# Nanotechnologies related to James Webb Space Telescope

I would like to know if you know of any nanotechnology involved in the James Webb Space Telescope. With 'nanotechnology' I mean any technology working on a 1-100 nm scale.

• +1 for a really interesting question and Welcome to Stack Exchange! I guess we should exclude the obvious nm scale integrated circuits, but I wonder if any of the infrared detectors have quantum dots? Or some batteries or supercapacitors have nanostructured electrodes perhaps?
– uhoh
Feb 2 at 0:36

There are also the microshutters. Not exactly nanometer scale, more like 100x200 microns, but pretty amazing nonetheless.

The following paper describes the actuator that is used to manipulate JWST's primary mirror segments. It is a very clever mechanism that can create 12 millimeter movement and nanometer scale movement using the same motor. Each primary mirror segment has 7 actuators.

https://www.esmats.eu/amspapers/pastpapers/pdfs/2006/warden.pdf

add by BradV: getting this degree of control and repeatability from gears (backlash issues) and bearings (slop issues) etc. is a neat trick!

• I don't think a palm-sized electric motor with a large gearing ratio counts as "nanotechnology". The precision isn't impressive as well - nanometer precision actuators are pretty standard technology. Feb 1 at 16:52
• I don't see "12 mm" anywhere in this table, is it 21 mm? 12 µm? Feb 1 at 16:57
• 12mm is what JWST actually has to move the mirrors, but that might be a coincidence. Feb 1 at 17:30
• 12mm was the distance the mirrors were moved to get them away from their "launch position", resting against snubbers to protect them from launch shocks. I do not know how much range of travel remains. Feb 1 at 18:45
• @asdfex I know what you mean and you are right, but maybe nanopositioning can be seen as a secondary or enabling nanotechnology? An atomic force microscope for example doesn't have any "nano" in it, and yet it's really been an enabling workhorse in the field.
– uhoh
Feb 2 at 0:29

The mirrors of the JWST are coated with a gold layer that is 100nm thick. Then the gold layer is coated with a thin layer of silicon dioxide.

From the NASA website:

Once a mirror segment's final shape is corrected for any imaging effects due to cold temperatures, and polishing is complete, a thin coating of gold is applied. Gold improves the mirror's reflection of infrared light.

Some Technical Details: How is the gold applied to the mirrors? The answer is vacuum vapor deposition. Quantum Coating Incorporated did the coatings on our telescope mirrors. Essentially, the mirrors are put inside a vacuum chamber and a small quantity of gold is vaporized and it deposits on the mirror. Areas that we don't want coated (like the backside and all the mechanisms and such) are masked-off. Typical thickness of the gold is 1000 Angstroms (100 nanometers). A thin layer of amorphous SiO2 (glass) is deposited on top of the gold to protect it from scratches in case of handling or if particles get on the surface and move around (the gold is pure and very soft).