@Aleksandr.Makarov
Q1: Was this system in space?
A1: The CubeSat system discussed in this webinar is a completely simulated system that was built to illustrate the OpticStudio → OpticsBuilder → FEA → STAR Module workflow. While this system was not manufactured and put into space, this workflow demonstrates how such a system could be simulated with Ansys Zemax software.
Q2: How was the temperature estimated at orbit?
A2: For this CubeSat example, we assumed that the system would operate in Low Earth Orbit at 700km. Originally, the operating temperature of the optics in the Hubble Telescope was used as a comparison point. For the Hubble, the operating temperature for the optics was at 21C, or room temperature. However, if 21C was used for the operating temperature of the CubeSat optics, the results using STAR would not have been very interesting. This is because the Sequential model as “built on Earth” was also assumed to be soaked at 21C. To showcase the advantages of the STAR module, an assumption was made to lower the operating temperature of the optics by a few degrees. By choosing an operating temperature of 15C +/- 3C, interesting results with STAR could be obtained. This is because the temperature condition in-orbit is now different to the temperature condition on Earth. While the external frame of the CubeSat will experience larger fluctuations in temperature, space-based optical systems will generally use a thermal control system to prevent the optics from experiencing those fluctuations.
@Andrew.Keys
Q: After adding the mechanical supports and structure, what is the final usable aperture of the optical system?
A: As the mechanical components do not limit the optical aperture, the aperture is still same as set in the initial sequential mode in OpticStudio, which is defined by the Entrance Pupil diameter and limited by the STOP surface on the first surface. So in this case this would be 55mm.
Q: In the Opticsbuilder/creo, is it possible to import CAD files for structural parts and integrate with the lens design?
A: The usual workflow for a Optomechanical system working with both Zemax OpticStudio (OS) and Zemax OpticsBuilder (OB) would be the following: A optical system is designed, analysed and optimized within OS, after that it is passed on to the CAD Environment into OB with via a .ZBD file. Once the optical components are imported into the CAD Environment the mechanical components are added to the assembly making it a optomechanical assembly. This can be all sorts of CAD files (E.g. STEP files), these mechanical components can then be assembled to the optical parts with the native CAD tools such as assembly constraints.
@Guanghua.Wang
Q: How do you verify the design simulations since so many tools used?
A: After the initial design within sequential mode of Zemax OpticStudio, the Convert to NSC Group tool can be used in order to automatically convert it to the Non-Sequential mode (To subsequently perform the boolean operation). Within that tool the Critical Rayset Generator can be used to verify the performance after the conversion.
Once the optical designed is finished within OpticStudio and the optical system was passed on via .ZBD file. The Optomechanical Engineer can verify the optical performance by running a simulation, within the results of that simulation OpticsBuilder will differentiate between the OS (OpticStudio) Baseline and the OB (OpticsBuilder) Baseline, so the optical performance without and with the influence of the mechanical components.
@Sergey.Nikitin
Q: Why for step #3 (Mechanical design) do you use CREO not Speos (Ansys)?
A: In order to show-case the workflow with mainly Zemax products, Zemax OpticsBuilder was used and as OpticsBuilder is an Add-in for Creo Parametric 4,5,6 and 7, the CAD Environment had to be Creo. However, the mechanical design could have also been done within Speos. In this case you would want to export a STEP file of the optical system out of Zemax OpticStudio and import it into Speos to assemble the optomechanical system. But please keep in mind that other than the .ZBD file, the STEP does not hold any optical data, but only the geometry of the optical components.
@Matthew.Warden
Q: How would you model thermal gradients such as would be experienced in orbit when one side of the cubesat is illuminated by the sun and the other is not?
A: If you already know the temperature gradient, mapping it to the mesh of the structural FEA is a simple step. The next steps are similar to those presented in webinar: the thermal expansion will cause a certain deformation, that can be exported and used in STAR.
If you do not know the gradient, you may need to perform a thermal analysis first, the results of which will be used in the structural analysis. There are several options for thermal analysis: You can study the transient behaviour or consider a steady state. It would even be possible to use the absorbed flux of a non-sequential analysis (simulating the illumination of the sun) as a boundary condition for the thermal analysis.
@Christophe.Gaschet
Q: How to relate the number of Nodes to the quality of the mirror (in RMS)?
A: I’m assuming you were referring to the fit quality of the mirror within STAR. There are many different ways to influence the fit quality. Among other things, there are two adjustment screws in the STAR Fit Assesment tool, the Max Level and the Grid parameters. Internal research has shown that the default values for these work best with a mesh of roughly 10 thousand nodes. The exact behavior varies and differs from case to case, that is why the Fit Assessment tool is very helpful to assess the error.
@Edwin.Casco
Q: Can shock loads from the rocket launch be simulated to assure your mounts will not deform the optics?
A: Yes, of course. This was not done here because the purpose was to show the workflow using a CubeSat as an example. For this, only the deformations during the operation phase were of interest. The existing FEA analysis could easily be modified to simulate the loads encountered during the launch. It might be necessary to reinsert the outer panels to simulate the interactions and the mesh density on the mirrors should be lowered as the deformations are not needed for STAR.
Where to find the recording
@Bernd.Harnisch, @mjlevene, @spock, @Pol.Ribes, @Sean Turner, @Sanjay.Gusain, @Börje.Emilsson, @Edwin.Casco, @Patrick.Thompson
The webinar may be found on-demand at this link: From Concept to CubeSat: Design and Iterate Faster with Zemax Software.
During the webinar, there were some technical issues with the slides. Please note that those issues were resolved in the on-demand recording!
Hello,
Thank you everyone for joining this webinar.
In this thread, our speakers will answer the questions they didn’t get to during the live event.
If you have additional questions, post them here! The thread will be open until March 10th to allow for discussion with the speakers.