experiments. The RMF system as run operated at 350 kHz, at 2 MW of power, far below its design rating. To measure the plasma's behavior, the STX experiment was fitted with an insertable magnetic probe, an array of diamagnetic loops, an interferometer, visible-light spectroscopy diagnostics, and a triple Langmuir probe. Contributions The STX experiment was able to use RMF to achieve temperatures of 40 eV, which is hotter than the surface of the sun but still a factor of 500 from the temperatures necessary in a fusion reactor. The STX experiment was able to achieve plasma density of particles per cubic centimeter, which is a factor of 200 from the temperatures necessary in a fusion reactor. While the STX was designed to demonstrate the formation of an FRC using RMF, it had more success in demonstrating the build-up and sustainment of FRCs created via the theta-pinch method. Shortcomings An FRC plasma is harder to heat at low temperature. Because of this, the RMF system on the STX was designed to produce dozens of MW at the beginning of the discharge to rapidly heat the plasma beyond this so-called "radiation barrier" to hundreds of eV of temperature, where the plasma could be more easily sustained. However, problems with the novel solid-state RF amplifier led to only a fraction of this power being available for heating. As a result, rather than the hundreds of eV hoped for, only 40 eV of temperature was achieved. Furthermore, it was initially hoped for that the plasma could be kept away from the walls of the vacuum vessel by using low-resistance loops of copper that fit snugly around the vessel called "flux conservers." However the plasma was often observed to be in contact with the 40 cm inner diameter quartz vessel. Legacy The findings of STX were used to improve the TCS experiment, which eventually did demonstrate FRC formation solely from RMF. The TCS went on to heat the plasma to 350 eV. The idea of using an RMF-driven FRC to create a fusion rocket persists to this day. One example is the Direct Fusion Drive. References Emerging technologies Magnetic propulsion devices Nuclear spacecraft propulsion Plasma physics Spacecraft propulsion