Testing the Da Vinci Satellite: Vibration Trials

Blog by the Da Vinci Satellite.

To be able to go to space, a satellite has to be launched to the required orbit. The launch of a rocket usually comes with heavy vibrations and shocks that the satellite and its subsystems need to be able to survive. Because the Da Vinci Satellite has a custom-made payload with loose objects(dice) on board, it is useful to conduct something called a ‘vibration test’ to simulate the launch environment and see if the payload will be able to survive the rigours of the ride to space.

About one year ago the Payload team went to the Royal Netherlands Aerospace Center (NLR) in Marknesse. The team gathered early in the morning in Delft to drive to Flevoland in the middle of the Netherlands. Here we first got a warm welcome from the staff, after which we got a tour of all the different facilities that NLR has at this location. This included an environmental testing chamber that has been used to test other satellites and space-faring components, and of course the vibration testing division of the NLR site. The latter consisted of one big room with a so-called ‘shaker’ in the middle. This shaker table is able to vibrate at different frequencies. By mounting sensors onto the payload during the test, the response of the payload can be measured.

Next to the vibration room, the payload team set up shop and started the preparations for the vibration testing of the Dice Payload. Previously we had mounted our new PCBs from Eurocircuits to the Dice Payload. These provided an updated and upgraded version of our previous PCBs and will be flown on the Dice Payload model that will eventually go to space. Additionally for the test, we also fabricated a special fixture for the Dice Payload to be mounted upon. We also conducted a pre-test check to see if everything was still working as we expected. After this, we mounted the Dice Payload via the special fixture onto the vibration table. Here, we also added the different sensors at places that would be interesting to get data from.

In total, we tested the payload in the three different axes(X, Y and Z) and did both a so-called ‘random vibration test’ and a ‘sine vibration test’ for all the different axes. In the random vibration test, the vibration table shakes at a lot of different frequencies just like a real rocket would. When we were standing next to the Dice Payload during this test, it also felt and sounded like we were standing close to a rocket launch! In general, random vibration provides the best simulation of many actual environments and is the predominant method for vibration testing. We also performed sine testing, because this is useful for determining the effects of resonance conditions in launch environments. Here the table would first shake through ‘big movements’ that would become smaller and smaller.

During the first test, the Payload team was surprised by the violent shocks that the Dice Payload had to undergo. We were relieved when the table finally stopped moving and we got our first results; everything seemed to look nominal. However, because the Dice Payload consists of loose objects and mechanisms that need to move, we also wanted to do a ‘performance test’ after every vibration axis. In this performance test, we wanted the Dice Payload to perform one cycle in which it throws the different dice and then clamps them again. We wanted to do this to make sure that once the Dice Payload would get to space, that we can actually play games and not that the mechanism would be stuck because it didn’t survive the launch. We all held our breath as we tried to initiate the first performance test…and….success! We were extremely excited to see that the payload was able to fully survive the first round of testing and we had high hopes for the test of the testing day.

After a full day of numerous tests, all of which the Dice Payload was able to successfully persevere, we gathered our results and packed our material to go back to Delft. But not before first celebrating a successful second test (after the 0g flight test) that is bringing us one step closer to the Da Vinci Satellite in Space with the help of Eurocircuits!