Weekly Report #5: Structure

A few weeks have passed since the last update from our work on the structure. We are getting closer to the critical design review which means the final design of the experiment will be checked by the expert-panel.

As you can imagine a lot has happened in those weeks since the last update. After a lot of second thoughts and discussions about details we made adaptions and changes in nearly every part of the structural design. In this article we will present the progress on four major parts of our experiment.

hdrm2As it is the heart of our experiment we have dedicated many hours to designing a mechanism that will bring great progress to the way a solar panel of a CubeSat can be released. From our last report a few weeks ago you might remember a mechanism with an SMA-spring to release the solar panel and a bias spring to pull it back into place after the SMA has cooled down. We even have a fully functional prototype of the Mechanism that you can have a look at in a different article.

Nevertheless we thought a smaller mechanism would even better suit our needs, since minimum size and weight are of major importance for every part of a CubeSat. So after rethinking the existing mechanism we came up with a design that has been reduced to half the size of the previous one, will weigh a lot less and will work just as well.

The key part of our newly designed mechanism are M4-type screws with springs inside them that put pressure on a small ball. The ball at the front end of the screw locks the hold down release mechanism into place until the SMA-spring is activated. When activated and the force of the SMA-spring exceeds a predefined value, the Ball will release the mechanism and ultimately enable the solar panel to swing open.

Solarpanel 2Talking about the solar panel – we also made great progress on the design we will be using. Since solar cells are expensive and we don’t actually need them for our experiment we decided to use a mock up with almost the same material properties – just without the ability to generate power. We therefore designed a panel that is made up of different fibre reinforced layers that will be glued together. You can see them on the picture.

Gopro boxSince we want to protect the camera with which we will be videotaping our experiment we designed a box which will be milled from one piece of metal. The GoPro camera will fit perfectly inside the Box and also accommodate the lighting.

Frame18_05_14_1After having redesigned our mechanism, and finalizing the panel design, also the frame had to be altered to fit the changes. An important part in order to put the mechanism together once it has been milled, are screws that have now been integrated into the CAD drawing.

Another reason why we changed the design of the frame is a new way of how we will be detecting the motions of the oscillating solar panel. But you will learn more about that in our next week’s update from the electrical design team – so stay tuned!