CGA/NRL Impedance Probe as a ThinSat Spacecraft Payload.

Coast Guard Academy (CGA) space initiatives in partnership with the Naval Research Lab have required the development of a ThinSat impedance probe to make direct temperature and density measurements of space plasmas using a surface-mounted dipole antenna. The roughly 10 cm x 10cm x 2 cm payload platform is modified from the ThinSat platform provided by Virginia Commercial Space Flight Authority (Virginia Space) through a partnership with CGA. An onboard 75 MHz~ Direct Digital Synthesizer (DDS) is used to sweep the AC frequency applied to the dipole where time-dependent current and voltage measurements are recorded. Plasma temperature and density are subsequently determined from the resonant impedance frequencies. Measurements are then converted from digital to analog values and processed for transmission through the ThinSat bus. While the design calls for an ATMega328p, for ease of programming and implementation, an Arduino Mini Pro MicroController is used instead. Details of the unique ThinSat impedance probe circuitry architecture and lab preliminary findings will be reported.~~~