Mars Sample Return SRH Drop Testing
Note: Due to the restrictive nature of the work environment, no photos or diagrams are included from my position. Everything on this page was created after the conclusion of my work with AV.
What is drop testing?
Theory can only take engineers so far. Test engineering seeks to validate every use case by replicating them as accurately as possible. This is a major challenge for a designing the landing gear for a helicopter that will go to Mars. There are conditions that cannot be fully replicated such as the lower surface gravity and many unknowns such as surface soil (regolith) composition. With over 500 drops of the kinematically accurate test model into Mars surface simulant with the gantry I modified at AV, I was able to effectively evaluate and identify flaws in landing gear designs for SRH. One of my favorite parts of this project was breaking things, because every failed part is an opportunity to learn how to make our design better. We collected thousands of datapoints, photos, and recordings for each test, which were sent through the data pipeline and processed into actionable results.
Coding the Data Pipeline
In a MATLAB environment, data from each drop was reduced into key information about the structural loads in the landing gear using two instruments: IR optical trackers on the drop model and IMU’s embedded in the model structure. While the types of data could be found using only optical trackers, their lower resolution (100 Hz) and noise (due to thermal fluctuations in the lab) necessitated a more accurate method of evaluating the loads. After all the data was processed in MATLAB, I coded a script that formatted the results of each test automatically into a file directory database for any engineer to view without special software. Aggregate test results were automatically summarized in a spreadsheet shared with the project manager. I then weaved this data processing architecture directly into the test procedures so that the PM had real time access to the results for rapid analysis.
The drop apparatus consists of a gantry with a mobile gravity offset tether that can replicate the drop conditions set forth by the test matrix. Data is sent through the data pipeline to evaluate and iterate on upon the current design
Test data flows through the pipeline from experiment to database. Numerous MATLAB scripts transform the many thousands of data points into a few performance metrics, used to inform subsequent design decisions