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Wang, Zhengdong

Publications and source records attributed to Wang, Zhengdong.

Command and Control Software Development

As NASA’s role in spaceflight operations change, so too does its design priorities. NASA’s flagship venture, the Space Launch System (SLS), is being created primarily to explore deep space. While commercial partners conduct low Earth orbit resupplies, tests, and even transportation of astronauts, NASA can divert more resources to more exciting projects - going back to the moon, or onwards to Mars. In the short term, this goal manifests in the upcoming Exploration Mission-1 (EM-1) test of the SLS, slated for as early as 2019. SLS, with the Orion capsule, will travel farther than any human-rated spacecraft has gone before. As the most powerful launch vehicle ever created, SLS requires many new innovations to ensure mission success. One such technology is the launch control software, which is the focus of this internship. The SLS launch control software is composed of many functions, all of which require rigorous testing to meet the standard of life-critical code. To facilitate easier testing, the first project I undertook was to customize the open-source tool Wireshark to the software team’s needs. Wireshark is a network protocol analyzer that can take in information about custom information packets. The launch control software will have several protocols that are custom to NASA. I ensured that all necessary component files were the correct file type and in the correct structure for Wireshark to compile. Having allowed Wireshark access to understand custom NASA data packets, testers of the launch control software will be able to find anomalies easier.

Wang, Zhengdong↗

Electron and ion kinetics in three-dimensional confined microwave-induced microplasmas at low gas pressures

The effects of the gas pressure (p{sub g}), microcavity height (t), Au vapor addition, and microwave frequency on the properties of three-dimensional confined microwave-induced microplasmas were discussed in light of simulation results of a glow microdischarge in a three-dimensional microcavity (diameter d{sub h} = 1000 μm) driven at constant voltage loading on the drive electrode (V{sub rf}) of 180 V. The simulation was performed using the PIC/MCC method, whose results were experimentally verified. In all the cases we investigated in this study, the microplasmas were in the γ-mode. When p{sub g} increased, the maximum electron (n{sub e}) or ion density (n{sub Ar+}) distributions turned narrow and close to the discharge gap due to the decrease in the mean free path of the secondary electron emission (SEE) electrons (λ{sub SEE-e}). The peak n{sub e} and n{sub Ar+} were not a monotonic function of p{sub g}, resulting from the two conflicting effects of p{sub g} on n{sub e} and n{sub Ar+}. The impact of ions on the electrode was enhanced when p{sub g} increased. This was determined after comparing the results of ion energy distribution function (IEDFs) at various p{sub g}. The effects of t on the peaks and distributions of n{sub e} and n{sub Ar+} were negligible in the range of t from 1.0 to 3.0 mm. The minimum t of 0.6 mm for a steady glow discharge was predicted for p{sub g} of 800 Pa and V{sub rf} of 180 V. The Au vapor addition increased the peaks of n{sub e} and n{sub Ar+}, due to the lower ionization voltage of Au atom. The acceleration of ions in the sheaths was intensified with the addition of Au vapor because of the increased potential difference in the sheath at the drive electrode.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗