About the Internship (Jun 5 – Aug 12, 2016)
AF-M315E is a green monopropellant being currently researched by NASA as a possible replacement for hydrazine. At Marshall Space Flight Center, the Spacecraft Propulsion Systems Branch is leading this effort. Many different activities, including my project, were being undertaken to understand AF-M315E and to gather more data to show its feasibility as a candidate for replacement of hydrazine.
My main goal was to investigate the feasibility of electrical ignition of AF-M315E. In conjunction with this, understanding electricity’s effect on the propellant and collecting data for other researchers to use and form hypotheses from became paramount.
Both analysis and setting up the test rig needed to be completed before any testing could occur. I was given little instruction on what avenues to pursue and so I could choose to go the way I felt was best. To prepare, I did two major analyses. One concerned the full circuit and the other wasto gain an understanding of propellant heating and the time to ignition based upon the power supplied. The full circuit was evaluated to give a theoretical estimate of the actual amount of voltage and current that the propellant would experience while also ensuring that no data acquisition system would encounter a damaging voltage or current. The power being supplied was investigated to confirm that the test would proceed at safe voltages and it would increase the temperature of the propellant to ignition temperatures within a reasonable timescale. The setup was relatively easy and consisted of two electrical probes stuck into a drop of propellant that rested on an electrically and heat resistive sheet. A voltage divider and shunt resistor were connected to the propellant in parallel and series, respectively. These were wired to the data acquisition system to collect the voltage and current in the system.
Results and Conclusions
The testing that was completed during the summer was considered to be a success. It resulted in multiple successful electrical decompositions and one ignition of the decomposed gases leading to the development of a small flame. This all occurred at lower powers and temperatures than what were expected which bodes well for the feasibility of this type of ignition. There is still much more work to be completed but this is a solid starting point.
Overall, I really enjoyed my experience at NASA Marshall Space Flight Center. The main lessons I pull from this experience are the knowledge I gained of electrical systems and how to work on a large project with limited oversight. In aerospace engineering at Iowa State, there is little room for any electrical courses in the curriculum so the electrical knowledge was welcome. Also, while in college, even student led projects have a lot of oversight so this permitted me to work independently and make engineering judgments on my own. This internship allowed me to add to my knowledge base in a way that wouldn’t have been possible otherwise. The only negative of this experience was learning the hard way on how long one late order can set you back. I have now learned to order items well ahead of time so setbacks in delivery won’t push the timeline back.