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UChicago-PULSE / documentation

Documentation repo, used mostly for managing general documents issues on the project.
https://github.com/orgs/UChicago-PULSE/projects/1
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Optical Mounting Hardware Research #23

Open vredwine opened 6 months ago

leongold42 commented 6 months ago

Preliminary findings: https://docs.google.com/document/d/1XV12qleV2Q9LJjyCi2Swax4QeYA0AQ23Q4PuZ05UgdE/edit.

TLDR: Leaf springs ideal decoupling mount design. CTE should be minimized but similar for all optical components. Has some guidelines from EU, CubeSAT, and general recommendations from literature review

leongold42 commented 6 months ago

Important findings:

Leaf springs are likely the ideal decoupling mount design. It is a very simple flexible element – basically a single-strip flexure. Advantages of leaf springs include that their performance is easily controllable and that they are easily manufacturable while not increasing the dimensions of an optical system significantly. Spring dimensions can be selected by the ratio between tensile and bending stiffness so that it is flexible enough to bend under temperature fluctuations but remain stiff to endure launch loads

To maintain optical alignment, flexure support forces should act through the CoG of the optical element. The resonance frequency should be higher than that of the driving forces by a factor of at least two (Above 1400 Hz for Ariane 6)

To reduce surface distortions over the operational temperature range, coating should have a similar CTE as the mirror

For an optical instrument, the temperature gradient should be less than 5 °C/mm (as low as possible)

The system shall withstand an in-flight maximum static load for Ariane 6 launch vehicle which is -6 g axial and ±2 g lateral acceleration.

Maximum static load with 1.25 factor is 8.25 g axial and ±2.75 g lateral acceleration. The system shall withstand the random vibration load which is 0.04 g^2/Hz @ 150 - 700 Hz for Ariane launch vehicle

The system shall withstand an in-flight maximum shock load for Ariane 6 launch vehicle which is 1000-1400 g in -Z direction.

CubeSat materials shall satisfy the following low out-gassing criterion to prevent contamination of other spacecraft during integration, testing, and launch:

  1. CubeSats materials shall have a Total Mass Loss (TML) < 1.0 %.

  2. CubeSat materials shall have a Collected Volatile Condensable Material (CVCM) < 0.1 %

    Invar was chosen by Mbryonics for the lens tubes due to its very low CTE which better matched the CTE of glass paraxial lenses and, thus, reduced thermally induced stresses.

RamseyBottorff commented 5 months ago

https://www.sciencedirect.com/science/article/pii/S0273117723008931

paper on baffles