Goddard Space Flight Center
June 7 – August 13, 2021
Goals of your project/s:
Throughout the internship, a meta-material called Black Silicon (BSi) was analyzed to test its optical reflective, transmissive, and absorptive properties. Over the Spring 2021 term, BSi’s material and geometric properties were tested and optimized. The Summer 2021 term required optimization of the testing environment within the multiphysics software COMSOL. Computer modeling allows researchers to test a wide variety of different environments and geometries. Many lab machines are purpose-built and can only test a limited range of scenarios. Computer modeling has the diversity to fill in the gaps when labs are shut down and cut costs while still maintaining close approximations of real-life scenarios. While the computer model has yet to be validated, great progress has been made. The main environment test to the computer model was a change from square to hexagonal packing. Previous computer models had been using a square packing structure to test cone geometries with circular bases. The data outputted from those models were close to data from lab testing but was off by 2-3 orders of magnitude. It was hypothesized that a hexagonal packing structure would eliminate some error in the model. This is hypothesized because circular based geometries leave smaller gaps when hexagonally, rather than squarely, packed. After testing this hypothesis, the data outputted from the model using a hexagonal base was within ½ an order of magnitude. Along with this project, the intern also aided with optimizing the camera placement for the vision system of the Earth Return Module (ERM). As part of the Mars Sample Return (MSR) mission, the ERM is a module tasked with returning Mars core samples to Earth. The ERM contains a heat shield that is susceptible to micrometeoroid impacts. Too many impacts to the surface of the heatshield could cause catastrophic failure when reentering Earth’s atmosphere. A vision system is required to monitor the surface of the heat shield throughout the mission. The intern’s project was to optimize this vision system camera placement while following three main constraints: keep 100% coverage of the surface, maintain a minimum resolution as prescribed by requirements, and use as few commercial, off-the-shelf cameras as possible. Using Solidworks, an assembly model of the heat shield and camera vision cones was created from dimensional and optical data. From there, a multitude of camera positions, angles, and quantities were tested. If a setup looked promising, the dimensional data was pushed forward to an optical engineer for resolution analysis. In the end, the variety of camera systems was analyzed, and a solution was recommended.
Describe what you did during the internship:
During my internship, I created COMSOL models and tested unit cell geometries for a new, highly absorptive material called Black Silicon. COMSOL is a multiphysics software that allows me to manipulate geometry shapes and material properties. In the end, we want the computer simulation to output the same data trends as lab-tested data. Optimizing the computer model was the main workload for this project.
Another project I worked on was the optimization of the vision system for the Mars Sample Return (MSR) Earth Return Module (ERM). A vision system is required to analyze the surface of a heatshield during flight, and optimization was required to reduce mass and save space. To do so, I created Solidworks models for both the heatshield and the camera vision cone. Then, I created an assembly model to visually analyze how much surface area 1 vision cone can see at any given distance and angle. Then I added more and more vision cones until the entire heatshield surface was covered. The setup was then pushed to an optical engineer for resolution analysis. If the cameras did not meet the resolution requirements at the positions I found, they were moved to new locations and tested again.
I also mentored a high school level intern on the same projects listed above. I supplied a workload over the 6-week internship for him and helped with any questions he had.
Did you achieve your goals? What were the results and conclusions?
For my Black Silicon project, the best computer models I created are generating data within 1/2 order of magnitude to that of lab-tested data from 1-5 THz. This is very good progress and very promising for the future. The next steps for this project are to replicate lab data from the 5-15 THz range, as the goal of the project is to absorb light in a broadband frequency range.
For the vision system optimization project, the most optimal setup was found for the commercial cameras I was analyzing. This project was a trade study, so other teams were analyzing different camera types. In the end, the camera setup I helped optimize was found inferior to that of another team’s camera type. While my work will not be used for this mission physically, the work helped rule out a less optimal solution and betters the mission as a whole.
Describe positive lessons learned from this experience:
The biggest lesson came from an engineer I worked with:
“Learn not only how to talk to fellow engineers, but also how to talk to scientists. While the two professions are similar, schooling for each major teaches a different way of thinking.”
This advice holds very true in the technical workplace. A scientist does not care what is possible to manufacture, they only care if a solution is POSSIBLE. An engineer may see the possible solution as impossible for a variety of manufacturing constraints. Learning how to talk/present to these two types of people is crucial to this line of work.
Describe negative lessons learned from this experience:
Negative lessons are hard to come by when working your dream job. A hardship I found, and this will always be the case, is time. In my last 2 internships at NASA, I haven’t been able to test everything I wanted to. Testing one small parameter may lead to another question and another test, then all of a sudden you are three weeks deep into what should have been a small analysis of a much larger project! I wouldn’t relate this hardship to time management, but rather the time required for a thorough analysis of science in general.