A Langmuir Probe Instrument for Research in the Terrestrial Ionosphere

Open Access
Escobar, Adam Corpus
Graduate Program:
Electrical Engineering
Master of Science
Document Type:
Master Thesis
Date of Defense:
April 02, 2009
Committee Members:
  • Sven G Bilen, Thesis Advisor
  • upper atmosphere
  • spacecraft
  • space environment
  • satellite
  • sounding rocket
  • ionosphere
  • plasma
  • probe
  • Langmuir
  • density
  • DC sheath
Langmuir probes have been used for plasma diagnostics on spacecraft ever since the first sounding rockets in the 1950s. As each decade passed, there have been improvements to the instrument design in order to obtain a more accurate solution to the plasma characteristics. In this thesis, a Langmuir probe instrument is designed and tested for use in the Earth’s ionosphere. The design includes the probe and boom development, as well as the on-board electronics. The probe is cylindrical and sized using orbital-motion-limited theory. The on-board electronics include two electrometers, two calibration boards, a control and processing board, and a power regulation board. Raw data is sent to the on-board spacecraft computer, where the computer can process the data or send raw data down to the data downlink ground station. The instrument has the capability to clean the probe surface of contaminants, calibrate the electrometers, and operate in four different probe biasing modes.