · Recommendation

I have a related question, how far are you turning the thumbscrews when making adjustments? I think M3 standard thread pitch is 0.5mm, so to a first approximation that almost 1000 wavelengths (if I have the SI units right in my head, and I'm not 3 orders of magnitude out?). I suspect the left/right and up/down adjustments have as fairly high lever ratio, but I can't imagine you could successfully adjust the in/out distance with any precision (not in the 690nm sense anyway)? Is the in/out distance not important so long as the beams are aligned? Dunno if you've seen it, but there's a great youtube video explaining how the actuators to align the James Webb mirrors work: [VIDEO] including a 3D printable version of them: [LINK] "This is a replica of JWST's mirror actuators. Six of these actuators are paired into a hexapod / stewart platform arrangement and used to control 6 degrees of freedom of each mirror segment (tip, tilt, roll, x, y, z translation)."

Read the original HN comment ↗

mywacaday · 2022-04 · Recommendation

This video [VIDEO] was posted here [LINK] about how the actuators work on the James Webb telescope. It's a great watch.

Read the original HN comment ↗