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My Third Coop Experience: Accion Systems

Simultaneous Depressurization & Vibration Testing

Objectives:

Apply 10 Grms random vibration in accordance with NASA GEVS (General Environmental Verification Standard) to a small test article
Simultaneously depressurize the test environment to roughly mimic a launch environment

Process:

Accion already had several vacuum chambers and a large vibration table. Initially, the project I was presented with was finding a mini shaker that would fit inside the existing vacuum chamber. I was charged with contacting several vendors to find the best option and with contacting the vacuum pump provider to ensure no damage would incur.

It was decided that roughly following the required depressurization profile was sufficient for this testing. Therefore a program was created in which a depressurization profile could be manually followed by gradually closing a valve.

After conducting some testing with the mini shaker, we came to the realization that a bell jar mounted to the top of the large shaker would be far easier to use. So I designed a new system that used this method.

Result:

The image to the right shows the system on the vibration table.

Within the bell jar, there is a mounting plate with a known hole pattern that mounts directly to the base plate upon which the bell jar sits.
The holes at the bottom of the bell jar are sealed off with epoxy.
Rubber bands were found to be secure enough to hold the plastic top on.
A portable vacuum pump was used to draw a vacuum - absolute vacuum was not required for this testing.
A pressure transducer was used to read the internal pressure on a laptop screen.

Ultimately, I used the final assembly as well as the mini-shaker system to complete several tests.

Final Vibration and Depressurization System

Skills Gained & Lessons Learned:

The original idea is not always the best idea. I was initially presented with a task of finding a mini-shaker. It turned out that using a bell jar on the large shaker was much simpler. However, this was hard to see at first given the original task.
Communication between testing and mechanical engineering.
I learned a lot about testing requirements for small satellites. I now understand what goes into designing something that will be launched into low-earth orbit.
How to operate a vibration table.
How to set-up a pressure transducer to be read through a DAQ.
The importance of modularity. This system needed to work for several different tests.

Machining

At Accion, I was given the task of machining parts for several different projects. I now feel comfortable on a mill and a lathe, and I became very familiar with the tormach PCNC which is pictured on the right. I also took on the maintenance of the machine in my time there - something that had not been considered in a very long time.

I definitely have a better understanding of what it means to design for manufacturing. As most of the parts that needed to be manufactured were very small, I now have a full appreciation for the precision that can be achieved with standard machine shop tools.

The Tormach PCNC that I used at Accion Systems

Other Work

Much of the work I completed at Accion includes proprietary content so I cannot include photos or many details. Below is a brief summary of my other work.

Brainstormed, prototyped, and tested several methods of thruster alignment
Conducted tests to better understand the water absorption of ionic liquid
Designed and 3D printed shipping protection for critical parts